Series And Parallel Wiring Formats

One common question that we get asked here at Tiny Build Electrics is in relation to series and parallel. Batteries in parallel? Solar array in series? Pros, cons?

This is a key stage in your Tiny Build and something you definitely want to get right! In this article we are going to break it down into small, manageable chunks to make it easy to understand.

Batteries in parallel

“In parallel the battery voltage remains constant and the amp hours increase”

Put simply, you connect the positive to positive, negative to negative. Easy, right? Well.. kind of!

The diagram below is why this type of connection is called ‘parallel’. The positives and negatives remain parallel to each other at all times. They never touch or connect, this is a parallel wiring format.


Every time a battery is added to the bank the voltage remains the same but the amp hours increase

So, you understand the basic layout of a battery bank connected in parallel, but the electrical principles are also worth understanding. Again, we can keep this simple.

Every time we add a battery to the bank the voltage remains the same but the amp hours increase by the size of the added battery.

Here, you can have a look at a real life example of this, as the batteries in our own Tiny Build Electrics example are wired in a parallel configuration.

Positive or Negative

The system above comprises of two individual 100ah lithium-ion batteries connected in parallel.

Here we have a total of 200ah at 12V. The common mistake here is to double the voltage and not the amp hours. In parallel the battery voltage remains constant and the amp hours increase.

Connecting your batteries in parallel is not just as simple as connecting all the reds and all the blacks. You also need to consider balancing the system.

How can you do this?

Instead of connecting both the positive and negative at one end of the bank via one battery, we connect the positive to the load at one battery bank and the negative to the load from the other end of the battery bank.

The diagram to the right depicts a battery bank correctly connected in parallel.

See how the negative has been taken from the last battery to the installation, whilst the positive has been taken from the first battery to the installation. The bank is now working as one unit. The current being drawn from the battery bank will now be equal across each battery and the bank will receive charge equally across all its batteries.

This way the charge and discharge is evenly spread throughout the entire battery bank. This way of wiring increases the likelihood that the manufactures specified life cycles will be met. If this is not adhered to you are in danger of damaging your batteries and depleting their lifecycles.


Common mistakes when connecting batteries in parallel

When connecting your batteries in parallel you must balance your battery bank as discussed above. This is a crucial step and often overlooked during the installation stage.

This diagram shows a common way in which parallel battery banks are incorrectly connected. The way in which these are connected puts strain on the primary batteries and is considered unbalanced.

As you can see in the diagram the battery closest to the installation, let’s call this the primary battery, is the first in line to be discharged and is also the first to receive a charge current.

Each set of connecting cables, between each battery, creates a resistance. Electricity will always take the path of least resistance, like water flowing in a river. The path with the least resistance always wins. In the diagram shown, the primary battery is the first power source which has least resistance and therefore this one takes the biggest hit.

This will then happen in reverse when the battery bank is being charged. The primary battery gets a largest amount of charge current, with every set of interconnecting cables the charge current depletes from one battery to the next leaving the last battery with very little charge current.

Useful Definitions

Resistance: A measure of the opposition to current flow in an electrical circuit.
Charge Current: A flow of electrical charge carriers


Batteries in series

“In series the battery voltage increases and the amp hours remain the same”

Batteries wired in series are different. The principles are in reverse to a parallel setup. Instead of the voltage remaining the same and the amp hours increasing, the voltage increases and the amp hours remain the same.

Keep in mind, if you plan to wire multiple batteries together in series, each battery needs to have the same voltage and capacity and rating, or you can end up damaging the batteries.

This may seem irrelevant as I’m sure, like most people, you plan on having a 12v system in your camper van.
But, with older vans and vehicles becoming ever more popular to convert into tiny builds, their onboard electrical systems may surprise you.

A lot of big lorries and buses are being converted into tiny homes and they often have a 24V or 48V systems. Something to definitely bear in mind to ensure you purchase the correct equipment for your system.

To Installation

4 x 12v 100ah batteries in series 48V 100ah Battery Bank

Series & Parallel Wiring for Solar Panels

Each solar panel has a positive and a negative. A series connection is created when one panel’s positive is connected to the negative of another.

Both series and parallel wiring formats can also be applied to solar panel arrays. There are pros and cons to both methods. This is something you should consider carefully before starting your build.

When you wire multiple panels in series, their output voltages add together and their output currents remain the same. Conversely, when you wire numerous solar panels in parallel, their output currents add together, but their output voltages stay the same.

Series Solar Panel Wiring

Each solar panel has a positive and a negative. A series connection is created when one panel’s positive is connected to the negative of another.

Wire Diagram

Total Voltage: 22v x 3 = 66V
Total Current: 4.52A
Total Power: 300W

*These calculations do not include resistance losses caused by the panels and the cables. These numbers are for example purposes only.

From the calculation above you can see that the voltage has been multiplied by the three panels to give us 66v, the current remains at 4.52 amps. The total power (watts) is also accumulative of the three panels. This accumulates to 300w.

So, what are the Pros to wiring in this series over parallel?

Pros to series wiring format

  • Higher voltage gives the MPPT controller (maximum power point tracking) more range when adjusting its charge current.
  • MPPT Charger requires 5 volts more than the battery voltage in order to start charging. This works well with the series wiring as it creates a higher voltage and the charger is able to charge from earlier in the day and later into the evening extending the daily charge period.
  • On cloudier days the solar arrays output voltage is reduced, but due to the higher voltages produced by the series wiring format, the MPPT is still able to create a charge current. Whereas a parallel array would drop below the MPPT’s minimum PV voltage and switch off.
  • A lot simpler to wire
  • Uses less cable than parallel

Cons to series wiring format

  • If any shade covers even a single cell on a panel, it will reduce the whole system’s power output. For example parking under a tree will seriously impede your output charging current. In simple terms, the array likes to be balanced, it likes to see the same amount of light over every cell and when it gets this, its incredibly effective.
  • Each panel and every cell within that panel are critical in a series format.
  • Any spots of dirt over any of the cells will impede how the system charges. Therefore if your panels are in series they will need to be kept clean to maintain a optimum charge current. In series you cannot connect different size panels together. The power (watts) from the first panel passes through both the second and the third to make the accumulation, they all must be equal in size.
Gland Diagram

Two solar panels wired in series fitted to the top of a camper van.

The panels themselves have two cables each, so 4 cables altogether, but by connecting the positive of one to the negative of the other we essentially create one giant panel. That then leaves a positive from one panel and a negative from the other. These are the two cables we send down to the electrical control panel to connect to the MPPT controller. As seen this in the photo.

Parallel Solar Panel Wiring

A parallel connection is created when the positive of one panel is connected to the positive of another, and the negatives are connected to each other.

Dod Diagram

Total Voltage: 22V
Total Current: 4.52A x 3 = 13.56A
Total Power: 300W

*These calculations do not include resistance losses caused by the panels and the cables, These numbers are purely for example purposes.

From the calculation above the voltage now remains the same, a constant 22v. The current is 13.56A (that’s the current of each panel multiplied by 3).

A solar array in parallel is fantastic if partially shaded. In simple terms, if a few cells were covered by an overhanging tree, the rest of the array would pick up the slack and still give a reasonable charge current.

Pros to parallel wiring format

  • One of the biggest pros to wiring in parallel is you can mix different size solar panels together. If, up on top of your campervan or motorhome roof, you have fans, surfboards, wifi boosters and therefore only have room for a 100w, a 50w and a 25w, they can be configured in different orientations around your equipment. Although this can be done, we at TBE do not advise this as it is very inefficient.
  • When in optimal conditions parallel can give a very good, strong charge current.
  • When shade hits any part of a solar array wired in parallel, the power output from that panel reduces significantly. BUT, any other panels in the configuration are unaffected.

Cons to parallel wiring format

  • The parallel setup needs a certain amount of power from the solar panels in order to create a charge current.
  • During the winter months, when the sun is low in the sky, the parallel format will struggle to produce enough voltage to initiate a charge.
  • Requires a lot more cabling to wire a parallel format therefore your cable costs will be higher.

*These calculations do not include resistance losses caused by the panels and the cables, These numbers are purely for example purposes.

Real world results

MPPT Parallel
MPPT Series

These two screenshots above were taken on exactly the same day under the same conditions. The difference being that one set of panels is wired in parallel and the other wired in series.

The main difference you can see is that the parallel system has around 18v to optimise the best charge current, whereas the series system has between 28V-70V. So, in the example above, the MPPT has dropped the voltage to 29.38V in order to increase the charge current to 5.2A.

The parallel system is just about managing a charge current but its very weak.

Where the parallel system shines is if the solar panels were suddenly to become partially shaded by a tree, for example. The series system would dramatically reduce while the parallel would be little effected as the panel which isn’t partially covered is still able to produce its power, the series system requires all cells to be clear to effectively create a charge current.

If you plan to travel in all seasons then series solar wiring is the better format for those conditions with less sunlight. The series wiring combined with an MPPT controller maximises your chances of getting a healthy charge current even on those overcast days.

Although you may suffer more losses during the optimum operating conditions, series can produce a high enough voltage to charge the batteries from dawn to dusk.

If you travel in a camper van or motorhome that has a roof full of vents and fans and the only option is to fit panels in here, there and everywhere, then parallel will provide you with the option of having multiple, different sized panels together on your roof but remember, the panels need to have the same voltage to maintain efficiency.


Diagram above demonstrating solar panels wired in series with a Victron Energy MPPT Controller

Our recommendations at Tiny Build Electrics

  • Wire your campervan solar setup in series.
  • Wherever possible, use the same size solar panels throughout the entire array.
  • If you must mix panels then try to get their specification as close as possible.
  • Pay attention to anything on your roof that could cast a shadow onto your solar panels, including maxxair fans, TV dishes and sports equipment.
  • Avoid parking in the shade or under trees to maximise performance.
  • Keep your solar panels really clean.
  • Use an MPPT controller when wiring in both series or parallel to maximise performance
Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help

Battery types you should be considering for your van conversion!

If you have undertook even a small amount of research regarding batteries for your tiny build, then you have quickly come to realise it is a bit of a minefield.

Battery technology is developing faster than you can imagine. They are becoming lighter, more powerful and their life cycles are ever increasing.

So what’s best? Well… how long is a piece of string?

There are a few fundamentals that are worth understanding before we proceed with the types of batteries in which you could fit into your tiny build.

Depth of discharge

The first being depth of discharge (DOD). Depth of discharge is how far a battery can be discharged relative to its capacity. Different batteries have different depth of discharge ratings, some batteries can be discharged further than others.

Dod Diagram

We recommend that you always use a battery monitor, such as the Victron BMV, to accurately determine the depth of discharge of your battery. Not only do the battery management devices monitor DOD, they also give you an array of information regarding your battery. Once setup correctly these monitors become extremely useful in your tiny build and help prolong the life of your batteries.

State of charge (SOC)

A batteries state of charge is simply the amount of charge within the battery.

A fully charged battery would be 100% SOC whilst an empty battery would be 0% SOC.

State of charge is the inverse of depth of discharge. Put another way, if a battery is at 100% state of charge, then its depth of discharge is 0%. The opposite is also true. If a battery is 100% discharged, its state of charge is 0%.

SOC Diagram


The second fundamental is a cycle. A cycle is when the battery has been fully charged, discharged and then fully charged again. Every time it completes this circle of events, that will be considered 1 cycle. Although by completing this cycle the battery is technically aging, it also keeps the battery active and healthy. Different batteries have different life cycles, some more than others.

The number of charge cycles a rechargeable battery can withstand before performance degrades is the method in which we use to measure how long our batteries will last, if taken care of properly.

Ohms Check

Battery Lifespan

A batteries lifespan is a time frame given by the manufacturer which depicts how many cycles a battery can perform in certain period of time.

Over time your battery monitoring system may tell you your system is at 100% charge but this isn’t necessarily accurate. This is a depletion in its lifespan, the battery will take longer to charge and be quicker to discharge in some circumstances.

Batteries coming to the end of their lifespan also struggle to hold a charge, so if everything is turned off in your tiny build and the battery is struggling to hold a healthy voltage you know your batteries are on their way out. If we look after our batteries, connect them in the correct way and use the correct equipment to charge them they will live long and prosper!

Cycle Complete

How can you increase the life of your batteries?

Once you begin to understand how different factors impact your battery’s life cycle, it becomes clearer how you can increase your battery’s life. Following some simple “best practices” can help you get the most out of your battery, regardless of whether it’s a lead-acid or lithium-ion battery.

Best Practice 1: As much as possible, use your battery in moderate temperatures. Of course, this may not always be possible but if you can keep your batteries in a moderate temperatures this can have a dramatic affect on its life cycles. Optimal temperature for most batteries is between 20 – 25 degrees centigrade. Lithium-Ion batteries are particularly sensitive to discharging and charging in colder weathers. To get around this you can surround your batteries with heat pads to keep them warm and operating efficiently.

Best Practice 2: If you have a lead-acid battery (FLA, AGM, GEL) ensure that you minimise how often you discharge the battery below 50% of its capacity. Ideally, the depth of discharge on each cycle should be between 10% and 50%. If you have a lithium battery, you can likely go down to 80% DOD and, in some cases, 100% DOD. Refer to your battery manufacturer’s recommendations to be safe.

Best Practice 3: If you have a flooded lead-acid battery, make sure to keep the electrolyte solution topped up.

Best Practice 4: Ensure you use the correct charging equipment for your batteries. Better yet, ensure the charge equipment that you are using has the correct charge parameters for your battery type. These parameters vary from battery type to battery type and needs to be done correctly. This is something that we, at Tiny Build Electrics, can help you with.

Battery Types

Batteries is a stage you want to get right, after all, no one wants to be sat in the dark sipping warm beers, right?!
Understanding the types of batteries available, the capacity you need for your van lifestyle, the relative cost and how to take care of them will help when it comes to choosing the best camper van batteries for you.

The four battery types we will be considering are:

Each type has a different make up and because of this perform differently under different circumstances.


Flood lead acid (FLA)

Flood lead acid batteries consist of two lead plates, one positively charged, the other negative. The battery is then flooded with a liquid electrolyte, sulphuric acid which covers all internal parts. When charging commences the acid and lead plates react to store electricity.


  • Low cost
  • Resilient to occasional over charging
  • Proven technology
  • Lifespan can be 4-8 years with regular maintenance and careful charging
  • Less susceptible to temperature differences


  • As the batteries age the performance will degrade to the point where the battery won’t hold a charge
  • Should be stored inside an enclosure (battery box)
  • Battery can only be drained to a maximum DOD of 50%, otherwise you’re likely to incur damage.
  • Must be vented in an enclosed area as some FLA batteries will emit gases.
  • Stricter regulations on how FLA batteries are fitted and how close they are installed to inverters and chargers.
  • Require regular maintenance
  • Heavy


Gel batteries use the same technology as FLA but instead of liquid acid they are filled with Gel. Gel gives us more advantages than FLA as you will see below.


  • Doesn’t emit any nasty gases
  • Sealed so can’t leak or produce any gas
  • Maintenance free
  • Operates in a wider array of temperatures than AGMS.
  • Ideal for vans that are stored over winter and not used for long periods of time


  • Very sensitive to depth of discharge
  • Do not recover well from a low DOD
  • More expensive than conventional FLA and AGM
  • Heavy

Gel batteries (GEL)

Absorbed glass mat (AGM)

AGM batteries work in a similar manner to FLA and Gel. Instead of acid or gel they have electrolyte soaked glass fibres between the positive and negative plates.


  • Long shelf life
  • Maintenance free
  • Ideal for vans that are stored over winter and not used for long periods of time
  • Can be installed sideways as its a sealed unit and cannot leak (unless damaged)
  • Smaller than the conventional Gel equivalent


  • Very sensitive to depth of discharge
  • Do not recover well from a low DOD
  • More expensive than FLA
  • Heavy
  • Poor performance in colder temperatures

Absorbed Glass Mat (AGM)

Lithium LiFePO4 / Lithium-ion / Li-ion

The famous lithium-ion battery. If you have done any sort of research on tiny building or off grid systems then it is highly likely you have come across the lithium battery, currently at the top end of the battery technology market. This is a battery you should be considering for your build, there’s just one downside… £££!


  • 30% lighter than FLA, GEL & AGM
  • Smaller frame size than FLA, GEL & AGM
  • 90% of their capacity is usable meaning you need less batteries for the same amp hours as FLA, GEL & AGM
  • Low internal impedance (resistance) mean these batteries also charge a lot quicker than the other types of batteries.
  • Can be installed in various orientations
  • Maintenance Free
  • Long life cycles if charged and discharged in accordance with manufactures instructions


  • Very sensitive to charging in low temperatures
  • Expensive, although prices have started to drop over the past few years
  • A battery management system is required to protect the lithium-ion battery bank from excessive discharging, over charging and to control the load and balancing of each internal cell. Most of the time this system is built into the battery itself.
  • Some extra monitoring may be required such as battery temperature monitoring

Lithium-ion batteries (LiFePO4)

Can I use a vehicle engine battery as a leisure battery?

Start batteries are the type of batteries that are used in cars, boats, lorries, buses and generators. Start batteries are not suitable for uses where they are discharged and then recharged again, also known as a cyclical use.
They also cannot be used in connection with an inverter, although technically they can the batteries make up means that it will not last very long while feeding an inverter.

The reason that start batteries are not suitable for frequent deep discharging is because of the way they have been constructed. They have thin plates with a large surface area. They are designed purely for short-term high discharge currents like engine starting.

During an engine starting the battery is exposed to high current draw in a short period of time. This high current draw turns a starter motor which in turns causes the engine to turn over and start. It might be tempting to use start batteries in a battery bank in smaller inverter systems, but please don’t do it. It will only cause trouble in the long run.


Price comparison

Battery Type Average Life Cycles @ 50% DOD Price (£) (TBE SHOP) Cost per Cycle (£)
Victron Energy 110ah AGM Battery 850 £316.99 0.37
Victron Energy 100ah LiFePo Battery 5000 £1,275.6 0.26

The table above clearly shows us that whilst the lithium-ion battery is more expensive than an AGM battery, it certainly is cheaper when you consider the cost per cycle over its lifetime. The life cycle of the lithium-ion battery is certainly unmatched and is something to seriously consider if you want a ‘fit and forget’ electrical system in your campervan.



If you are wanting the cheapest method of powering your tiny build then Flood Lead Acid is for you.
These batteries are as cheap as chips and can be picked up in various frame sizes as well as amp hour sizes. But please note, these batteries need ventilation and you need to monitor them to ensure they do not leak. We advise against installing FLA deep in your build. They need to be installed with in a battery enclosure and well vented should they need to vent or worst case, leak. When they vent, FLA batteries will emit dangerous gases into your campervan or motorhome.

If you are wanting a ‘fit and forget’ system with efficiency and a long cycle life then Lithium-ion is for you.
The lithiums are expensive, but, they are slowly coming down in price due to their popularity. When you consider the price of the lithium you must consider its lifecycle and DOD. Considering a AGM battery will enter in at around 500 cycles, lithiums are 5000+ cycles. Not only will they last longer (if installed and charged correctly) they’re a LOT lighter which is important when it comes to conversions such as vans, motorhomes, buses and lorries which have weight limits.

Tiny Build Electrics’ experience

I upgraded my campervan system from absorbed glass mat (AGM) to lithium-ion at the end of 2021. The main reason for this change was to save weight as I knew my self built van conversion was starting to get heavy. I removed my AGM batteries and weighed them. Both batteries weighed in at a whopping 35kg each! 70kg of batteries being pulled around by my van. It is not only the weight though, as the maximum DOD was 60% for my two x 100ah batteries which meant I only actually had 80ah of usable power.

Well, each lithium battery weighed in at… 11kg, yes 11kg! 70kg swapped out for 22kg. My van certainly thanked me! The weight saving was fantastic but what was even better was the power upgrade. My two 100ah lithium batteries now gave me 180ah of usable power, this is because the lithium batteries can be drawn down to 10% DOD without causing any damage. (They can theoretically go to 0% but most manufactures do not recommend this) I had literally doubled my power bank whilst saving two thirds of the weight!

I haven’t had any power worries since and because I have an electric hot water system the batteries take a beating. They cycle regularly but with a manufacture rating of over 5000 cycles this is not something I’m yet worrying about.

Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help

Basic visual checks and testing procedures

To carry out on your campervan conversion electrical system.

In this article we will cover some basic tests that you can carry out on your own self built electrical system within your van conversion or tiny build. These very simple tests can be the difference between a safe or dangerous installation. They help to identify loose connections and ensure that you take some time to check over your system upon completion, a stage that many miss.

Set Up12V DC Electrical System with Lithium-Ion Batteries
Controller12V DC Control Panel

Safe isolation of your campervan’s DC system

For the purpose of this article and the discussion of basic testing, we consider the reader to have a basic understanding of their electrical system and a basic arsenal of tooling and test equipment.

Before you start, it’s always wise to safely isolate the circuit(s) in which you wish to test. To do this you will require a device which can measure voltage, it will need to be capable of measuring direct current (‘DC’). This is the setting you will use to see the voltage in your system.

Ohms Check
We will be using continuity (with beep or without beep, either is fine) and Volts – Direct Current (DC)

Firstly, you need to fully isolate your campervan’s DC system via your main isolator. If you do not have a main isolator for your DC system, we highly recommend that one is installed, as should an emergency arise, you need to be able to shut the entire system down quickly and efficiently.

If your system contains solar panels, please use your solar panel isolator to isolate the PV array. If there is sunlight hitting your panels the PV system will produce a voltage and therefore needs to be isolated so that we can test in a safe manner.

Once your main isolator is in the off position you can then perform the basic test of switching on lights and other DC equipment. These should, of course, not turn on.

Just because these devices do not turn on, does not mean your system is safely isolated yet, for this we need to use our test equipment.

You can then take your voltage tester and test across your positive (+) and negative (-) at any point after the main isolator. The reading should be 0v. For the purpose of the installation specified in the photos, we tested from the positive busbar to the negative busbar. Another good place to test for voltage is on any devices that have exposed terminals, such as a solar charge controller (pictured right), here you can test for both your system voltage and your solar panel voltage, because both isolators are in the off position, these should both read 0v. Once you have read 0v from both your system voltage and PV voltage the isolators must remain in the off position. This now gives you a safely isolated DC system which you can test.

Visual Checks Campervan
1 (Pos) + Busbar,
2 (Neg) – Busbar,
3 Multimeter reading 0V

Visual Checks
4 System Voltage,
5 PV Voltage

Useful Definitions

System Voltage – The nominal voltage of the system as whole.
PV Voltage – The voltage that your solar panels produce before the solar charge controller.
PV Array – A linked collection of solar panel(s).
Multimeters & Voltage Testers – A piece of electronic test equipment used to determine the presence of electricity.

Visually inspecting your campervan’s electrical installation

A visual inspection of your campervan’s electrical installation is crucial. It is good practice to sit and run your eyes over the system, thinking of the flow of electricity like the flow of water through pipes. Ensuring that all the right cables are making their way correctly from A to B to C to D. This a not only a good way of ensuring that your system is correctly connected but also a good way of understanding your system and how it works.

This is also a great stage of the inspection process to reference your wiring digram (schematic) that you used during the installation process. Follow the diagram like a flow chart and ensure all devices are in the correct sequence and have the correct cables running to and from them.

A visual inspection of your cable management is also a key aspect here. All cables should be secure and protected from external influences. Cable trunking is a good example of cable management. It protects the cable from any external damage from the likes of surf boards and mountain bikes thrown in the back of the campervan at the end of the day.

The trunking also provides the cable with some air flow, enabling the cables to dissipate any heat effectively and operate at their designed specification.

Visually inspecting how your cables enter enclosures such as control panels and jointing boxes is also another key way of ensuring system longevity. Cables entering via sharp edges can cause potential damage to the cable over time. Here we must ensure that the cables are protected whilst the vehicle is moving and vibrating. Over time the sharp enclosure edge could slice into your cables and cause substantial issues, so you can make a quick wiggle check, ensuring the gland or grommet is holding our cable firm and protecting it as it enters the enclosure.

Campervan wiringCable trunking providing mechanical protection and ventilation
Campervan lugLifting the fuse holder tab to visually inspect the crimps

Tug testing your campervan’s electrical system

If the cable pulls out during a tug test then it was never going to stand the test of time.

Tug testing is an extremely basic electrical test but a critical one. Too many people forgo this step and issues that later on arise could have been solved by simply tugging on a cable to reveal a loose connection. 
Tug every single termination that you have made, yes every single one, there are probably hundreds, but do this! 
For terminations using lugs, these have more than likely been fixed using a nut and bolt method, a wiggle of the lug will suffice.

Checking that the lug is secure, creating a good, solid face to face connection and also that the copper within the lug is crimped tightly and that no strands of copper protrude the lug from the side in which the cable enters.

Key areas for tug and wiggle testing are at the fuses and protection devices. A loose connection here can cause a high resistant joint, the high resistance joint will ultimately result in a higher current being pulled though the loose joint and this could result in arcing, which can potentially lead to a fire.

If you have used through crimps, boot lace ferrels or, the ever popular, WAGOs in your installation then these can also be tug tested. Remember if the cable pulls out during a tug test then it was never going to stand the test of time. When you start taking your campervan down those bumpy lanes to get to the best surf location these connections need to be solid. Finding these loose connections is what tug testing is all about, you would rather find it now at this point than when your miles from home enjoying your travels.

Campervan wiring boardWiggle testing a Yellow M6 Ring Crimp
Campervan wiringWiggle testing M4 Ring Crimps

Identification of cables within your campervan’s electrical system

Identifying your cables is a really good way of future proofing your installation.

Buy a labeller and label everything! You’ll be on your travels, an issue will arise and the labelling process that you undertook will save you hours.

Labelling all your DC circuits is the key to identifying which cable is supplying which piece of equipment in your tiny build.

You should also label every isolator. Knowing which isolator you’re turning is crucial. If your van sits for a period of time you may want to isolate certain aspects of the installation. This is a great way of knowing exactly what is isolated and what is not.

Labelling your individual fuses is also a must, this can save a whole lot of time fault finding another day. Knowing what part of the system has failed and then knowing where said components are is crucial to any installation.
Ensure your cable colours are correct. This is crucial in any good installation. Using a red colour for your DC positive and black for your DC negative is a good place to start. If you have a plain black cables, such as cables coming from your solar panels, its always a good idea to label your positive and put a little red band or heat shrink around the neck of the cable.

Campervan switchIndividual Fuses labelled
Campervan powerLabelling for individual Isolators

Basic continuity testing of your campervan’s electrical system

Once you are satisfied with your visual and tug testing you can then move onto some basic continuity testing.

Continuity testing is simply ensuring that the start of your cable is connected to the end of your cable.

Campervan cable

As an example, you will have a cable that is connected at your battery or busbar (origin), and will run to your 12V DC distribution panel (load), to power your lights, fridge and fan.

Now, that cable should be continuous, from the origin to a fuse and then from the fuse to an isolator and from the isolator to your distribution panel.

Sounds obvious when said, but by the time you get to the end of your build these cables will be covered by your cable management, buried in walls and hidden behind kitchen cabinets and shower rooms so they can no longer be seen in their entirety.

Once your test equipment is on the continuity setting (see pictures below) you can simply touch the ends of the probes together and you should either hear a beep, get 0.00ohms or sometimes both (diagram above left). You are simply creating a loop. Your meter is sending out a signal on one probe, it touches the other probe and returns said signal to the test equipment.

1 Continuity settingsTest probes not touchingTest probes not touching (open circuit)
2 Display reading: 0 OhmsTest probes touchingTest probes touching (closed circuit)

Remember: Lower number = Lower resistance & Higher number = Higher resistance

You are doing exactly that, but the probes will be at each end of your cable. Your cable becomes part of the loop, this is how you test for continuity, you are ensuring your cable is continuous and has no breaks.

At this basic level of testing you are simply listening out for a beep or looking for a low value. Just bear in mind that values will vary due to the differences in the length of cable, fuses, switches and thickness of the cable.

Every joint that you make adds a level of resistance the the circuit. That is what you are measuring with your test equipment. A thick piece of cable with no joints will produce the lowest reading whilst a thin piece of cable with plenty of joints, fuses and switches will create a higher reading as there are more obstacles in the way, that is what we call resistance.

You can run through a scenario with the diagram below.


You first, touch one of the probes (it doesn’t matter which) on to the positive busbar(1), (if your system doesn’t have a busbar, the nearest positive terminal to the dead side of the isolator will suffice).

Once the probe is firmly on the positive busbar, you can then put the other probe onto the next connection in the diagram, which is at one end of the fuse(2). Here, if the cable is uninterrupted and continuous you should hear beep from your multimeter and, or a low reading.

You now know the cable between the busbar and the fuse is continuous.

You can then move to the fuse itself, put the first probe on one side of the fuse(2) and the second probe on the other side of the fuse(3), beep/low reading! This confirms to you that your fuse is intact and has not been broken or has blown.

Next you take a probe, put it on the outgoing side of the fuse(3) and connect the second probe to the positive connection on the lamp(4), beep/low reading!

You have confirmed that from the busbar, the origin of the circuit, you have continuity to the load, the end of our circuit and therefore the electricity can freely flow along this route without any issues.

*Note, your test leads may not be long enough to reach end to end of every circuit. You can make a longer bit of cable which will help you reach other parts of the installation, this is known in the electrical industry as a wandering lead.

*Not all cables need to be continuity verified, I appreciate this takes time and if you can see the cable in its entirety then you can be 100% sure this cable is entire and connected at both ends.

This is a really good way of proving you have good connections and your circuit is entire. If this is your first installation I recommend doing as many cables as you possibly can. If you are more experienced you can apply diversity factor and do a random selection.

Useful Definitions

Continuity testing – Used to establish whether an electrical circuit can be made between two points.
Origin – The point or place where the electrical system begins. (Campervan leisure Batteries).
Load – A device that consumes electrical energy. (Lights, fan, inverter, pump).
Fuse – An electrical safety device having a metal wire or strip that melts and interrupts the circuit when the current becomes too strong.
Busbar – A metallic strip or bar used to distribute electricity to several circuits from one location.


We at Tiny Build Electrics believe the words “electrical testing” can seem daunting. You may think it involves complicated procedures and equipment, and sure, it can do, but, we believe by doing some small, basic tests like the ones that we have discussed here in this article it is certainly better than none at all. If during your testing process you find one slightly loose cable or a mislabelled fuse then it was worth it.

Visually testing, tug testing and carrying out basic levels of continuity testing does not need to be complicated nor scary. By carrying out these basic, yet important, tests you can safely sleep in your home on wheels knowing the fundamentals of your installation are correct.

Whether you’re testing a van conversion, boat, motorhome, log cabin or any other tiny build electrical system, these basic, yet important procedures can be applied to all electrical installations, big and small!

*For the testing of your 230v systems, we advise contacting a qualified electrician to test and inspect this part of the installation. The tests conducted require more complex equipment and a portion of the testing is carried out live and therefore needs to be conducted by competent person(s).

Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help

12V vs 230V Systems in Campervans

Are you a campervan owner looking to upgrade or improve your electrical system? Understanding the difference between 12V and 230V systems is crucial to ensuring your van conversion is properly powered and equipped for your adventures.

In this article, we’ll delve into the basics of voltage, explore the characteristics and uses of 12V and 230V systems in campervans, and compare the two to help you make informed decisions about your campervan’s electrical setup.

Basics of Voltage in Campervans

Voltage, also known as electrical potential difference, is the force that pushes electric charge through a circuit. It is measured in volts (V) and is the key factor in determining the amount of power that can be transmitted through a circuit. In a campervan, voltage is used to power lights, appliances, and other devices.

12V DC Systems in Campervans

Simply put, these systems run on a 12-volt direct current (DC) and they’re used to power things like lights, fans, and other smaller appliances. They’re also handy for charging batteries, which can then be used to power other devices.

One of the best things about these systems is how simple and easy they are to use. They’re usually a more affordable option and require less maintenance compared to the 230V systems.

However, it’s important to remember that they have some limitations when it comes to powering larger appliances like air conditioners or microwaves.

Keep in mind that the 12V system relies on the campervan’s auxiliary battery for power, which means you need to keep an eye on the battery’s charge and make sure it gets charged up regularly. Otherwise, you might find yourself without power!

230V AC Systems in Campervans

In campervans, 230V AC systems supply power to larger domestic appliances and devices that require more energy than 12V systems can deliver. These appliances include microwaves, air conditioners, and other home-like conveniences.

To get power for these systems, campervans traditionally rely on an external hookup or ‘shore power’. In more recent years, however, onboard inverters have become the norm. These handy devices transform the typically 12V DC power from the campervan’s battery to 230V AC power, which can then be used to power appliances.

Inverters come in various sizes and capabilities, so it’s important to choose one that matches the power requirements of your appliances. But don’t worry, if you’re not sure, we can help size your system for you.

One of the main benefits of 230V AC systems in campervans is their ability to provide more power, making it possible to run larger appliances. They also allow you to use the same appliances you have at home, which can make your campervan feel more comfortable. However, these systems tend to be more expensive and complex to install and use. Additionally, the necessary components and battery storage can add extra weight to your vehicle, which can affect its overall weight distribution and fuel economy.

12V or 230V Systems in Campervans?

When it comes to choosing the best power system for your campervan, you need to think about what kind of stuff you want to power up. If you just need to keep the lights on and charge your gadgets, then the 12V system will do the trick. But, if you’re planning to bring along big-ticket items like a microwave or air conditioner, you’ll need to step it up to a 230V AC system.

It’s also important to think about how long you’re planning to be out on the road and how much juice you need to keep your devices powered up. If you’re planning a short trip and just need to charge your phone, then a 12V system is probably more than enough. But if you’re planning on living off the grid for an extended period of time, you’ll need to make sure you have enough power to sustain your needs.

Of course, you also need to think about the cost and upkeep of each system. A 12V system is generally more affordable and requires less maintenance, but a 230V AC system will give you more power to play with. Ultimately, you need to choose a system that fits your budget and technical abilities, and that will meet your power needs on the road.

Having Both 12v and 230v Systems in Your Campervan

Having both 12V and 230V systems in your campervan can offer the best of both worlds, as it allows you to power both small and large appliances. This is achieved by using a combination of a 12V DC system for low-power items and a 230V AC system for larger appliances e.g. the blender you can’t live without.

One common setup is to use an inverter to convert the 12V DC power from the auxiliary battery to 230V AC power for larger appliances. This can provide more flexibility in your power supply while keeping costs and complexity to a minimum.

Overall, the decision to have both systems in your campervan comes down to personal preference and your individual power needs. It’s always recommended to consult with a professional (cough, that’s us) to ensure that your system is properly sized and installed to meet your specific requirements.


In conclusion, understanding the difference between 12V DC and 230V AC systems in campervans is essential for ensuring your vehicle is properly powered and equipped for your adventures.

12V DC systems are typically simpler, more affordable, and easier to use, but have limited power capabilities. On the other hand, 230V AC systems can provide more power, but are generally more expensive, complex and require more maintenance. By considering your specific needs and the types of appliances and devices you plan to use, you can make an informed decision about which electrical system is right for your campervan.

Remember, a well-informed decision is the key to a successful and enjoyable campervan experience. Take the time to understand your needs, weigh the pros and cons, and make a decision that will serve you best. Happy travels!

Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help

Campervan Inverters: Essential for On-the-Go Power

If you’re a vanlifer, you know how important it is to have reliable access to power while on the road. Whether you need to charge your phone, run a laptop, or power small appliances, a campervan inverter is an essential component of your electrical system.

But what exactly is an inverter, and why is it so important?

Simply put, an inverter is a device that converts direct current (DC) power from your vehicle’s battery into alternating current (AC) power, which is the type of power used by most household appliances and electronics. Without an inverter, you would not be able to use or charge your devices while driving. In addition to charging your devices, an inverter can also be used to power small appliances such as a microwave, coffee maker, or mini fridge. This can be especially useful if you’re staying in a remote location with no access to electricity.

Types of Inverters

There are two main types of inverters: modified sine wave inverters and pure sine wave inverters.

  1. Modified sine wave inverters are the more basic and inexpensive option, and they work well for most basic, non-sensitive devices such as chargers and tools. However, they may not be suitable for more sensitive electronics, as the power output is not as clean as with a pure sine wave inverter.
  2. Pure sine wave inverters, on the other hand, provide a more accurate representation of AC power and are suitable for use with sensitive electronics such as TVs and audio equipment. They are generally more expensive than modified sine wave inverters, but they offer better performance and compatibility with a wider range of devices.

Sizing an Inverter

When choosing an inverter for your campervan, it’s important to consider the total cumulative wattages of your appliances and electronics. You’ll need to select an inverter that can handle the combined wattage of all the devices you plan to use. For example, if you have a laptop that requires 60 Watts and a phone charger that requires 10 Watts, you’ll need an inverter with a minimum deliverable power rating of 70 watts. This is why you also need to consider inverter efficiency, (most entry level inverters start at around 85% efficiency, with higher quality models reaching 93-94% efficiency). Other considerations include the size and weight of the unit, as well as any additional features such as remote control.

Installing an Inverter

Installing an inverter in your campervan is a relatively straightforward process, but should be approached with due diligence.

First, you’ll need to choose an appropriate location for the inverter. It should be easy to access, in a well-ventilated area to prevent overheating, and should ideally also be mounted on a non-combustible surface. Under no circumstances should an inverter be installed directly above Lead-Acid batteries. Under significant load, or when approaching sulfation, Lead-Acid batteries can off-gas, meaning gas is released from the battery. This gas could be drawn through the fans of the inverter and result in fire! So, once an appropriate location has been confirmed, next you’ll need to connect the inverter to your auxiliary battery using the correctly sized cables, paired with an correctly sized overcurrent protective device.

Lastly, your local regulations may require a true neutral. In some cases, where the inverter is not fitted with a Neutral to Earth Bond, one of the AC output wires must be connected to the chassis, and the chassis must be connected to a reliable ground. Reason being that a true neutral is needed to ensure correct operation of an earth leakage circuit breaker (RCCB / RCD / GFCI)

Maintaining an Inverter

Once your inverter is installed, it’s important to maintain it to ensure it stays in good working order.

  1. This includes cleaning the terminals and checking the battery connection regularly. By taking good care of your inverter, you can ensure that you have reliable access to power while on the road.
  2. It’s important to manage your power usage carefully. This includes turning off appliances when they’re not in use, unplugging chargers when they’re fully charged, and avoiding using high-wattage appliances at the same time.
  3. It’s also important to properly maintain your auxiliary battery to ensure that you have a reliable power source for your inverter. This includes keeping the battery charged, cleaning the terminals, and in the case of VRLA batteries, checking fluid levels.

Here are some potential pros of using an inverter in your campervan:

  • Convenience: An inverter allows you to use and charge your electronic devices while on the road, providing a convenient source of power.
  • Compatibility: Inverters are compatible with most household appliances and electronics, so you can use them to power a wide range of devices.
  • Safety: A quality inverter will have built-in safety features such as short circuit protection and thermal shutdown to help prevent accidents or damage to your tiny home.
  • Versatility: In addition to charging your devices, an inverter can also be used to power small appliances such as a microwave or coffee maker, making it a versatile power source.
  • Durability: With proper care and maintenance, an inverter can last for many years, making it a reliable and long-lasting power solution.

In conclusion, a campervan inverter is an essential component of any vanlifer’s electrical system. Whether you’re using it to charge your devices or power small appliances, an inverter will allow you to enjoy all the comforts of home while on the road.

So if you’re building or upgrading your campervan electrical system, be sure to include an inverter in your plans.

Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help

Solar Panels for Campervans

Solar panels are a great way to power your camper van and allow you to get off the grid. These panels use the energy from the sun to generate electricity, which can be used to power your appliances and electronics. With a solar panel system, you can enjoy all the comforts of home while on the road, without relying on hookups or generators.

What Solar Panel Should You Choose?

There are a few things to consider when choosing solar panels for your camper van:

  1. The first is the size of the panel. The size you need will depend on the amount of power you need to generate and how much space you have available on your van. A larger panel will be able to generate more power, but it will also take up more space.
  2. The efficiency of the panel is also an important factor to consider. A more efficient panel will be able to generate more power per square foot, which means you’ll need fewer panels to generate the same amount of power. This can be especially important if you have limited space on your van.
  3. Another thing to consider is the type of panel you choose. There are two main types of solar panels: monocrystalline and polycrystalline. Monocrystalline panels are made from a single crystal of silicon and are typically more efficient than polycrystalline panels. However, they are also more expensive. Polycrystalline panels are made from multiple crystals of silicon and are less efficient but also less expensive.

What Other Electrical Equipment Will You Need?

Solar Charge Controller: In addition to the panels themselves, you’ll also need a solar charge controller to regulate the flow of electricity from the panels to your battery. The charge controller ensures that your battery is not overcharged, which can damage it.

Batteries: You’ll also need a battery to store the power generated by your panels. There are several types of batteries to choose from, including lead-acid, lithium-ion, and nickel-metal hydride. Historically, Lead-acid batteries are the most common and are relatively inexpensive, but they are also heavy and have a shorter lifespan than other types of batteries. Lithium-ion batteries are lighter and have a longer lifespan, but they are also more expensive. Nickel-metal hydride batteries are a good middle ground, offering a longer lifespan and lower weight than lead-acid batteries but at a lower cost than lithium-ion batteries.

Mounting Solar Panels to a Camper Van

Once you have your panels, charge controller, and battery, you’ll need to mount them on your van. There are a few different options for mounting the panels. You can either mount them on the roof of your van or on a rack on the side. Roof-mounted panels are typically more efficient, and are less likely to be shaded. However, they can be more difficult to install and may require special brackets to hold them in place. Side-mounted panels are easier to install, but will never be as efficient as roof-mounted panels.

Once your solar panel system is installed, you’ll need to keep an eye on your battery levels to ensure that you have enough power. You can do this using a battery monitor, which will show you the current state of charge of your battery and how much stored power it has left. You can also use an inverter to convert the DC power generated by your panels into AC power, which can be used to power your appliances and electronics.

One of the major advantages of using solar panels to power your camper van is the ability to get off-grid. With a solar array in your system, you don’t have to soly rely on hookups or generators, which can be expensive and inconvenient. You can simply park your van in a sunny spot and let your panels do the work. This can be especially useful if you plan on spending extended periods of time in remote locations where hookups may not be available.

Another advantage of solar panels is the environmental benefits. Solar energy is a clean and renewable resource, which means it won’t contribute to greenhouse gas emissions or pollution. By using solar panels, you can reduce your carbon footprint and do your part to protect the environment.

Solar panels are also relatively low maintenance. Once you have your system installed, you’ll only need to clean the panels occasionally to ensure that they are functioning at their best. You’ll also need to check your battery levels regularly and top them up as needed. Other than that, there isn’t much else you need to do to keep your system running smoothly.

One potential downside of solar panels is the initial cost. While the cost of solar panels has come down in recent years, they can still be expensive to purchase and install. However, the long-term benefits may outweigh the initial cost. By using solar panels, you can save money on fuel and electric hookups, which can add up over time. You may also be able to take advantage of government incentives or rebates, which can help offset the cost of your solar panel system.

Here are some pros and cons of using solar panels for vanlife:


  • Solar panels are a clean and renewable energy source. They do not produce any greenhouse gases or pollutants, so they are a more environmentally friendly option than fossil fuels.
  • Solar panels are relatively low maintenance. Once they are installed, they require very little attention, and you can expect them to last for many years.
  • Solar panels can be used to power all kinds of devices and appliances, including lights, laptops, and refrigerators. This can be very convenient if you are living in a van and want to be able to use electricity while on the go.
  • Solar panels can be very cost effective over the long term. While the initial investment may be higher than other options, the energy produced by solar panels is free, so you can save money on your energy bills over time.


  • Solar panels can be initially expensive to install, especially if you are hiring a professional to do the work.
  • Solar panels require sunlight to function properly, so they may not be as effective in cloudy or rainy conditions.
  • Solar panels can be heavy and may take up a significant amount of space on your van. This could be an issue if you are trying to maximise the available storage in your vehicle.
  • Solar panels may not be able to produce enough electricity to power all of your needs, especially if you are using a lot of energy-intensive appliances. In this case, you may need to supplement your solar panel system with another energy source, such as a generator.

In conclusion, solar panels are a great way to power your camper van and get off-grid. They are relatively easy to install and maintain, and they offer a number of benefits, including environmental benefits and low maintenance. While the initial cost may be higher, the long-term benefits in our opinion, always outweigh the initial investment.

Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help
Camper van by the beach

MPPTs for Vanlife Electrical Systems

A solar MPPT, or Maximum Power Point Tracker, is a device that is used to optimise the performance of a photovoltaic (PV) system. It works by continuously monitoring the output of the PV panels and adjusting the current and voltage to maximise the power output.

The MPPT is able to track the maximum power point of the panels and adjust the current and voltage to maximise the power output. This is important because it allows the system to operate at maximum efficiency, resulting in more electricity being generated and potentially lower energy costs.

Using a solar MPPT in a vanlife electrical system can help to optimise the performance of the solar panels and ensure that they are operating at maximum efficiency. This can be especially important in a van, where space and weight are often limited and every watt of power counts.

How does the MPPT Work?

The MPPT works by continuously monitoring the output of the solar panels and adjusting the current and voltage to maximise the power output. This can be especially useful in vanlife, where the intensity of the sunlight and the temperature of the panels can vary significantly depending on the location and weather conditions.

In addition to maximising the power output of the solar panels, an MPPT can also help to extend the life of the batteries in the van’s electrical system. By ensuring that the batteries are charged efficiently, the MPPT can help to prevent overcharging or undercharging, which can damage the batteries and shorten their lifespan.

How to choose an MPPT

  1. There are several factors to consider when choosing an MPPT for a vanlife electrical system. One of the main considerations is the size of the solar panels and the electrical system in the van. The MPPT should be able to handle the maximum power output of the panels and the current and voltage requirements of the system.
  2. Another important factor to consider is the type of battery being used in the van’s electrical system. Different MPPTs are designed to work with different types of batteries, such as lead-acid, lithium-ion, or nickel-metal hydride. It is important to choose an MPPT that is compatible with the type of battery being used in the van.
  3. In addition to the size of the solar panels and the type of battery, it is also important to consider the features and capabilities of the MPPT. Some MPPTs come with advanced features such as Bluetooth connectivity, a LCD display, remote monitoring, or the ability to control multiple solar panels or batteries. These features can be useful for vanlifers who want to have more control and monitoring of their electrical system.

Finally, it is important to consider the price and reliability of the MPPT. There are many different brands and models available, and it is important to choose one that is reliable, has good customer support, and is within your budget.

In summary, there are several factors to consider when choosing an MPPT for a vanlife electrical system, including the size of the solar panels and electrical system, the type of battery, the features and capabilities of the MPPT, and the price and reliability of the device. By carefully considering these factors, vanlifers can choose an MPPT that is well-suited for their needs and helps to optimise the performance of their solar panels and electrical system.

Tom Alderdice

Hey, I’m Tom – founder of Tiny Build Electrics

My mission is to help sustainable-minded folks develop their electrical knowledge, giving them the confidence to do their own tiny build electrics.

Discover how we can help