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Free tool · Victron systems · BS 7671:2018+A4:2026

Victron system designer

Tap what you'll run. Get the whole Victron system: every cable and fuse, a wiring diagram and a parts list.

1

Your build

Let's size your system. What's it going in, and where?

Checked by Tom Alderdice, qualified electrician · Authorised Victron Energy InstallerTom checked the rules and sources this tool works from. Free · no sign-up

What it's going in

Campervan Motorhome Cabin or tiny homeOff-grid, no mains

System voltage

AutoWe pick the lowest voltage that carries your peak load and battery bank. 12 V 24 V 48 V

Typical builds (for scale)

Where in the UK South EnglandMidlands and WalesNorth EnglandScotland

Plan for Summer (May to Aug)Spring and autumn tooAll year, winter included

2

12 V things

What will run straight off the battery? Tap what you've got.

3

230 V things and sockets

Now the 230 V side. What will you plug into a socket?

230 V circuits

Each on its own double-pole RCBO. Auto picks the board from what you plug in.

Auto (recommended)1 circuit2 circuits3 circuits4 circuits5 circuits6 circuits

Its own circuit for

Each gets its own RCBO on the board.

Truma Combi E (230 V element) Air conditioner We confirm its breaker on a free call

4

How you'll charge

How will you keep the battery charged?

Days on battery alone

No sun, no driving, no hook-up. 1½ to 2 suits most vans.

1 day1½ days2 days3 days4 days5 days

Solar: start with your roof

Pick your van to fill in the roof size

Make

Model and lengthChoose a make first

Or measure the flat roof

Length of usable roof

m

Width of usable roof

m

Don't know your roof size? Tell us how many panels instead

Average driving a day

0 to 10 h

h

Charge while driving

Victron Orion XS DC-DC charger

50 A (our pick)70 ANone

Hook-up (shore power)

Never Sometimes Most nightsSolar tops up

Cable runs (one way)

Typical defaults · change any you've measured

Parts you already have

5

Remote monitoring

Want to see your system from anywhere?

Remote monitoring

Yes, add itCerbo GX + touch screen · VRM appRecommended No, keep it simpleFree Victron app on your phone

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© 2026 Tiny Build Electrics Ltd. Proprietary tool. All rights reserved. Free to use for your own build. Copying, scraping or reusing the tool, its results or its method is not permitted. A design aid only: the plan must be checked, and the 230 V side tested and certified, by a qualified electrician.