5 year warranty
On structure and installation, 12 months on finish and adjustment. Components carry their manufacturer's warranty.
Off-grid electrics · solar · West Sussex workshop
Off-grid campervan electrics.
Solar that has stopped charging, a battery that will not last the weekend, or a van that needs a proper off-grid system. Our workshop in Partridge Green, West Sussex, finds the fault before changing parts, sizes systems from how you actually use the van, and builds to BS 7671, Section 721.
Hero photograph: Victron SmartSolar MPPT and Orion XS mounted on an aluminium plate.
Built to BS 7671, Section 721
The section for caravan and motor caravan electrical installations.
25 years in the trade
Fault-finding, upgrades and full systems on self-builds, conversions from other builders and our own.
Half-hour diagnostic
£50 plus VAT for the first half hour of fault-finding, then £85 an hour plus VAT. We tell you plainly what it needs, what can wait and what it will cost.
Choose your starting point
Three useful ways into the workshop.
Repair or diagnose
- Something has stopped working: solar not charging, a battery that will not hold, an inverter that trips or hook-up that does nothing.
- Tell us the symptom. Send a photo of the equipment label if you can.
- Diagnostic fault-finding: £50 plus VAT for the first half hour, then £85 an hour plus VAT.
- We check the whole charging system, not just the part you suspect, and explain your options before replacing anything.
- Repair work is quoted in writing before it starts.
Upgrade what you have
- The system works, but you need more: lithium in place of lead acid, a bigger inverter, a DC-DC charger or more solar.
- Power for a kettle or microwave, or better charging from a smart alternator.
- We check the existing wiring and equipment so the new parts work with what is already fitted.
- Start with the five-minute questionnaire. We then look at the van and give you a written quote.
A new off-grid system
- Starting from scratch: self-builds, conversions from other builders or work vans needing power away from the mains.
- A first-pass system and planning estimate from the five-minute questionnaire.
- A written quote after we have looked at the van.
- Powerframe 3000 or a smaller 12 V system: the questionnaire helps identify what you actually need.
What we work on and how a diagnostic runs
Campervan electrical fault-finding
We investigate faults across 12V DC and 230V AC systems, including batteries, inverters, battery-to-battery chargers, hook-up, lighting, USB, cameras and security.
Campervan solar repairs
If solar has stopped charging or output is not what you expect, we can look at the controller, connections and wider charging system before recommending what to do next.
Battery and inverter sizing
Plan a change to battery capacity, solar, alternator charging or inverter provision around how you use the vehicle and the equipment already fitted.
Campervan solar repairs and electrical fault-finding.
Charging faults, a battery that is not keeping up, or a system ready for an upgrade. Our Partridge Green workshop works on campervan and motorhome habitation electrics, including self-builds and conversions from other builders. Workshop appointments in Partridge Green, West Sussex. We work on vehicles we have not built, including DIY and professional conversions.
Partridge Green. West Sussex workshop. 12V DC + 230V AC habitation electrics.
Previous service introduction: Solar repairs, off-grid fault-finding, considered upgrades and system planning for campervans and adventure vehicles. Tell us what the electrics are doing, or start with the Powerframe 3000 and sizing tool.
Solar fault or planned upgrade? You can contact the workshop directly without completing the sizing tool.
Find the fault before changing parts.
Tell us what is happening, what is already fitted and when you need the vehicle. We assess the work, explain the options and agree the repair before booking it into the workshop.
- 01 Describe the work. Tell us about the symptom or upgrade. A photo of the equipment label or installation can help.
- 02 Diagnostics if needed. We investigate the system. Diagnostic fault-finding is £50 plus VAT for the first half hour, and £85 an hour plus VAT beyond that.
- 03 Options in plain English. We explain what needs attention, what can wait and what a proposed upgrade would change.
- 04 Agree a workshop slot. We plan the work around the vehicle and the job before it starts.
Three ways to move forward. Start with the work you need.
The original repair or diagnose description was: Solar, batteries, inverter/chargers and other habitation electrical faults. The upgrade description was: Check how the new parts work with the existing installation before changing it. The Powerframe 3000 description was: See the pre-built system, its specification and what fitting involves. Its original link label was View Powerframe details.
What a system does for you
Three planning examples show how the loads you choose shape a first-pass system.
Weekend Warrior, spring to autumn
- Daily essentials: fridge, lights, water pump, phones and a laptop.
- Cooking allowance: one six-minute travel-kettle use each day.
- Time parked up: about three and a half days with no sun.
- Selected system: a 230 Ah lithium battery with 200 W of solar.
- Kettle-only comparison: about 21 boils of a 1,000 W travel kettle from a full battery, if it did nothing else.
Show the working
| Load | Watts | Effective hours/day | Wh/day |
|---|---|---|---|
| Compressor fridge | 45 | 7 | 315 |
| LED lights | 15 | 4 | 60 |
| Water pump | 40 | 0.25 | 10 |
| Laptop charging | 65 | 2 | 130 |
| Phones / cameras | 30 | 1 | 30 |
| Travel kettle, not a domestic 2kW+ kettle | 1000 | 0.1 | 100 |
Raw daily total: 645 Wh. With 12% general losses and the tool's total rounding: 722 Wh/day.
Effective hours are consumption allowances, including fridge duty cycling, not promises of continuous operation.
Battery: Fogstar Drift 12V 230Ah; 1 bank; 2944 Wh nominal; 2649.6 Wh usable; 12 V system.
Days with no charging, modelled figure: 3.7. Target: 2 unsupported days.
Solar: 200 W through Victron SmartSolar MPPT 75/15. Inverter: Victron MultiPlus 12/1600/70.
Vehicle charging: Victron Orion XS 12/12-50A, 700 W effective, 50 A.
One-week Alpine trip with Starlink
- Daily loads: everything in the Weekend Warrior example, plus Starlink every evening and the occasional microwave.
- Time without charging: about two and a half to five days, depending on battery size.
- Longer stays: charging while you drive and solar to top up.
- Poor mountain weather: the alternator does most of the charging work.
Show the working
| Load | Watts | Effective hours/day | Wh/day |
|---|---|---|---|
| Compressor fridge | 45 | 7 | 315 |
| LED lights | 15 | 4 | 60 |
| Water pump | 40 | 0.25 | 10 |
| Laptop charging | 65 | 2 | 130 |
| Phones / cameras | 30 | 1 | 30 |
| Satellite internet | 60 | 4 | 240 |
| Microwave (short use) | 900 | 0.0833 | 75 |
| Travel kettle, not a domestic 2kW+ kettle | 1000 | 0.1 | 100 |
Raw daily total: 960 Wh. With 12% general losses and the tool's total rounding: 1075 Wh/day.
Effective hours are consumption allowances, including fridge duty cycling, not promises of continuous operation.
Battery: Fogstar Drift 12V 230Ah; 1 bank; 2944 Wh nominal; 2649.6 Wh usable; 12 V system.
Days with no charging, modelled figure: 2.5. Target: 2 unsupported days.
Solar: 0 W, none selected. Inverter: Victron MultiPlus 12/1600/70.
Vehicle charging: Victron Orion XS 12/12-50A, 700 W effective, 50 A.
Battery: Fogstar Drift 12V 230Ah; 2 banks; 5888 Wh nominal; 5299.2 Wh usable; 12 V system.
Days with no charging, modelled figure: 4.9. Target: 4 unsupported days.
Solar: 0 W, none selected. Inverter: Victron MultiPlus 12/1600/70.
Vehicle charging: Victron Orion XS 12/12-50A, 700 W effective, 50 A.
No-charge days range, modelled figures: 2.5 to 4.9.
Content creator, induction cooking and Starlink
- Daily essentials: fridge, lights, water pump and phones.
- Daily cooking and work: half an hour of induction cooking, four hours of Starlink and two hours of laptop charging.
- Time parked up: about three and a half days with no charging.
- Selected system: 24 V for these loads.
- Winter charging: driving or hook-up needed to keep up.
- Not included: all-day Starlink and e-bike charging need their own allowance.
Show the working
All-day Starlink and e-bike charging are not included and need their own allowance.
| Load | Watts | Effective hours/day | Wh/day |
|---|---|---|---|
| Compressor fridge | 45 | 7 | 315 |
| LED lights | 15 | 4 | 60 |
| Water pump | 40 | 0.25 | 10 |
| Laptop charging | 65 | 2 | 130 |
| Phones / cameras | 30 | 1 | 30 |
| Satellite internet | 60 | 4 | 240 |
| Single induction hob ring | 1800 | 0.5 | 900 |
Raw daily total: 1685 Wh. With 12% general losses and the tool's total rounding: 1887 Wh/day.
Effective hours are consumption allowances, including fridge duty cycling, not promises of continuous operation.
Selected battery bank: 300 Ah at 24 V (25.6 V nominal for energy calculations).
Battery: 2 × Fogstar Drift 12V 100Ah in series (24V 100Ah); 3 banks; 7680 Wh nominal; 6912 Wh usable; 24 V system.
Usable energy and no-charge days: 25.6 V × 300 Ah = 7680 Wh nominal; × 0.9 usable fraction = 6912 Wh usable; ÷ 1887 Wh/day = 3.7 days (modelled, rounded to one decimal place).
Days with no charging, modelled figure: 3.7. Target: 3 unsupported days.
Solar: 600 W through Victron SmartSolar MPPT 100/30. Inverter: Victron MultiPlus-II 24/3000/70-32.
Vehicle charging: Victron Orion XS 1400 (12V to 24V, derated), 700 W effective, 25 A.
These are planning examples, not a promise of what every van will achieve.
Illustrations of how use changes a first-pass specification, not completed customer installations or final engineering plans.
From about £2,250 + VAT
Details
A planning estimate. We confirm the price in writing after we have seen the van.
The planning tool
Answer the useful questions first.
Choose real-world loads. The tool then selects named battery, inverter/charger, DC-DC and solar-controller combinations and checks the battery current limit.
Small upgrades from about £550 plus VAT. A full system, with battery, inverter, solar and charging, from about £2,250 plus VAT. These figures are for upgrades and new systems. Repair work is quoted in writing before it starts. The estimate below updates as you choose. It is a planning estimate, not a quote, and we check the van before we confirm a price in writing.
Step 1 of 90% complete
Is this for leisure or work?
You can change any answer before sending the result.
Why winter solar is different from summer
UK winter reality
Solar produces less power in winter.
For a modest 200 W roof setup, this illustrative model gives about 120 Wh/day in January and about 560 Wh/day on a good summer day. Clouds, shade, low sun and where the van is parked can reduce either figure.
A planning example, not a forecast for a particular roof or a promise of days off-grid.
Illustrative energy from 200 W of solar
Summer~560 Wh/day
January~120 Wh/day
Illustrative yield for a modest roof setup. Actual output varies with weather, shade, orientation and charging conditions.
Keep your sizing result
Want a second pair of eyes?
Send the assumptions and calculated specification to the workshop. We will be clear about what still needs checking.
Send this to Wildbox
Checks before parts
Common mistakes
Designing around a domestic kettle/induction then balking at cost and weight.
Use the 1,000 W travel-kettle option or choose a cooking strategy before choosing an inverter.
Assuming summer solar output will hold in November.
Model January separately and keep a charging plan.
Checking inverter continuous output but not battery surge current.
Check inverter peak watts against the battery bank's maximum continuous BMS discharge current.
No plan for cold-weather charging of LiFePO₄.
Check the battery BMS and prevent charging below its allowed temperature.
More things we check
Quoting an Orion XS 1400 at full power across mixed voltages.
A 12 V to 24 V installation is limited to roughly 700 W by the 50 A input/output limits.
Under-fusing or using cable that is too small.
Set protection around current, length, routing and installation method.
Good to know
A few straight answers.
How do I size an off-grid vehicle electrical system?
Start with daily watt-hours, then choose the unsupported days, battery reserve, solar space and charging sources. The tool shows its assumptions.
How many amp hours do I need?
Divide the nominal battery watt-hours by the assumed system voltage. The useful figure is the usable portion of that nominal capacity, not the label alone.
What size inverter do I need?
Size the inverter for the AC appliances that will run at the same time, allowing for startup demand and checking battery discharge limits. If appliances are used one at a time, start with the largest load; work equipment may run concurrently. Do not treat VA and watts as interchangeable.
Can I fit a van electrical system myself?
You can, if you understand isolation, fusing, cable routing, charging equipment, battery temperature limits and testing. Final protection should be checked by someone competent.
What does having a system certified mean?
It means the installed system has been inspected and tested against the relevant requirements by an appropriately qualified person. It is not the same as a component having a CE mark.
How many solar panels does a van need?
Use the roof you actually have. A clear roof may allow around 500 W in this planning model; shade and obstructions reduce the result.
Will solar work in winter in the UK?
Yes, but January yield is roughly a quarter of a good summer day in this simple model, and it is not guaranteed.
Do I need a DC-DC charger?
Combustion vans often benefit from one. Electric vehicles and trailers need a vehicle-specific approved charging interface or a different charging plan.
What cable and fuse size do I need?
Final selection needs current, cable length, route, temperature and equipment instructions. The tool flags the planning current but is not installation sign-off.
Can I use this calculator for a work vehicle?
Yes. Choose work and select the loads used on a normal day; tool charging can change the inverter and current requirement quickly.
A ready-built option
Pre-built off-grid electrics
Wildbox Powerframe 3000
About 58 kettle boils, or 7 air-fryer sessions, from one full charge.
Our pre-built off-grid system: a 3000VA inverter/charger, 8 kWh of lithium, alternator and solar charging and full protection on one aluminium frame, bench-tested in Partridge Green and built to BS 7671, Section 721. £5,627 plus VAT (£6,752.40 including VAT). Fitting, solar panels and monitoring are quoted separately.
Planning examples, not a promise. Details and assumptions are on the Powerframe page.
Previous Powerframe description
Bench-tested in our Partridge Green workshop, with a Victron MultiPlus-II 3000VA inverter/charger, Fogstar Drift Gen2 628Ah battery and hardware for alternator and solar charging. Vehicle fitting, solar panels and monitoring are quoted separately.
Workshop support · Partridge Green
Tell us what the electrics are doing.
Our workshop is in Partridge Green, near Horsham, West Sussex.
Solar not charging, a battery that will not hold charge, an inverter fault or a system you would like to improve? Tell us about the van and we will work out the right next step.
Diagnostic fault-finding is £50 plus VAT for the first half hour, and £85 an hour plus VAT beyond that.
Manufacturer documentation
Use the relevant equipment documentation when checking component limits. Solar and runtime figures on this page are Wildbox planning estimates, not manufacturer guarantees.