200 watts of van solar — enough for the essentials.
200W is the entry point: lights, fans and keeping your phone and laptop charged for weekends off-grid. Wattonomy shows exactly what 200W keeps running, sizes the battery to carry the night, and hands you the wiring and parts to build it safely.
Wire & fuse sizes follow ABYC E-11 — each conductor carries its fuse and stays under a 3% voltage drop.
Built to ABYC standards
Gauge · fuse · volt-drop sized
Every spec sourced
Small doesn’t mean it can skip the fuses.
Even a modest 200W setup puts a lithium battery one short circuit away from a serious fault. Wattonomy sizes the bank, inverter and every cable to your real loads — to ABYC E-11, with fuses and voltage-drop checked — so a weekender build is as safe as a full-timer’s.
What 200W of van solar gets you
On a fair day, 200W tops up the essentials for a weekend or part-time build. Here’s the picture.
What it runs
LED lighting, a roof fan, and phone & laptop charging — comfortable for weekends and shoulder-season trips.
Battery to match
About 2.5 kWh of LiFePO4 at 12V carries the essentials overnight on an honest depth-of-discharge.
Where 200W stops
Add a 12V fridge or stay out longer and you’ll want 400W+ — the tool shows the jump the moment you add the load.
Cables & fuses
Every gauge and fuse sized to the load and your run lengths, with the AIC checked — to ABYC E-11.
What you walk away with — free
A full 200W system sized to your appliances — battery, inverter, solar, charging
A real wiring diagram with every cable gauge and fuse
Cable & fuse sizing with the voltage drop checked for your runs
A shoppable parts list, each line traceable to ABYC or Victron specs
Building it for real? Unlock the build binder.
Free gets you a safe, correctly-sized design. The build binder gets you the documents to build it right — and prove it's right.
Printable wiring diagram, yours to keep & tape inside the van
Full parts list, every line sourced
The volt-drop & fusing calculation trail — the "why" behind every spec
The build binder is a one-time unlock — no subscription, no auto-renew.
Questions
Is 200W of solar enough for a campervan?
For weekends and the essentials — lights, fans, charging — 200W is a sensible entry point, paired with a battery that carries the night. Add a fridge or go full-time and you’ll want 400W or more; Wattonomy shows exactly where the line is for your loads.
What can I run on 200W?
LED lighting, a roof fan and phone/laptop charging sit comfortably on 200W plus a battery. A 12V fridge running around the clock is the point most people step up to 400W.
How big a battery does 200W need?
For an essentials build the tool sizes around 2.5 kWh (roughly 200Ah at 12V) of LiFePO4 — but enter your real appliances and it sizes the bank to you.
Do I need an account?
No. Design the whole system free, no email. Accounts are only for saving builds or the printable build binder.
The standards we build to
Plain version: these are the recognized rulebooks your design is sized against, so the numbers hold up to a surveyor, an inspector or an insurer.
ABYC E-11The US standard for AC & DC wiring on boats — what a surveyor or insurer actually checks.
Wattonomy applies these standards in its calculations. It is not certified, sponsored or endorsed by ABYC, ISO, NFPA or Victron — it sizes your design to meet what they require, and shows the working.
Sized and checked to ABYC E-11. Last reviewed June 2026 — see the full methodology for the exact rules behind every number and how each design is validated.
Built by anABYC Certified Master Technician