More markets cap noise or ban generators outright — and many pitches have no power at all. Wattonomy sizes a quiet battery system for your lights, cooler, card reader and fans, sized to last the trading day, with the wiring and parts to build it safely.
A real Wattonomy output — a market-stall power pack
System
12 V
Battery
2.56 kWh
Solar
600 W
Inverter
MP 12/2000 120V
SmartSolar 100/501×
200W solar panel3×
Battery → inverter cable4×
Battery → inverter fuse1×
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
No power at the pitch — and no generators allowed.
It’s the squeeze every vendor knows: the good markets provide no shore power yet ban or noise-cap generators, leaving only batteries — and a cheap pack that dies by mid-afternoon costs you sales. Wattonomy sizes a bank to carry your real loads through the whole day, with every cable and fuse sized to carry its load.
What stall power has to get right.
Quiet, allowed-everywhere power that lasts the whole day.
Trading-day energy
Lights, a cooler or small fridge, the card reader, a fan and charging — summed as real Wh for a full day.
Battery to last
LiFePO4 sized to the day on an honest depth-of-discharge — no dead pack at 3pm, no hauling spares.
Surge headroom
Sized so a cooler compressor or a kettle start-up never trips the inverter mid-trade.
Cables & fuses
Every gauge and fuse sized to its load and your run lengths, to ABYC E-11.
What you walk away with — free
A validated system sized to your equipment — not a one-size kit
A clean wiring diagram with every cable gauge and fuse spelled out
Cable & fuse sizing with the voltage-drop checked for your run lengths
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 stall
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
What size battery to power a market stall all day?
Enter your real loads — lights, cooler, card reader, fan — and the tool sizes the bank to carry the whole trading day with honest reserve, rather than the optimistic nameplate rating of a portable power station.
Why a built battery system over a portable power station?
A sized system gives you the right capacity, real fusing and cabling you can trust, and room to add a fridge or kettle — instead of discovering the limit when the alarm beeps mid-market.
Can it handle a small fridge or kettle?
It sizes for their start-up surge and tells you honestly when a high-draw kettle needs a bigger inverter or bank — so you find out at design time, not at the stall.
Do I need an account?
No. Design the whole system free, no email required. Accounts are only for saving builds or the printable build binder.
Is this just trying to sell me a kit?
No. The parts list is vendor-neutral and standards-referenced — buy the components anywhere. We make the design, not the markup.
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