A free AI-assisted tool for working out roughly what solar array and battery bank your situation needs. Educational estimates only — not engineering, not a quote, and nothing here is for sale. Built and given away by Lucas Ballek.
Enter your daily energy use and location. The calculator simulates your site hour-by-hour against five years of NASA satellite weather and finds the smallest system that keeps the lights on — at three levels of generator independence. Educational estimates only.
Wattages are typical values — yours may differ. Cycling appliances (fridges, freezers, air conditioners, pumps) only draw power while running: their slider is hours actually running per day, capped to realistic compressor time, and each row shows the resulting 24-hour average. A modern fridge at the default (100 W running, ~10 h/day) really does use about 1 kWh/day.
Results appear here: three side-by-side systems — one that never needs a generator, one that needs it about one day a year, and one for people happy to run it now and then.
Run a sizing first — every constant used (derates, temperature model, efficiencies, weather data years and source) is listed here.
A ballpark comparison between self-sourced components and a packaged retail battery, using published list prices. Indicative only — real costs vary enormously by country, freight, duty, and what you can actually buy locally.
| Option | Capacity | Component cost |
|---|---|---|
| Packaged retail battery (list price, Aug 2026) | 100 kWh | $85,185 |
| Self-sourced cells + BMS (ex-factory basis, Aug 2026) | 100 kWh | $5,000 |
Component cost only. It excludes international freight, customs duty, taxes, tools, enclosure, wiring, permits, and any labor — which together are often a large share of the real total. For orientation: landed DIY costs (cells + BMS + fusing + rack + freight + duty) typically land around $95–125/kWh, and cells alone DDP around $60–70/kWh — destination drives most of the spread. The retail figure is a published list price used as a reference point, not a quote, and a packaged product includes certification, warranty, and installer support that self-sourced parts do not. Do not treat this as a savings promise.
A reference parts list so you know what the pieces are and roughly what they cost. Nothing here is sold by this site — prices are indicative figures seen on the open market and change constantly.
Brand new Grade-A prismatic LFP cells. 16S configuration per pack (51.2V nominal).
Smart active balancing (2A balance current), dual temperature probes, RS485/CANbus comms with Sol-Ark & Victron.
20kA AIC interrupt rating @ 160V DC. Clears very high short-circuit DC currents in milliseconds — sized to protect the BMS and wiring.
Belleville spring washer endplates hold uniform compression (about 3,000 N). Manufacturers cite cycle-life benefits; treat specific gains as unverified.
This is free and always will be. If it helped you and you want to chip in toward the AI and hosting costs, here's where.
Contributions go directly to Lucas Ballek personally.
Please read before sending anything. Contributions are voluntary gifts to an individual, not payment for a service. They are not tax-deductible — this is not a charity or a registered nonprofit. They buy nothing: no priority, no features, no personal advice, no support obligation, and no continued availability of this site. Everyone gets exactly the same free tool whether they contribute or not. Please don't send money you need. If you were hoping to pay for professional engineering help, spend it on a licensed local engineer or electrician instead — that is genuinely the better use of it.
Short version: this is a free educational toy that produces rough estimates, run by one person, with no warranty of any kind.
Output is an automated educational estimate. It is not engineering, not a stamped design, not a quote, and not a safety certification. It may be wrong. Have any real system reviewed by a licensed electrician or engineer before you build or energize it.
The advisor is a large language model. It generates plausible-sounding text and can state wrong numbers with total confidence. Treat every figure as a starting point to check, never as fact.
No signup, no cookies for advertising, no analytics profile. Your chat text is sent to the AI provider to generate a reply and is not stored here. Don't type anything sensitive into it.
You're welcome to email me: lucasballek@gmail.com
This is one person answering email in his own time, as a favor — not a support desk. I read what I can and reply when I'm able, but I can't promise a response or a timeframe. Anything I send back is a friendly opinion for your own further research, not professional engineering, electrical, or financial advice, and it doesn't create any professional relationship or obligation. For anything you're going to actually build, energize, or spend real money on, please talk to a licensed electrician or engineer in your area.