Ohmio

Off-grid solar sizing and a daily production log — no ads over your numbers.

Ohmio sizes your off-grid or backup solar system with no ad covering your numbers while you work.

A worked example
Say your cabin uses 3 kWh a day (a 125 W fridge running 24 hours). Ohmio turns that into a battery bank of 1,000 Ah at 12 V with flooded lead-acid — or 625 Ah with LiFePO4 — and a 900 W panel array at 4.5 peak sun hours. Every result comes with its formula and its source, never a black box.

After you read your inverter
1. Open Ohmio and log the kWh your inverter or charge controller shows today.
2. The Balance updates: generated against consumed, and your logging streak goes up.
Under 10 seconds, with the readout still in front of you.

Included at no cost
- Full sizing of one project: consumption, batteries, panels, charge controller, inverter, wire gauge and fuse — no ads on any step.
- Unlimited daily production log, with each day's balance.
- Every result with its formula and its source, so you can check the math.
- Wire gauge in AWG or mm², automatic by your country.
- CSV export, backup and restore.
- No account, no connection needed.

What Ohmio doesn't do
It calculates capacity, consumption and sizing — it never gives step-by-step wiring instructions ("connect X to Y"), and it's never a substitute for a licensed electrician or certified installer.

Premium, if you want more
Premium adds four things: unlimited projects (free gives you one), a PDF report of your sizing, comparing your production between periods, and no ads. The yearly and monthly plans start with a 7-day free trial, and there's also a one-time payment that never renews — size it once, and premium is yours for good.

Questions people ask
Do I need an account? No. Everything you log stays on your phone, not on a server of ours.
AWG or mm²? Automatic by your country, and you can change it in Settings.
What about a second project, like a boat and a cabin? The first is free; Premium removes the limit.
Where's the privacy policy? At https://ohmio.alekla.com/privacy/

The free version has ads: a banner on the Journal and Projects screens, and occasionally a full-screen ad after a second project or a third wire run or fuse. No ads on Home or anywhere inside Sizing.