My battery bank died after two years
Batteries almost never die of old age off-grid. They die of a specific, identifiable abuse — and which abuse depends on the chemistry you bought.
What actually works
Every cycle below half kills them faster, and a bank regularly run to 20% is finished in a couple of years. Size for **50% usable**, not 80%, or buy a different chemistry.
A bank that never quite reaches full sulfates — the plates harden and capacity vanishes quietly. Absorption must actually complete, which in winter often means it doesn't.
**Permanent damage, every time, with no warning.** LiFePO4 with a low-temperature charge cutoff is mandatory equipment, not a feature.
The failure is gradual and invisible. Log resting voltage and state of charge daily and you'll see the decline a year before the bank quits.
Sold for exactly this, with claims far beyond the evidence. Spend the money on sizing the bank properly the first time.
Run the numbers
- Solar array & battery sizing → — free calculator, works offline.
- Battery runtime → — free calculator, works offline.
Also searched as
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