Lifespan by the numbers
- Flooded lead-acid: ~1,500 cycles. On one shift a day, five days a week, that works out to roughly 5 years. On three shifts, closer to 2.
- Sealed lead-acid (AGM/gel): similar cycle life to flooded, with no watering — but less tolerance for abuse.
- Lithium-ion: typically 2–3x the cycle life of lead-acid, with minimal maintenance. Higher upfront cost.
Those are healthy-battery numbers. In the real world, most batteries die young — and almost always for preventable reasons.
The five things that kill batteries early
- Dry cells. Flooded batteries with exposed plates sulfate fast. Watering is the single highest-leverage maintenance task there is.
- Sitting discharged. Every hour a lead-acid battery sits empty, sulfation hardens. Plug in at end of shift, every shift.
- Opportunity charging on the wrong charger. Topping up a conventional lead-acid battery during breaks — without an opportunity-rated charger — cooks it over time.
- Skipped equalizing charges. Cells drift apart; weak cells drag the pack down and die first.
- Heat. Hot charging areas and overcharging accelerate every aging process in the book.
Habits that add years
- Water after charging, with distilled water, on a schedule someone owns.
- Equalize on the manufacturer's interval.
- Match the charger to the battery — voltage, capacity, and chemistry.
- Keep tops clean; acid film causes stray discharge and terminal corrosion.
- Log per-cell readings periodically so weak cells get caught early.
- Do not run a battery flat “just to finish the pallet.”
When to stop maintaining and start replacing
If capacity has faded evenly across all cells and the battery is near its expected cycle life, maintenance has done its job — it is time for a new one. If the battery is young and the problem is isolated, repair is usually the better spend. A dealer with a load tester can tell you which situation you are in within an hour.
The maintenance shortcut
If watering and equalizing keep falling through the cracks at your facility, that is exactly what scheduled maintenance plans are for — a dealer handles it on a weekly or monthly visit, and your batteries live out their full rated life instead of half of it.