Lithium or tubular battery for load-shedding?
For a few cuts a week, a tubular battery is often enough. For daily load-shedding, the difference that matters most is how fast each kind refills between cuts.
How they differ
| Tubular lead-acid | Lithium (LiFePO4) | |
|---|---|---|
| Usable share of capacity | about 80% before the UPS cuts off | about 90% |
| Fastest safe charging | about 0.1 × its Ah in amps | about 0.5 × its Ah in amps |
| Energy kept when charging | about 80% | about 95% |
| Slows down when nearly full | from about 80% | only near 100% |
Typical values; see the sources and estimates.
What that means with daily cuts
The same typical home (1 kVA UPS, fans, lights, router, phones and a fridge, 6 h a day, 1 h every 4 h):
- 200 Ah tubular: 47 min per cut once settled, covering 4.5 h of 6 h.
- Lithium of the same size, same UPS: 3.8 h per cut, covering 6 h.
- 2.5 kWh lithium on a hybrid inverter with a faster charger: 3.9 h per cut, covering 6 h.
The difference comes mostly from charging: lithium loses less energy and can take more current, so it refills in the short gaps between cuts.
Before you switch
- Your UPS must support lithium. Many UPS chargers are made only for lead-acid batteries and charge lithium wrongly. Check with the maker, or use a hybrid inverter built for lithium.
- Compare cost per year, not price. Tubular batteries are cheaper to buy; lithium usually lasts many more cycles. Ask for the rated cycle life of both.
- If your cuts are short and far apart, a tubular battery may refill fully anyway. Check your own pattern first.
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