"Which battery is better" is the wrong question. A battery serves a working pattern, and the pattern decides the answer. So do not start by comparing technologies — start with a count: how many operating hours the machine puts in per day, and how many consecutive hours it stands free.
How many hours the machine really works
The usual mistake is to count a shift as eight working hours. A forklift is actually moving for three or four of them at best; the rest goes on waiting, paperwork and gaps between lorries. So read the hour meter, not the staff rota.
If a machine clocks up to four operating hours a day and has eight free hours overnight, a classic lead-acid battery charges fully and lasts the 1,200 to 1,500 cycles it is rated for.
Where Li-Ion wins outright
A lithium-ion battery has no memory and takes charge in pieces quite happily. The operator plugs in over their lunch break, picks up 20 to 30 per cent, and finishes the shift. For a two-shift warehouse that means one machine does the work of two — along with the second set of batteries, the charging room and the swapping procedure.
| Measure | Lead-acid | Li-Ion |
|---|---|---|
| Service life, cycles | 1200–1500 | 2500–3500 |
| Full charge time | 8–10 h | 1.5–2 h |
| Opportunity charging | Harmful | No effect |
| Maintenance | Weekly water top-up | None needed |
| Separate room | Yes, with extraction | No |
| Capacity lost in the cold | Up to 40% | 10–15% |
| Battery price | ×1 | ×2–2,5 |
The line everyone leaves out of the sum
A charging room for lead is not an abstraction. It is floor area, forced ventilation, an acid-resistant floor and a safety procedure of its own. In a rented warehouse those square metres cost money every month. Li-Ion charges where the machine stands, and the line disappears from the estimate.
The second forgotten line is labour. Topping up distilled water, checking electrolyte density, swapping batteries between shifts: together that is several person-hours a week for every five machines.
Li-Ion pays for itself not on the electricity bill, but by ending the payments for a second set of batteries and the room they live in.
Cold storage is its own case
In freezer chambers a lead-acid battery loses up to 40 per cent of its capacity, and a machine that used to last a shift stops halfway through. Li-Ion drops noticeably less, and versions with heated cells work down to −30 °C without losing output. If you have a cold zone, the question is effectively settled.
When lead is still the right answer
One shift, steady volume, the machine on charge every night, a charging room that already exists and has paid for itself. In that picture the doubled price of lithium will not come back within any sensible period — the lead battery will serve its five years and be replaced by another like it.
One more argument: weight. On small forklifts the lead battery doubles as the counterweight, and a lighter lithium pack means making that mass up separately.
