Why battery chemistry decides more than the truck spec
Most forklift comparisons start with capacity and mast height. Both matter, but on a machine that runs five or six days a week, the battery determines how many hours the truck is actually available. A counterbalance truck on lead-acid batteries spends roughly a third of its life attached to a charger (approximate industry figure), because a full charge takes about eight hours and a cooling period follows before the pack can go back into service. A lithium pack in the same truck charges over a break and returns to the aisle.
Chemistry also drives three cost lines that never appear in a quotation: the labor of watering and equalizing lead-acid cells, the floor space consumed by a dedicated ventilated charging room, and the energy lost to charge inefficiency over thousands of cycles. This is why fleet buyers increasingly fix the battery decision first and treat the truck as the component wrapped around it.
There is a safety and infrastructure dimension as well. Flooded lead-acid batteries gas during charging, which is why the charging room must be ventilated and why the area around chargers is often regulated. A sealed LiFePO4 pack charges where the truck parks — the EP25 even offers an integrated charger option — so the ventilation requirement and the battery-changing equipment disappear from the project scope entirely.
Two chemistries dominate warehouse duty today: lithium iron phosphate (LiFePO4), the chemistry used across the Granvolt EP series, and lead-acid in its flooded and sealed variants. The comparison below sticks to numbers a buyer can verify.
Head-to-head comparison
The table pairs each criterion with the specification of a representative lithium truck, the Granvolt EP30 (80 V LiFePO4, 206 Ah), against typical flooded lead-acid values. Figures marked approximate are industry-typical ranges, not Granvolt test data.
Where a number depends on how the truck is used — cycle life above all — read it as a range to be confirmed against your duty cycle, not a constant. Suppliers who quote a single cycle-life figure without stating depth of discharge and temperature assumptions are describing a test bench, not a warehouse.
| Criterion | Lithium (LiFePO4) — EP30 data | Lead-acid — typical values |
|---|---|---|
| Energy density | Higher usable capacity per kilogram of pack weight; no counterweight exchange needed | Lower per kilogram; pack also serves as counterweight, which works in its favor here (approximate) |
| Charge time 0–80% | 2 h (100% in 4 h) | About 8 h charging plus a cooling period before use (approximate) |
| Opportunity charging | Designed for it — top up during breaks and shift changes | Not recommended; interrupted cycles shorten battery life (approximate) |
| Cycle life | 2,000–4,000+ cycles depending on depth of discharge (approximate) | 1,000–1,500 cycles (approximate) |
| Maintenance | Sealed pack; no watering, no equalizing charge, no acid handling | Weekly watering, terminal cleaning, periodic equalizing charges |
| Cold performance | Capacity derates in cold; EP-series battery thermal management mitigates the loss; IPX4 sealed electrics | Capacity derates in cold; electrolyte and terminal behavior demand closer attention (approximate) |
| Upfront cost vs TCO | Higher purchase price; lowest total cost in multi-shift duty | Lower purchase price; higher lifetime cost in energy, labor and battery replacement (approximate) |
Read the charge-time row twice. It is the one that compounds: an eight-hour charge forces either a battery rotation scheme with spare packs and a changing room, or a truck that sits idle overnight. The EP30's 2 h charge to 80% turns charging into something that happens during a lunch break, which is what makes three-shift operation practical on one battery.
Energy efficiency deserves the same attention. A lead-acid battery loses a larger share of its input energy as heat during charging than a lithium pack does (approximate), so the electric bill per hour of work is higher. Across a fleet and a five-year horizon, this difference compounds into a figure worth asking every supplier to quantify.
Where lithium pays back fastest
Three operating profiles account for most of the lithium business we quote:
- Multi-shift and three-shift operations. The EP30 is specified for exactly this: AC traction 6 kW, opportunity charging and battery thermal management for continuous duty. When a truck runs 16 or 24 hours a day, the lead-acid alternative needs spare packs, a ventilated charging room and scheduled pack swaps — costs that usually exceed the lithium premium within the first battery replacement cycle (approximate payback, multi-shift duty).
- Cold storage and freezer warehouses. Cold cuts battery output on both chemistries, but thermal management and opportunity charging recover the lost availability. Our cold storage solution page works through the full specification: EP30 in the freezer aisles, ST15 walkie trucks at the dock, and why diesel is not an option inside food-storage rooms.
- Sites where charging floor space is expensive. A lead-acid fleet needs a dedicated, ventilated charging area with cranes or hoists for pack exchange. Lithium trucks charge where they park. In distribution centers where a square meter earns revenue, deleting the charging room is a measurable saving.
The pattern behind all three profiles is the same: lithium converts fixed infrastructure — charging rooms, spare packs, swap labor — into a single operating asset. Wherever your cost structure is dominated by truck availability rather than truck count, battery chemistry is the lever with the most travel.
Where lead-acid still makes sense
None of this makes lead-acid the wrong choice. The chemistry remains rational in three situations. Single-shift operations with an overnight pause get a full charge for free, so the eight-hour cycle time costs nothing. Budget-constrained purchases where capital, not operating cost, is the binding constraint favor the lower upfront price — provided the buyer plans for watering labor and earlier battery replacement. And sites that already operate a compliant charging room with spare packs can keep using that sunk investment rather than writing it off. Low-hour duty is another honest case: a truck that runs a few hours a week at a seasonal warehouse barely registers battery chemistry at all, so the cheaper pack wins by default.
The honest summary: lead-acid is a capital-cost decision, lithium is an operating-cost decision. Match the chemistry to which of those budgets you are optimizing.
A practical checklist before you decide
Work through these in order — the first three usually settle the chemistry question before price is even discussed:
- Write down your real shift pattern, including peak season. Two shifts or more is the point where lithium's charge-time advantage starts converting into fewer trucks needed.
- Measure your heaviest pallet and its load center. Chemistry does not change the capacity you need — the EP30 is rated 3,000 kg @ 500 mm — but it decides whether one truck can cover the whole pattern.
- Cost your current battery routine: watering labor, spare packs, charging-room floor area, energy per charge. Most buyers find this line item is larger than they assumed.
- Check cold-room exposure. If trucks enter -25°C spaces, ask for thermal management and sealed electrics (IPX4 on the EP series) in the specification.
- Ask each supplier for cycle-life data at your duty cycle, and for the certification status of the battery system — Granvolt's EP-series packs are TÜV Rheinland certified (battery system).
- Compare quotes on a five-year total cost basis, not purchase price. Request the energy, maintenance and battery-replacement assumptions behind any TCO figure so the comparison is auditable.
- For mixed duty, consider splitting the fleet: lithium for the continuous core, lead-acid or short-term rental units to absorb seasonal peaks. This keeps capital discipline without blocking the shift-intensive trucks from lithium economics.
Frequently asked questions
Can I convert an existing lead-acid forklift to lithium?
Not as a field retrofit in most cases. The battery, charger and control electronics have to be validated as a system, and the counterweight geometry differs. Fleets normally specify lithium at purchase and run lead-acid trucks to end of life in parallel. Where a supplier does offer a conversion, ask for the validation document covering charger, BMS communication and counterweight — without it, capacity ratings and warranty terms no longer apply as certified.
Do lithium forklift batteries work in freezer warehouses?
Yes, with two provisions: expect some capacity derate in cold (true of lead-acid as well), and require battery thermal management plus sealed electrics in the specification. The EP series pairs LiFePO4 packs with both, detailed on the cold storage solution page.
Is lithium cheaper than lead-acid overall?
Depends on duty. In multi-shift operations lithium's lower operating cost usually recovers the higher purchase price within the first battery cycle (approximate). In single-shift, capital-constrained purchases, lead-acid often remains the rational choice. Whichever way you lean, ask for the TCO model behind the claim: energy price, labor rate and cycle-life assumptions change the answer, and a supplier should be able to show the worksheet.