First, find your class
Forklift batteries are organised by voltage, and the truck decides: 24V for small pallet trucks and stackers, 36V and 48V for the mainstream counterbalance fleet, 72V and 80V for the heavy trucks, and builds up to 96V at the top. Capacity follows the truck's size and its shift pattern — roughly 100Ah to 600Ah across the classes we build.
Our reference point is the 48V class, including custom NFPP builds such as the 48V 160Ah configuration One warning, and it is not boilerplate: take the voltage from the truck's data plate or from the old battery. Never guess it from a catalogue. A 36V truck on a 48V pack is an expensive afternoon.
The battery is also a counterweight
Now the detail that catches people out. On a counterbalance forklift the battery is not just a power source — its mass is part of the truck's rated stability. A sodium-ion or lithium pack does not match the lead-acid block's weight, and on a counterbalance truck that weight is part of the machine's rated stability — so a proper conversion adds ballast inside the pack case to bring the total back to spec. If a supplier never asks what the original battery weighs, they are not doing the job properly.
Fitment is the same story. Tray dimensions. Cable exit position. Connector type. Send those with the truck model when you inquire — a made-to-order pack starts from the truck it has to fit.
Charging is where the money is
Lead-acid has a routine and it does not bend: a long full charge, a rest afterwards, no interruptions. Run two or three shifts and the arithmetic forces two or three batteries per truck, a changing routine, and a ventilated room for the hydrogen that charging gives off. Sodium-ion accepts fast charging — a top-up during a break, another at shift change — so the charge pattern can follow the shift pattern instead of the other way round. Whether one pack per truck covers your shifts comes out of the duty data: shifts, breaks and charger situation, worked against the pack's figures.
Do budget for the charger conversation, though. The charging profile differs from lead-acid, so the existing charger may need replacing or reprogramming. That is a real cost. Put it in the project quote, in ink — not in a footnote somebody finds afterwards.
Cold stores and hard yards
Cold is where sodium-ion earns its second look. Lead-acid loses capacity fast in a freezer warehouse and charges reluctantly when it is cold. One of the shop's forklift listings states fast charging and a −40°C to 60°C working range, which is the combination that matters in cold-storage and winter yard work. And NFPP chemistry is the option we steer safety-first buyers toward: a poly-anion structure with a strong thermal-stability record, bought at the price of some energy density the truck never misses.
Cycle life tells the same story stretched over years. A traction pack that gets charged at every break and cycled daily wants a chemistry rated in thousands of cycles, not hundreds. That — more than any single line on a spec sheet — is what moves a fleet's cost per operating hour.
A practical project checklist
Collect, per truck: make and model, data-plate voltage, existing battery dimensions and weight, capacity, connector type, charger make and settings, shifts per day, and the working environment — cold store, outdoor yard, food-grade site. With that list, the reply can cover the build, the ballast and the charger pairing, with a firm quote. Without it, anyone's price is a guess.
And start with one truck. One. Run it for a month against its lead-acid siblings and compare the things that actually show up in a working week: charging time, downtime, driver complaints. Start in stages for a reason: the pilot truck makes the argument with your own numbers better than any catalogue can.
Total cost, framed honestly
A sodium-ion pack costs more to buy than the lead-acid block it replaces. Anyone who hides that is selling, not advising. The comparison that matters is cost per operating hour across the pack's life. On the lead-acid side of the ledger: the spare batteries, the watering and equalising labour, the ventilated charging room, the distilled water, the corrosion damage to floors and trucks, and a replacement every few years. On the sodium side: the pack, one charger change, and very little else.
We will not pin a payback month on your fleet from a catalogue page. It depends on your shifts, your labour cost, your electricity tariff — your numbers, not ours. What we can do is run them with you, from your actual data — truck count, shifts, current battery spend — before you commit to more than the pilot. And if the arithmetic does not work for your operation, better to learn that at this stage than after a fleet order.
What the changeover actually involves
The physical swap is the easy part: sodium-ion packs come in standard and custom formats, sized to the compartments lead-acid vacates. The work around it matters more. Charging profiles differ, so chargers are specified with the packs, not reused on assumption. Operators need a short briefing — the new packs ask for no watering, no equalising and no acid checks, and old habits die hard. The battery room itself is part of the conversation: its ventilation and washing facilities were specified for lead-acid, and the conversion plan should say what happens to them.
Plan the changeover by truck group rather than all at once: convert one shift pattern, watch a month of real duty cycles against the old fleet's records, then roll the rest. The sites that do it this way end up with their own numbers — which, as this article has argued throughout, are the only numbers that should settle the question.
Keep the old batteries' maintenance records when you do it. A year later, when someone asks why the fleet changed chemistry, the watering logs, the equalising hours and the early replacements will make the argument better than any brochure — ours included.
Counting the cost of the changeover
The honest ledger has more lines than the battery price. On the cost side: the packs themselves, the charger change or reprogramming, the data collection before the first quote, and a pilot period where one truck gets two systems' worth of attention. None of it is hidden in this guide. Budget for the changeover lines in the first quote: discovering them mid-project is how conversions stall.
On the saving side, the lines are labour and overhead rather than parts: the watering and equalising hours, the spare-pack rotation, the battery room's ventilation and floor space, the corrosion repairs to floors and trucks. They are real money in a multi-shift operation and nearly nothing in a single-shift one — which is why this guide insists on running your fleet's own numbers before anyone talks about payback.
Wholesale inquiries
Tell us the model, your quantity and your market — we reply with a quotation and lead time.