Lead-Acid to Lithium Fleet Replacement Guide

Why Fleets Convert

Operators who run vehicles, machines or site systems on lead-acid batteries know the pattern: weight that eats payload, water checks that nobody enjoys, capacity that fades visibly after a season of deep work, and a charging ritual that punishes every shortcut. LiFePO4 removes most of that pattern. The conversion is rarely a like-for-like swap, though, and the projects that go well are run as programs with an audit, a sizing method, a charger decision and a pilot. This guide walks through the steps a fleet operator or a dealer running a lead acid battery replacement program should expect.

Step One: Audit the Fleet

The audit is paperwork before it is purchases. For each battery position in the fleet, record the rated voltage and capacity, the actual duty cycle in depth and hours, the charger or charge source it meets, the physical envelope including terminals and hold-downs, and any monitoring the site already uses. Two positions with the same label can carry different duties, and the audit is what turns a fleet of exceptions into two or three standard conversions. It also produces the disposal list, because every lead-acid battery removed has a regulated destination.

Size by Usable Energy, Not Nameplate

Lead-acid delivers roughly half of its rated capacity in daily deep-cycle work before its life collapses, while LiFePO4 routinely delivers a much larger share within its cycle-life rating. The practical consequence is that a 12.8V 100 Ah LiFePO4 pack, about 1.28 kWh nominal, replaces a 12 V lead-acid battery of the same or larger nameplate in most duty cycles, with weight falling to a fraction and usable energy holding or rising. The sizing check is always the same: take the audited daily energy of the position, divide by the usable share of the candidate pack, and keep margin for the worst week of the year rather than the average one.

Settle the Charger Question Early

The charger is where conversions stumble. Lead-acid profiles charge in bulk, absorption and float stages, and some include equalize programs that a lithium pack must never see. The options, in order of preference:

• Set the existing charger to a lithium profile, where the controller supports one, using the pack datasheet's charge voltage and current
• Fit a DC-DC charger between the charge source and the pack where the source cannot be reconfigured
• Keep a lead-acid profile only where the supplier confirms in writing that its float and absorption behavior is acceptable for the model, and remove any equalize stage

Instrumentation and Communication

Lead-acid fleets read state of charge from voltage and habit; LiFePO4's flat curve makes voltage a poor gauge. The conversion should include a shunt-based monitor or a read of the BMS data over its serial link, so operators and drivers see a number they can act on. Where the fleet's telematics already exist, the protocol between BMS and controller is confirmed in writing for the controller brand in use, because integration is firmware work that is cheap at design time and slow on a deadline.

A Phased Pilot Beats a Big Bang

1. Convert a handful of positions across the hardest duties and the worst climate the fleet meets
2. Run a full season and record usable energy, charge behavior and any alarm events
3. Freeze the standard: pack model, charger settings, fusing, cabling and mounting hardware
4. Roll out in waves, with installers trained on the frozen standard and each position documented

Dispose of the Old Banks Properly

Lead-acid batteries are a regulated waste stream with an established recycling industry. The conversion program should name the licensed collector, keep the chain-of-custody paperwork with the project file, and schedule collection to match each wave of the roll-out so no removed batteries accumulate on site. A clean disposal trail is part of the program's value to the operator, and it is increasingly part of what their own customers ask about.

Where YueQi Fits

YueQi New Energy, based in Zhongshan, Guangdong, builds 12.8V LiFePO4 packs in 100, 150 and 200 amp-hour ratings and 25.6V packs in 100, 200 and 300 amp-hour ratings, the classes most fleet positions convert to, alongside 51.2V storage for site systems. Terminal type, footprint and hold-down matching for a given position, charger profile confirmation and commercial terms are to be confirmed in writing against the audited fleet list, so each wave of the program installs without surprises.