Scissor Lift Battery Replacement: A Dealer & Fleet Guide to LiFePO4 Conversion

When a scissor lift’s flooded battery set reaches end of life, the default move is like-for-like replacement. Increasingly, dealers and rental fleets ask a better question first: is this machine a good lithium conversion candidate? This guide gives you the checks that decide it — the same checks we run before quoting a conversion kit — including the one most sellers avoid: battery weight.

Step 1: Confirm the machine’s battery system

Most electric slab scissor lifts run 24V from four 6V GC2 deep-cycle batteries of roughly 220–225Ah (Genie GS, JLG ES, Skyjack, Haulotte Compact, Snorkel and Dingli JCPT models all follow this pattern, with Dingli lead-acid fitments up to 240Ah). Record:

Brand, model and year
System voltage and current battery specification (from the battery label or manual)
Battery tray dimensions and how the set is secured
Charger make and model (photograph the charger label)

Electric rough-terrain scissors and DC boom lifts are usually 48V systems with much larger battery sets. Treat those as engineered per-model projects, not standard conversions.

Step 2: Answer the weight question before anything else

On many scissor lifts, the batteries are part of the counterweight system. OEM documentation reflects this: Genie’s operator manuals specify minimum battery weights and prohibit batteries lighter than the original specification, and Haulotte restricts replacement batteries by weight as well. A flooded GC2 set weighs about 112 kg (248 lb) in total; a lithium pack of useful capacity can weigh 50–65 kg less.

Before quoting or buying any conversion, obtain the model’s minimum battery/tray weight from the operator or service manual. If the lithium configuration falls below it, the kit must include engineered weight compensation, or the machine is not a conversion candidate. Any supplier who cannot discuss this point in writing is not selling you a conversion — they are selling you a battery and a liability.

Step 3: Decide the charger path

LiFePO4 cannot be charged correctly on a flooded lead-acid profile. A 25.6V pack needs a lithium profile of about 29.2V CC/CV, with no equalisation charge and no lead-acid float stage. Three paths exist:

Reprogram the existing charger — possible on programmable units such as Delta-Q IC-series chargers fitted to many Genie and Skyjack machines, using a lithium algorithm
Replace with a lithium charger — the cleanest path for older fixed-profile chargers
Keep the lead-acid charger — not an acceptable path; it undercharges or overcharges the pack and voids any sensible warranty discussion

Also budget for a real state-of-charge meter: lead-acid voltage gauges misread LiFePO4’s flat discharge curve, so operators will think the machine is full until it is nearly empty.

Step 4: Size the pack to duty, not to the old label

Lead-acid’s 225Ah label delivers roughly half of that as usable energy. A 25.6V LiFePO4 pack in the 100–150Ah class already matches the usable runtime of the flooded set for many duty cycles; packs in the 200–280Ah class extend runtime well beyond it for high-utilisation fleets. Size from the machine’s actual shift pattern and charging windows — opportunity charging during breaks changes the calculation in lithium’s favour. Cold-climate fleets should specify heated packs: Genie’s factory lithium option includes built-in heaters for a reason.

Reference models for sizing: the standard 25.6V (24V class) batteries 24V 100Ah (2.56kWh), 24V 150Ah (3.84kWh) and 24V 200Ah (5.12kWh) show the energy classes behind the ranges above. They are references for voltage and energy, not a conversion kit for a specific lift: tray fit, weight compensation and charger path are confirmed per machine.

Step 5: Pilot before you roll out

The low-risk fleet method:

Pick one model family with high utilisation and documented battery pain
Convert a small batch with the full kit — pack, charger path, SOC meter, weight solution
Measure for one quarter: downtime events, watering/maintenance hours eliminated, runtime complaints, charger behaviour
Roll out by model family using the documented kit, and keep the per-model paperwork with the machine file

Red flags when comparing conversion offers

“Universal drop-in” claims for aerial work platforms — no such thing once weight is considered
No answer, or a dismissive answer, on the counterweight question
Quotes that reuse the lead-acid charger without a profile change
Compatibility promised for your model without asking for the charger model or the manual’s weight specification
Capacity quoted without stating whether it is C5 or C20 — ratings bases differ between brands and inflate comparisons

What to send a supplier for a real quote

Machine brand, model, year and quantity (per model, and total fleet plan)
Current battery specification and tray photos with dimensions
Charger make/model photo
The manual’s minimum battery weight statement, if available
Operating climate and shift pattern

With those five items, a competent supplier can confirm feasibility, the charger path and the ballast requirement for that model — before any price discussion. That is the sequence LJY Energy follows: our AWP battery series page explains the kit approach, or go straight to a model check request.