Shift count does not decide between TPPL and lithium. Measured workload does, along with what each system recovers during your real breaks.
The short answer
The choice is not settled by chemistry preference, and not by how many shifts you run. It is settled by what your trucks consume across a duty cycle, meaning how hard and how long each truck works including the breaks when it could be charging, what your real charging windows allow, and what the package costs once maintenance, replacement and electrical work are counted.
Shift count is a rough proxy for the first of those, not a substitute. EnerSys has documented a TPPL evaluation for a 150-store supermarket chain running narrow-aisle reach trucks on three eight-hour shifts, built on average daily amp-hour throughput and annual truck hours rather than on the schedule. Measure first, then compare.
What TPPL is, and what it asks for in return
TPPL stands for thin plate pure lead. It is lead-acid, but thinner plates of higher purity lead let the battery accept charge at a higher rate and handle partial charging far better than a flooded battery.
The headline benefit is documented: no watering, no battery washing, no long equalize routine. For a fleet carrying a watering program, that is genuine labor off the maintenance schedule. The conditions attached are equally real.
It requires an approved charger and an approved configuration. EnerSys states that NexSys TPPL batteries must be charged with an EnerSys-approved charger running the approved TPPL profile. That does not automatically mean new chargers: NexSys+ chargers carry profiles for TPPL, iON and flooded technologies, so some installed units may qualify once their specification and configuration are checked. What you cannot do is assume it either way.
Opportunity charging works inside a schedule, not instead of one. The profile permits opportunity charging as often as needed, but the owner’s manual still instructs you to allow up to six hours for a full charge at least once per week, with equalization on the same schedule. TPPL retires the watering program and the long equalize routine a flooded battery needs. It does not remove the product’s own prescribed schedule. If your operation has no six hour window anywhere in the week, design around that before you buy.
Depth of discharge drives service life. EnerSys recommends limiting daily discharge to 60 percent of nominal capacity for optimal life and classes anything beyond that as a deep discharge. Deeper discharge reduces expected cycle life. The manual also lists load cutoff settings that apply under specified conditions, so check the limits for your configuration and have the supplier size the product against your operating pattern rather than quote a service life.
Note too that daily amp-hour throughput and depth of discharge are different measurements. If the battery is topped up through the day, consumption can be high while the charge level never falls far.
Charge return factor, and what it does not tell you
Charge return factor is how many amp-hours you put back for every amp-hour you took out. Advanced Charging Technologies’ worked comparison uses charge return factors ranging from 110 percent to 120 percent for the flooded-battery charging systems it evaluates.
It is a useful input, not the whole calculation. Charging time also depends on the current through the session, including the tapering and absorption stages at the end. Electricity cost needs voltage and charger losses, since amp-hours are not kilowatt-hours. Comparing two trucks needs voltage alongside amp-hours.
So treat it as one number among several and make the supplier do the work. Ask them to show how much charge the proposed battery and charger restore during the breaks you really have, and to estimate the electricity consumed at the wall separately. Our 2026 forklift battery cost breakdown covers the wider energy picture.
What would justify either quote
Whichever chemistry a supplier proposes, the same four tests decide whether it is right for you.
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Runtime. Does it cover the longest operating period between planned charging opportunities, at the discharge depth the manufacturer recommends?
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Recovery. Does it put back enough charge during the breaks you genuinely have, including the periodic full charge its manual requires?
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Fit and compliance. Does the assembly meet the truck manufacturer’s weight and dimension requirements, with written approval where the change affects capacity or safe operation?
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Total cost. Purchase, chargers, electrical work, maintenance labor and expected replacement, across the period you plan to keep the trucks.
A proposal that fails any of the four becomes a problem later, usually at the worst moment.
Weight and fit: check the assembly, not the chemistry
On a counterbalanced truck the battery is structural ballast, and the truck’s rated capacity depends on it. A lithium pack of equivalent capacity typically weighs much less than the lead battery it replaces. So the check is not that lead keeps the weight. It is the weight and dimensions of the specific replacement assembly against the truck manufacturer’s requirements, whatever the chemistry: compartment dimensions, connector position and the minimum battery weight on the data plate.
This is a compliance question as well as a fit question. OSHA 1910.178(a)(4) states that modifications and additions affecting capacity and safe operation shall not be performed without the manufacturer’s prior written approval, and that capacity, operation and maintenance plates, tags or decals shall be changed accordingly. Adding ballast to make a lighter pack work is not an informal fix.
Temperature: specify it, for either chemistry
Limits are set per product, so check the ones for the battery you are quoted. For the EnerSys NexSys lines, TPPL permits discharge from minus 20 degrees Fahrenheit and iON from 14, but neither permits charging below 32. TPPL capacity falls considerably once internal temperature drops below about 41 degrees, a discharged TPPL battery can freeze, and EnerSys Engineering must approve iON cold storage operation in writing.
So where the battery is charged often matters more than where the truck runs. If any part of your fleet works in the cold, specify that application separately rather than folding it into a fleet wide decision.
Send us your duty cycle, not just your part number
Beal has supplied industrial batteries and chargers across Maryland, Northern Virginia, Delaware and South Central Pennsylvania since 1980. We stock flooded lead-acid, gel, TPPL and lithium, and we are independent of any forklift OEM.
Send us five things and the comparison stops being a chemistry debate and becomes arithmetic:
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Daily amp-hours consumed per truck, or the truck hours and load profile we can work it out from.
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Battery voltage.
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Your real charging windows, including whether operators actually plug in during them.
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Truck make, model and the minimum battery weight from the data plate.
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The ambient temperature range where the trucks run and where they charge.
We will show you the working, including when the cheaper option is the right one. If you would rather establish the first number yourself, our 30 day fleet battery readiness audit walks through measuring it.
Contact us for a quote · Industrial batteries · Battery rental and leasing
Sources
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EnerSys, NexSys TPPL owner’s manual (GLOB-EN-OM-NEX-TPPL 0925): approved charger and profile requirement, weekly full charge of up to six hours plus weekly equalization, 60 percent depth of discharge recommended for optimal life, load cutoff settings, discharge and charging temperature ranges, freezing risk when discharged. enersys.com
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EnerSys, NexSys TPPL technical manual: charge time curves plotted against depth of discharge and recharge current, charge rate range, absorption phase, cycle life against depth of discharge for TPPL blocs. enersys.com
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EnerSys, NexSys iON owner’s manual: discharge and charging temperature ranges, written EnerSys Engineering approval required for cold storage. enersys.com
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EnerSys, NexSys+ charger: profiles for NexSys TPPL, NexSys iON and flooded battery technologies. enersys.com
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EnerSys, retail supermarket Class II case study: 150 store chain, narrow-aisle reach trucks, three eight-hour shifts, evaluated on average daily amp-hour throughput and annual truck hours. enersys.com
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OSHA, 29 CFR 1910.178(a)(4): modifications and additions affecting capacity and safe operation require the manufacturer’s prior written approval, and capacity, operation and maintenance plates, tags or decals shall be changed accordingly. osha.gov
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Advanced Charging Technologies, Battery Charging Technology Overview (2023): a worked comparison for a 36V 1000Ah battery at 2.0 EBU per day, giving charge return factors of 120 percent for ferroresonant and SCR chargers, 115 percent for a typical high frequency charger and 110 percent for the manufacturer’s own unit. Figures from that one scenario, not category specifications. act-chargers.com
Frequently Asked Questions
Can I use my existing chargers with TPPL?
Possibly, after compatibility is confirmed. EnerSys requires NexSys TPPL batteries to be charged with an approved charger running the approved TPPL profile, and says its NexSys+ chargers carry profiles for TPPL, iON and flooded technologies. Whether a unit you already own qualifies depends on its specification and configuration, so get that confirmed in writing before you budget.
Is TPPL or lithium better for freezer work?
Neither is a freezer specification on its own, and limits vary by product. For the EnerSys NexSys lines, both TPPL and iON have a charging floor of 32 degrees Fahrenheit, and EnerSys Engineering must approve iON cold storage operation in writing. Specify cold applications separately and get the manufacturer's approval for the exact battery quoted.
Does shift count decide between TPPL and lithium?
No. Shift count is only a rough proxy for workload. The decision is driven by daily amp-hour throughput per truck, your real charging windows, the depth of discharge the manufacturer recommends, and total cost once chargers, electrical work, maintenance labor and replacement are counted. Measure the duty cycle first, then compare the quotes against it.
What depth of discharge should I plan for with TPPL?
EnerSys recommends limiting daily discharge to 60 percent of nominal capacity for optimal life, and classes anything beyond that as a deep discharge that reduces expected cycle life. Note that daily amp-hour throughput and depth of discharge are different measurements: if the battery is topped up through the day, consumption can be high while the charge level never falls far. Have the supplier size the product against your operating pattern.
Does TPPL really need no maintenance?
TPPL retires the watering program, battery washing and the long equalize routine a flooded battery needs, which is genuine labor off your maintenance schedule. It does not remove the product's own prescribed schedule. The owner's manual still instructs you to allow up to six hours for a full charge at least once per week, with equalization on the same schedule. If your operation has no six-hour window anywhere in the week, design around that before you buy.
Can a lithium pack drop straight into my counterbalanced truck?
Not without checking the assembly. On a counterbalanced truck the battery is structural ballast, and a lithium pack of equivalent capacity typically weighs much less than the lead battery it replaces. Check the specific replacement assembly against the truck manufacturer's compartment dimensions, connector position and minimum battery weight on the data plate. OSHA 1910.178(a)(4) requires the manufacturer's prior written approval for modifications affecting capacity and safe operation, so adding ballast is not an informal fix.
What information does Beal need to compare TPPL and lithium for my fleet?
Send five things: daily amp-hours consumed per truck (or truck hours and load profile we can work it out from), battery voltage, your real charging windows including whether operators actually plug in, truck make and model with the minimum battery weight from the data plate, and the ambient temperature range where the trucks run and where they charge. With those, the comparison stops being a chemistry debate and becomes arithmetic. Beal stocks flooded, gel, TPPL and lithium and is independent of any forklift OEM.
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