Key takeaways
- A 100Ah LiFePO4 battery replaces roughly a 200Ah lead-acid battery, because lead-acid should only be discharged to about 50%.
- LiFePO4 delivers 5000+ cycles at 80% depth of discharge; tubular lead-acid gives 1500–3000+, and standby VRLA around 400.
- Lithium iron phosphate contains no cobalt and no nickel, and resists thermal runaway far better than nickel-based lithium chemistries.
- Round-trip efficiency is roughly 95% for LiFePO4 against 80–85% for lead-acid — energy lost in charging, before the battery is even used.
- Lead-acid loses usable capacity as you draw harder; LiFePO4 barely does. This is why lead-acid is quoted at C10 or C20.
- Lead-acid still wins for pure standby duty, for lowest purchase price, and on established recycling infrastructure.
Ask which battery technology is better and you will get an argument. Ask which is right for a given application and the answer becomes far clearer — because lithium iron phosphate and lead-acid are not competing for the same job as often as the debate suggests.
This guide compares them on the measures that actually decide a purchase: usable capacity, cycle life, weight, safety, charging, and cost across the life of the battery rather than at the counter.
The number on the label is not the number you get
The most common and most expensive misunderstanding in this comparison is treating amp-hours as directly comparable. They are not.
A lead-acid battery should not routinely be discharged much beyond 50% of its rated capacity. Go deeper and cycle life falls away sharply. So a 200Ah lead-acid battery realistically delivers around 100Ah of usable energy — the other half exists to protect the first half.
LiFePO4 delivers its full rated capacity. A 100Ah lithium battery gives close to 100Ah usable, and is rated for deep discharge as normal operation rather than abuse.
In practice this means one 100Ah LiFePO4 battery replaces roughly a 200Ah lead-acid battery — at 60 to 70% less weight and in a smaller space. Any comparison that puts 100Ah against 100Ah is comparing the wrong quantity.
| Model | Rated | Usable energy | Roughly replaces |
|---|---|---|---|
| LiON Max EP12100 | 12.8V 100Ah | 1280Wh | ~200Ah lead-acid |
| LiON Max EP12150 | 12.8V 150Ah | 1920Wh | ~300Ah lead-acid |
| LiON Max EP12200 | 12.8V 200Ah | 2560Wh | ~400Ah lead-acid |
Cycle life is where the cost argument is settled
A cycle is one discharge and recharge. How many a battery delivers before capacity falls away determines what it actually costs to own, and the gap between technologies here is wide — but it is only decisive if the battery is genuinely cycled.
| Technology | Rated cycles | Usable capacity | Built for |
|---|---|---|---|
| Nucleus Max SMF VRLA | 400+ at 50% DoD | ~50% | Standby, occasional discharge |
| Inverto Max tubular | 1500+ | ~50% | Daily home and office backup |
| Solar Max tubular | 3000+ at 50% DoD | ~50–80% | Solar storage |
| LiON Max LiFePO4 | 5000+ at 80% DoD | 100% | Frequent deep cycling |
Read that table carefully. VRLA looks weakest on cycles and it is — because it is not a cycling battery. It is a standby battery, rated for 8 to 12 years of float life at 25°C, designed to sit charged and be called on occasionally. Using one for daily deep cycling is the most common specification mistake in backup power, and it will exhaust the battery within a year or two.
Where a battery is cycled every day — solar storage, an inverter carrying nightly outages, an e-rickshaw, a telecom site running solar hybrid — cycle life is the number that decides cost per unit of energy delivered, and LiFePO4 leads it comfortably.
Efficiency, voltage and what happens when you draw hard
Three differences never appear on a datasheet comparison but change what the battery delivers in service.
Round-trip efficiency
Not all the energy put into a battery comes back out. Lead-acid returns roughly 80 to 85% of what it takes in; LiFePO4 returns around 95%. On a grid-charged system that is a modest cost. On solar, where every kilowatt-hour had to be harvested by panels you paid for, losing 15 to 20% in the battery means oversizing the array to compensate — a cost that lands on the solar side of the budget rather than the battery line.
The voltage curve
Lead-acid voltage sags steadily as it discharges. LiFePO4 holds a much flatter curve, staying near its nominal voltage until close to empty. For the user this is the difference between lights that dim through the evening and lights that stay at full brightness, and between an inverter running efficiently and one working harder as input voltage drops.
It has a practical consequence too: with lead-acid you can estimate state of charge reasonably well from resting voltage. With LiFePO4 you largely cannot, because the voltage barely moves — which is why a battery monitor or the BMS readout matters more on a lithium system.
Capacity falls when you draw harder
Lead-acid delivers less total energy the faster it is discharged. This is why lead-acid capacity is always quoted with a rate — C10 over ten hours, C20 over twenty — and why a 200Ah C20 battery is not equivalent to a 200Ah C10 battery. Draw it harder still and the usable figure falls further.
LiFePO4 is far less affected. Its rated capacity holds up close to the label across normal discharge rates, which is part of why the usable-capacity gap widens under heavy load rather than narrowing.
When comparing quotes, always confirm which C-rate a lead-acid capacity is quoted at. A supplier quoting C20 against a competitor's C10 is not comparing the same battery — and in solar and inverter duty, which draws harder than twenty hours, C10 is the honest figure.
Self-discharge and sitting at partial charge
Both technologies self-discharge slowly — the Solar Max and Nucleus Max ranges specify under 3% per month, and LiFePO4 is typically lower still. The more important difference is what happens when a battery sits part-charged for a long period. Lead-acid sulphates, losing capacity permanently, which is why chronic partial state of charge is the most damaging condition in an under-sized solar system. LiFePO4 tolerates partial charge without the same permanent loss.
Neither chemistry has a "memory effect" — that belongs to older nickel-cadmium cells, and it is worth saying plainly because the question still comes up.
How long does each actually last?
Cycle counts are the honest technical measure, but most buyers want years. The answer depends entirely on how hard the battery is worked, which is why the same technology carries very different figures across applications.
| Battery | Stated design life | Duty assumed | What shortens it |
|---|---|---|---|
| Nucleus Max SMF VRLA | 8–12 years float at 25°C | Standby, rarely discharged | Heat above 25°C; deep cycling |
| Inverto Max tubular | 5–7 years float | Daily outage backup | Over-discharge; missed watering |
| Solar Max tubular | 7–10 years float | Daily solar cycling | Partial state of charge; heat |
| LiON Max LiFePO4 | 10 years, 80%+ capacity retained | Frequent deep cycling | Wrong charge profile; extreme heat |
Two things are worth reading out of that table. First, heat is the common enemy — every lead-acid figure is quoted at 25°C, and sustained operation well above that shortens life substantially. In tropical and Gulf installations, ventilation is not optional. Second, the lithium figure is expressed differently: not "it dies at ten years" but "it still holds more than 80% of its capacity at ten years", which is a more useful way to think about any battery.
Warranty terms sit separately from design life and are set by the authorised distributor at the point of sale. Whichever technology you choose, register the product at purchase — it records the serial number and purchase date so a future claim does not depend on finding a receipt years later.
Weight and space
LiFePO4 weighs 60 to 70% less than the lead-acid equivalent for the same usable energy. That matters more than it first appears:
On a rooftop or a mezzanine, structural loading limits what can be installed. In a vehicle or a boat, weight is payload. On a remote site, weight is the cost of getting the battery there — and in markets where the last stretch is unpaved, that can dominate the installation budget. In a wall-mounted UPS beside a router, size is simply whether it fits.
Safety: why LiFePO4 rather than other lithium chemistries
Not all lithium is the same, and the distinction matters. Most consumer electronics and many electric vehicles use nickel-based lithium chemistries, which offer higher energy density but a less stable cathode.
Lithium iron phosphate trades some of that density for a markedly more stable chemistry: it resists thermal runaway, tolerates higher temperatures, and contains no cobalt and no nickel — the two materials most associated with supply chain and ethical sourcing concerns in battery production.
Energy density matters enormously in a phone. In a stationary storage installation or a backup system it rarely does. That trade is why LiFePO4 has become the standard choice for solar, UPS and off-grid work.
Every LiON Max unit also carries an integrated smart BMS — battery management electronics that monitor each cell and intervene automatically against overcharge, over-discharge, short circuit and over-temperature, while balancing cells so they age evenly. A lithium pack cannot be operated safely without one, which is why it is standard rather than an accessory.
Charging: the check people forget
12.8V LiFePO4 is designed as a drop-in replacement for a 12V lead-acid battery, and 25.6V, 48V and 51.2V options cover larger systems. The mechanical swap is usually straightforward.
The critical check is the charger. Lead-acid chargers use a different voltage profile, and some older inverters and solar charge controllers have no lithium setting at all. Confirm the charge source can be set to a LiFePO4 profile — or specify a compatible charger — before converting, not after.
LiFePO4 also accepts charge faster and more efficiently, which matters where the charging window is limited — a solar array with a few hours of useful sun, or a vehicle on short runs.
Where lead-acid still wins
A guide that concluded lithium is always better would not be worth reading. It is not.
Pure standby duty
A UPS battery that discharges a few times a year is never cycled enough for lithium's cycle advantage to repay its higher purchase price. For telecom cabinets, data centre backup, fire alarms and switchgear, sealed AGM VRLA remains the right specification — 8 to 12 years of float life, high rate discharge for instant switchover, and no maintenance.
Lowest purchase price
Where capital cost is the binding constraint and the duty is moderate, tubular lead-acid delivers 1500 to 3000+ cycles at a considerably lower entry price. Solar Max at 3000+ cycles is a serious solar battery, not a compromise.
Established recycling
Lead-acid is among the most recycled products in general commerce, with collection and smelting infrastructure present in most markets and material returning to the same product rather than being downcycled. Lithium recovery infrastructure is developing but less mature in many of the regions we supply.
How to choose
Work through it in this order:
| Question | If yes | If no |
|---|---|---|
| Is the battery cycled deeply most days? | LiFePO4 or tubular | Consider VRLA standby |
| Is weight or space constrained? | LiFePO4 | Lead-acid viable |
| Is purchase price the binding constraint? | Tubular lead-acid | LiFePO4 repays over life |
| Can the charger run a lithium profile? | LiFePO4 possible | Budget for a charger |
| Is it unattended or enclosed? | Sealed VRLA or LiFePO4 | Ventilated tubular fine |
Most disappointing installations are not the result of choosing the wrong brand. They come from putting a standby battery on cycling duty, sizing from rated rather than usable capacity, or pairing a lithium battery with a charger that cannot charge it correctly.
The short version
If the battery works every day, LiFePO4 usually wins on cost per unit of energy delivered despite costing more to buy — and wins decisively where weight or space is constrained. If it sits waiting for an outage that rarely comes, VRLA is the better and cheaper answer. If the duty is daily but the budget is tight, tubular lead-acid sits sensibly between them.
Match the technology to the duty cycle, size from usable capacity rather than the label, and check the charger. Get those three right and the brand argument matters far less than it appears to.
If the application is solar, capacity is only half the question — array output and charge controller sizing decide whether the bank ever reaches a full charge. That is covered in Solar + Storage: Designing Off-Grid Power Systems for Rural Markets.