For years the tubular lead-acid battery was the only realistic choice for a home inverter. Today LiFePO4 (lithium iron phosphate) batteries cost more up front but last many times longer. Here is how the two compare, point by point.
At a glance
| LiFePO4 lithium / Lead-acid | |
| Usable capacity | About 80% or more of rated capacity / typically about 50% |
| Cycle life | 6000+ cycles at 80% depth of discharge (PowerRun rating) / typically a few hundred to around 1,500, depending on type and use |
| Maintenance | None / regular distilled-water topping for flooded batteries |
| Weight | Much lighter for the same energy / heavy |
| Charging | Fast, efficient / slow, and loses more energy as heat |
| Fumes and acid | None / gives off gas while charging, can leak acid |
| Upfront price | Higher / lower |
1. Usable capacity: the number that actually matters
A battery's label shows its total energy, but you can't use all of it. Lead-acid batteries age quickly if they are regularly drained below about half, so in practice you get roughly 50% of the label. A LiFePO4 battery is rated for thousands of cycles at 80% depth of discharge.
In practice this means a 5 kWh lithium battery delivers about as much backup as an 8 kWh lead-acid bank.
2. Cycle life: how many years you get
One cycle is one full discharge and recharge. With daily power cuts or a solar system that cycles the battery every day, cycle life decides how long the battery lasts. Every PowerRun LiFePO4 battery is rated for 6000+ cycles at 80% depth of discharge - at one cycle a day, that is well over a decade of rated use. Lead-acid batteries typically need replacing several times in that period.
3. Maintenance and safety
Flooded lead-acid batteries need their water level checked and topped up, give off gas while charging and should sit in a ventilated space. LiFePO4 needs no topping up, gives off no fumes, and is the most thermally stable lithium chemistry. PowerRun packs add a smart BMS that cuts off over-charge, over-discharge and short circuits.
4. The real cost: per year, not per battery
Lithium costs more on the day you buy it. But because it gives more usable energy per kWh and lasts many more cycles, the cost per year of backup is usually lower. If you only see a few short power cuts a year, lead-acid can still make sense. If you have daily cuts, run solar, or simply don't want to replace batteries every few years, lithium pays for itself.
Can I switch my existing inverter to lithium?
Often yes, if two things are true:
- The battery voltage matches - a 12 V system needs a 12 V-class battery, a 24 V inverter a 25.6 V battery, a 48 V inverter a 51.2 V battery.
- The inverter can charge lithium batteries, either with a lithium mode or adjustable charging voltages.
Not sure about yours? Send us the inverter model on WhatsApp and we will check before you order. A PowerRun hybrid inverter paired with a matching PowerRun lithium battery works out of the box.
Which lithium battery should I pick?
Choose the voltage to match your inverter, then the capacity by the backup hours you need. Our guide to calculating battery backup time shows exactly how.