Lithium (LiFePO4) vs Lead-Acid Batteries for Solar

Please note: this guide was written with the help of AI and may contain mistakes or outdated information. It is general information only. Always do your own research (DYOR): check product specifications with the manufacturer, and use a qualified professional for any electrical, security or gate installation.

The battery is usually the biggest decision in a solar system. Most homes now choose lithium iron phosphate (LiFePO4), but lead-acid still has its place. Here is an honest comparison.

Usable capacity

A battery’s label shows its total capacity, but you cannot use all of it. Lead-acid batteries last longest when only about half of their capacity is used regularly. Lithium iron phosphate batteries can typically be discharged much deeper, so the same labelled capacity gives you far more usable energy. In practice a smaller lithium battery can do the work of a larger lead-acid bank.

Lifespan

Lithium batteries are rated for many more charge cycles than lead-acid. Over years of daily use that usually makes lithium cheaper per kWh delivered, even though it costs more upfront. Always check the cycle rating and warranty of the specific model.

Weight, size and maintenance

• Lithium: lighter and more compact, no topping up, and many models come as wall-mount or rack-mount units.
• Lead-acid: heavy and bulky. Some types need watering and good ventilation; sealed AGM and gel types need less care.

Cost

Lead-acid wins on upfront price, which suits a small backup system used only occasionally. Lithium costs more to buy but gives more usable energy, a longer life and less maintenance, so it usually wins for daily solar use and heavy load shedding.

Which should you pick?

• Daily solar use and regular load shedding: lithium (LiFePO4).
• Small, occasional backup on a tight budget: a sealed lead-acid (AGM or gel) battery can be enough.
• Large or commercial storage: look at rack-mount or high-voltage lithium systems.

Make sure it fits your inverter

Check that your inverter supports the battery voltage and, for lithium, that the battery and inverter can communicate. Mount batteries safely with a proper battery cabinet or brackets, and protect the wiring with the right fuses and combiner boxes.

Browse batteries

See our full range of solar batteries, or find the inverter that suits them. Not sure what size you need? Read how to size an inverter and battery.

AI-assisted content. Please do your own research (DYOR) before you buy or install.