What Can a 12V 100Ah LiFePO4 Battery Run? Runtimes Worked Out

A 12V 100Ah LiFePO4 battery stores about 1,280 Wh, enough to run a 12 V camping fridge for roughly four days, a CPAP for about four nights or a full-size refrigerator for about 21 hours through an inverter. Battle Born’s 100 A continuous limit keeps loads near 1,000 W, so a 1,500 W heater is out of reach.

How much energy a 12V 100Ah LiFePO4 battery holds

Capacity on a 12V 100Ah LiFePO4 battery is about 1,280 Wh, because lithium iron phosphate batteries sold as 12 V are commonly rated at a 12.8 V nominal voltage. Renogy, for example, lists its 100 Ah Core Mini at 12.8 V nominal and 1,280 Wh. Battle Born lists its BB10012 as a 12 V, 100 Ah battery.

Nearly all of that capacity is usable. Dometic’s guidance on running its CFX3 coolers says lithium iron phosphate batteries give nearly 100% of their stated Ah capacity, against about 50% for lead-acid. A 100 Ah LiFePO4 battery therefore does roughly the work of a 200 Ah lead-acid bank, and Battle Born lists the BB10012 as equivalent to 200 Ah of lead-acid.

Running AC appliances loses some energy in the inverter. EcoFlow’s runtime guide suggests multiplying capacity by 0.80 to 0.90 for AC loads. At the middle of that range, 0.85, the working figure is about 1,090 Wh of AC power. Loads that run on 12 V DC skip the inverter and get closer to the full 1,280 Wh.

Runtimes on a 12V 100Ah LiFePO4 battery

Each runtime below is a worked estimate, not a measurement: usable watt-hours divided by the appliance’s average watts. AC loads use 1,090 Wh; the 12 V cooler uses the full 100 Ah.

Your own appliance may draw more or less. A plug-in watt meter on the actual fridge or CPAP gives a better number than any table. For the same math on a power station, see what a 1000Wh power station can run.

The 100 A limit and inverter size for a LiFePO4 battery

The continuous discharge limit decides how big a load a 12V 100Ah LiFePO4 battery can carry, separate from how long it lasts. Battle Born lists the BB10012 at 100 A continuous and 200 A peak for 30 seconds. The battery’s management system (BMS) cuts power if a load pulls more than that for too long.

At 12.8 V, 100 A is about 1,280 W at the battery. Inverter losses take a share before the power reaches the outlet, so a 1,000 W inverter is about the practical ceiling for one battery. Check the continuous rating on the exact model you buy: some 100 Ah batteries list lower limits, and the maker’s stated limit is the one that counts.

Charging a LiFePO4 battery in cold weather

LiFePO4 batteries charge only above freezing unless they have built-in heating. Battle Born’s manual lists a charging range of 32°F to 131°F for the BB10012 and a discharge range of -4°F to 140°F, and its BMS blocks charging below 32°F. A cold battery can still run loads but should not be charged. Battle Born’s data sheet and temperature guide give a slightly lower charging floor of about 25°F, so staying above 32°F fits both. Renogy also notes that standard lithium batteries stop charging at 32°F.

Self-heating batteries solve the winter problem. Renogy says its DuoHeat 100 Ah model starts heating when the cells fall to 41°F and stops at 50°F, and that the battery can be ready to charge within 60 minutes even at -22°F. For a cabin or RV used in winter, that feature is worth paying attention to.

Charging voltage matters too. Battle Born lists 14.2 to 14.6 V for charging and 13.4 to 13.8 V for float, so set your charge controller or charger to a lithium profile. Our solar panels section covers the panels that refill a battery like this. Our guide to solar charge controllers covers sizing and wiring order.

LiFePO4 battery or a power station

A bare 12V 100Ah LiFePO4 battery needs a charge controller, an inverter, fuses and cables before it runs a household appliance. A portable power station puts the same chemistry, the inverter and the solar charger in one box. Battle Born lists its 100 Ah battery at 31 lb, before any of the extra parts.

A loose battery suits a van, boat or cabin with a fixed 12 V system. A power station suits renters and anyone who wants to plug in and go. Our LiFePO4 vs NMC comparison explains how LiFePO4 power stations compare on cycle life, safety and weight, and what size solar generator runs a refrigerator covers fridge sizing in more depth. To size the inverter on a fixed system, see off-grid solar inverters.