How Long Will a 100Ah Lithium Battery Last in an RV?
A 100Ah lithium battery has no single runtime because the answer depends on voltage, usable capacity and what you power. Converting the bank to watt-hours makes the comparison much easier.
Convert amp-hours to watt-hours
At about 12.8 volts, a 100Ah lithium battery contains roughly 1,280 nominal watt-hours. That does not mean every watt-hour reaches an AC appliance because reserve, wiring and inverter losses reduce usable output.
Small DC loads can run a long time
LED lighting, water pumps, device charging and control boards use far less energy than resistance heaters, microwaves or air conditioners. Runtime is determined by the average combined load over time.
Inverters add conversion loss
When a 12-volt battery powers 120-volt AC equipment through an inverter, some energy is lost in conversion. The inverter can also consume power while idle depending on model and settings.
Cycling appliances require energy estimates
A refrigerator or furnace may switch on and off. Instead of using peak watts continuously, estimate watt-hours consumed across an hour or day for a more useful battery budget.