Originally Posted by Alex
Why are LifePO4 batteries rated in Amp Hours while Portable Power Stations rated in Watt Hours? How would you compare the two? If you had a 100 Amp Hour battery, what size Portable Power Station would be the equivalent?
Ah is only meaningful in the context of VOLTAGE, i.e., 100Ah @ 12V.
Wh is a measure of energy independent of voltage. It equals Voltage * Ah.
Batteries have a specified nominal
voltage depending on cell count and chemistry, so Ah is a common measure of capacity. I emphasize nominal
because that's the voltage used to compute Wh, e.g., a 12V 100Ah lead-acid battery has 1200Wh, not 13.6V * 100Ah. A "12V" LiFePO4 (LFP) battery is actually 12.8V nominal, so they have 1280Wh for a 100Ah "12V."
Power stations may be at 12, 24 or 48V on the inside. You're not tapping the battery directly, so Ah tells you nothing, and it's more sensible to quantify the total energy in the storage device as Wh.
If you want to compare apples to apples, always convert to Wh.
Again, Wh = Nominal Volts * Ah.
Lastly, note that "power stations" will typically only deliver about 70-80% of their rated Wh. The circuitry inside them consumes power to generate the features provided. If you leave a power station ON with no loads attached, it will likely consume all of its own capacity in a few days to a couple weeks depending on battery/features.