100Wh to Ah — 8.3 Ah at 12V
100 Wh is 8.3 Ah at 12V, 4.2 Ah at 24V, and 2.1 Ah at 48V. Below: usable energy per chemistry, what it runs, and which module count gets you there.
100 Wh at 12V is 8.3 Ah of battery capacity.
Formula: Ah = Wh ÷ V. Divide by the nominal battery voltage of the bank, not by the charger voltage.
Result
Energy in Wh equals capacity in Ah multiplied by battery voltage. 1000 Wh equals 1 kWh.
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Design Your SystemAt every system voltage
The same capacity stores four times the energy at 48V that it does at 12V, and draws a quarter of the current for the same load.
| System voltage | Capacity | Energy | kWh |
|---|---|---|---|
| 12 V | 8.3 Ah | 100 Wh | 0.1 |
| 24 V | 4.2 Ah | 100 Wh | 0.1 |
| 48 V | 2.1 Ah | 100 Wh | 0.1 |
How much of it you can actually use
Nameplate energy is not usable energy. Depth of discharge caps what you may take out before you damage the battery, and it differs by chemistry.
| Chemistry | Depth of discharge | Usable energy | Usable capacity | Cycles at that DoD |
|---|---|---|---|---|
| LiFePO4 | 80 % | 80 Wh | 6.7 Ah | ~3,500 |
| AGM | 50 % | 50 Wh | 4.2 Ah | ~600 |
| Gel | 50 % | 50 Wh | 4.2 Ah | ~800 |
| Flooded lead-acid | 50 % | 50 Wh | 4.2 Ah | ~400 |
What that runs
Runtime from the usable LiFePO4 energy at 12V (80% depth of discharge), one load at a time, no inverter losses on the DC rows.
| Load | Power | Runtime |
|---|---|---|
| LED lighting | 15 W | 5.3 h |
| 12V compressor fridge (average) | 45 W | 1.8 h |
| Diesel heater (fan and glow plug average) | 30 W | 2.7 h |
| Water pump (while running) | 65 W | 1.2 h |
| Laptop plus router | 75 W | 1.1 h |
| Kettle through an inverter | 1200 W | 0.1 h |
What this size is in practice
100Wh is the aviation threshold: lithium batteries up to 100Wh may normally travel in carry-on baggage without airline approval. That is why this number is searched far more often than its tiny capacity would suggest.
Building the same energy from standard modules
How many standard 100Ah 12V modules add up to this energy, and what capacity that becomes at each system voltage.
| System voltage | Capacity | Standard modules |
|---|---|---|
| 12 V | 8.3 Ah | 1 x 100Ah / 12V |
| 24 V | 4.2 Ah | 1 x 100Ah / 12V |
| 48 V | 2.1 Ah | 1 x 100Ah / 12V |
Other energy values (Wh)
Other capacities (Ah)
FAQ
How many Ah is 100 Wh?
100 Wh is 8.3 Ah at 12V, 4.2 Ah at 24V, and 2.1 Ah at 48V. Divide the watt-hours by the nominal battery voltage: Ah = Wh ÷ V.
How much of that 100 Wh can I use?
On LiFePO4 at 80% depth of discharge you get 80 Wh (6.7 Ah at 12V). On AGM or gel at 50% you get 50 Wh (4.2 Ah). Same nameplate, very different usable energy.
How long does that run a 12V fridge?
A compressor fridge averaging 45 W runs about 1.8 hours on the usable LiFePO4 energy at 12V. Cycling depends on ambient temperature, so treat this as the upper bound for a well-insulated unit.
What capacity is 100 Wh on a real LiFePO4 module?
At the true LiFePO4 nominal voltage of 12.8V, 100 Wh corresponds to 7.8 Ah. At a round 12V it is 8.3 Ah. Datasheets use 12.8V, most calculators use 12V.
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