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Charging an E-Bike From a Power Station
What size station you need to put a full charge back into an e-bike, and how to work it out for your own pack.
The short version
Take your bike’s battery in watt-hours, add about 20% for charging losses, and buy a power station with at least that much usable capacity. A 672Wh e-bike pack needs roughly 800Wh of station to go from empty to full in one go.
Working out the number
E-bike chargers are not perfectly efficient, and neither is a power station’s inverter. Between them you lose somewhere between 10 and 25% of what leaves the station.
| E-bike pack | Energy needed at the wall | Sensible station |
|---|---|---|
| 360Wh (36V 10Ah) | ~430Wh | 500Wh+ |
| 500Wh | ~600Wh | 700Wh+ |
| 672Wh (48V 14Ah) | ~810Wh | 1,000Wh+ |
| 720Wh (48V 15Ah) | ~865Wh | 1,000Wh+ |
| 960Wh (48V 20Ah) | ~1,150Wh | 1,500Wh+ |
Buying a station the same size as the pack will not do it. A 700Wh station will not fully charge a 700Wh bike, because some of that energy is lost on the way through.
Output matters less than you think
E-bike chargers are modest loads — typically 100 to 200W, occasionally 300W on a fast charger. Almost any power station with a pure sine wave AC outlet will run one. Capacity is the constraint, not output.
Do check for pure sine wave rather than modified sine. Switching power supplies generally tolerate modified sine, but running one warm and unhappy for four hours is not worth the saving. Every station we track uses pure sine.
How long it takes
Charging time is set by the bike’s charger, not the station. A 2A charger on a 48V pack delivers about 96W, so a 720Wh battery takes roughly seven to eight hours. A 4A fast charger halves that. The station simply supplies the wall power.
Two-day trips need solar. Charging a bike once will empty a mid-size station. If you are out for more than a night, pair it with panels — see solar generators.
Charging safely away from home
The same rules apply as at home, and they matter more when you are in a van or a tent.
Never charge a pack that is below freezing or still hot from a ride — let it settle to something like room temperature first. Charge outside the tent or vehicle where you reasonably can, and never leave a charge unattended overnight in an enclosed space. Use the charger the bike came with; a generic one running off an inverter is exactly the combination that causes trouble.
What about charging straight from solar?
Not directly. An e-bike charger expects mains AC, and a solar panel produces variable DC. You need something in between, which is what a power station is: the panel charges the station, the station runs the charger.
For a full e-bike charge from sunlight in a day, plan on 200W of panel or more, and accept that a cloudy day will not do it.
Sizing a station generally? Our what size power station do I need guide covers the same arithmetic for fridges, CPAP machines and tools.