Flying · explainer
Watt-hours, explained.
One number decides whether your battery flies. Here’s how to find it, and how to talk about it at check-in.
Airlines don’t care how heavy your battery is or how many amp-hours it holds. They care about watt-hours, because watt-hours measure how much energy is stored — and stored energy is what a battery safety rule is actually about.
The trouble is that most battery labels don’t print watt-hours. They print volts and amp-hours. So the single most useful thing you can learn before you fly is how to turn one into the other.
The one sum
Volts × amp-hours = watt-hours.
A 24-volt battery rated at 10 amp-hours is 24 × 10 = 240 watt-hours. That’s the number an airline wants, and it’s the number marked on every Seraphin pack so you don’t have to work it out at the desk.
If your label shows milliamp-hours instead of amp-hours — some do — divide by 1,000 first. A 20,000 mAh pack is 20 Ah. Then multiply by the voltage as usual.
The numbers that matter
Every threshold an airline applies to a mobility-aid battery is a watt-hour figure. There are only three worth memorising.
| Watt-hours | What it means |
|---|---|
| Up to 100 Wh | No airline approval needed. Most wheelchair batteries are above this, so it rarely applies to a powerchair. |
| 100 to 300 Wh | Allowed on a mobility aid with airline approval. This is where every Seraphin sits. Notify the airline in advance and you’re fine. |
| Above 300 Wh | Not permitted as a spare, and problematic even fitted. The large optional packs on some chairs cross this line — which is why we tell you to buy the standard pack if you fly. |
Where every Seraphin sits
All within the approvable band. The two that run dual packs we confirm in writing for your exact configuration.
| Chair | Battery |
|---|---|
| Carbon Air | 144 Wh — the smallest pack in the range |
| Carbon GT / Lite | 187 Wh |
| Carbon | 240 Wh |
| Carbon HD | 250 Wh standard — larger packs exceed 300 Wh, don’t fly them |
| Micro / Carbon Trail | Dual packs — confirmed in writing before you fly |
Airline policies change and vary by carrier, route, aircraft and destination. This is a starting point, not a substitute for confirming with your airline before you travel. Seraphin supplies your battery documentation; only the airline can approve your battery. Last reviewed July 2026.