How to calculate if my battery will be allowed in hand luggage? (Voltage in mAh to Wh conversion)
Follow-up question to Are battery packs allowed in hand luggage?
I have a 26,000 mAh battery pack ("Intocircuit Power Castle") which I want to take on a plane (Royal Air Maroc). Airline battery capacity limits tend to be based on Watt hours (Wh), and I'm confused about the conversion formula - specifically, the voltage part.
The conversion formula is mAh divided by 1,000 (or, Ah) times V = Wh. From what I can find online, V means "operating voltage", and this is where I get confused.
I can't see any reference to operating voltage on my battery. As for output voltage, there are four possibilities:
- USB at 5V
- DC at 12V
- DC at 15V
- DC at 19V
...which could give anything from 130 to 494, if any of these even are the operating voltage.
How do I find out the operating voltage to make this calculation? Or, is it possible to check based on mAh alone?
Funnily enough, someone asked my exact question about my exact brand of battery at some forum. Unfortunately, in a perfect example of why forums are terrible, instead of answering the question, they just started arguing about whether the asker even needed a battery (trust me, I do), whether it's standard to have power sockets on airlines these days (trust me, where I'm flying, it isn't), and recommending solar charging (that's already how I charge this battery!).
Best Answer
Broadly speaking you have the problem that if you can take it on or not is at the discretion of airport security. If you can't clearly show that it is within their rules, then good luck convincing them to beleive your calculations. On the other hand, they may not be aware that there are any restrictions, or choose not to inspect the battery too closely.
The current-time rating of a battery normally refers to the voltage of the actual battery itself. However it isn't entirely clear here what that is - in fact it is possible that changing to voltage output rewires how the cells are connected in the battery. Equally, there is a marketing reason to give bigger numbers throughout the product range, even though the smaller devices only provide 5V through USB.
This amazon page however does provide some useful hints. It says that a full charge takes 5-6 hours at 18.5V/2 Amps. So that's a maximum of:
6 * 2 * 18.5 = 222 WH
We know that there will be inefficencies there, so it will definitley be less than that.
As several other items in the range are USB only, and it's the only value from the 4 that fits under our calculated maximum, I'd guess that they are referring to the battery capactity at 5V, meaning 130WH.
But as we're making assumptions here based on limited information I'd suggest two things:
- Contact the manufactorer asking for the capacity in power-time units as opposed to current-time.
- Don't try to take it unless you are prepared to leave it behind in the event of an unusally thorough security check.
Pictures about "How to calculate if my battery will be allowed in hand luggage? (Voltage in mAh to Wh conversion)"
How do you calculate mAh from WH?
Formula is (mAh)*(V)/1000 = (Wh). For example, if you have a 300mAh battery rated at 5V, the power is 300mAh * 5V / 1000 = 1.5Wh.How many WH is a 20000 mAh battery?
20000 mAh at 3.6v is 72wh this is under the carryon limit.How do you calculate WH in power bank?
How to calculate the actual output capacity of a Power bank?Battery Capacity - Amp-Hours, mAh, and Watt-Hours
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Images: Mikhail Nilov, Karolina Grabowska, Karolina Grabowska, Karolina Grabowska