Battery runtime calculator
Working: 20,000 mAh at 3.7 V is 74 Wh on paper, and about 80% of that survives the conversion to the 5 V or 12 V your gear actually draws. Divide by 15 W and you get the runtime above. Cold weather and a hot bank both cut it further, so treat it as a ceiling.
Embed this tool
Free to embed on a blog, wiki, or resource page. Both options link back, which is the only thing we ask.
Frequently asked
How long will a 20,000 mAh power bank run an IRL streaming rig?
A 20,000 mAh bank holds about 74 watt-hours on paper and delivers roughly 60 after conversion losses, so a backpack rig drawing 15 watts runs about four hours and a phone-only setup drawing 6 watts runs closer to ten. Cold weather and a hot bank both reduce it, so treat the figure as a ceiling.
How do you convert mAh to watt-hours?
Multiply the milliamp-hour rating by the cell voltage, normally 3.7 volts, then divide by 1000. So 20,000 mAh times 3.7 divided by 1000 is 74 watt-hours. This conversion is the reason mAh alone tells you nothing: a 20,000 mAh phone bank and a 20,000 mAh 12 volt battery hold very different amounts of energy.
What size power bank can you take on a plane?
Airlines allow lithium batteries up to 100 watt-hours in carry-on without approval, which covers most banks up to roughly 26,800 mAh. Between 100 and 160 watt-hours you need airline approval, and above 160 they are refused. Batteries must travel in hand luggage, never checked, which catches out people packing a V-mount.
Why does my power bank die faster than the numbers say?
Three reasons compound. Converting cell voltage up to the 5 or 12 volts your gear wants loses roughly 20% as heat. Cold weather cuts usable capacity further. And a rig draws more than its idle figure whenever the encoder works hard or a modem fights for signal, which on an IRL stream is most of the time.
Sizing a battery for a specific kit? Browse power banks or plan the whole backpack, which estimates draw from the parts you actually pick.