I currently have a bullet helmet cam which has an internal rechargable battery and also can be run directly from a usb power socket but my question is can it run off a power bank.If I fully charge the unit and then connect it to a power bank how does it work,will the power bank keep the unit charged up until the power bank itself goes flat.Or does the powerbank only start to recharge the internal battery once it runs flat?The reason I ask is the internal battery only last 90 mins and I'd like an alternative source to power it.I ps have no knowledge of how power banks work Thanks
A power bank is essentially a large capacity battery that delivers a regulated 5V output. If your camera can run from a USB port it can run from a power bank.
I have two electric hand warmers (hot rocks) that double as power banks. Only tried them that way once, charged my iphone in a jiffy. Just the same as connecting to a USB mains charger or powered hub. They make great hand warmers. I want a cycle safety camera that will do 8 hours on a charge. Hard to find!