I'm putting some battery-powered lights into a boat, and I have the following question:
I bought a bunch of cheapo LED lights, as pictured:
They run on 3 AAA batteries. They work fine using 1.2V NiMH rechargeable batteries, and I've wired them up just to share one set of batteries, rather than each containing their own (still works fine). Rather than recharging batteries all the time, I figured it would be more convenient to get one of those USB LiPo power-packs for phones, and charge that when needed.
My question: Is anything bad going to happen if I hook up 5V USB power-pack in place of the (3.6V total) batteries? If I need a resister in series, how do I tell what resistance I need?