For an emergency use or little use which type of battery should i use?

[Madeeon]

@flydiver

Absolutely disagree with leaving an alkaline battery in any kind of device for long periods, especially devices subject to extremes of temperature. I’ve simply had way too many leak and destroy the device.

Primary lithium or CR123A would be my first choice. Huge shelf life, decent output, very little chance of leaking.
2nd choice is a good quality LSD NiMh. It will suffer a bit in the long haul due to less than optimal care but that’s just part of the price.

LiFe lithium is lower voltage but pretty robust. Some lights might be just fine with that.

I think your choice of lights is about as critical as the battery for this application. You want simple, robust, without parasitic drain.

I was just curious , because i know all of us have an emergency light inside the car. My question was about how they do, considering that is not convenient leave batteries inside the flaslight.

·How work Primary lithium, CR123A and LiFe lithium?. Do you have to charge them like any other 18650 or Nimh?

·I would appreciate some recommendation of battery for a keychain that i would use for few specific moments. I was looking for some usb rechargeable battery. I would choose AAA/AA if there is no any danger considering the Nimh would be inside the flaslight for a long time due to my use.

Thanks!