The answer here may be that a rechargeable battery is not the correct solution, and that a battery that is just used and replaced is more suitable but the intended application is:
- An industrial environment where the battery may be subjected to hotter or colder temperatures (it is especially likely to be warmer when charging)
{EDIT} The temperature may get as high as 80 degrees C.. The more I read the harder this will be to find a battery for, rechargeable or not
- Only likely to be charged in bursts of <1 minute (though this could be up to 12V ~1A)
- Constantly draining at uW levels, with much less frequent instances of 100mW level draw for a couple of seconds
- Aiming to power either 3V3 or 5V circuitry
- Likely to be shipped internationally, which makes Lithium batteries more of a pain
Without wanting to give away too much information about the intended application, it will essentially be powering a piece of measurement equipment that records the amount of time a device is 'on'. This 'on' state is where the 12V comes from. This 'on' state would only last a minute or so usually (though you may get times where these minute periods happen quite frequently, maybe a 50% duty cycle for an hour). On top of that, the equipment could stay in storage for prolonged periods, with no charging at all. The instances of higher power draw are when measurements are read back from the device, but these may be even less frequent than operation, possibly at monthly intervals for example.
NiMH cells in an AA/AAA form factor (that can be easily replaced) were attractive, but some reading leads me to believe that they wont like being charged above room temperature.
Anyone have any suggestions for something that might be suitable? Many thanks in advance!
