Hi, I'm considering using a (roughly 400-700mAh) AA-sized LiFePO4 lithium iron phosphate battery for a design. I will probably use a fuel gauge to monitor the battery for safety, but I have 2 questions about this design and wanted to get everyone's input.
1. if users ignore my instructions to use the provided LiFePO4 battery, and instead they use a plain old AA alkaline battery.. what kind of problems can happen with the fuel gauge? I'm thinking of using one of Texas Instruments' bq-based fuel-gauge solutions, so idk if/how it will even detect that the battery is not the correct chemistry. The other problem would be if they try to charge this AA alkaline battery - and this sounds like a fire hazard.
2. there are 2 sides to this design - the remote controller, and the "hub". The hub (powered off a wall adapter) will have a BLE module running at 3.3V, but the remote controller is powered off a battery - as I just described above. For the remote controller side, can I just use the direct battery voltage on the BLE, and not go through a voltage regulator - so the BLE module will get about 3V to 4.2V input? (which is within the acceptable input voltage range of this BLE module - since it can take 1.7-5.5V input). So the question is: what happens when one BLE module runs off 3.3V, and the other paired BLE module runs off 3V to 4.2V? Will it even properly make a connection?
Thanks for your input and help.