I would like to run a smartphone using a primary battery instead of rechargeable for a project I'm experimenting with.
Most phone batteries will have a connector of some type with 4 contacts. Of course two of those I'd expect to be +- Voltage, but the other two compose some sort of mystery input to the phone (thermistor? signal? I don't know). I was hoping to substitute a primary battery instead of the factory one for my project (I have a 3.6v primary battery), but my device always seems to have a problem with it, presumably due to the battery protection circuit. I thought I might just leave the protection circuit in place and wire power to both input and output- that way whatever input the phone needs to see is still there, but even that approach seems not to work. Please help me bypass this system so that I can use a custom battery in this device. Here is a diagram with some measured resistance/voltage values. If a value between points isn't shown, you can consider it an open circuit (although I didn't measure battery resistance)
I've actually tried fooling the device by installing resistors of that value(s) appropriately but still it won't power up. Also, I tried just powering it through the usual USB charging port (5v) but that's so far been very inconsistent. Is there a way to find the main power terminal in the PCB and go directly to it? For reference- the donor phone here is an older Motorola Droid Razr
Most phone batteries will have a connector of some type with 4 contacts. Of course two of those I'd expect to be +- Voltage, but the other two compose some sort of mystery input to the phone (thermistor? signal? I don't know). I was hoping to substitute a primary battery instead of the factory one for my project (I have a 3.6v primary battery), but my device always seems to have a problem with it, presumably due to the battery protection circuit. I thought I might just leave the protection circuit in place and wire power to both input and output- that way whatever input the phone needs to see is still there, but even that approach seems not to work. Please help me bypass this system so that I can use a custom battery in this device. Here is a diagram with some measured resistance/voltage values. If a value between points isn't shown, you can consider it an open circuit (although I didn't measure battery resistance)
I've actually tried fooling the device by installing resistors of that value(s) appropriately but still it won't power up. Also, I tried just powering it through the usual USB charging port (5v) but that's so far been very inconsistent. Is there a way to find the main power terminal in the PCB and go directly to it? For reference- the donor phone here is an older Motorola Droid Razr
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