Hello everyone! I've been working on a solar powered boron device and recently I've been having issues with the charging component. Everything seemed to work just fine for the first month or so of owning the boron, but recently it has started acting up and refuses to charge the lipo connected to it. I have it programmed to be sleeping for most of the time (ulp mode), and then wake up every 15 minutes to check the internal temp of its enclosure (it is stationed outside in a hay field) and if the temperature is higher than ~40c it is supposed to disable charging until temperature becomes safe again, and this worked just fine for a while. However, a couple weeks ago for whatever reason it decided not to stop charging the lipo and ran the internal temp to almost 60c before I ran outside and cracked it open to cool off. Since then, I have been having odd power issues and have tried everything I can think of like replacing the lipo cell and even trying to charge it off of usb vs solar. After replacing the battery with a brand new one, the boron charged it up to 100% as expected, but it refuses to charge it anymore and the battery has slowly drained to 21%. The charging light is on and the console reads that it is charging, but occasionally I'll wake up to see it flashing the orange light as if there's a charging fault. Anyone have any idea what's going on? My current working theory is something must have happened to the pmic, but I'm not sure how to verify that.
If the charge LED is on and the software indicates that charging is in effect, it's either the battery or the PMIC, and since you swapped the battery, it's probably the PMIC. It's unusual, but not impossible for the bq24195 to fail. And if it were the battery, the charge LED usually goes into 1 Hz blinking mode.
If the charge LED did not come on, it could be a software setting, but that does not appear to be the case here.
Is there a way to check internal error logs on the board or anything like that? Also, could a damaged JST connector on the board trigger a similar issue? It was a bit of a fight to get the battery plug to release from the socket when I swapped them out (no visible damage, but crossing off possibilities).
If the charge LED is on solid (not blinking), then the bq24195 believes it's charging so there would be no logs. The actual charge logic is basically discrete in the bq24195, using a series of DACs to set voltage limits and using analog comparators. There's code to set up the DAC levels, but once set, it runs on its own.
I'd think a damaged JST connector would tends to cause no charge LED or some variation of blinking, but you never know for sure.
If you look at the plug end of the JST connector on the battery side, on the side with the key (not the one you can see the pins through), you'll see two tiny ramps on either side of the key. For test devices I just cut those off with an x-acto knife and then it will no longer lock which makes removing it very easy.