I have a strange problem with my SmartSolar MPP 75|15. I'm in the testing stage of an art project with this charger, a 25W solar panel, and a Victron AGM 14Ah 12V battery. The load is a Raspberry Pi Zero 2W taking photos during the day; it draws only around 100-200mA and then shuts off at night. I collect and log data about the panel and battery from the SmartSolar over Bluetooth on the Pi.
I left it for around 10 days off-grid for a recent test in cloudy Amsterdam. The logs showed that for the first few days there was the expected variation of battery voltage, load current, and watts collected over the course of the day. Then, when the Pi turned on the next morning, the SmartSolar just sent the exact same data at each monitoring interval for the next few days: the battery voltage was exactly the same (12.62V), there was no indication of load current (it read 0 even though the Pi was on), and there was no indication of any sun (it read 0 throughout the entire day which is, well, impossible given that there was some sun). Then, the battery voltage plummeted to around 6V, even though I have logic in the code running on the Pi to turn itself off if there is a low battery voltage (which of course was not being run as the battery voltage being reported was erroneous).
I'm using Bluetooth instead of a wired VE.Direct to USB connection because it's a bit difficult to run the USB to the device, but I can make that work if it's the only way to address this problem.
I'm somewhat new to this Victron and to solar panels and batteries in general, so perhaps there is something fundamental I'm missing here. But I'm a bit at a loss as to how to diagnose this problem. Has anyone else had issues like this? Or are there any suggestions of what to look into?
I currently have to travel to the device to check on the data, but, potentially, I could get a GlobalLink 520 to monitor things remotely. However, if I can figure this out without having to invest in that expense I would prefer that.
Thanks in advance for any suggestions you might have!
