My RPi3B+ is power cycling every night when the sun goes down which is unexpected. I'm concerned the battery in my unit has gone bad. I've included a screenshot of the various voltages and currents in the system at the time of the power cycle. The sharp drop in battery voltage is concerning to me and makes me wonder if my battery is dying?
I’m using the SolarMAX2 with this battery: www.amazon.com/gp/aw/d/B003S1RQ2S The system has been up and running full time for between five and six months. The kit is not in direct sunlight so hopefully the battery isn’t experiencing heat stress.
New battery was installed on Saturday and so far data looks good. Still seeing power cycles throughout the day which makes me wonder if I have a suboptimal USB cable. Need to do some more poking around.
Takes less than 12 hours to discharge the battery below the power threshold for the protection circuit. I think I need to spend some more time trying to minimize power consumption on the RPi 3B+ in the box.
I’m using the SolarMAX2 kit. For the first month or so, the new battery had enough juice when the sun went down to power the RPi 3B+ all night. Consistently in the last week or so, it no longer makes it all night. What worries me is our days are only getting longer and we’ve had very few days of prolonged clouds here in NC over the last few weeks.
I decided to look further at power collection to see if there might be any additional root cause. I wrote a query to calculate number of peak hours per day of solar collection defined as an hour where the average intensity is 1000 W/m2 using a conversion of 1 lux = 0.0079 W/m2. The graph below shows performance:
Interestingly enough, in spite of 5, 5, and 4 peak hours of collection from 5/17 through 5/19, the RPi powered down around 5AM on 5/20. I'm not sure I agree with the possibility that the panel may be in need of replacement as 5-5.5 hours of peak hours is spot on for estimates from solar panel vendors for my location in North Carolina. We've had a run of very cloudy and overcast days here that is very uncharacteristic for this time of the year since 5/20 so the zeros from 5/21 through today are spot on. I'm left continuing to believe the battery is not performing properly.
I need to get back to this 🤦♂️ The nightly power cycle is getting earlier and earlier in the evening. At the outset, the power cycle would happen at ~5AM. Last night was around 10:30PM. Is it okay to use a 12V 12AH lead acid battery in place of the 12V 7AH battery recommended for the kit?