It’s been cloudy enough this winter that the solar plant charging has not been able to keep up with demand. Short days and new consuming devices contribute to the problem. I have had to use a trickle charger to keep up.
I’d like to automate this process so that the back-up charger comes on when the panels can’t keep up. When the battery voltage drops below a certain level, the charger should take over.
Here is what I spec’d out.
/*
Solar Monitor – RHR March 2020
Monitor voltage on solar installation and initiate back up charging
when voltage drops below 11 volts.
ESP8266 microprocessor so it can talk to the interwebs
Real Time Clock to time operations
OLED to display parameters
Measure voltage on AO (analog to digital line) via 5 to 1 voltage divider
Report to Adafruit IO
IF voltage falls below 11 volts, turn on trickle charger for one hour
Turn off and check voltage
If below 12 turn charger back on.
*/
The Real Time Clock measures the charging time and any other timing requirements.
These LEDs indicate that the back up charger is active (red) or off (green)
and this relay actually controls the trickle charger.
Next steps – add the IOT software to talk to the internet, actually wire in the trickle charger, and then come up with a case.