I think my “MPPT” controller is mistakenly sensing my full 12V AGM as a discharged 24V battery and over-voltage charging it - has anyone seen this happen and know a solution?
I bought a new Kings 160W folding solar panel which included an MPPT controller (a 12/24V model AKSR-MPPT_20A_01 pic below). The controller has no data connection or setup adjustment I can see
On initial connection and testing with my brand new 105AH AGM battery under no load it seemed to charge OK (14.6V) . Then the controller charge/battery voltage jumped up to about 16 to 17VDC and stay there! Disconnect, retest, same thing.
When it’s working correctly
1. Only the “solar” LED is on.
2. I’ll connect the battery,
3. then the MPPT seems to sense the battery voltage, decide it’s a 12av system then indicate 3 green “Battery” LEDs as per the manual.
4. Then the load light comes on and it starts sending current (6A full sunshine).
notes: Panel is putting out about 18V into MPPT. Battery was full before connection (open cct 13.1V) after just coming off a bench charge. No load connected to battery (MPPT “load” terminals never used)
5. Then after a few minutes it starts to ramp up voltage a few points then back down again.
6. Finally the 3 green “Battery” LEDs drop to one flashing (manual states this is low battery voltage)
7. Then voltage ramps up quickly to 16 to 17VDC and stays there
8. Hydrogen smell within a few seconds! - so I quickly disconnect.
9. Battery open cct voltage slowly drops back to 13ish V over next 10 mins or so.
With a load on my battery (my fridge attached via inverter ) it doesn’t over-voltage as quick, maybe taking a few hours in full sunshine or all day overcast