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Hi everyone, new here and have been reading so much! What a great forum.
We have an off grid solar system comprising 24x270w panels, 8kw hybrid inverter and 16x12v 200ah batteries. Batteries are connected as 4 sets of 4 batteries in series to create 4x 48v 200ah, 800ah total. Average production is 6kw a day and average consumption is 3kw per day. The system has been running OK for 2 years but now we are showing very low voltage early in the morning before the sun comes up. The load is only about 200 or 300w per hour overnight. State of charge is never lower than 92% but voltage is low. This could have been gradually getting worse over time and we have only just noticed.
I have tested the batteries and 1 battery within each 48v bank were showing 10.5v and all the others were 12.8 to 13v, so 4 bad in total. The low ones were only one in each string. So I removed the bad and set up the system to have 3 sets of 4. Same problem overnight with low voltage so I tested again and there was again one low in each new set.. So I tested the first 4 low ones I checked and removed and they were all testing good again! I put them back in and the next night tested again. Once again, one low battery in each set but completely different batteries.
I have now cleaned all the connectors and tried again, same 4 showing low but I know if I move them around they will show normal voltage in different positions. It's driving me crazy. I only have a multi meter at present and we live off grid on a remote island in Fiji with no access to real shops or amazon! Has anyone got any suggestions before I replace the whole damn lot?
We have an off grid solar system comprising 24x270w panels, 8kw hybrid inverter and 16x12v 200ah batteries. Batteries are connected as 4 sets of 4 batteries in series to create 4x 48v 200ah, 800ah total. Average production is 6kw a day and average consumption is 3kw per day. The system has been running OK for 2 years but now we are showing very low voltage early in the morning before the sun comes up. The load is only about 200 or 300w per hour overnight. State of charge is never lower than 92% but voltage is low. This could have been gradually getting worse over time and we have only just noticed.
I have tested the batteries and 1 battery within each 48v bank were showing 10.5v and all the others were 12.8 to 13v, so 4 bad in total. The low ones were only one in each string. So I removed the bad and set up the system to have 3 sets of 4. Same problem overnight with low voltage so I tested again and there was again one low in each new set.. So I tested the first 4 low ones I checked and removed and they were all testing good again! I put them back in and the next night tested again. Once again, one low battery in each set but completely different batteries.
I have now cleaned all the connectors and tried again, same 4 showing low but I know if I move them around they will show normal voltage in different positions. It's driving me crazy. I only have a multi meter at present and we live off grid on a remote island in Fiji with no access to real shops or amazon! Has anyone got any suggestions before I replace the whole damn lot?
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