sprucegum
New Member
I'm in the process of ordering a replacement LFP battery, but am still trying understand what is on with my FLA bank (4x 6v GC-2 215ah) which I've had for about 6 years.
While I've always had voltage drop issues on my battery bank (for about the past year it has often been dropping to by 1V or more for loads of about 20-100w), yesterday afternoon, after charging it to float with a new Victron MPPT, it suddenly began completely failing. I had my bank configured as 24v and it was cycling to 11v and back up when placed under even the slightest load (less than 5w DC). And sometimes it seemed they were dropping to 6v.
I checked SG and while my batteries are depleted (SG .1220-.1225), they should still be able to provide at least 50% of their original AH. Degradation in my understanding of an FLA should be on the path of smaller and smaller storage capacity, not suddenly from one day to the next being unable to power even the smallest load.
I rewired for 12v, taking the best two 6v batteries and my least corroded cables and thought I was in the clear. It was working well enough in a quick test with no equipment other than my small load. So I hooked up my MPPT again, adjusted settings, and went on with my day planning on ordering my LFPs in the evening. But when the sun went away they were dropping to to 11v under a very small load again. And this morning, dropping to 6v when I tested them with nothing but one of my 12v USB outlets turned on.
I'm probably doing something wrong, but on the theory that it was somehow the cables (even though those have remained constant and I've now hooked up a clean one between the two 6Vs in my reduced bank), I checked the voltage at the individual batteries, and whether the bank as a whole is dropping to 6v or resting at 12.6v the individual batteries are both reading 6.2-6.3v.
I get that they're shot, but still want to understand what exactly going on so I can learn from it. Plus, if there's some way to possibly get them working enough to skate by for another week it would greatly simplify my life (the LFPs are going to take at least a week to arrive, and we're off grid).
While I've always had voltage drop issues on my battery bank (for about the past year it has often been dropping to by 1V or more for loads of about 20-100w), yesterday afternoon, after charging it to float with a new Victron MPPT, it suddenly began completely failing. I had my bank configured as 24v and it was cycling to 11v and back up when placed under even the slightest load (less than 5w DC). And sometimes it seemed they were dropping to 6v.
I checked SG and while my batteries are depleted (SG .1220-.1225), they should still be able to provide at least 50% of their original AH. Degradation in my understanding of an FLA should be on the path of smaller and smaller storage capacity, not suddenly from one day to the next being unable to power even the smallest load.
I rewired for 12v, taking the best two 6v batteries and my least corroded cables and thought I was in the clear. It was working well enough in a quick test with no equipment other than my small load. So I hooked up my MPPT again, adjusted settings, and went on with my day planning on ordering my LFPs in the evening. But when the sun went away they were dropping to to 11v under a very small load again. And this morning, dropping to 6v when I tested them with nothing but one of my 12v USB outlets turned on.
I'm probably doing something wrong, but on the theory that it was somehow the cables (even though those have remained constant and I've now hooked up a clean one between the two 6Vs in my reduced bank), I checked the voltage at the individual batteries, and whether the bank as a whole is dropping to 6v or resting at 12.6v the individual batteries are both reading 6.2-6.3v.
I get that they're shot, but still want to understand what exactly going on so I can learn from it. Plus, if there's some way to possibly get them working enough to skate by for another week it would greatly simplify my life (the LFPs are going to take at least a week to arrive, and we're off grid).