I know this isn’t anything to do with Arduino, but I didn’t know where else to ask it.
I bought an air compressor at a yard sale, and the battery was “completely dead” as the previous owner had said. So, I brought it home to try and fix it. I turned it on and the analog meter needle read about halfway. So the battery was not dead. So, I hook up my bench power supply to the charging port, set it to 12v (the voltage printed next to the port), and let it sit overnight.
I woke up the next morning to an unchanged meter needle. I thought maybe something was wrong with the charging circuitry, so I cracked it open, and there was the rather large SLA (Sealed Lead Acid) battery.
I disconnected it from everything and hooked up my multimeter. Instead of seeing the expected 12v, the battery read 8.3v.
I hooked the battery itself up to my bench supply, set it to 12v, and left it overnight again. When I got up the next morning and checked it with my multimeter, the battery read pretty much the same 8.3 volts as before.
Is the battery recoverable? Am I doing something wrong charging it? Or do I just need to buy a new battery?
The battery is a 12v 7Ah SLA battery.
How can I recover this battery, if possible?
I’m not entirely sure of the exact age, but the battery is definitely old. TASK FORCE # 202754 is the compressor.