I bought a new 110ah leisure battery in August. I've never run it down to nothing and I've never overcharged it.
Today, after about 4 hours I had to drop the flow rate down as the battery wouldn't supply enough power to keep going. The pump was cycling every now and then.
The thing is, the battery was 13v this morning going on the van and when I connected up to recharge this evening it was 12.5v. According to the volts I should still have had plenty to keep going. The flow controller reads the volts as about 12.5v when the pump is dead ended but once the pump is running the volts are in the range of 11.5v to 11.1v.
I've checked all the cells, none are dry and none are furring. The electrolyte seems clear (from what I could see in the semi dark).
What's going on?