Lost capacity

[dan_b]

I've got a 4kWh lead acid Powervault battery at home. Had it for quite a few years now, 5 I think?
Anyway, I've noticed that it's not giving anything like 4kWh of capacity anymore.
I asked PowerVault to do a diagnostic and they said that it's offering 2.6kWh of capacity.

My warranty ends in December. The PowerVault warranty will only replace it if it loses more than 50% of capacity.

Is there anything I can do to claw back some lost kWh with these lead acid batteries or is it a one-way street?
I can't remember the type/make/capacity of them any more.

[nowty]

Its a one way street and lead acid is said to be fecked when down to 70% or 80%. In fact I'm surprised they have lasted that long, only the good old forklift cells or maybe the Rolls brand with solid lead plates have the long life.

I'd love for Camillitech to post as he's the lead acid god, what he don't know about lead acid is not worth knowing. He has joined this forum but has never posted yet.

[Stinsy]

Lead acid batteries like to be at 100% all the time. The "leisure" batteries fitted inside a PowerVault can be damaged if discharged below 60% repeatedly or for extended periods. DO you know how much of the nameplate capacity a PV uses (how deeply does it discharge the batteries)?

Some people have reported good results reviving lead-acid batteries by overcharging them for a very long time. However this is usually temporary and they soon go back to their previous depleted state.

[Oliver90owner]

I use a CTEK battery charger for reconditioning lead acid batteries. It works, but lead acid are never going to be returned to 100% ‘as new’ condition.

My wife’s 607 lost all its ‘stand-by’ power and would not start the engine due to extended non-use during the first covid lock-down. Recharging with a normal battery charger was not unsuccessful, so I borrowed a CTEK charger from a friend and revived the battery. It has survived a further winter and summer but will likely be changed at the onset of winter.

I have since purchased two CTEK chargers (one for myself and one for my brother) and am very happy with mine. My friend has both the smaller version (same as mine) and the larger capacity version (charges large tractor batteries mainly).

I recently left my 106 with a discharged battery for a week (a fuel delivery problem and no time to fix it before leaving for Scotland). That came off and was recharged/reconditioned and is again working perfectly satisfactorily.

Best part of seventy quid, but definitely worthwhile, IMO.

[dan_b]

Thanks - I guess I can try force charging it for an extended period of time overnight and seeing if that does anything?

2.6kWh is better than nothing I guess, so it's still useful.

[Stinsy]

The challenge is that lead-acid batteries don't just lose capacity as they age, they become less efficient. So you lose more energy to heat. Not as big a problem if the PV is in the kitchen and it is winter...

You might think now is a good time to upgrade...