Undercharging lead acid starter batteries 1

[OGz]

Hi,

I have three vehicles that very rarely are used for long runs. This means that in general the batteries are under-charged.
I would expect 12.8v at rest from a fully charged battery in good condition. Mine are more like 12.2v. What I have noticed is that when the vehicle is started up and the alternator supplies current to the battery, the voltage rises very rapidly to 14.4v, so presumably there's little point at this stage of giving the batteries a long charge via the alternator. Unfortunately I don't have a good battery to use for comparison - would a good battery take time to gradually rise to 14.4v when the alternator is supplying current?

At the moment I am experimenting with applying a re-conditioning charge to one of the batteries to see if it will result in removing some of the sulfation and hopefully increase the resting voltage / capacity. I'm using a smart charger, and the rising voltage from 14.4 - 15.5v seemed to take a little while so am hoping it's having some effect. The resting voltage several hours after reconditioning charge was 12.5v as opposed to less than 12v, which it was after cranking the engine and failing to start (didn't take a reading before). How many reconditioning charges can I apply without risking damage to the battery?

 

[GregLocock]

Modern mass production automotive batteries are designed very exactly to their designed use cases. So the basic assumption is they'll never go flat, not be needed to churn the engine over for half a minute, will get charged up immediately after starting, etc. That's why they cost so little, but also why they are not robust once you mistreat them, and don't last forever.



Cheers

Greg Locock


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