Yuasa 12V lead acid gel batteries- keep or throw?

[Alan Fistula]

I have had three of these 12v batteries sitting in a drawer for a number of years after accumulating them from various places. I don't have a Yuasa ch arger and I have never attempted to charge them. The multimeter shows each one at ~1V. They are 12V batteries. Are these things likely to be knackered, or might they be serviceable? I'm not sure what would be the appropriate way to charge them. Would a car batt ery charger be dangerous, being designed for batteries that take a much big ger charge?

Cheers. Alan.

[Dave Plowman (News)]

If any type of lead acid battery is left flat for a long time, they're usually scrap.

[cl]

After being left discharged for a long period they will almost certainly be dead, lead acid batteries don't like being left discharged.

[Brian Gaff]

Yes, I had some dryfit ones like that. Since you cannot get to the cells to do anything with them, they are probably knackered. You might be able to charge them with a car charger that has a trickel charge setting as this would not warp the plates with the current being drawn by knackered cells, but I think you are on a loser, personally. Brian

[newshound]

As others say, almost certainly dead. You don't say what size they are but I think you will get more than a fiver for a car sized battery from a scrap metal dealer these days so maybe worth scrapping if you have one locally.

[Dave Plowman (News)]

If a cell is truly knackered, it won't draw any (appreciable) current - that's the problem, as the internal resistance goes high. A way to try and recover a completely discharged lead acid is to use a much higher voltage than normal in an attempt to reverse the chemical state by getting at least some current flow. Something like 30v to a 12v battery is a good start - using a decent bench top power supply with current limiting. (Many car battery chargers won't even connect to the battery if the battery voltage is too low) Maybe over several days. If the cells do recover, its internal resistance will go low and it can then be charged normally. I've had some success doing this to a car battery where lights were left on over a couple of days so it was totally flat - but not tried it with one which has been left flat for ages.

[Lobster]

On 23 Nov 2014, newshound grunted:

I have a small pile of scrap copper and lead round the back of my shed which usually gets weighed in every few years, depending on the level of my DIY activity (my house used to have lead gas piping all over the place, and it gets hauled out every time I have a floor up!), and as it happens I've just added a knackered, sealed car battery to it having replaced mine last week.

Just wondered - is it worthwhile/costeffective to drain/flush it out and carve it up with an angle grinder or something, to get the raw lead out before taking it to the scrappy?

[harryagain]

I have tried thi in the past. Couldn't find any metallic lead at all. Just gunge between th spacers.

[meow2222]

If you do you'll have a bunch of powdered lead compounds to deal with.

NT

[Grimly Curmudgeon]

Usually futile. My successes have been with ones that have not been dead flat for very long - forgotten about and self-discharged, yes, then discovered not long after that. In all these cases they've been batteries which would have normally had a fair bit of life expectancy in them, but old knacked ones are a lost cause. Otoh, I'm keen to try out the alum treatment on one or two old ones to see if they can have an extended life as back-ups in a low-demand, occasional-use bank.