Reviving a 12v jump start battery from 0v - possible?

[Beanwood]

I'm helping clear out my dad's garage.
I've managed to avoid most of the rubbish, but couldn't say no quickly enough when he foisted a Halfords 100 jump start pack on me.
Of course, it was flat, and has been for some time (Probably years) and he has no idea where the charger is.
Pulled the 12v lead acid battery from it this morning, and iy's COMPLETELY dead. No volts at all.
I tried charging it in parallel wit another battery, and it got up to 2.5v.
I have no need for a jump start pack, and can't see where I'd ever use one - so don't want to spend £30 on a new battery.

Long story short - before it all goes to the tip, (Or on here as free to collector) has anyone ever succesfully revived a dead 12v battery?

 

[knighty]

if it's been at 0v for years it'll be dead/useless now, no real point trying to save it :-(

 

[Robotstar5]

I used an SLA (sealed lead acid) slow charger to bring one back, but it died again after a few days so probably scrap.

 

[anto44]

I was given a booster pack under similar circumstances a few years back and managed to get it back by charging it in parallel with another battery but its capacity was so low it was useless

 

[RonA]

I was told that if the battery voltage drops below 10V they're as good as scrap. RonA

 

[gordon stephenson]

Bin it,

 

[Nomad]

I had a flat (2 volt ?) gel battery on a modern 2007 BMW, that came back to life fine using a modern smart charger - I was very surprised !

I've also spent far too long trying to bring back dead (under 6 volt) SLA batteries, some do improve but are never good enought to use. Now I don't even bother trying...

Modern smart chargers refuse to even try to charge dead batteries, if you want to attempt it your best chance is to get something into it using an older "dumb" charger then switch to a smart charger Keep us updated

 

[Ross365]

I was told that if the battery voltage drops below 10V they're as good as scrap. RonA

When they go below ~10V the chemical reactions change. Above 10 volts, it's fully reversible, so charge-discharge goes on for years. As some point around 10V, the battery can provide power, but it's achieved through an irreversible reaction. It won't necessarily destroy the battery but it will certainly reduce its future performance. Repeated deep discharge just causes more damage.

The modern "smart" chargers sometimes have a "pulsator" function which generates high-frequency voltage spikes which appear capable of "blasting" off layers of sulfate from the plates and restore (some) performance. I have a stand-alone pulsator built from a kit many years ago and I'm convinced it works, but the supplier is no longer in business. For more info, Google "battery de-sulfators".

 

[julianf]

There is also a theory that leaving a non sealed battery gassing for some time will also remove the junk from the plates.

A dumb old charger is needed for this.

I would try this, just out of interest rather than hope of success, and then take the unit to the scrap yard (ie get paid for the unit) rather than the dump.

 

[knighty]

^^^ that's a good point... if doing it for intrest

I saved a 24v forklift battery bank like that... left it on charge forcing 10amps into it for a week after advice from people living off grid on batteries. ... don't know what % I 'recovered' it to.... but it was more than enough for my use :-)

 

[Beanwood]

Thanks all. For interest only, I'll have a dig around and see if I can find an old battery charger, but I don't hold out much hope.

 

[Barking Mat]

My boss tells a story, of how his colleague, had a dead battery, changed the acid, inversed the polls, ie, +ve and -ve, and managed to reuse it, I hesitate to say, this is just a story I heard.

 

[The_Yellow_Ardvark]

The batteries are sealed Lead gell batteries.
They are cheep enough from screwfix of othe rplaces.
They only have a life of 4 years.

 

[brightspark]

once there gone thats it. if it was possible no one would be buying new battery's

 

[Screwdriver]

I did once try every internet old wives tale for restoring dead lead acid batteries, High voltage, epsom salts, flush and acid etc.

Nothing worked. Sometimes you can get some volts but no amps and for no time. Epsom salts "work" by destroying the battery, maybe just long enough to jump start an iPhone.

Scrap if for lead.

 

[premmington]

When they go below ~10V the chemical reactions change. Above 10 volts, it's fully reversible, so charge-discharge goes on for years. As some point around 10V, the battery can provide power, but it's achieved through an irreversible reaction. It won't necessarily destroy the battery but it will certainly reduce its future performance. Repeated deep discharge just causes more damage.

The modern "smart" chargers sometimes have a "pulsator" function which generates high-frequency voltage spikes which appear capable of "blasting" off layers of sulfate from the plates and restore (some) performance. I have a stand-alone pulsator built from a kit many years ago and I'm convinced it works, but the supplier is no longer in business. For more info, Google "battery de-sulfators".

I got a Bosch battery charger that does "reclaim". I reckon too it works to a point.

 

[Ross365]

I got a Bosch battery charger that does "reclaim". I reckon too it works to a point.

Yep, the fact is that there are 3 or 4 factors that will kill off a battery and sulfation is only one of them and the pulsators don't work on the other issues.

 

[Keith 66]

I remember reading a fix in the morris minor magazine, some people claimed that adding EDTA powder to each cell would remove the sulphate & allow a dead battery to be revived. I thought it might be hard to acquire but a quick google reveals its freely available on amazon, Havent tried it myself!

 

[Cobbler]

There used to be some pills sold that would revive a tired battery. I tried them once, turned a tired battery into a knackered battery!

 

[8ob]

There used to be some pills sold that would revive a tired battery. I tried them once, turned a tired battery into a knackered battery!

Bat aid? guaranteed to disappoint

https://images.esellerpro.com/3449/I/659/70/GRA0020 - Bat Aid 24g.jpg