charging a dead battery (Now more interesting!)

[Smokey Eddy]

Any tips on getting a very dead battery to charge?
I was away for about 2 months and in that time almost 1 litre of water had evaporated from the battery so I topped it up but the battery only reads 0.65v and my charger won't start charging it..  should I jumper cable a charged battery to it for a while or what? I think its still under warranty but if its just an issue of juicing it with a charge I'd rather do that.

[R.O.R-2.0]

Any tips on getting a very dead battery to charge?
I was away for about 2 months and in that time almost 1 litre of water had evaporated from the battery so I topped it up but the battery only reads 0.65v and my charger won't start charging it..  should I jumper cable a charged battery to it for a while or what? I think its still under warranty but if its just an issue of juicing it with a charge I'd rather do that.

did you add distilled water/sulfuric acid? or normal water?

usually when the plates go dry, they get oxidized, and are no good.. if that battery will come back, its gonna need a big charger to cook it for a few hours..

we used to have a 480 amp charger that did wonders to dead batteries.. it would make them boil in short order.

that batteries best chance is a big charger to cook some of the oxidation off the plates..

[8v-of-fury]

If its still under warranty get it replaced, it will never be as good as it once was without work.

[maxfax]

Sounds like you have one of those !@#$%^ new fangeled "smart" chargers if I'm reading this right.. They won't charge a completely dead battery, just a low one...  You can jumper it to another battery and let it charge a while till there's enough juice for it to charge on its own...  AS Kevin mentioned though, the plates probably dried out, even cooking it with a big arsed charger is never going to bring it back to what it was..

X2 on If you can warrenty that bugger at no cost do it....  

[bajacalal]

The way we used to deal with these when I worked at an auto shop was to throw it on a charger that puts out a lot of amps, like one that has a crank assist function and "shock" it a few times, cycling between off and a high amp charge every few minutes. Then, place it on a slow trickle charge. I'm not exactly sure of the physics behind it but it seemed to work on very dead batteries.

And if you have a high-frequency battery charger that might help, they deliver high-frequecy, high(er) voltage pulses to the battery which knocks the sulfate compounds off the plates. If the plates were exposed to air, I think they would have instead oxidized and I'm not sure it would fix that.

[Smokey Eddy]

I don't think the plates got dry. What I did was set my older charger to 12 amps and connect my digital charger to the battery and zap the battery with the older charger until it held or at least saw 11v. Then at that time the digital charger kicked on and measuring with my multi meter I saw that the voltage would indeed rise and fall (as high as 15.5v) when on the "recondition" cycle. The amperage I kept at 12 for the first few minutes then set the digital charger to a setting intended for super dead batteries which is a trickle charge that slowly increases. Once I find the warranty paper ill see if I can trade it in.

[maxfax]

Isn't it nice that someone had the common sense to design a battery charger that won't charge a dead battery??     I will say they are nice for maintaining a battery that sees little use.

[Smokey Eddy]

Well said :p

[ORCoaster]

Remember that the warranty is pro rata.  That means every month it is worth a little less when doing an exchange or will cost you more to replace it.  If it is an 84 month warranty and you paid 84 dollars for it then every month you have used it costs you a buck.  So don't be surprised when the man hands you a new battery and a bill. 

I do the shock and high amp charge with my charger.  It hits them with 50 amps then cycle it to 10.  Once the meter on the charger gets close to the 100% charged area I flip it down to 2 amps and it seems to drop the % down to 70 or so.  Hours later the little yellow light is flashing and I take it off.  Until the next time something goes wrong and drains it. 

I purchased a new battery a few months ago and it drained pretty quick on me one weekend when I was fooling with the timing.  Why do we do that stuff.  I thought it odd that the new battery would do that so I took it back and the shop tested it, my alternator, and starter.  When that was done he came back to the battery and found it to be much lower and draining outside his comfort level.  He pulled it, gave me a bigger cranking amperage one and sent me on my way.  No Charges leveled.  They only do batteries, starters and alternators and the guy knew I was just there and he really likes the VW.  Says something about high school days or something when I pulled in.

Any way, hope it all works out for you.  Either getting the old one to juice up or a replacement for free. 

[Smokey Eddy]

Thanks! It's a huge battery. Not original size at all. It's juicing up nicely now

[ORCoaster]

Any Clue why it went dead in the two months of non use?  Seems like something was amiss.  Leave the light on in the car so you could find it when you got back?

I have my radio wired direct so at times when I turn it down to talk to someone outside the car I forget to turn it all the way off.  It makes a funny click noise when the glow plugs kick on and I know I left it on overnight.  I have an Amp gauge that tells me I have juice going to the battery for longer than it should when I forget the radio overnight.  Otherwise it snaps back to about 5 amps after a bit down the road from start up.

[Smokey Eddy]

My deck always has power yes. It is the culprit I'm quite sure.

[bajacalal]

If it is an 84 month warranty and you paid 84 dollars for it then every month you have used it costs you a buck.  So don't be surprised when the man hands you a new battery and a bill. 

That's not exactly how it works. There is a free replacement period, usually between 1 and 2 years and after that the pro-rated period starts. Depending on how far into the pro-rata period you are, you might want to consider buying a new battery outright. This is because the warranty applies to the original sale date, so if you are on month 80 of month 84, you are paying most of the full cost of the battery for only a 4 month warranty. Of course, different battery might have different policies and individual shops do sometimes deviate from the warranty policy but this was how things were supposed to work when I sold batteries and I did not know of anyone else doing it differently.

Anyway, leaving any battery connected to the car's electrical system will eventually discharge (and possibly ruin it) if left for over a month or so as there are enough parasitic loads on the battery to do that (like the clock on your radio). Of course, it was low on it's fluid so that wouldn't help either but I really can't see how a liter of water evaporates out of a battery that fast considering it's regularly exposed to high underhood temperatures and you don't see that happening. Was it in direct sunlight?

[R.O.R-2.0]

If it is an 84 month warranty and you paid 84 dollars for it then every month you have used it costs you a buck.  So don't be surprised when the man hands you a new battery and a bill. 

That's not exactly how it works. There is a free replacement period, usually between 1 and 2 years and after that the pro-rated period starts. Depending on how far into the pro-rata period you are, you might want to consider buying a new battery outright. This is because the warranty applies to the original sale date, so if you are on month 80 of month 84, you are paying most of the full cost of the battery for only a 4 month warranty. Of course, different battery might have different policies and individual shops do sometimes deviate from the warranty policy but this was how things were supposed to work when I sold batteries and I did not know of anyone else doing it differently.

Anyway, leaving any battery connected to the car's electrical system will eventually discharge (and possibly ruin it) if left for over a month or so as there are enough parasitic loads on the battery to do that (like the clock on your radio). Of course, it was low on it's fluid so that wouldn't help either but I really can't see how a liter of water evaporates out of a battery that fast considering it's regularly exposed to high underhood temperatures and you don't see that happening. Was it in direct sunlight?

if i leave a car siting, and its a runner, i always start/drive it atleast once a month to keep the battery charged, and to keep all the fluids flowing..

[Smokey Eddy]

It was in a cool dark garage. Shocked to find it still charging at 12 amps this afternoon and the battery its self hot and steaming. Topped it off with more distilled water. Charger still classifies it as being "low". I'm thinking I should add more acid to it.