[ksowden1]

I have a Maintenance free Ac Delco battery which I have left in the garage and has lost all its charge over about 10 months. I've come to recharge it and I've read in the Haynes Manual that these batteries if allowed to completely discharge have to be charged by a special charger because home chanrger haven't got the oomph (best word I could find!) to do it. On leaving it to slow charge for 12 hours, I can see what they mean. What/where can I go to sort this? or is the local battery tip going to be beckoning, I hasten to add it's a good battery, only taken out because the saab it was in has been off the road for that time.

 

[cdcarlsson]

Hi,
The problem is that a normal charger won't be recognising that the battery is connected, as the voltage (in the battery) is so low.
A possible solution can be to connect the duff battery and a good battery in paralell, with the charger connected to the duff battery as well. This may have the effect of 'waking up' the charger allowing it to start charging. After a while, if charging commences, dissconnect the good battery to just charge the duff one.

 

[MikeH]

Most garages with breakdown facilities carry the gizmo you need , also the RAC & AA I think.
I will be interested to know if you manage to resurect it,
If all fails try this,buy a Halfords battery,with its three year guarantee , it will not last the three years so swop it under the guarantee ,I am on my third having purchased the original over four years ago.

 

[Paul D]

Nice one Mike H!
I once had a similar experince with Kwik Fit exhausts, which had a two year guarantee and a life on one year before the baffles failed!

I understand that some 'modern' car batteries will do not hold their charge well after they have been completely run flat. But I will watch the conlclusions to this thread with interest.

CDCarlssons is a good trick, but always be careful charging any battery, especially in tandem, as the charged battery may discharge at a high current rate into the dead battery. And all batteries normally produce hydrogen gas when charging, so watch the sparks when connecting and disconnecting!

 

[Harvey]

If the battery has been standing for as long as 10 months it may well be *dead*.
Any battery 'in store' should be charged regularly to keep it fully charged.
btw 'Unipart' also do a lifetime gaurantee battery. I had one on my 9000 for 5 years before it died and now have a free new one. This gauantee is not transferable to a subsequent owner though.

Harvey

 

[JFP]

I can't remember the name of the manufacturer, but I purchased a ''battery conditioner'' (£40 approx) for my motorbike which I also use on my cars if they have not been used for a while. Allegedley they give out a ''spikey voltage'' which breaks down the build up on the battery plates. I put it down to black magic personally but they definately work and can bring batteries back from the dead if all thats wrong with them is that they have not been used for a while.

£40 seems a lot for a battery charger device, but i have ruined 2 or 3 £60 motorcycle batterys using a normal battery charger

I will look for the manufacturer tonight.

 

[cdcarlsson]

The motorcycle device is an Optimate charger, which puts out around 21 volts to wake up a discharged battery(but drops down to a normal charge later). It now retails at around £45 or so.
I've got one and it certainly brought an old motorcycle battery to life, but as for a larger car type I'm not so sure, although I've heard encourouging third hand reports.