question Flat Battery won't take any charge

[N.O.S.]

OK I've forgotten something fundamental here.

 

6V conventional lead acid battery, 3 months standing went from full charge to zero. My old fashioned 'as many 2v cells as you care to put on' rectifier charger has packed up and I've only got these new fangled 'intelligent' chargers - although they seem too dim to realise there isn't any charge in the battery, and don't seem able to get the charging process underway.

 

So how to get it to charge?

 

Voltage readings : Cell 1 (neg. post) 0.19V :-( Cell 2 0.13V :-( Cell 3 (pos. post) 0.04V :-(

Edited September 21, 2011 by N.O.S.

[ChasSomT.]

Someone will be along soon with an exact answer, but as I understand it, you have to put something with a voltage your charger can 'see' in circuit with your dead battery to 'kid' the charger to start. Another small battery, perhaps?

 

Best I can do, sorry!

 

'Chas.'

[N.O.S.]

Like another 6V in series and try on 12V charge, or another 6V in parallel and try on 6V charge......

 

I suspect the series set-up would cause the charger to still think it was open circuit, but will go and try this.

[Tony B]

Have you a six volt vehicle? Plug it in and jump start with twelve volts. Then let it tick over. The plates may well have sulphated, something like bat aid might work. The intielligent de sulphating chargers work by pulsing the current intially, mine has a handy manual desulphate button. Though if the battery is totally flat it may well be worth leaving the charger connected for twenty four to forty eight hours to see if it will take a chrage. One of mine took a week, but now is perfect. You might also try a couple of minutes at twelve volts to defibbulate it.

[rbrtcrowther]

We have a huge "intelligent" charger at work and it won't charge a dead battery. i normally connect another battery in parralel with jump leads to give the flat one a kick up the arse and and let the charger know there is a load on it, then disconnect the good battery. However if the battery has been left flat for a few weeks it is more than likely knackerd. Does it look fat?

[Tony B]

On this subject, looking at long range forcasts we are due for a long bloody cold winter. Worth wrapping batterys in insulation, even if use. There are purpose built kits available. I normally use old rubber mats.

[paulbrook]

Long and bloody cold eh? Well that will be a bit like last year then where for an entire week my workshop never got above minus 7. My store got down to minus 18, killing a brace of batteries and a tractor engine block which had anti freeze in but obviously not strong enough.

 

Dont let anyone tell you that even a weak solution of anti freeze never goes solid, it does.

[N.O.S.]

Well, those wretched chargers are crafty and take a bit of fooling....

 

I put another good 6V battery across the dud in parallel (no flow of wrigglies as flat battery appeared virtually open-ciruit to the good battery), then after 4 minutes connected charger. Light comes on - so after 2 minutes I disconnected good battery from jump leads. Light stayed on - hahaha I thought.

 

After another 4 minutes I had to momentarily disconnect charger so I could remove the insulated jump lead croc clips, plugged charger back in and no light .

 

 

So - put on jump leads differently so I could later remove them yet keep charger croc clips comnnected, and put good battery on line, charger worked, immediately removed good battery and jump leads with charger still connected and all good so far.

 

I have concluded that my intelligence, whilst not great, appears to be marginally greater than that of the charger. :cheesy:

Edited September 23, 2011 by N.O.S.

[N.O.S.]

Progress report - Sep 25th, 2011, 23.00hrs.

 

I'm begining to suspect that I might have been outwitted by the charger after all - the light is on, but nothing seems to be going in. I'm going to give it a few more days to play ball and then.....:angry