[Harry Lake]

Because of continuing electrical problems, if I don?t use my car for a week or so I have to charge the battery. I connect the charger to the battery terminals without disconnecting the battery from the car?s systems. This has never given any problem and I have been using the charger this way for several years now. I have an electronic charger which states very clearly that there is no need to keep checking whether the battery is charged or not because you cannot overcharge the battery thanks to the system?s cunning electronics.

Last time I put the battery on to charge, illness and rain combined to persuade me that there was no need for me to disconnect the charger.

Last night I wanted to use the car for the first time for about three weeks, and although the last time I looked, a few days ago, the green light had happily told me the battery was charged, now the car and battery are as dead as a dodo. Even the central locking doesn?t work. Even the LED on the front of the radio has gone out. Reconnecting the charger produces nothing at all.

Have I fried my battery, my charger, the car?s electronics, or a combination of these?

Cheers,
Harry Lake
'93 CSE2.3T auto

 

[MikeH]

I think you should start from the begining,check the fuse in the battery charger,also make sure that you have mains voltage,then check the battery.Have you tried fitting another battery?
Mike

 

[Harry Lake]

Haven't had a chance yet, as I only discovered the immediate problem (i.e. deadness) late last night (Saturday). Nor have I had time to find out how to extract the fuse from the charger: it had occurred to me to check it, and I know where it is, and I know how to insert a screwdriver and turn its holder 90 deg, but I haven't worked out how to actually extract it. This thing is made in the Saarland, which suggests to me (I jest, of course) that it may be a mit bixed up, not to mention combining bits of the German and French mentalities.

Your reply nevertheless is most heartwarming in that it doesn't immediately conclude I am in for bills running into several times the value of the car!

Cheers,
Harry

 

[djtaylor]

Harry, I agree with Mike. What's most likely is that the battery charger fuse blew (or some other fault in the battery charger/mains supply) and then the car battery has just run flat.

Deep discharging a car battery can severely damage the battery. Probably best just to buy another and end the problem.

David.

 

[Harry Lake]

Thanks David. I'll keep you all posted.
(As a matter of interest David, what kind of camera are you using for those shots of your A/C?)

Harry

 

[djtaylor]

Just a plain little Canon S30 (3.2 Mpixels)

 

[Harry Lake]

Well, I went in to buy a new battery but the manager overheard the conversation I was having with the salesperson and took an interest, suggesting I bring in the old battery and the charger and he would have a look. Upshot: battery now recharged by dint of charging with another battery in the circuit; apparently this is a cunning trick that sometimes works with an apparently utterly dead battery like mine.

The mystery remains: why did my battery run down so comprehensively? Failing anything else, I am sticking to my theory that my charger is a bit primitive and was simply unable to tell that the charge in the battery had fallen again.

Anyway, it didn't cost me a penny (I'm not counting the spare wiper blades I bought). That's what I call service!

Cheers all,
Harry

 

[kommando]

My God, you wouldn't get service like that from a parts place in the UK like that. I had an Audi 100 and was sick of all the £70 quotes I was getting for batteries, when challenged why it was always 'Oh its a special battery sir' Luckily I knew otherwise

.

 

[djtaylor]

Harry, when I was trying to revive a dead battery, I did a whole lot of digging around on the web and I think you'll find that the problem is that when the battery deep discharges, the plates suphate. This is a hard coating that is high resistance with the result that some battery chargers can't deliver the current to break down the lead sulphate.

The Accumate range have some that do but that's another issue altogether.

I would expect that if you stick another battery in the circuit, the charger is able to deliver the current to that battery but i would have thought that if the flat battery was still presenting a high resistance that all the useful current would still be going to the good battery. I'll be interested to know what longevity this solution offers.

Deep discharging a starter battery is a bad thing, deep discharging is for leisure batteries of the kind that you find in caravans and boats whereas a car battery is aimed at a high start current which should be replenished straight away to prevent sulphation of the plates.

David.

 

[johncc]

Did he connect them all in series, or all in parallel? In parallel would make more sense.

My old boss said that when lead-acid batteries do that they need a big kick. This could be either physical or electrical, he said. Sometimes he reckoned a physical shock would be enough to disrupt the sulphate coating and start the charging. Sometimes he said you needed to give them an electrical "jolt" but I can't remember exactly how he said to do that! He was always quite gung-ho though, that guy.

Glad you got it sorted, anyway.

 

[Mark B]

If you put a good battery in parallel, it would provide the dead battery with a very significant jolt indeed. The charger would then charge both together.

 

[Harry Lake]

The batteries were definitely connected in parallel - I checked as I was interested myself (you never know - might need to do it myself one day!). The story was that these electronic chargers (at least, I think it was the electronicness of my charger that made the difference) need to have what the chap called (in Dutch) what I will call for purposes of argument and laziness "contra-current". This is something deeply discharged battery can't provide, whereas connecting the second battery into the system does, thereby fooling the charger into doing its stuff. I think it is basically a way of getting round what was conceived as a safety device to stop a charger trying to charge a broken battery.

Cheers all,
Many thanks for everyone's input!

Now all I have to do is find out what is draining the battery...