trickle chargers

Hello,

We recently had a baby so my other half has not been using her car for a few weeks. This, and perhaps the cold weather, caused the battery to go flat. It was flat enough that the starter would barely turn and the engine would not start but not completely flat: the central locking still worked, no memories were lost (or are they non volatile?).

I connected it to my battery charger and left it for a few hours. When I tried to start the engine, it came to life perfectly.

Do I need to be concerned that:

  1. this happened in the first place; at the moment I am not worrying because I think it was simply that the car had stood for so many weeks unused.

  1. that the battery may have been damaged by being discharged? I'm hoping since it wasn't completely flat and that it is working now that everything is ok.

Am I being over confident about either of these?

I've read that some people use trickle chargers to prevent this happening when their vehicles are not used. I've read about accumate, optimate, and the oxford maximiser which I understand are very clever and also de-sulphate (but it would appear that the battery didn't get that bad in this case). I think one of them (accumate?) is for bikes only; what's the difference between a bike battery and a car battery: just the size/capacity?

Do I need on of these or is that overkill? How long do you leave your car standing unused before you connect one of these?

One problem I had was that I had to charge the car on the drive because our garage is so full of junk that we can't get the car in! I see that these manufacturers sell a kit so that you can quickly and conveniently plug the charger into a bumper-mounted socket, rather than have to open the bonnet each time.

What are these kits? Are they just a couple of crocodile clips connected to the battery that run to a socket you drill in the bumper? Is it ok to leave these connected to the battery 24/7? I was just worried about the potential for short circuits if the cover was removed from the battery terminals.

TIA

Reply to
Fred
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It depends what is left running on the car when it's standing - burglar alarm etc? It's not susprising that after that length of time the battery was flat.

It is bad for ordinary lead acid car batteries to be discharged like this - the lead plates disintegrate. But it takes quite a few (30/40) deep discharges to do that. In normal use, the battery stays more than 50% charged. I wouldn't be worried about this if it's a once-off event. You can get deep discharge batteries that can withstand this sort of treatment - but expensive and heavy.

You may have reduced its life a bit, that's all.

I personally wouldn't bother if the car is normally in use. Your downside risk after all is just that you need a new battery a bit sooner than otherwise would be the case. Hardly worth fiddling around with a charger.

Reply to
GB

I would get a volt meter and check the voltage. If it's much below 12-

12.5.v before you try to start the car, then either charge it first or jump start from a spare battery . Trying to start the car on a flat battery will be even worse than letting the battery go flat in the first place.

I have a couple of batteries I keep spare, one from my old car that was scrapped 6 months after getting a new battery. I keep these charged up with a current regulated PSU . My automatic battery charger shuts off as soon as the terminal voltage hits 14.4v however you can charge batteries for several hours more . Therefore you battery is not fully charged when the charger shuts off. It probably needs a good couple of hours driving to get the battery to

The varta batteries I bought came with a 3yr warranty so no worries once you finally do have to bite the bullet and replace it !

Cheers, Simon

Reply to
mr p

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