Battery woes

[Granadaman72]

Hi all, ive been having trouble with my battery not holding charge for more than a few days, ive had it checked and the guy said it had a bad cell i think it was. Now i know batteries don't last forever but this is the 3rd one in three years thats gone the same way Anybody suggest a cause for this? The car does spend a lot of time doing short runs or being parked up for a week or two at a time. Ive got a couple of amps fitted with a power cap, could there be a fault there or could the alternator be overcharging etc. Any suggestions would be welcome

[ejenner]

Doubt it's overcharging.

It's possible the battery you are using isn't powerful enough to run the car and the amps. Ford in the 70s and 80s (much like the rest of Britain) were doing things 'just good enough to work' and not leaving much margin for error.

That problem combined with leaving the car sitting around. You probably also have a power drain if anything is connected directly to the battery... which from what I've seen... amps often are.

You can check for current drain using a multi meter. With all accessories, engine and interior light off you take off the positive battery cable and put the multi-meter in between, i.e. one probe on the + terminal on the battery and the other on the positive battery lead. The multi-meter will then tell you if your car is draining the battery. A couple of hundred milliamps should be allowed for the clock and memory on the stereo.

Also check to make sure your alternator is charging properly. It may be the case, again with the amps, that it isn't able to charge while the stereo and other accessories are running. If you don't know how to do an alternator test just say, millions of people on here who can tell you what to do.

So would recommend a better battery, test the alternator on full load (i.e. stereo, headlamps, heater, etc, etc) and also test to see if the car is consuming excessive power while not in use.

You can fit a battery isolater if you don't want to do anything else. Although if the car is consuming faster than it is charging the battery will still fail.

[taurus]

As above - only just to add that one cell going down repeatedly is a sign that the batteries have been running at a low level of charge for long periods. Alternators won't top up a battery to full charge, they just replace the charge used to start the engine. So the battery may have been depleted and stayed at a low charge level even though the car was firing up OK.

In addition to checking for drain and fitting a better/bigger capacity battery - if you're only doing short runs consider a monthly overnight trickle charge to keep the battery above the charge level where cells will die.

[Granadaman72]

Cheers guys, will check for a current drain and a bigger battery might be a good idea, the car is loaded with electrics, heated screen seats, etc etc so the battery is probably on the limit before i fitted the sounds.

[breng]

Buy the best battery you can afford.

It sounds as if the one in yours is marginal at best.

[clubbyal79ch]

I had a similar issue on my old maestro, turned out to be the boot light staying on. Just a thought

[ejenner]

That's the sort of fault you'd hope to uncover with a current draw test. Just to see if there is anything sucking power when it's meant to be all turned off.

[fred]

Apr 20, 2014 6:49:23 GMT clubbyal79ch said:

I had a similar issue on my old maestro, turned out to be the boot light staying on. Just a thought

Indeed, had the same hassle with my 7 series, went through 2 batteries (Big mo fo's)
in 12 months only to discover the darn boot lights wouldnt go out 160 quid in batteries for a bloody boot light be curse word

[retrowrongun]

If you do see a current draw via the multimeter when all is supposed to be off then to save some time and help diagnose we're fault lies try this

Just pull each fuse one by one until you see the meter reading drop , this should then pinpoint the circuit with fault on it so you can then investigate further

Would also go over every earth point and clean them up too

[Granadaman72]

Thanks all, ill have a good check on things once i get chance