I Think My Battery Has Had It....

[alphacharlie 0]

The car has been parked up a few times recently for more often than usual and each time I've come back to it its a non starter, with the battery charged overnight its fine. Spent some time today looking for culprits and first off found a draw of 58mA (if I got the scale right) with the multimeter in between the + post and lead. After reading about faulty interior lights I removed the bulb from the glovebox, boot and interior door switched light. That left me with 18mA. So with the battery charged and connected I get 14V across the posts, engine running 16.4V, all elec stuff on, 15.9V. All higher than the Haynes stated 14V but on an uncalibrated multimeter. So just went for a drive ( in the dark) all lights on and fan blowing too, every time I braked the battery symbol on the dash illuminates

 

I am lead to believe that a battery beyond its best can cause all sorts of issues including pulling too much power from the alternator.

 

So do I bite the bullet and spend £60 on a nice new Bosch Silver from Halfords (trade price) and hope that the alternator isn't the cause of killing the battery due to a knackered regulator? although I believe that would prevent any charging taking place.

 

Any comments welcome as I'm a dullard regards electrical stuff at very best.

Cheers

AC

[Tom Fenton 1,548]

Andy, from when I had the car I'm fairly sure it is that alarm which is draining the battery down, I'm also fairly confident there is nothing amiss with the alternator.

I would try your currrent draw again, but pull the fuse to the alarm if poss and then see what you get!

 

Is the battery light illuminating dimly, if so this seems to be quite a common problem on 205's, my red car does it, but it doesn't seem to have any ill effects.

[jackherer 543]

If your multimeter is right it sounds like the voltage regulator in your alternator has failed which has then overcharged the battery as you say.

 

If you don't trust your multimeter then you should buy a new one first, then if it is really 16+ volts when running buy a new alternator. Is the 14v reading when the engine is off? If so that does sound like its been cooked a bit by the alternator.

 

It might be worth putting a new battery in your multimeter, they sometimes give odd readings when the battery is low.

[Anthony 1,003]

Those voltage figures sound too high, but if your multimeter is out of calibration that would explain it.

 

I'd expect to see around 12.5-12.8v from a charged battery, and 13.5-14.4v with the engine running (depending on load and alternator condition).

 

When you say that the battery light comes on when you brake, is it only very dimly, or is it bright? If it's very dim and only when you've full electrical load (in particular the fan) then I wouldn't condemm it just yet, as that's fairly common. If it's bright, then you might want to check that the alternator exciter wire (the thin wire with the spade terminal) isn't moving and shorting on anything under braking.

 

Have you checked to see whether the battery still goes dead now that you've only 18mA draw? The 58mA you had previously is quite high and would have flattened the battery over the space of a few days, particularly if the battery is getting tired, whereas 18mA sounds far more reasonable.

 

Only other thing I'd say is that I'd personally avoid Bosch Silver batteries on a car that doesn't get used very much and which can slowly flatten the battery - I've had no end of trouble with them on non-daily drivers and going flat seems to kill them, never holding charge properly again properly. The general Halfords batteries seem far better in that regard from what I've seen, and usually a fair bit cheaper too - something like £40 on trade I think.

[alphacharlie 0]

Andy, from when I had the car I'm fairly sure it is that alarm which is draining the battery down, I'm also fairly confident there is nothing amiss with the alternator.

I would try your currrent draw again, but pull the fuse to the alarm if poss and then see what you get!

 

Is the battery light illuminating dimly, if so this seems to be quite a common problem on 205's, my red car does it, but it doesn't seem to have any ill effects.

 

Cheers Tom,

 

Not found a fuse for the alarm as yet, the battery light was very bright with the headlight noticeable dimming each time I braked. I'm thinking the new battery and a conditioner should see me right but just wanted to run it passed folk on here as a sanity check

AC

[jackherer 543]

Is the battery light illuminating dimly, if so this seems to be quite a common problem on 205's, my red car does it, but it doesn't seem to have any ill effects.

 

There is definitely something wrong if the light glows, even dimly. Its not one of those things they do as such.

 

Mine did it for ages and I ignored it as it seemed to work fine but one night it suddenly went on full brightness and it turned out the ring connector on the fat wire to the alternator had completely snapped off. I crimped a new one on and it didn't have the dim battery light ever again so the old ring connector must have been marginal for years.

[alphacharlie 0]

UPDATE:

 

After cleaning up the battery connections and confirming as many other connections as I could were clean and on the car has behaved itself, after the car was off the charger on Thursday I ran it over the weekend and this week and it has been faultless so far, picked up another multimeter so will have another poke around over the weekend and try and locate the alarm fuse and double check the drain and voltages with the new meter.

 

If it does play up again Halfords stock the batteries so I'll get one for the £43 they want for the calcium 4 year guarentee.

 

Cheers

AC