Flat Battery

[KirstMin]

Hi all, I've read through all of the relevant posts on this topic and am still a little stumped...

I suffered from a dead battery a few months back - about 3 weeks after I had my engine switched to 1275 and halogens fitted. I assumed the old, knackered looming battery was the problem so I bought a new one from Halfords.

However, I went to start the car on Saturday after 10 days of non-use to find the battery didn't have enough juice in it to turn the starter. I managed to get it started with the handle and drove for 20 minutes - in the light with no heater etc. This morning, I checked and the car started OK.

My last 300 miles have been in the dark, with heater, stereo on, some has been motorway but some (2hrs at least) in traffic jams.

So I am wondering what the problem is? It seems that it occurs when the car is not moved for about 10 days or so. I've checked the earth straps and they are ok. Could it just be that the dynamo is being asked to cope with too many things and as a consequence I am not getting the battery fully charged?

I know a few people suffered from battery problems and their answer was to convert to alternator, would you say that it would be a good idea for me to do this?

Cheers

PS: the ignition light goes off and stays off when the engine starts

[Multiphonikks]

Hi Kirsten

1)I reckon you need an alternator. Come and join the dark side!

2) Take your other half with you to help start the car if she runs out of battery juice. Having said that - my other half wouldn't want to help start Hebe!

Seriously though - I'd recommend an alternator, especailly if you want to do more stuff in the future on a customization front ...

Finally - check that your radio (if you have one) doesn't have a constant live. Sometimes these modern radios can be a problem when it comes to draining the battery. Oh - and your last few hundred miles... Have they been quite short journies??? It could be that the battery doesn't have chance to re-charge between journies because they're short.


Oh, and have my sympathy. Carrie didn't want to start yesterday after a series of cold days where I had everything on but made short trips (not enough to charge the battery back up)

[Andy]

If you regularly leave your car unused for long periods then you can check that nothing is draining the battery whilst the car is parked by disconnecting the battery when you do so.

If the car then starts okay after being left, I would think that you have an electrical fault which is causing the battery to discharge over time. If the car will still not start then I would think that the battery is being insufficiently charged for some reason.

So long as the dynamo is in reasonable condition I don't see why it shouldn't be able to cope with halogen headlamps. It could be that your dynamo needs a bit of TLC. New brushes and a bit of clean up might be all that's required. The fact that the ignition light goes out doesn't tell you much about the charging capacity of the dynamo. It tells you a lot more when it comes on whilst your driving along!

Regards

Andy H

[simmitc]

There are lots of tests that you could run on the charging circuit, but it sounds as if the problem is a dain on the battery when it's not in use. You seem to have proved that when you drive the battery is charged. Also it's holding it's charge overnight (as it should being brand new!). I guess that you're looking for something using power when the car isn't being driven - courtesy light stays on, stereo left on, alarm going off undetected, instruments or warning lamps not switched from ignition, dashboard light, etc (dash lights should go out with the side lights, but on cars of 30 + years old, who knows what wiring previous owners did?).

To prove this, (if you're going to leave the car again) run the car as normal; then when you park up, disconnect the earth from the battery. Leave for ten days, reconnct battery and start. If all is OK then you have proved that there is a drain. Now all you've got to do is find it. It could be worn insulation or a faulty switch.

Happy hunting.

[KirstMin]

Happy hunting.

I never did like treasure hunts!

Thanks all for your advice. I guess I need to run some tests to find out where the fault is.

Nikki - it was in fact two LONG journeys - Sheffield to london and back again. But I was stuck in a tailback both ways, in the dark, stereo on, heater blasting and occasional windscreen wipers!

That said, I dont seem to have any probs when the car is running. It just seems to go flat when left for a length of time and this problem only seems to have started since the garage worked on the car over 2 months ago - before that I was able to leave the car for a month with no probs. Very odd...

[Packedup]

Did the garage do any welding by any chance? I know dynamos are pretty simple and robust, but I've seen alternators suffer if the electrics are all left hooked up when the mig comes out...

[Matt]

What did the garage do?

[KirstMin]

What did the garage do?

they replaced the engine with a Ital A+ lump. And then bunged the old periferals back on...

And a fair bit of welding. And a new gearbox.

[rayofleamington]

Well done for using the starting handle!

I'd recommend getting a battery charger and a mains extension lead (cheaper than an alternator and this also takes a lot less time than fitting an alternator)
Alternators are not very reliable, so unless you are driving hundreds of miles each week in nose to tail traffic, the dynamo will be fine and just top up the battery with the charger a couple of times in winter

Well - that's what I'd recommend, it's your choice about what you do.

[KirstMin]

What did the garage do?

they replaced the engine with an Ital A+ lump. And then bunged the old periferals back on...

And a fair bit of welding. And a new gearbox.

[Matt]

Now ray, thats impressive, getting your post between KirstMin's double posting

[KirstMin]

Now ray, thats impressive, getting your post between KirstMin's double posting

I've just seen a de'ja vu - must be glitch in the matrix

thanks for the info Ray. I've got a charger so good idea!

[Willie]

KIRSTMIN, I run a dynamo with radio,halogens, heater blower mostly on and
the Halfords battery is six and a half years old. I have no problems despite
sometimes leaving the car unused for three weeks at a time lately,so would
agree that you probably have something draining the battery. Assuming that
you do not have an Ammeter to test with then you could try the simplest
check which means disconnect one of the battery connections and,preferably
in the dark, gently touch it back to its battery terminal. If there is a current
drain somewhere in the car you will see a spark when you touch them together. DO NOT DO THIS WHEN THE CAR HAS JUST RETURNED FROM A
RUN as the battery would be gassing and could ignite. It is safe if the car has
stood for some time. Make sure the doors are properlyclosed when you do this.

[newagetraveller]

If you fit an ammeter you will find that while you are sitting in a traffic jam with the headlights on the battery is discharging at a not inconsiderable rate.

[rayofleamington]

If you fit an ammeter you will find that while you are sitting in a traffic jam with the headlights on the battery is discharging at a not inconsiderable rate.

true..
.. and to alleviate boredom, you can watch the ammeter jumping about when you put the indicators on. (my traveller has an ammeter - it seems fairly pointless to me, but it would probably highlght a fault if one occurred).

When to charge the battery is a bit of guesswork - I used to do it if/when the engine 'felt' like it was turning over a bit slower than normal.

[Chris Morley]

Standard lights, wipers and heaters draw 18 Amps together. Add a couple for the radio. A standard dynamo when brand new & 100% recharges at up to 22 Amps. An old dynamo with worn brushes might not even manage 18 Amps.

However to recharge the engine needs to rev above about 1500 - 2000 rpm. The dynamo doesn't work at all if the engine is simply idling (even when the ignition light goes out), you are simply draining the battery. I'm afraid this is one of the downsides of owning an old car. I would follow Ray's advice (& keep the starting handle to hand). An alternator is great until it fails: then you'll need a towtruck. It seems to be a regular & familiar experience for many owners with an alternator.

When to charge the battery is a bit of guesswork - I used to do it if/when the engine 'felt' like it was turning over a bit slower than normal.

Ditto! Started slowly this morning, on the recharger tonight.