Car Batteries

[Beswad]

Having park my car for a week I started up my car today but discovered the battery was flat. I would imagine there are quite alot off people will have this problem this time of year. Does anyone know any good tips on how keep a car battery from going flat? I thought about disconnecting the battery leads would that help?

[booksworth]

A good battery that is being charged properly shouldn't go flat in a week. --- One reason for a battery to not be charged properly is a loose fanbelt. Do you hear a screaming sound under the bonnet for a few seconds after you have started the engine? If so, the fan belt is loose, and needs to be tightened. --- Another possibility is that you do lots of short journeys, which do not give the system enough time to charge the battery. --- Also check that the battery terminals are clean and tight. If they are a mass of corrosion, the current will not get through. -.-.- Disconnecting the battery leads is unlikely to help. If you have an alarm, it will probably sound off when you disconnect. If you don't have an alarm, the only thing draining the battery is probably the clock, which is truly negligible. --- Oh yes, electric radiator fans will also run on after you have switched the engine off. Check that yours stops, and doesn't keep blowing all week. -.-.- Hope this helps.

[booksworth]

Sorry, one more thing then off to bed. Make sure the interior lights all go out when the doors are closed. They are _very_ effective battery drains.

[Beswad]

Thanks Booksworth. I will have look at what you suggested.

[thebookbloke]

park on a hill

[Ralph]

I've been having EXACTLY the same problems with my 99 Golf. I used to use it every day, but now I only get to take it out at weekends. When I go out to it, there's never enough juice to turn it over.

I got one of the �2.99 multimeters from Maplins, disconnected the negative wire and put the meter between the wire and the battery (fully charged by now) set to read up to 10 amps. With nothing at all switched on, there was 0.9 amps being drawn out of the battery. It doesn't take a maths degree to work out that a 70 Ampere Hour battery with 0.9 amps being sucked out will be flat in around 3.5 days. Then I started methodically pulling and reinserting fuses untill I got to the one for the remote central locking. With this pulled, the current draw dropped to 0.06 amps! The fuse is still out to make sure the car starts next week!

None of this helps you, but it may give you a plan of attack to track down your problem. Mine is in for a service on Wednesday evening when I shall ask them about the electrics. I have two horrible feelings. The first is they will say this is normal (!?!) and nothing can be done, the second is that it will be really expensive to sort out. I'll let you know if you like.

[hertz]

Common causes of battery drain is a glovebox light or a boot light not going off. Suggest looking around at night to see if any stray light gives it away!

[BillyNoMates]

You should also consider the age of the battery which you did not mention. A typical lead-acid car battery has a useful life of at most 4-5 years. After that time, regardless of the type of journeys, the lead plates get coated in sulphate which you can little to reverse.

What is the age of the car ? Is the alternator a little aged perhaps ?

[Beswad]

The car is about 6 years old and I had this problem exaclty last year, so I bought a new battery.

I would guess it could be the alternator, but I will investigate all the possibilities suggested on here.

Thanks people.