Car Battery Life (and testing)

[Sheepshanks]

WorldBoss said:

Ideally you'd want to hook up an amp clamp to either to positive or negative cables from the battery, and check the charge rate going into the battery from the alternator. There's kind of a knack for reading an amp clamp and/or battery tester that you only really pick up by dealing with a LOT of dead batteries, but generally a charge rate of 10Amps or below on a completely dead battery is what I'd consider to be pretty knackered. A healthy battery will take in at least 25Amps+ before starting to trail off, but generally over a period of 10 minutes checking the amp charge rate you can make a decent prediction as to the health of a battery.

That's interesting - I thought 'modern' charging systems did little more than float charge the battery so a lot of time the issue is the car isn't being run for long enough.

The big battery on my little used Merc failed last week - at a mere 14yrs old! The AA man's tester said "replace battery" but he said it only just failed the test. It was showing charge at 14A which he seemed to think was fine.

[Red 4]

Yuasa.

Use GSF car parts or similar and use a discount code.

There's a reason why Yuasa batteries are OEM in lots of Jap stuff.

[Dave.]

ninjag said:

Dave. said:

Oooof, they're setting off my nerd-alert!

Ditto!

Ctek do them too, but twice the price.

[ninjag]

Sheepshanks said:

That's interesting - I thought 'modern' charging systems did little more than float charge the battery so a lot of time the issue is the car isn't being run for long enough.

I've always been under the same impression, perhaps partly because the alternator has to power all the electrics as well as charge the battery but also because if the charge rate is too high it may generate too much hydrogen gas and also prematurely wear out the battery, make senses to me. I'm guessing between 2A and 5A but certainly not 12A. Charging the BMW was a pain using the terminals under the bonnet as it wouldn't go above 2A and I didn't want to disconnect the battery in the boot in case it needed to be reprogrammed.

[PGN]

Somebody on this thread mentioned Tayna batteries on-line. They are good to deal with and generally the prices are very competitive. The only downside I have found is what happened to me when the battery failed within the warranty period. Tanya were fine about replacing it but it proved impossible to get it back to them. When a battery is sent out it is well packed in a kind of sealed bag thing. Apparently this method of packagaing has been approved by many couriers but they will not accept a battery from an individual however well they are packed. So I'd say that in reality if you buy a battery from any on-line retailer the warranty is worthless.

Edited by PGN on Tuesday 18th December 11:09