Battery check

[Crispin]

So after suffering a bit of abuse (I forgot to remove the key from the ignition for a couple of days), I was certain my batteries are not up to the job any more.

I spoke to Mr-T (from whom I bought them 25 months ago) and he said I can bring them in, they'll check them and replace if necessary.
I got Halfords to do a quick test yesterday and they said “yup, each battery is only about 30% of what it should be.” They wanted to sell me two new ones at £109 each.
Roll on today and get them checked by Mr-T and he said they are fine. “They do need a really good charge” he said but no dead cells and hold the load.

So, why would Halfords say they poked and Mr-T did not. (let’s ignore the “Halfords want to sell me new ones, Mr-T would have to change under warranty) The “proof” I have that they are no great is on Friday night, the doors stood open for a few hours (maybe 3-4?) and the engine struggled to turn over when I started it. The same happens when I work on it with the radio on – it battles to turn after a couple of hours.
Anyone know what a drop test does? Load it places, duration which is considered acceptable etc?

 

[Chas]

Digressing slightly, is the illumination around the ignition switch supposed to go out when the key is removed, on mine it is on permanently.

 

[Beau]

sounds like your batteries are failing.

I had my music playing reasonably loud last weekend for about 5-6 hours, with my bass speaker in the back allong with the amp, doors open ect. Then started it the following morning and noticed nothing different. It doesnt take much to get these engines going to be honest but you do need good amps. If its struggling to turn over get them replaced by MR T under warranty.

 

[Jon Wildsmith]

Can't be much wrong with the batteries if they managed to winch you up that steep hill at Lincomb, that would take a lot more juice than your alternator can supply.

 

[Crispin]

I wish I had had a meter to show me voltage / current etc (next on list!) as I would have liked to have seen during the winch.

I've gone and got me another charger so will sort them out, one by one, over the weekend and see how things are.

Still have 11 months on warranty, here's hoping their either fail or last another 2 years.

 

[Brett]

Crispin,

take it to a proper battery seller or Auto spark & ask them to do a drop test on the batteries, if you're not buying new batteries from them they might charge you a couple of quid but they'll give you an honest indication of the batteries state.

 

[nivapilot]

Battery test procedure....

First off measure battery voltage. should be between 12.2v and 12.8v. if not charge them up.
Disable engine from running, diesel remove stop solenoid wire, petrol remove pump or injector fuse.
Crank engine for 15seconds and observe battery voltage. voltage should not drop below 9v during crank and should not lose more that 0.3v after.

If voltages drop off too quick, or battery fails to crank for 15 seconds and then start engine..........battrey/ies goosed and need replacing.

 

[Crispin]

I'll be finding a local guy tro test 'em and see.

nivapilot -
nice idea. Will give it a go and see how it fairs.

 

[nivapilot]

It used to be the standard battery test for the AA, before they got a battery tester.

 

[Crispin]

So after each battery spending 24 hours on a smart charger, I did the test on each battery individually. Each battery dropped to 9.8v during the performance and recovered to about .3 or .4 of the original voltage. There was very little drop off during cranking.

The fluke I have has a silly fast sample rate and graph to show history. You can clearly see where I started cranking as the voltage dropped to 6 odd volts for a couple of milliseconds and then back up to 9something thereafter.


Conclusion: I'll stop worrying now for another 10 months and check again just before warranty runs out.




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