Battery on its way out?

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edd_jedi

Active member
I've noticed that my car is struggling more to start at the moment. It may just be winter, but I've done over 1500 miles in the last month so there's no way the battery isn't getting enough of a charge. The car is on its original battery (I think) so could well be on its way out, just wondering what the best method to test it is? I have a multimeter but no idea what to do with it :) Also have INPA too if that's any help. I just don't want to spend £100 on a new battery if it's the alternator or something.
 
check what voltage your getting across the battery with everything turned off.. anything less than 12.4 or 12.6v indicates a faulty battery (I can't remember if it's 12.4 or 12.6.. I'm sure CJ will be here in a sec to confirm lol).

You can also pop into EuroCarParts and they can test it for free for you :thumbsup:
 
.........and then test with the engine running |(and no additional electrical items in use) and if the alternator is OK you should read between 13v-14v across the battery terminals. Sounds like the battery - after 5 years its done fairly well.
 
Thanks guys. So I take it I need to remove it from the car (or at least disconnect the terminals) for the first test? As there are various electric things running even with the ignition off, eg boot light.
 
Not really, if that little bit of current is enough to materially drop the measured voltage, your battery is done anyway.

Technically, you are correct, a connected load skews the voltage reading, in this case it's not enough to make a difference.
 
I had done over 1100 miles a little while before my battery and starter motor died.

£67 for a bosch s4 from eurocarparts. Worth it for the peace of mind over winter.

Previous battery was a bmw one that lasted 5 years.
 
Just gave it a try, getting 12.6 with engine off and 14.8 with car running and everything off. Sound about right? If so what else could be causing it to struggle to start? It doesn't REALLY struggle, it just sounds like the starter motor is a little slower than it was a month or two ago. And it's more noticeable when the car hasn't been used for a few days. Maybe just the weather?
 
All sounds spot on voltages to me. Firstly if the battery is struggling after starting the engine you'd expect to see the warning light on the dash.

Turning a little slower in cold weahter is also normal as the oil is thicker, more engine friction, etc.

Personally I would not worry, but if it really struggles then I'd be looking at the starter motor failing, but I don't think it is, nor bother investigating. See how it all goes for a week or so.
 
Changed my battery as the zed was starting to struggle in the colder morning. Fitted a Bosch S4 from Euro Car Parts and now the zed starts without any hesitation :D
 
Proper voltages are only part of the picture. Low voltages indicate a problem, but proper voltages do not necessarily mean everything is fine. Batteries need do a certain amount of work without significant voltage drop. I've no idea what that specification might be for automotive batteries. There are battery load testers available that are essentially heaters in that a resistive load is applied to the battery, resulting in generated heat. If the battery's voltage is above a certain threshold with this load, the battery is deemed serviceable.

It probably not worth buying such a device ourselves, but auto parts stores and indy mechanics may have such a device.
 
Totally agree BCW, but given the circumstances I'd not worry unduly yet.
We have a Halfords chain that will check free if carve. Alternative is to put the headlights on and see if if still starts or they just dim greatly.
 
AlanJ said:
.........and then test with the engine running |(and no additional electrical items in use) and if the alternator is OK you should read between 13v-14v across the battery terminals. Sounds like the battery - after 5 years its done fairly well.
Click to expand...

My BMW battery is close to its 10 year birthday - I guess that I've been lucky.
I realise that it's on borrowed time though and I'm expecting it to start playing up before too long!
 
I should have posted this here in the first place ...
:headbang:



Battery Replacement

Postby Bumpy - Thu Nov 28, 2013 5:18 pm
Replaced the battery today.
Of course I waited til the temp was -8 degrees celcius
But it was sunny.
The original battery was just over 5 years old and had been getting more and more lazy.
After a short time resting in the garage, the Zed would labour to spin the starter.
So I had been using the smart charger and often it would take 24 hours to return to fully charged.

Picked up an H6 battery at Walmart. $123 Canadian.
I avoided any electrical issues by leaving a battery charger connected to the remote connectors under the hood (bonnet)
In the trunk (boot) it was pretty straight forward.
The H6 was a little more than an inch longer, so the stock plastic hold down / brace on the right side was removed.
Actually that port is where the tire (tyre) repair kit is stored, so that hold down is redundant.
Not to worry cause there are two other hold downs to keep the battery where it is supposed to be.

Could have been a 15 minute job except that I was convinced I could mod the redundant hold down bracket to work.
After I gave up on that it looked like an hour to me.

Cheers
Bumpy
 
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