Car battery failure in a year

rodders

rodders

rodders

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When I bought a second hand Cmax, Ford replaced the battery as the previous one was faulty.
When I arrived home, I checked it and the voltage stabilised around 12.65, not too bad, but I thought it would be higher, perhaps around 12.8 for a brand new battery?

One year on, the missus said it struggled to start, checked the voltage, 12.25v and today 12.17v

Just charged it, charger said fully charged, checked voltage and it was 12.45v and I sat there for about 1 minute whilst it dropped to 12.31v. I'll see what its like in the morning.

Can I really have killed a battery in 1 year? Missus does use it for short school runs etc... but it normally get a decent drive over the weekend. Or did Ford just fit any old battery they had....
 
12.6v is about right for a fully charged battery. The car shouldn't struggle to start at 12.2 though. Newer cars feature smart charging alternators which only top up the battery when required so a fluctuating measured voltage is normal.
 
OK, I'll keep an eye on it. Don't want to splash out 200quid on a battery for no reason.

Do you think it's odd it was dropping from 12.45 to 12.3 straight off the charger?
 
What's the voltage with engine running, might be a dodgy alternator.
Also take a look at the date code on the battery, you may have been given one from another car. New battery usually has at least 3 year warranty.
Andi.
 
Just had a new battery fitted, Focus 1.6 for £70. That included the garage coming out to jump start me. I'd shop around if they're asking £200
 
Its the voltage under cranking that you reallyneed to know. If you have voltmeter with a Max/Min hold function you can hook it up, start the engine and check to see what the minimum voltage is.

It should not really drop below 10.5 volts under cranking.

If it drops below 10.0 it has definitely had its day.

adolf hamster said:
you spend 200 quid on batteries!? :eek:
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That isn't too far off the mark If the car has stop/start, but just think of the Jerry cans worth of fuel that you are saving each year for the trifling penalty of having to replace the special, double the standard price, battery every couple of years
 
Armageus said:
Depends what size engine and what technology battery is needed. The EFB and AGM batteries needed for start/stop systems are more expensive for example.
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My dad says that his mate has a bought a stop/start car and the batteries are stupid expensive.
 
Yes, it's start stop, but I never use it. First thing I do is turn it off.
I'll carry out some start voltage tests at work tomorrow.
Didn't know they cost that much when it first went faulty two weeks after buying the car. That's why i was straight back down ford.
 
Orionaut said:
That isn't too far off the mark If the car has stop/start, but just think of the Jerry cans worth of fuel that you are saving each year for the trifling penalty of having to replace the special, double the standard price, battery every couple of years
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jesus, if i get less than 4 years out of an £80 battery i feel short changed :eek:
 
Take a voltage reading as you're cranking the car. If you've got a graphing multi meter even better as it'll be really easy. Wouldn't pay much attention to battery voltage when sitting there but when cranking, and then also when running to see if it is being charged.
 
rodders said:
0 degree C this morning. 12.1v prior to crank 10.44v min on crank.
14.85v whilst running.
Seemed to crank ok
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especially Given that it is a chilly morning I would say that was fine.

Of course, the other cause of slow cranking is a dying starter, this is a bit harder to diagnose because you need a high current (500A+) DC clamp ammeter to measure the current reliably and this is a bit specialist.

Bad starting due to starter motor can also be intermittent.

As a rough guide, if it is cranking slowly, and the starter cables are getting warm then it is evidence that you have a starter issue (The warm cables show the battery is delivering lots of power, the slow cranking show that the starter is not making good use of it. Either that, or the engine is siezed :) )
 
OK, I'll leave it for now. It's been fine since that one episode the other day.
Once, and if it breaks, I'll know what to fix, lol

Thanks.
 
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