Battery issue......

[00slk]

The battery on my 55 is about 11 years old and was registering 3.4volts a few weeks ago, so charged it up and it was fine until it went flat while I stopped off to fuel up. A jump start saw me back on the road again. Just been out to check the volts as the 55 hasn't been used for a week and the volts registered 12.3volts. On start up it registered 15volts at idle, so I decided to check the boot battery which was 12.9volts.
My question is should the starter battery be reading 15 volts or would it be safe to assume its on the way out? Don't want to spend money on a new battery if this one still has a week or two left

 

[mattkh]

2 Qs
When it was 3.4v, how long did you leave the charger for, and how many amps were going thru, 1 or 2 or 3 ?
Were you sing a voltmeter to check the voltage..?

 

[00slk]

2 Qs
When it was 3.4v, how long did you leave the charger for, and how many amps were going thru, 1 or 2 or 3 ?
Were you sing a voltmeter to check the voltage..?

I use my normal battery charger, but set it for 6volts over night then upped the volts to 12 volts, the amps were 2.2 amps on 6volt and 3 amps on 12 volt.
Using a my voltmeter to check.

 

[mattkh]

Thanks.
I always set it to 12v all the time. Then ideally use a low amperage for a longer time, like 24 hours.
Looks like you have successfully recovered the battery. It may last months.
15v when engine running is only a wee bit high. If it is not a digital meter, then may be the needle needs resetting.

 

[00slk]

Thanks.
I always set it to 12v all the time. Then ideally use a low amperage for a longer time, like 24 hours.
Looks like you have successfully recovered the battery. It may last months.
15v when engine running is only a wee bit high. If it is not a digital meter, then may be the needle needs resetting.

Thank you Matt.
It is a digital meter, maybe the battery is taking too high a charge, is that possible when they get old enough?

 

[mattkh]

Thanks.
I would check the voltage when revving the engine and see if the voltage gets any higher.

 

[Mr Greedy]

The battery should never be as low as 3 volts I would hazard a guess. Even deeply discharged car batteries are within around 10-20% of the normal working at-rest voltage.

3v something says to me the cells are damaged and I would be looking to replace ASAP for the sake of under £200 as a DIY. The battery is very old, so it's due.
I replaced my 9 year old battery a few months ago, not because it had failed, but because it's getting to the age it's likely to fail. And when will it fail? In a random car park on a freezing dark night in the rain miles from home with a crying child in the back.

No thank you!

 

[jimbg]

That is a dead battery!

 

[00slk]

Thanks guys, I think I'll order a new battery, as this did let me down when I filled up with petrol. Though the freezing nights are most likely over now but still an inconvenience when your car wont start when you need it most

 

[stefanovich]

The battery on my 55 is about 11 years old and was registering 3.4volts a few weeks ago, so charged it up and it was fine until it went flat while I stopped off to fuel up. A jump start saw me back on the road again. Just been out to check the volts as the 55 hasn't been used for a week and the volts registered 12.3volts. On start up it registered 15volts at idle, so I decided to check the boot battery which was 12.9volts.
My question is should the starter battery be reading 15 volts or would it be safe to assume its on the way out? Don't want to spend money on a new battery if this one still has a week or two left

Thanks guys, I think I'll order a new battery, as this did let me down when I filled up with petrol. Though the freezing nights are most likely over now but still an inconvenience when your car wont start when you need it most

Its the time of year that batteries are more likely to fail. the age of the battery should have given you good reason to want to change after going flat
constantly charging a failing battery does no favours to the charging system and can cause premature failure of the alternator so there is zero gain in trying to get the last out of a battery as having to replace both alternator and battery becomes a lot bigger cost and Inconvenience
( ret AA patrol 16 yrs )

 

[mioba]

I am all for MB batteries, they last a remarkably long time and well worth it.

 

[Tony Dyson]

MB branded Batteries are manufactured in the Main by Varta, MB don't make batteries.

 

[mattkh]

......... can cause premature failure of the alternator

Please explain why this can happen. Thanks in advance.

 

[mioba]

MB branded Batteries are manufactured in the Main by Varta, MB don't make batteries.

ahhh this old chestnut again.
MB have certain specs they require manufaturers to put in the battery then getting the MB stamp.

 

[Tony Dyson]

ahhh this old chestnut again.
MB have certain specs they require manufaturers to put in the battery then getting the MB stamp.

Do you have a source for your theory? and can you confirm with evidence the "Certain Specs" exceed standard Varta Silver specifications?

 

[stefanovich]

Please explain why this can happen. Thanks in advance.

Car alternators are not designed to charge at the highest rate all the time which is what they have to do with a battery with diminished capacity this Is why when jump starting a car with a flat battery best practice is to give the flat battery a few minutes to regain some power from the donor source before attempting to start the car this is to avoid putting an excess load on the charging system when the car is started .

 

[SL63 Mark]

That Sir, is an ex-battery. It is deceased, it lives no more, it has ceased to be. Bereft of life, it rests in peace. It has gone to the great battery shop in the sky.

 

[sl500amgsport]

Thanks guys, I think I'll order a new battery, as this did let me down when I filled up with petrol. Though the freezing nights are most likely over now but still an inconvenience when your car wont start when you need it most

Seems they always fail at Petrol Stations, you are not allowed a jump at the pump but have to push it away

Mercedes SL500 R231

 

[mioba]

Do you have a source for your theory? and can you confirm with evidence the "Certain Specs" exceed standard Varta Silver specifications?

Do you think MB would be allowed to brand a shelf battery of Varta as MB if there was nothing different?

 

[sl500amgsport]

Do you think MB would be allowed to brand a shelf battery of Varta as MB if there was nothing different?

VARTA® is the manufacturers' choice when it comes to batteries because of their premium experience

VARTA® is the confident choice for the world's leading automotive, heavy commercial, marine, caravan and motorhome manufacturers.

www.varta-automotive.com

Mercedes SL500 R231