Charging sl55

[karozza]

So the SL55 has 2 batteries, different sizes too. Normally on other cars, when not in use, I hook up a CTEK battery conditioner to keep the battery healthy.

If I do this to the front battery; will this keep both batteries fully charged without anything going bezerk??

 

[Vilus]

You should not need to charge the front battery. It is used for starting only, and can take charge if low from the consumer battery in the boot. It is isolated from the electrical system during sleep mode and cannot lose charge unless faulty. Just leave the CTEK connected to the systems battery in the boot.

 

[karozza]

You should not need to charge the front battery. It is used for starting only, and can take charge if low from the consumer battery in the boot. It is isolated from the electrical system during sleep mode and cannot lose charge unless faulty. Just leave the CTEK connected to the systems battery in the boot.

Cheers mate.

Now that I brought up the batteries, apparently, I've been told the front one is a specific size not commonly found. It is very expensive from MB & I've also been told that a SMART battery will do the job & fits very close to original size; is this correct?

 

[AMGeed]

This is the battery used for the front fitment. You can check the sizing below.

Exide Mercedes-Benz YT14B-BS Motorcycle Battery | Euro Car Parts UK?s No.1 Car Parts Retailer

 

[karozza]

This is the battery used for the front fitment. You can check the sizing below. Exide Mercedes-Benz YT14B-BS Motorcycle Battery | Euro Car Parts UK?s No.1 Car Parts Retailer

I've actually been offered that same size battery by VARTA here but I couldn't understand the square posts when the SL terminals are round!?

 

[AMGeed]

I haven't so much as looked at mine so can't confirm whether the battery & terminals are the same for my E55 and your SL55.

It's possible I have given you the wrong info in which case, apologies.

Can you use the link I used to check the model you require?

 

[karozza]

I haven't so much as looked at mine so can't confirm whether the battery & terminals are the same for my E55 and your SL55. It's possible I have given you the wrong info in which case, apologies. Can you use the link I used to check the model you require?

Tried the link but not really sure which is the correct fitment!

You could be right as this is the exact type of battery recommended by VARTA when I requested & gave them the car derivative; it's just I was confused when I saw the square posts!? So, I'd like to check if other SL 55s use this battery or can confirm this is correct for the vehicle. I also find this a bit strange to use such a small motor bike battery for a 5.4 liter V8 Kompressor engine!?

 

[Vilus]

The SL dual battery setup is completely different to the E Class. The SL uses a larger starter battery under the bonnet, with a normal sized systems battery in the boot which powers the folding roof and other ancilliaries.

The E class uses a motorcycle sized 'booster' battery under the bonnet, with the main battery in the boot used for starting and ancilliaries.

The SL must be jump started from the FRONT under-bonnet battery, wheras the E Calss must be jump started from the Main BOOT battery.

Photos of the SL setup are in the following document...

http://www.mercedestechstore.com/pdfs/507 Systems I/507 HO R230 Dual Battery System 11-28-02.pdf

Details of the E class auxillary battery setup can be found here..

http://www.mercedestechstore.com/pdfs/W211_technician/319 HO Dual Battery (ACB - ICC) 11-29-02.pdf

 

[richard]

And, its possibly worth noting that I have a 10 year old SL55 (owned from new) which is on it's original starter battery, and has been through many 'boot' batteries.

It doesn't get driven much (30k miles since new), but never an issue starting (but quite often consumer battery low)

Its recently had a full battery system check by MB since the consumer battery failed under warranty and they check charging etc etc to ensure it is the faulty battery and not something else causing the issue. So I guess they checked the starter battery was OK and not causing the car to have to start from the consumer battery

R

 

[karozza]

And, its possibly worth noting that I have a 10 year old SL55 (owned from new) which is on it's original starter battery, and has been through many 'boot' batteries.

It doesn't get driven much (30k miles since new), but never an issue starting (but quite often consumer battery low)

Its recently had a full battery system check by MB since the consumer battery failed under warranty and they check charging etc etc to ensure it is the faulty battery and not something else causing the issue. So I guess they checked the starter battery was OK and not causing the car to have to start from the consumer battery

R

Hi Richard, I sent you PM with the VIN but got no reply??

Back to the issue, yes I have also noted the consumer battery does lose charge regularly.

So far the solution other than OE MB, is the SMART battery which I now have in hand. Apart from dimensions, I would like to check if it matches the OE specs or at least is up to the job!

 

[camerafodder]

Oops misunderstood, thought it was another hunting thread.

 

[karozza]

The SL dual battery setup is completely different to the E Class. The SL uses a larger starter battery under the bonnet, with a normal sized systems battery in the boot which powers the folding roof and other ancilliaries.

The E class uses a motorcycle sized 'booster' battery under the bonnet, with the main battery in the boot used for starting and ancilliaries.

The SL must be jump started from the FRONT under-bonnet battery, wheras the E Calss must be jump started from the Main BOOT battery.

Photos of the SL setup are in the following document...

http://www.mercedestechstore.com/pdfs/507 Systems I/507 HO R230 Dual Battery System 11-28-02.pdf

Details of the E class auxillary battery setup can be found here..

http://www.mercedestechstore.com/pdfs/W211_technician/319 HO Dual Battery (ACB - ICC) 11-29-02.pdf

Just checked these, good information, & it seems the VARTA SMART battery has less cranking power.

OE battery is 35AMP & the VARTA battery, 45AMP but the cranking power for OE is 520(EN) & the VARTA is 400(EN)

Will this still be sufficient??

 

[JRH30]

Have put 2 x smart condition chargers on my SL55 as only tend to use it on decent dry days so in winter can sit in garage for weeks on end. Seems to be doing the trick so far.