Dead battery

[Yianni1066]

I have a brand new starter battery in my sl350 (the small one in the front) that I bought a year ago. Because I don't use the car that often, I installed a remote control battery disconnect gadget. I use the car mainly at weekends. Covid hits and I haven't used the car in a year. Decided to use it today... battery is dead. Measured the volts, its at 3.6v.

Is this salvageable? Especially as it was hardly used. I dont have a charger, so do I buy a charger or a new battery?

 

[Blobcat]

I'd look at putting a battery conditioner on it first

 

[Yianni1066]

I'd look at putting a battery conditioner on it first

Thanks for reply.

No idea what that is (conditioner)... but you seem to think it is salvageable then. As I was told under 10v and its trash.

 

[Blobcat]

Thanks for reply.

No idea what that is (conditioner)... but you seem to think it is salvageable then. As I was told under 10v and its trash.

A battery conditioner is a smart charger that you can leave connected all the time your car is sat in the garage.

The battery might be dead although as you're using it so little you need a conditioner anyway so it's not wasted money either way.

Optimate, Ctek or a number of others are pretty good (I've 6 in use on my vehicles)

 

[Yianni1066]

A battery conditioner is a smart charger that you can leave connected all the time your car is sat in the garage.

The battery might be dead although as you're using it so little you need a conditioner anyway so it's not wasted money either way.

Optimate, Ctek or a number of others are pretty good (I've 6 in use on my vehicles)

Ok, i'll look into getting one. Unfortunately I don't have a garage, and can't have a cable running to the car, which is why I chose the disconnect gadget. But i'll remove the battery and bring it in to condition it and see what happens.

Thanks again.

 

[Blobcat]

Ok, i'll look into getting one. Unfortunately I don't have a garage, and can't have a cable running to the car, which is why I chose the disconnect gadget. But i'll remove the battery and bring it in to condition it and see what happens.

Thanks again.

Keeping an R230 outside is risky as they have an annoying tendency to leak causing numerous electrical issues
I also have a solar charger on my Smart as that lives in a cap park with no electrickery near it. Not a complex car compared to an SL though...

 

[mattkh]

.......... I haven't used the car in a year. Decided to use it today... battery is dead.

This has been a blessing in disguise for you.
Before starting an engine that has been unused for a such a long time, you have to make sure there is some lubrication in the cylinders.
If it is a manual transmission, then with the car in a gear, push it forwards. This will turn the engine over slowly.
If it is an auto, then once you get some umph in your battery, disconnect anything you are confident to do, in order to stop the spark plugs firing.
Then with the ignition key turn the engine over a few times.
Finally, reconnect and start the car as normal keeping an eye on the oil pressure.

 

[EmilysDad]

I'd doubt that a smart charger will begin to charge a battery that's so flat.

 

[SL63 Mark]

I'd doubt that a smart charger will begin to charge a battery that's so flat.

Some do, some don't. I have used another car to recharge a really flat battery in the past. Just make sure you disconnect it from the R230 first. they don't like jump starting.

 

[Yianni1066]

Thanks for all the responses.

I ordered a ctek charger and will give it a go. But reading the responses, I'm getting the impression that the charger won't restore the battery to normal order, and as I don't use the car often, it will just be flat again in a few days... I'll then have to lug it in to keep it on charge ready for when I need to use it... which isn't me. Lol.

I bought a remote control disconnect gadget because I didn't want to open the bonnet everytime to disconnect the negative cable. My thought being that simply disconnecting would preserve the battery.

Need another solution, I think.

If I get a new battery, is there a solar option for the two batteries in an SL that would trickle charge them, if anyone knows?

Also, and apologies for my ignorance, I have looked at the battery I need and it ranges from £150 to £250... but when I called Tayna Batteries, I didn't tell them it was for an SL, but that it was a starter battery. They asked for the AH, CCA and dimensions. The dimensions are clearly so it can fit in the space. I responded 35AH, 420CCA, 210mm, 175mm and 140mm height, but said not to worry about the height.

Their recommendation? A battery that has 35AH, 540CCA - which seems better to me, 3.5cm taller, yet... over £100 less!!

I feel like the headroom exists under the bonnet... so what am I missing?? Is there actually a technical difference? Tayna didn't seem to think so when I pressed them.

So, is the price for the correct battery simply because its for an SL and the assumption is that the millionaire who bought the car brand new 20 years ago (and 5 owners ago), still owns it today?

I appreciate the help.

 

[mioba]

Good luck with the battery charge. Take a chill pill regarding the battery costs.
Keep us updated

 

[SL63 Mark]

Also, and apologies for my ignorance, I have looked at the battery I need and it ranges from £150 to £250... but when I called Tayna Batteries, I didn't tell them it was for an SL, but that it was a starter battery. They asked for the AH, CCA and dimensions. The dimensions are clearly so it can fit in the space. I responded 35AH, 420CCA, 210mm, 175mm and 140mm height, but said not to worry about the height. Their recommendation? A battery that has 35AH, 540CCA - which seems better to me, 3.5cm taller, yet... over £100 less!! I feel like the headroom exists under the bonnet... so what am I missing?? Is there actually a technical difference? Tayna didn't seem to think so when I pressed them.

So, is the price for the correct battery simply because its for an SL and the assumption is that the millionaire who bought the car brand new 20 years ago (and 5 owners ago), still owns it today?

I appreciate the help.

I would buy the original correct battery from Mercedes, it costs around £100 as I recall. Quote the VIN of your car and you will get the correct one. I have replaced both batteries on my SL with MB ones, and neither was particularly expensive. The rear battery in particular is MB specific AGM. The front is lead acid, but why go through all the hassle of trying to find an equivalent, when the main dealer ones are cheap enough ?

 

[Jason63]

35Ah doesn't sound right to me. Double check what it says on the old battery.

 

[Tony Dyson]

The OP should assume that not knowing the previous owner, he/she was a pillock and replaced any original parts on the car with components from a car boot sale! As above, armed with the VIN, MB will be able to confirm the correct battery spec, what is important is that you replace the correct chemical technology whether it's wet/flooded or AGM.

 

[peterws1957]

I would buy the original correct battery from Mercedes, it costs around £100 as I recall. Quote the VIN of your car and you will get the correct one. I have replaced both batteries on my SL with MB ones, and neither was particularly expensive. The rear battery in particular is MB specific AGM. The front is lead acid, but why go through all the hassle of trying to find an equivalent, when the main dealer ones are cheap enough ?

This absolutely. One thing SL's (and most modernish MBs) don't like at all are cheap wrong spec batteries. Get the correct one from MB. MB Grangemouth give good prices on batteries with free delivery. Speak to Euan for the price. Having said this, with something like an 8 amp battery charger, you will probably be able to resurrect the battery if it's a recent one. If it's dropped to 3.6 v though you may have a battery drain. I'd be checking this with an Ammeter before draining another new battery.

 

[Yianni1066]

Thank you all for the responses. What a great forum!!

So, I called my local MB and was put through to someone that can answer my questions.

The guy told me that their battery is £140, he told me that 062 means nothing to him, their batteries aren't numbered like that, but he told me that it is a standard lead battery, 35AH and as long as it fits... I asked him about CCA and he didn't know what the CCA is for their battery... enough to do the job, he said laughingly. Well, if the MB battery is the Varta Silver, then that would be 35AH 520CCA. But considering that the battery in there right now is an 062 that I paid £110 for, 35AH 420CCA and worked fine the few times I did use the car over a year ago, with no issue as I recall, and was the same battery, as in brand and model, that was in there for 2 years (my fault that one died) and again no issues, I'm wondering why buy the MB one for £140... and why even buy the replica one for £110 with what seems to be same spec or why buy the Varta Silver for £170, when there is a same spec battery, with slightly different dimensions, and less than half the price?? The Bosch 063.

How different could the Bosch Battery be which is also 35AH 520CCA but 3.5cm taller, yet only £58?

All the 063 batteries are 3.5cm taller. And there are a whole host of other brands with 063 batteries, including Varta, but with higher AH also for between £40 and £70.

Varta Silver 063 is 52AH, so higher than the required 35AH, but I'm not totally sure how bad this is, as the AH is the max constant rate a battery can give, if it's asked for it, as I understand it... so if the car isn't demanding this, and as it really only needs 35AH why would it demand any more... I'm not understanding why even having this Varta Silver 063 battery for £53 is an issue?

I wonder if its all marketing, as the 062 battery is listed by everyone as an MB Starter Battery. Its the only manufacturer that needs this size. For some that might mean its special because MB's need something special... but to me it sounds like strategic design and marketing and taking advantage of MB owners.

Any thoughts?

 

[SL63 Mark]

3.5 mm too tall sounds quite a lot. Clearance is really tight for leads and cables in the front compartment. The cable connectors only just reach the genuine battery, so anything taller won't fit. You may also find other issues, e.g. the battery may not clamp in correctly. It's all very snug in there.

Personally I would fit the genuine battery, but your call. Let us know how you get on.

 

[Yianni1066]

Bought a cheap battery conditioner and charger. £20 from Amazon.

Worked brilliantly. Took 24 hours or so, but the battery has been in for 10 days no problems.

Thanks all for the information, I really appreciate it!

 

[mattkh]

Thanks all for the information, I really appreciate it!

How did the engine sound when you fired it for the first time after all that standing..

 

[davemercedes]

Thanks for all the responses.

I ordered a ctek charger and will give it a go. But reading the responses, I'm getting the impression that the charger won't restore the battery to normal order, and as I don't use the car often, it will just be flat again in a few days... I'll then have to lug it in to keep it on charge ready for when I need to use it... which isn't me. Lol.

I bought a remote control disconnect gadget because I didn't want to open the bonnet everytime to disconnect the negative cable. My thought being that simply disconnecting would preserve the battery.

Need another solution, I think.

If I get a new battery, is there a solar option for the two batteries in an SL that would trickle charge them, if anyone knows?

Also, and apologies for my ignorance, I have looked at the battery I need and it ranges from £150 to £250... but when I called Tayna Batteries, I didn't tell them it was for an SL, but that it was a starter battery. They asked for the AH, CCA and dimensions. The dimensions are clearly so it can fit in the space. I responded 35AH, 420CCA, 210mm, 175mm and 140mm height, but said not to worry about the height.

Their recommendation? A battery that has 35AH, 540CCA - which seems better to me, 3.5cm taller, yet... over £100 less!!

I feel like the headroom exists under the bonnet... so what am I missing?? Is there actually a technical difference? Tayna didn't seem to think so when I pressed them.

So, is the price for the correct battery simply because its for an SL and the assumption is that the millionaire who bought the car brand new 20 years ago (and 5 owners ago), still owns it today?

I appreciate the help.

There are one or two (prominent) members who recommend Tayna batteries. They have extremely good feedback.