SL55 - Leaving for long periods

[ead]

When left for two months or so my SL55 runs its battery down. The subsequent jump start (ugh!) can cause problems. MB Milton Keynes advise that the battery should not be disconnected. As the car is in a public garage I have no access to mains for a trickle charge. It therefore seems I must arrange for someone to drive the car every two or three weeks (the chap at MK kindly offered...).

Any ideas, please? And if it must be run every few weeks, how about just running it stationery for a while?

 

[Phynyxun]

Well leaving it stationary would work the alternator so I guess that would work...

But from engine no load you could premature bore wear... But were talking like a year here...

Limousines suffer from premature bore wear... Waiting outside keeping the car warm I suppose...

BTW I have an SL55 AMG and Sunday is my fun day...

Why dont you have a bit of fun yourself every sunday?

 

[Arnie]

There are some solar panel devices that can trickle charge a battery (used on boats etc), but you'd need to be able to fit it somewhere outside the garage.

Actually, I think that disconnecting the battery will do no harm whatsoever, but of course, then:

1.) Your alarm will not work,
2.) You'll need to have the manual key to lock the car.
3.) The timed-service timer will stop counting, while disconnected (no big deal).
4.) The engine will need a few minutes on initial start-up to re-learn it's ideal idling map.

If I were you and happy that the car was safe, I would disconnect the battery or is it batteries...


BTW, I think that you actually have one battery for the starter (12/14v) and another (36/42v) for the electrical systems. Actually, which battery do you find is the one which goes flat. I would guess that it's the 36v systems battery??

 

[pluggers]

Would it be possible to hook up another battery in the boot to work along side the original,might last a bit longer then?

 

[Francois]

I agree with the premature bore wear problem. Whenever you let a car idle to warm the engine up, it takes longer for the engine to warm up than when you drive it. This causes a lot more wear on the pistons and bore, since they remain colder for longer.

 

[ead]

SL55 flat battery when left standing

Thanks to all who replied.

On balance I'm going to try running stationary (not stationery - oops). OK, the wear problem may be a bit of a bore but probably not in my lifetime.

Best solution would be a trickle charger but no mains accessible...

 

[Francois]

Another problem when leaving a car for a long time is that the oil drains from the engine insides to the sump. When you start the engine after a while the wear is exstreme untill oil has been circulated.

I know some people buy cars as investments but they ussually have someone drive them around the block once a week.

 

[ead]

SL55 battery drain - further thoughts

Arnie - thanks. I don't know whether one or both batteries goes flat - maybe I should test if it happens again.

Who in MB / AMG is the ultimate technical authority here? Is there an established point of contact? There should be. I talked to a guy in Milton Keynes who advised trickle charge, failing which, don't jump start but get the batteries charged before starting. Is MK the authority or someone in Germany?

 

[Arnie]

Jump starting can cause voltage spikes which may damage sensitive electronics, so it's best avoided. However, it would be a bit difficult to trickle charge the 36/42v battery directly (with a standard 12v charger).

The dual voltage system is quite new and I only know some sketchy details, but there may be an electronic DC-DC boost converter in the car that when you charge the 12v starter battery, it also feeds a stepped-up trickle charge to the 36v system battery.

Your user manual may tell you what is what.

As for this forum, there are one or two people out there who have quite a bit of know-how, but I don't think that there is really an official Guru. Although, having said that, both Andy and Talbir know quite a bit.

 

[ead]

SL55 battery drain - further thoughts

Arnie
Thanks - comments appreciated.
In seeking an authoratitive source I was thinking of the manufacturer rather than the admittedly knowledgeable members of the forum.

 

[piestore]

sl55 flat batt

Hi

Coming in a bit late on this one, sorry.

The SL55 has two batterys one in the boot to run all electrics (system Batt)
and another smaller batt under the bonnet which is only used to start the engine, this batt should not go flat in a couple of weeks, Even when the car appears to be dead it should still start and charge the system batt.

If yours will not start after two weeks you have a fault. The batts an all MB's seem to give trouble from new usually due to abuse while in storage and as it is very difficult to get them on warrenty dealers are slow to replace them it could be that your fault would go if you replaced both batts.