wongl
MB Enthusiast
"When you have eliminated the impossible, whatever remains, however improbable, must be the truth"
SL500 re-starting problem
- Thread starter BiKenG
- Start date
I'll be honest, I've never managed to fully get my head around how the split charge system in the R230 works. I've seen cars with battery faults, alternator faults and battery control module faults over the years and I'll admit that it has been trial and error with them many a time. So much so I keep a battery control module on the shelf as a known good unit to try. If you aren't too far away and it would help I'd be happy to loan it out.
Petrol Pete
Hardcore MB Enthusiast
Replace the battery. Last year I replace the original 2006 battery on my C55, it had not shown any signs of dying , I replaced it as a precaution. It was only after I replaced it did I remember a few times in the summer when the car was driven to be VERY hot (there is not much room under the bonnet for that big lump of a V8, the battery is in there as well) I had slow 'cranking' and only just starting, usually after 15 minutes in the petrol station/outside shop etc.
I read up on it and yes, under hot conditions an old battery can break down.
I read up on it and yes, under hot conditions an old battery can break down.
MikeInWimbledon
Hardcore MB Enthusiast
- Joined
- Nov 8, 2014
- Messages
- 13,266
- Car
- (Ex S211 E500, W212 E500, C216, S212 E500, W211 E500 5.5, W221 S500, S211 E500, SL500, S500, E55)
Why not just replace the Bosch starter battery, at a cost of less than £150 ?
While I don't agree with your theory (who cares?), if you think it's the battery, why not just swop it now? Can't do any harm.
If there's another problem, well, you've got yourself a new battery which will last another decade.
While I don't agree with your theory (who cares?), if you think it's the battery, why not just swop it now? Can't do any harm.
If there's another problem, well, you've got yourself a new battery which will last another decade.
wongl
MB Enthusiast
Logically speaking, slow cranking can only be caused by
1. Poor earth strap/power strap
2. Faulty starter relay
3. Poor starting motor
4. Poor battery
5. Seized engine
When you have eliminated the impossible, whatever remains, however improbable, must be the truth.
Petrol Pete
Hardcore MB Enthusiast
Easiest of the above to change after checking the Earth strap is there ?? The battery.
This link has info on the R230 charging system if it helps....Dropbox - R230 Dual Battery System 11-28-02.pdf - Simplify your life
MikeInWimbledon
Hardcore MB Enthusiast
- Joined
- Nov 8, 2014
- Messages
- 13,266
- Car
- (Ex S211 E500, W212 E500, C216, S212 E500, W211 E500 5.5, W221 S500, S211 E500, SL500, S500, E55)
Agreed, given that he's visually checked the earth strap, and knows he hasn't got a seized engine (chuckle) most likely has to be the battery.
Petrol Pete
Hardcore MB Enthusiast
'Nuff said. Over to you OP
wongl
MB Enthusiast
Brilliant, thanks for sharing. Interesting to note that the starting battery (located in the engine bay) is only rated at 35Ah with an EN cold cranking ampere of 520A. This seems small compared to the EN ratings for diesel engines, even small diesel engines!
I noted with interest that the System Battery (located in the rear) has a higher rating of 70Ah and an EN rating of 798A given that it supplies electrical power for the entire vehicle (including the starter solenoid) with the exception of the starter motor armature. Therefore, while the starter motor can provide electrical power to the system as a backup, the reverse is not true of the System Battery. In fact there is a warning not to jump start the R230 via the System Battery in the rear!
Interesting to note also that on the Varta battery locator site, the starter battery for the R230 is label as the Aux battery with the official Varta part number 'Silver Dynamic Auxiliary SLI 535 106 052'.
