SL/R230: Battery charge
Thread Starter
Junior Member
Joined: Dec 2017
Posts: 62
Likes: 10
From: England
R230 SL500 W211 E220
Battery charge
Hi all
I started my sl500 up yesterday morning without any problem done a 25 mile drive switched off then when i went to start it again it wouldn't turn quick enough to start it like the battery was nearly dead. I put a jump box on & it started straight away. The alternator is putting out the correct charge so obviously not that.
The car is not my every day car so it can sit for 1 to 2 weeks but always been ok starting. So basically can a battery be good one minute then bad the next minute.
Thanks
I started my sl500 up yesterday morning without any problem done a 25 mile drive switched off then when i went to start it again it wouldn't turn quick enough to start it like the battery was nearly dead. I put a jump box on & it started straight away. The alternator is putting out the correct charge so obviously not that.
The car is not my every day car so it can sit for 1 to 2 weeks but always been ok starting. So basically can a battery be good one minute then bad the next minute.
Thanks
Super Member
Joined: Sep 2019
Posts: 624
Likes: 213
From: My house
SL55AMG, GL450, SLK, S550, Maserati Coupe
My R230 more than any other car I've owned as far as the battery slowly releasing its power when parked. Onboard electronics like the car alarm for one thing, slowly use a little electricity while it's not being driven around. Two weeks is enough to weaken the big battery in the trunk, if I were you I would get a CTEK battery tender, whether you get a new battery or not. An R230 should come with one when you buy it! If driven every three or four days, and sometimes a week in between drives, that's a little better, these cars were made to be driven. The entire car will thank you for driving it every four or five days. I got a calendar where each day I write down what cars I drove that day, so I always know how many days it's been since I drove this or that car. I'm lucky, I can drive the ones in the garage at least a few times a week. But when it's over three days in the garage I quickly plug in a CTEK and when I get back around to that car, it's like I just parked it an hour ago. Slowly draining over time does harm the battery's lifespan.. The batteries will last longer too, the CTEK everyone talks about electronically reconditions your battery.
Last edited by tonylinc; Mar 10, 2020 at 07:48 PM.
Member
Joined: Jan 2018
Posts: 152
Likes: 36
From: Nashville Tn
2011 mercedes sl550, 1995 corvette
To answer your question, a battery can act as you have described. It can start your car then as you drive it for a while, cut it off, then the battery may not have enough cranking amps to start the car. Sounds like your starter battery may be starting to fail. It can show adequate Voltage with a volt meter that should start the car, but it needs to be tested for cranking amps. I don’t think your problem is with the battery in the trunk. I don’t think any of the vehicle electronics are pulling from the starter battery. Any advance auto can do a quick check of the starter battery and they have the starter battery for $135.00 if you order on line and pick up in store
Last edited by ray0214; Mar 10, 2020 at 09:47 PM.
Thread Starter
Junior Member
Joined: Dec 2017
Posts: 62
Likes: 10
From: England
R230 SL500 W211 E220
My R230 more than any other car I've owned as far as the battery slowly releasing its power when parked. Onboard electronics like the car alarm for one thing, slowly use a little electricity while it's not being driven around. Two weeks is enough to weaken the big battery in the trunk, if I were you I would get a CTEK battery tender, whether you get a new battery or not. An R230 should come with one when you buy it! If driven every three or four days, and sometimes a week in between drives, that's a little better, these cars were made to be driven. The entire car will thank you for driving it every four or five days. I got a calendar where each day I write down what cars I drove that day, so I always know how many days it's been since I drove this or that car. I'm lucky, I can drive the ones in the garage at least a few times a week. But when it's over three days in the garage I quickly plug in a CTEK and when I get back around to that car, it's like I just parked it an hour ago. Slowly draining over time does harm the battery's lifespan.. The batteries will last longer too, the CTEK everyone talks about electronically reconditions your battery.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 1,232
Likes: 168
From: Glasgow, Scotland, UK
SL 350 R230 (3.7L with AMG Speedshift autobox)
I would start with checking your Voltage Regulator is producing around 14.1V consistent, then obtain a genuine Merc battery. I have never had to use a trickle charger.
MBWorld Fanatic!
Joined: Mar 2018
Posts: 1,442
Likes: 260
From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
A1EK, fair chance you’d see accessories being switched off when you leave the car unused for 2-2,5 weeks, AGM or non-AGM battery. The ‘normal’ drain is just like that.
