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The batteries are an unknown age and not OE, the health is showing 100% but the charge capacity has dropped to about 70% voltages are in the region of 12.35. Both batteries perform perfectly.
I was thinking about de-sulfating both front and back batteries before the weather starts to turn cold and the car will be stored for the winter months.
Has anybody considered this or even completed the process who may have some advice?
I do know the de-sulphate equipment will pulsate a higher voltage with a smaller current, could this be used with the consumer battery in place and connected without causing any damage to the temperamental and sensitive electronics?
Hi John, desulphating is a wonderful idea and as you point out voltage spikes will be generated so be sure to disconnect the battery prior to attempting.
I have just received this...
Rebooting the car computers is a healthy habit against F-SAM staying awke to drain main AGM... I am getting ready to install battery disconnects to help that process.
I have a Noco Genius 5 battery charger and the website says it automatically detects sulfation and will automatically repair. I dont know how to check to see if that is happening or not but hopefully it is working. I use the charger on the battery about once a month because i dont put many miles on it, drive short trips. The harness is connected directly to the batterys positive post and to the batterys negative where it is grounded to the car on the strut tower. I just run an extension cord to the car and hook the charger to the harness and charge it till its done.
Thank you for the reply. I was intending to maitaing a 12v supply to the system while I desuphated the battery. It sounds like youre disconneting the battery completely, is this you rebooting the computers when you reconnect?
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
There should be a date code somewhere on each battery. If they are older, you may want to replace them.
In my 2004 SL500 (R230) I never connected to the starter battery (engine compartment) and only to the "consumers" battery in the truck (boot). I used a CTEK MUS 4300 (which I think has been replaced with the CTEKMXS 5.0). CTEK is the manufacturer of the Mercedes battery charger, which they label with the Mercedes star.
I leave my battery connected. I only have the one battery in the engine bay. The Noco comes with clamps that can be unscrewed to use the eyelets. I read somewhere that it is best to connect the ground of the charger to a ground on the car and not directly to the battery so I connected it to the battery ground on the strut tower. The eyelet wouldnt fit so i used a small half round file to open it up a little. On my car I could not fully unscrew the positive battery post nut so I used a pair if wire cutters and snipped the eyelet to make a spade type connector. I just run an extension cord out to the car and fish the end through the front grill, this way I can close the hood while its charging. I only charge it when im able to keep an eye on it, never at night while im sleeping. I had origianlly bought the Noco 1 amp charger which did work but it just took way too long, had to leave it plugged in overnight. With the Noco 5 it takes around 3-4hrs, most of that time its spent "Bulk charge complete, optimizing battery for extended life".
Takes hardly any time to reach green.
When I read up on these types of chargers like the Noco and the Ctek it looks like everything is automatic. I dont know the technical stuff about desulphating batteries. I guess if the battery is really bad theres a "repair mode" to use, but I havent yet. My battery is a year old and so far no warning lights on the charger so im assuming everything is good. I read on Ctek that if you use a charger once a month you can extend the life of the battery 3x's. My old MB battery was 7yrs old when it stopped holding a charge, i wish I had this charger then just to see if I could have fixed it or gotten a little more life out of it. i got the new MB battery at my local dealer which wasnt that bad, around $214 after giving them the old battery.
Here's about the extent of what I know about sulphated batteries and charges.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
You cannot assume that the R230 and W204 instructions about the battery are the same. The R230 battery set up is different than the W204. It has a starter battery used exclusively for starting the car and a larger "consumers" battery to run all the electronics. And it seemed to be much more sensitive to battery conditions.
Jump starting the R230 could only be performed with the battery in the engine compartment, as with the W204. However, to charge the starter battery, you needed to disconnect the consumer battery. This is why I would only connect my battery charger to the consumer battery, which was more sensitive to the battery condition. No such warnings are given for the W204. From the 2004 SL owner's manual:
08-30-2023, 03:21 AM
