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I am the original owner of a 2009 S550 4matic, and the car has a recurring problem with the battery dying to the point of being not revivable. I have replaced about 10 batteries, and no one can identify a cause of a parasitic battery drain. After investigation, I am always told the technician didn't find anything draining the starter battery.
Apparently, due to the requirements of the battery in the car, no one (Any and no passenger cars, vans, SUVs,) I know is able to jump start the car successfully. Also, I am realizing that no on can identify the cause of a parasitic battery drain, and I should be ready to "jump start" it when the battery dies. I work from home, and I drive the car about once a week, which is apparently not enough to recharge the battery.
What are the specs for the battery and charging it? Will this charger will work when the temperature is around zero degrees? How about this model?
I too recommend the CTEK brand of battery chargers. I have used them professionally on my work fleet of vehicles and never had a problem. They are a smart charger that will rapidly revive a battery that has been abused, condition it and then keep it on trickle charge so that it is ready when you need it.
However, I feel that a competent auto electrician, with a decent multi-meter should be able to identify which component is still drawing that much power. Is it an after market alarm system, a globe in the glove box or trunk, that doesn’t turn off? I would also be looking to identify and fix this issue rather than managing it via a charging unit….
I don't drive my car daily and this is what I use...
this is actually wired wrong!
You don't want to bypass the "battery sensor". It needs to measure ALL the charging current to tally charge level. It is self managed and works independently from ECU or engine running.
Last edited by CaliBenzDriver; Jul 25, 2022 at 11:42 AM.
+1 for Ctek. Safe to use and once a quick connector is installed (negative to the chassis please - i simply used the bolt on the bracket of the battery holding clamp), even a rookie can't do any harm. Plug in, leave it, drive it.
You guys may all have a garage but here in Germany this is something many people don't have. So no AC power and extension cords are not the final solution. Being a once-per-week driver aswell I have made a small box equipped with a lifepo4/lithium battery that is light enough to carry, and a DC to DC RC battery charger that can charge lead acid aswell. Most of the time i simply set it to power supply mode at 14.6 volts and plug it to the ctek connector which i have wired to the water screen below the wipers. That way the car can suck juice for a few hours and fill its battery above what the main system does due to economic/startstop algorithms. Model of the charger is "toolkitrc M6D" and has been working for more than a year now.
my father has a CTEK it gets very hot in use on his E class 211 and then the car started a fight and I thought "oh good" just like other makes the high temps caused by the switching inside they use to control the charging has killed it - then I worked out no, the unit is fine its just the rubbish connector under light use has given up connecting properly because its cheap and nasty (worse still it not the replacement fly lead but the charger that's worn) just like the cheap nasty ones manage - I've forced them tighter and it behaves again - but still runs at melting point all the time
in between my nicer expensive other brand (using same tech) which also ran at melting point trying to keep my 221 happy, gave up - so I got a later more powerful version of my fathers ctek - within 2 mins of plugging in I went "well great its running at melting point too... and I'm already missing the volts and amps reading I get on both my old and replacement Oxford bike one's"
then I see "Oh even better" its so clever its not able to switch to just pushing a feeble 5 amps at the car now, I've got to waste two hours getting touchy feely and pathetic first - so it not actually any use to anyone as I can't use to keep volts up for the 20 min diagnostic session I want to do now - so I just go and get my $15 dollar fake out and I use that - after 5 years its just as good, except it shows the volts on a real display and I can select how I want it to work straight away
the reality is now these stupid things are so clever you have NO idea if they are doing what you need in the moment - my old oxford one I could switch to its highest ouput and manage the workload on the bike based on are the volts too low, to be trying this work (programming on the bike) and what demand from the amps is the vehicle needing so I can work out when I need a break as its not powerful enough to cope - but then its replacement Oxford one is more clever and stupidly closer to the ctek, arguing it knows best, when I can (with the same display as its older better brother) see exactly what I need now - without either don't buy your next charger - unless on a budget cheapie - the electronics tech is all the same
on the car less than 10 amps isn't really good enough to try anything, so I blew $500 on something than can pumps a real 40 amps at the car so you can try and fight the diagnostics for more than 10 mins without dwindling to 11.5v and it self destructing - turns out the one I want is quite pricey.. and they only had one demo one in the country.....
cheapish as only 12v and bangs out 100 amps - but the current cars use a lot of 48v
the nasty shock, ones able to do 6 to 48v and can push a sustained 120 amps out that you MUST have if you need to programme a modern Land-Rover ...start around $4000
... it shows the volts on a real display and I can select how I want it to work
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That's what i love about the rc charger just as you do - display - status - numbers. For connecting, i have made some adaptors from Ctek to Anderson Powerpoles. This way i can have decent cabling and still connect to the ctek quick connect socket at the car. I have compared many others but feel the cteks are still the best and come with a nice rubber seal. The blinky indicator ones die soon or behave weird, i learned not to care as i also have the battery sense Bluetooth box installed so i can quickly check for voltages of all cars if one is sitting in the driveway for more than a week.
Last edited by Neuschwanstein; Aug 14, 2022 at 07:38 AM.
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