And this one works just fine on my mower!

 

Absolute minimum is get a charger that has an AGM setting, if that is the battery type in your car (which most of us do have). I was intrigued by the "lock the doors" on a MB even in the garage - but we just got a new F150 that also has a Battery Maintenance System (BMS), similar in concept to the Benz's. The Ford's system keeps track of the age of the battery and the State Of Charge (SOC) and the manual tells you what systems, and in what order it will shut things down if it detects the battery's charge is low; hence the Command system being off on start-up, or Start/Stop not working as a clue to not having enough battery charge. Back to the "lock the doors" thing: for Ford (at least the BMS in our F150), once the doors are locked it will reset the SOC on the BMS every 8 hours of NO use. But if you leave the vehicle on a float charger, any of them, it will never do a BMS reset for SOC. Why is this important? Because the way these new fancy: save gas and shut the Alt down, charging systems work, is them knowing what they are working with: How old is the battery, maybe how many start cycles, and its resting SOC. That is why "registering" a battery change is important (my guess is it also tells MB when you "need" to change your battery).

On the Ford I can use free software to disable or reset the BMS, and charge or float charge the battery at will. Have no clue on the MB, but I do have a Noco Genius 3500 that once the motor is cooled, I hook up to always (I would never buy one of these again, CTEKs are so far ahead of them...).

Got lots of battery chargers, and have learned a lot about charging batteries: RV, Starting, etc. over the years... If I could only have one charger and had to use it or leave it for float on all of my batteries? It'd be a CTEK - so. worth. the. money... Even on the Ford forum I hang out on they don't bring up cheap azz charger/maintainers like I've seen mentioned here... Just Sayin'

I am on a Mercedes forum, am I not?!

 

LOL, The best or nothing, I'd settle for an alternator that actually charges the battery fully, wonder if I could get that option programmed in.

 

I've paid cash for all 6 of my vehicles -- including two Mercedes-Benzes -- since 2001. One of them brand new. I don't mind paying top dollar when I think I am buying quality that is necessary. I already have two "regular" battery chargers, one of which I used just yesterday.

I am not convinced that a battery trickle charger/maintainer is necessary, so I am not convinced I need to spend top dollar for what may be a frivolous, needless gadget, used largely for ATVs, lawn mowers, and children's electric scooters. I will look for an AGM type maintainer, and trust that what's stated on the box is the truth within.

Throw the rocks all you want, and I'll explain why I haven't bought a Ford since 1994, replaced in 2001 with my C320.

 

Second the CTEK recommendation, the units are not expensive and have appropriate charging profiles for flooded normal/AGM/small battery/reconditioning . I had two, a MXS 5.0 (newer) and gave my older MUS 4.3 to my father. I feel more confident using them, than the cheapo maintainers I had prior. Their only downside, they are maintainers, so charging a discharged car battery can take 10+ hours. Granted they sell higher amperage chargers... for quicker bulk charging I use our old Snap-On manual charger (20+ amp).

 

It would seem to me that locked or not, the car has some sort of battery protection. After my recent run in with a deer I had a headlight that would not go off, but the car would shut all power down to the car after about a minute regardless.

 

Yes, I still have a Solar 360 wheeled charger 40 amps with 60 amp boost and a 2 ah trickle charge setting, I'm still trying to figure out if this old school charger will ruin my AGM battery, I use a Battery Tender brand .75 amp on my Ducati, seems to work fine. I disconnect it once in a while during the winter, then plug it back in after a week or so. My friend has one for his car same brand and he ran the connector to behind the tow hook door, seems to work OK.

 

I have the same question, namely will my conventional charger work with my AGM battery.

The description highlights of my one-year-old STANLEY BC15BS are...

1) 15 amp bench battery charger with 40 amp engine start. (I doubt I will ever use engine start.)
2) Fully automatic high frequency charging delivers 3 stage charging, automatically switching from fast charge, to top-off, to trickle charge, Once on float, I assume I could leave it connected for weeks, but so far I always disconnect it.
3) Charge and maintain any AGM, GEL, or WET automotive or marine 12V battery.
4) a patented alternator check to evaluate the battery voltage under load to indicate if the alternator is maintaining battery level.
5) This battery charger eliminates the need to manually input settings like battery type and size, and charges up to 40 percent faster than other conventional chargers.
6) $45 now on sale at Amazon...

Amazon

Amazon

BUT... The battery gurus here say it's blasphemy to charge the AGM battery with more than 11-12 amps. This charger will hop to 15 amps when first started, but quickly falls to 9 amps or less in minutes. After 3 hours -- mostly running at 1.9 amps -- it's done, and on FLOAT mode. This treatment will last a good 4-6 weeks before a repeat, if needed.

Instead, I'm told to spend twice the money on a pocket-sized, plastic wonder that babies batteries for motorcycles, ATVs and yard toys (seldom mentions cars/trucks FIRST) to a maintenance charge level.

I seriously question whether my built-like-a-tank Mercedes needs to be babied like this, when I can hook the Stanley to my other three vehicles without concern. Convince me I'm wrong...

 

Paranoia runs high on car forums... these things are not fragile like many would have you believe.

It was mentioned earlier in the thread that the alternator only works if the car is in motion. My data scanner does not back that up. Car will charge at 14.8v idling in park.

 

I don't think its a question of being fragile...

You can use a basic power supply to charge any battery as long as you can maintain the appropriate voltage and current. Smart chargers just automate that process and reduce the risk overcharging or damaging batteries. Those cart chargers (older ones) seen in shops are nothing but a multi-tapped transformer and you can easily overcharge/boil/damage a battery if not careful. We had a Snap-On that eventually was replaced (it came home) with a newer one that was programmable for variety of battery types and voltages, battery testing and engine starting... though it was, I think, $700.

I think any "automated" charger you buy today will "work" with minimal concern. My preference is for a unit that has worked for me, I can leave it alone with no concerns, doesn't cost much more, is endorse by auto manufacturers and its users and has lasted years trouble-free. I don't think you can go wrong with a NOCO, CTEK, SOLAR, battery minder, etc...

I'm not convincing anyone, use what you want... sharing my expierence.

 

really? wow, mine doesn't. I think maybe they tweaked this charging program over the model years, likely. mine is a '12 so first year of the 276 and I have the "Blue Efficiency" emblems on my front fenders, which my '13 does not.
So Mercedes was proud of this, I'm sure it's the emblems that improve the mileage !!!!!!! LOL.

Also maybe unrelated, it has always bothered me that my '12 gets 30-31 mpg's on the highway and my"13 gets 27-28 mpg, it is lower by an inch, has the ground effects all around and should be the more aerodynamic of the two? Both are E350 4Matics. This seems like a lot of difference, so it's either the aero's and lowering makes the car get less gas mileage or it could be the smart charging system?

 

I'm not sure. My 2016 will get 31-32mpg at 80mph(+ depending on traffic) on the freeway consistently. It is RWD with staggered rims, rears being 265mm wide.

The Macan will do 22 if you hypermile it.

 

Well, it's always bothered me, I would be interested in what all you guys think, thoughtful analysis, rumor or wild a$$ guesses.

 

Yeah, I'm not sure what to make of the statement "the alternator doesn't charge the battery all the time." I haven't checked, but then again I haven't had an issue with the battery in the E550 after 4+ years.

I have an older model "Battery Tender Jr" (actually I have two). I do keep it on my Corvette over the winter. I also "top off" my truck every other week. It hasn't hurt either battery, and the battery in my truck lasted 9 years, so perhaps it has helped. YMMV

 

I have the original AGM battery in my W211 that's been in the trunk for 13 years now. Never put a battery tender on it. But I'm sure a tender on the battery certainly helps, a fully charged battery lasts longer than one that's partially discharged all the time.

 

Just want to know :
Do we need to disconnect the battery from the car when we charge it?

Thanks

 

No

 

No. There's a very convenient bronze or brass bolt on the passenger shock tower for the neg grounding clamp...

 

Starting with the 2012 I believe, the battery is only charged to 80% to leave room for regenerative braking, so the battery is purposely left discharged to leave room for that. So you can't compare any earlier Benz battery life with these, the batteries in my older Benz's lasted a long time too. even if you do charge the battery to 100% the car will immediately let it discharge to 80% they call this Blue Efficiency, or smart charging.

 

Regen braking on the W212? That's the first I've heard of that. I thought the smart charging thing was just where the charging of the battery is not as aggressive, meaning the alternator parasitic drain on the engine is less improving efficiency.

 

Their term, their definition, Obviously there are no electric motors in the wheels to act as electric generators and recharge the batteries, what they mean by "Regenerative Braking" is, when braking the alternator kicks in to recharge the battery, Mine doe this, it also charges when you are coasting, but not under moderate acceleration.

 

Gotcha. Had a Mazda3 with true regen a few years ago. It would charge a super capacitor located behind the front bumper cover. Interesting concept, but didn't seem to make any appreciable difference.

I have noticed that mine does not charge battery under acceleration.. but does at idle and coasting as well.

 

https://media.daimler.com/marsMediaSite/

I'm guessing here but they likely updated this programming as models years progressed. And yes, I've been gotcha-ed for days now, my 32 and 36 year old daughters are home! LOL, Merry Christmas!!!!!!!
Interesting yours charges at Idle, now I wonder if my '13 does that.

 

I'm 35 so...

 

When you install a new main battery in these cars, you need to tell the car it has a new battery. It has something to do with voltage memory or something along those lines, and the car won’t fully charge the battery. I read about this recently when I asked about batteries on this forum a couple months ago. Went and bought a Diehard to replace my OEM from 2014. I didn’t pair it with the car (didn’t know how). Then I took it in for new plugs and an oil leak repair about a month ago, and their scan equipment picked up on low voltage readings that didn’t make sense given the obvious new battery. They programmed the car to recognize a new battery was present, and the low voltage errors all went away. I also noticed the car seemed to crank better. Mine sits for several weeks at a time, untouched in the garage. Never a problem until recently when I knew it was time to replace the original battery via the radio not stating on for more than 2 seconds while the car was off.

call an indi to program the car for the new battery, or maybe YouTube has something that can show you via comand system mode? It is Exhibit A for German over-engineering...