Mercedes-Benz GLA Forum banner
1 - 20 of 20 Posts

·
Registered
Joined
·
307 Posts
Discussion Starter · #1 ·
I use the black & decker version and it has 3 ways to attach for charging to the vehicle. The car I use it on I simply plug it into the cigarette lighter and then plug into wall outlet. It flashes until battery is fully charged, at which point it goes solid green.

I'm not driving the 45 much this year, and am worried that like this other car, I'm slowly creating a weaker and weaker battery, just hesitant to plug it in unless I know some of you have been doing this, and if so, can you confirm how you are attaching to vehicle for charging. Just worries me with having the 2 batteries, one for eco start/stop, though that should not matter (I'd think).
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #3 ·
Thanks Wayne, all plugged in and charging as per your guidance, so now I'm curious how long it will trickle charge, giving me an indication perhaps of discharge since I have not been driving the vehicle much.

Does this also charge the little battery for eco, I would think so as part of the "charging system"
 

·
Super Moderator
Joined
·
2,186 Posts
On a weak battery my Black & Decker can take almost two days to fully charge a battery. My CTek takes overnight.

Either one will shut off at full charge to avoid boiling the battery. This makes the tender different than a trickle charger.

By having the battery tender hooked up my eco start always works for the first hour or so of driving.

I believe the smart alternator system screws up the aux battery and thus the eco start. Supposedly there is a software or firmware fix to this but I haven't bothered to worry about it.
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #5 ·
This would be my observation as well. It was plugged in for 46 hours (not quite 2 full days) and was still blinking. I had to drive the car today so now it's unplugged. It should not surprise me though. My other car I use it on has a physically smaller battery by probably 30% less size. And it has no small second battery in the system. And that took 36+ hours. I don't mind the slowness if it means it's doing the "tender" job nice and slow. My GLA battery is only about 2 yrs. old, replaced under warranty. I suspect the previous owner killed the battery at some point, and once you do that, even with a jump, they are never the same. My other car's battery is stock, original from 2009. We only drive that car about 500 miles annual and so the tender is a must.
 

·
Registered
2016 GLA250 4matic
Joined
·
24 Posts
I use the BatteryTender Plus. It single-handedly revived my auto start/stop feature which worked only once in 9mos before BT+. Now it never fails to work.

If you want the de-sulfating feature, go for C-Tek.
 

·
Super Moderator
Joined
·
2,186 Posts
Note: De-sulphating is important if you have ever gone below 6 volts in charge. The CTek costs a bit more but assuming you do not have 6 volt batteries in your fleet it is the better way to go IMHO.
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #8 ·
Which CTek version do you have? I'm looking at the 40-206 MXS 5.0
 

·
Super Moderator
Joined
·
2,186 Posts
I got this one (see photo) with extra battery cables for easy hookup based on my various needs. The extra cables included LED status indicators that the one in the kit did not have. I also bought enough extension cables to get to my outside vehicles (I can testify that the tender works fine with 48 feet of extension). I debated fabricating my own wall and accessory mount but opted to buy theirs. It didn't work for this model so I had to modify it with aluminum straps.
26286
26287
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #10 ·
Thanks for this, the CTEK unit I was looking at was likely fine, but in getting into the specs, mainly the Amp hour, I see the difference. The B&D was 1.2Ah as are most $25 or even less rating. The CTEK I was looking at is 4.3, and this one is 7.
 

·
Super Moderator
Joined
·
2,186 Posts
And thus the difference in bringing a flat battery back to life overnight vs over multiple days. Also the CTek has the ability to de-sulphate the battery which is important if you've done a few deep discharges.
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #12 ·
to recap the last week or so, I plugged the MB in and let the B&D go at it for 46 hours, it was still blinking. I drove the car. Came back and sometime later plugged it back in, and it was still blinking/charging another 40 hours later. So not sure what was up with that, the reason I started thinking about something better. B&D seems to work fine on my other older car, but not sure what's up with this? When I get the Ctek I'll start with the MB and get it to where I know the battery is fully charged.

I will also use the Ctek on the older car since the battery is from 2009 to do that desulpate.
 

·
Super Moderator
Joined
·
2,186 Posts
The smart alternator system will not keep the battery at full charge. It leaves some charging space for braking assistance and under normal driving conditions it will free wheel the alternator to reduce loads until the battery gets lower than a certain point. So you can fully charge a battery with the tender and when you go out for a drive the battery is discharged and the tender has to go back to work when you plug it back in.

I live at the top of a hill so driving home I'm not using the brakes. So I don't get the top off charge. Inevitably after a drive when I get home and plug in the B&D it reads under 80% charged. This isn't a problem with the battery or the tender. It's just how it is.
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #14 ·
What do you use to check how charged your battery is (% wise)?
 

·
Super Moderator
Joined
·
2,186 Posts
The Black & Decker tender reads the voltage and then shows the % based on a look up table. The GLA can start a drive fully charged and when I get home the tender might indicate 77%.

Note: The battery charging curve has a major flat ramp between discharged and charged. This makes calculating actual % of charge difficult. This could vary from one battery to the next. That is, I don't trust the B&D numbers for absolute accuracy. But I do have a Fluke DVM that indicates variable end of drive voltages that would be proportional to the remaining charge at the battery and these readings fluctuate based upon the amount I've been braking just before shutting the igniting off.
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #16 ·
Just as an update Wayne, I bought your same Ctek unit, it is very nice, definitely more inside than the B&D as it's bigger and weighs more. But it's super easy to use and I did find out today that the B&D still must have pretty much done the job on the MB. Same procedure for hookup so that was no biggie, and it powered on, I stayed in Normal mode just to give it a run (it's only about 40* as a high today). It only ran in mode 1 less than 5 mins. before moving to 2, and again about 5 mins. max and it moved to 3 (absorption, analysis). It stayed here about 90 mins. or so, and now it's been solid green light on 4.

Tomorrow I may try it on our other car with original Delco battery from 2009 to see how it's doing.
 
  • Like
Reactions: Wayne

·
Registered
2017 GLA 250, 2017 X3 35i
Joined
·
2 Posts
I use the black & decker version and it has 3 ways to attach for charging to the vehicle. The car I use it on I simply plug it into the cigarette lighter and then plug into wall outlet. It flashes until battery is fully charged, at which point it goes solid green.

I'm not driving the 45 much this year, and am worried that like this other car, I'm slowly creating a weaker and weaker battery, just hesitant to plug it in unless I know some of you have been doing this, and if so, can you confirm how you are attaching to vehicle for charging. Just worries me with having the 2 batteries, one for eco start/stop, though that should not matter (I'd think).
Well, the internet isn't so big after all! How are you old friend? Wife got a GLA and the battery is dead today, so I just happen to find this post and an old Bronco friend.
 

·
Registered
Joined
·
307 Posts
Discussion Starter · #18 ·
Well, the internet isn't so big after all! How are you old friend? Wife got a GLA and the battery is dead today, so I just happen to find this post and an old Bronco friend.
Too Funny, I'm good Bossind, hope you are doing well too. Ya know, after 20+ yrs. with the Bronco and mods, and teaching myself to weld, I got tired of lifting the 100 lb tires and was not wheeling anymore. I'm not on here all that much, and don't get over to the Bronco forum anymore, but yes, back in 2018 I sold Shadofax to Willec who lives down the road from me, and bought an off lease 2015 GLA 45 AMG with only 18k on ODO. I just passed 31k on the car and recently tuned it, so have been posting about that. Mods on my baby benz are much easier on my back than the bronco, a hand held tuner, and a high flow air filter. :D (y)

Good thing I kept the internet "handle" or you'd have never known. I didn't go back through all the posts, but I did also have to replace my primary and then the little battery for ECO mode, but for sure, once you have new batt, get the trickle charger, I recommend the Ctek as others do on here. I'm not driving the car much, two/three days a week on avg. 10-15 mile trips and the parasitic draw over times brings it down, so I plug in the charger 2-3 times annually.
 

·
Registered
2017 GLA 250, 2017 X3 35i
Joined
·
2 Posts
Too Funny, I'm good Bossind, hope you are doing well too. Ya know, after 20+ yrs. with the Bronco and mods, and teaching myself to weld, I got tired of lifting the 100 lb tires and was not wheeling anymore. I'm not on here all that much, and don't get over to the Bronco forum anymore, but yes, back in 2018 I sold Shadofax to Willec who lives down the road from me, and bought an off lease 2015 GLA 45 AMG with only 18k on ODO. I just passed 31k on the car and recently tuned it, so have been posting about that. Mods on my baby benz are much easier on my back than the bronco, a hand held tuner, and a high flow air filter. :D (y)

Good thing I kept the internet "handle" or you'd have never known. I didn't go back through all the posts, but I did also have to replace my primary and then the little battery for ECO mode, but for sure, once you have new batt, get the trickle charger, I recommend the Ctek as others do on here. I'm not driving the car much, two/three days a week on avg. 10-15 mile trips and the parasitic draw over times brings it down, so I plug in the charger 2-3 times annually.
Things are good, sold the Bronco ages ago. I prefer the builds more than the driving, once I got it to where it was I got bored of it. Living in the salt belt didn't help either, was time to move on. My wife always wanted a black mercedes, when this one came up with low milage we grabbed it. Its nice and all, but to be honest Im a little disappointed in the ability to code it and add features like I can on my BMW. I'll pickup up a Ctek for the GLA this week, where do you guys run the cord out to for easy plug in to power? Cheers!
 

·
Super Moderator
Joined
·
1,007 Posts
Years ago when I had to Winter park an outside sportscar I was fortunate to be able to run an extension cord from the back of the house to the rear-top of the driveway. I proactively semi-permanently mounted the waterproof version of Battery Tender Jr. in a cooler region of the engine bay and ran/secured its cord just to the bottom of the bay thru an existing belly pan grommet, where I could reach under and plug to the extension cord. On milder/drier Winter days I could just unplug, remove the cover, and head out for an exercise drive. :)

Alas rather reactively I also secured a sonic deterrent in the bay given mouse wire/firewall insulation damage during one very snow blanketed stretch when even the neighboring cats stayed indoors, but mice still tunneled. :(
Things are good, sold the Bronco ages ago. I prefer the builds more than the driving, once I got it to where it was I got bored of it. Living in the salt belt didn't help either, was time to move on. My wife always wanted a black mercedes, when this one came up with low milage we grabbed it. Its nice and all, but to be honest Im a little disappointed in the ability to code it and add features like I can on my BMW. I'll pickup up a Ctek for the GLA this week, where do you guys run the cord out to for easy plug in to power? Cheers!
 
1 - 20 of 20 Posts
Top