Battery Trickle charger
Super Member
Joined: Aug 2020
Posts: 782
Likes: 266
G63, G65
A little more info on the model year of G might help diagnose better. I'm just theorizing on this because I don't know for sure, but it's possible the cigarette lighter "times out" after awhile so you aren't getting a charge. I've heard of a few cars (not sure of the brand) that will time out so the cigarette lighter doesn't drain the car if something is left plugged in all the time (like a radar detector). I always charge Gs straight from the positive lug and grounding post under the hood. The G is actually one of the easiest vehicles to hook up to a charger thanks to this convenient feature.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
The 12 volt outlets power down when the vehicle is shut off, and are disconnected from the battery through relays. You won't succeed trying to trickle charge this way. Find the battery jump start terminals if you can't locate the main battery and connect there. Not sure what MY your G is, but 2019+ main battery is under the cargo floor and jump start terminals are in engine compartment on passenger side. If you need to trickle charge frequently, you could add a connector for quicker access.
MBWorld Fanatic!
Joined: Feb 2015
Posts: 1,643
Likes: 830
From: NC
2026 G63
Yeah the lighter adapter way won't work unless the vehicle is on. From a quick search it looks like the Mercedes OEM charger is just a rebadged CTEK charger. It should have come with alligator clips?
If so locate the charging posts in the hood and connect it that way. I have a Noco charger and it says to connect positive/red first, then ground/black, then plug in the charger and when done reverse the order. Also, I think the batteries are AGM.
If so locate the charging posts in the hood and connect it that way. I have a Noco charger and it says to connect positive/red first, then ground/black, then plug in the charger and when done reverse the order. Also, I think the batteries are AGM.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
Senior Member
Joined: Jan 2006
Posts: 348
Likes: 60
From: SoCal
3phase-4pole
What a timely topic - I’ve been hunting around for the battery last night. Most MBs have the battery in the trunk so a wired connection to the terminals is feasible. For the G, has anyone wired a plug in socket in the cabin to the main battery?
Last edited by z168; Dec 20, 2020 at 01:04 PM.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
Trending Topics
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Senior Member
Joined: Jan 2006
Posts: 348
Likes: 60
From: SoCal
3phase-4pole
I posted a thread on the battery location last July 28th on this forum. Adding a charging connection directly to the battery is feasible, but fishing the cable around the floor panel without some modification could be a problem as the panel fits quite tight. Instead, you might be able to fish a cable forward following the routing of the main battery cable and locate a charge connector under the rear seat. You'd still need to feed a cable through the rear window while charging (better than leaving a door ajar). My preference still would be attaching a connector to the jump start terminals in the engine compartment.
MBWorld Fanatic!
Joined: Feb 2015
Posts: 1,643
Likes: 830
From: NC
2026 G63
I googled charging through towing socket and found the picture. Looks like it's from a UK vendor, here are some options:
https://www.mobilecentre.co.uk/ctek-...-towing-socket
https://www.mokmaskw.com/index.php?m...ucts_id=210377
I'm not sure if this will work with the G but in the Land Rover world it seems to work well.
https://www.mobilecentre.co.uk/ctek-...-towing-socket
https://www.mokmaskw.com/index.php?m...ucts_id=210377
I'm not sure if this will work with the G but in the Land Rover world it seems to work well.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
I googled charging through towing socket and found the picture. Looks like it's from a UK vendor, here are some options:
https://www.mobilecentre.co.uk/ctek-...-towing-socket
https://www.mokmaskw.com/index.php?m...ucts_id=210377
I'm not sure if this will work with the G but in the Land Rover world it seems to work well.
https://www.mobilecentre.co.uk/ctek-...-towing-socket
https://www.mokmaskw.com/index.php?m...ucts_id=210377
I'm not sure if this will work with the G but in the Land Rover world it seems to work well.
Senior Member
Joined: Apr 2020
Posts: 390
Likes: 83
From: North Dakota
2021 G550, BMW X5M, 2020 Toyota Supra LE
I would only charge from the post under the hood, not on the battery or through the lighter.
I don’t know the technical terms, but there is a voltage regulator that connects inline with the battery, if you connect directly to the battery you are bypassing that and can risk damaging the (sensitive) electronics.
I am not saying it can’t be done, but do so at your own risk.
I don’t know the technical terms, but there is a voltage regulator that connects inline with the battery, if you connect directly to the battery you are bypassing that and can risk damaging the (sensitive) electronics.
I am not saying it can’t be done, but do so at your own risk.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
I googled charging through towing socket and found the picture. Looks like it's from a UK vendor, here are some options:
https://www.mobilecentre.co.uk/ctek-...-towing-socket
https://www.mokmaskw.com/index.php?m...ucts_id=210377
I'm not sure if this will work with the G but in the Land Rover world it seems to work well.
https://www.mobilecentre.co.uk/ctek-...-towing-socket
https://www.mokmaskw.com/index.php?m...ucts_id=210377
I'm not sure if this will work with the G but in the Land Rover world it seems to work well.
Senior Member
Joined: Jan 2006
Posts: 348
Likes: 60
From: SoCal
3phase-4pole
Without hacking anything, I will see if its possible to wire a connection straight from the jumping points and lead it down to the right hand side front bumper.
Edit: trickle charging it from the jump points takes forever. Will have to route a line to directly to the battery somehow
Edit: trickle charging it from the jump points takes forever. Will have to route a line to directly to the battery somehow
Last edited by z168; Dec 23, 2020 at 01:21 AM.
Senior Member
Joined: Jan 2006
Posts: 348
Likes: 60
From: SoCal
3phase-4pole
Update: with the trickle charger taking forever to charge from under the hood, decided to access the battery directly. 4 hours later its fully charged.
Already ordered a cable connecter. I plan to route it to the driver seat underneath for easy access. Will post photos when I get to it
Already ordered a cable connecter. I plan to route it to the driver seat underneath for easy access. Will post photos when I get to it
Thread Starter
Newbie
Joined: Sep 2019
Posts: 8
Likes: 3
G500
Pls !!!!
plsQUOTE=z168;8231994]Update: with the trickle charger taking forever to charge from under the hood, decided to access the battery directly. 4 hours later its fully charged.
Already ordered a cable connecter. I plan to route it to the driver seat underneath for easy access. Will post photos when I get to it[/QUOTE]
plsQUOTE=z168;8231994]Update: with the trickle charger taking forever to charge from under the hood, decided to access the battery directly. 4 hours later its fully charged.
Already ordered a cable connecter. I plan to route it to the driver seat underneath for easy access. Will post photos when I get to it[/QUOTE]
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
Update: with the trickle charger taking forever to charge from under the hood, decided to access the battery directly. 4 hours later its fully charged.
Already ordered a cable connecter. I plan to route it to the driver seat underneath for easy access. Will post photos when I get to it
Already ordered a cable connecter. I plan to route it to the driver seat underneath for easy access. Will post photos when I get to it
MBWorld Fanatic!
Joined: Sep 2020
Posts: 1,126
Likes: 280
2025 G 63
What difference does it make as to how long it takes to charge? I don’t think it Will charge any faster going directly to the battery. I’m using a one amp maintainer and using the charging points under the hood. My Porsche charges through the cigarette lighter and is much easier. Can’t charge the Mercedes through the cigarette lighter, it’s switched off when you turn off the vehicle.
Senior Member
Joined: Jan 2006
Posts: 348
Likes: 60
From: SoCal
3phase-4pole
It usually doesnt take me more than a day to fully charge a battery. Plus its inconvenient to open and close the hood. If my plan works it should be plugged directly to the battery and accessible by the driver door.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,155
Likes: 1,769
From: Colorado
G550
The H8 AGM battery used in the G and many other ECO start/stop vehicles has a rating of about 100 amp/hours. If your battery is depleted to the point where it won't spin the starter, much of the battery's capacity needs to be restored. A 1 amp trickle charger will take a couple days to top it off, while a 40 amp charger wil do the job in a couple hours. A 5 amp charger will probably get the battery up to starting in 8-10 hours. I use a 1 amp charger to maintain the battery on a car I store during winter and it's adequate for this.
Senior Member
Joined: Jan 2006
Posts: 348
Likes: 60
From: SoCal
3phase-4pole
The H8 AGM battery used in the G and many other ECO start/stop vehicles has a rating of about 100 amp/hours. If your battery is depleted to the point where it won't spin the starter, much of the battery's capacity needs to be restored. A 1 amp trickle charger will take a couple days to top it off, while a 40 amp charger wil do the job in a couple hours. A 5 amp charger will probably get the battery up to starting in 8-10 hours. I use a 1 amp charger to maintain the battery on a car I store during winter and it's adequate for this.
