Hi,

I recently picked up a 2017 GT S and now I'm looking into my options for winter storage. Got a nice and soft car cover, and since we have a shared garage without power outlets available I got the CTEK CS Free portable charger.
https://smartercharger.com/collectio...oducts/cs-free


What are my options for having it connected during winter? I know about the connections next to the battery under the hood. Anything else? Maybe in the boot or inside the cabin? I don't have a physical manual, only the Mercedes "guide" app, and it's lacking a lot of info.

If I use the connections under the hood I need to leave it unlocked and slightly open, and have the charger on the floor outside the car. I couldn't find room for the (quite large) charger to store it with the hood completely closed.

The car


Cheers!

 

Factory charger is probably best, trunk area power port.

 

Well, the factory one isn't a portable charger with built-in battery, like this one.
The CTEK CS Free can also automatically charge both lead-acid and lithium batteries, and do jump starts and more. It's probably one of the best chargers available anywhere. Did you look at the link?

About the port in the trunk, where can I find it and what kind of connection type is it? 12V cigarette lighter (aux power) type?
Are you sure you really can use it to charge the car battery? And do you know if it's limited compared to using the connections near the battery?

 

Yes, you can use the 12V power lighter style port in the trunk to charge the Li-Ion battery. I just plugged mine in today. Have been doing that for 8 years, leaving the OEM charger connected continuously all winter, still using original battery and never had a battery problem. The port is on the driver side near the taillight. You can close the trunk over the wire which can move through the rubber gasket of the trunk lid without binding or pinching (check it), so you can lock the car. Of course the 12V port is limited compared to a direct connection to the battery as you can only pas a light current through its fuse, but for trickle charging, not an issue. I only ever use the OEM charger, so no idea how yours will fare.

 

Ok, thanks.
It's this kind of port? https://smartercharger.com/collectio...nnect-cig-plug (CTEK cig plug adapter)

If it works I can put the charger in the trunk and close it without any wires through the lid

Looks like it will be limited to 8A compared to 20A.

 

Found it in the trunk. Max 15A for the socket, but the adapter for the charger says max 8A.

 

When you connect the Charger to the boot socket, it will supply only 5Amps; Your charger should have 8Amp fuse in case of power spikes when you first plug the connector.
You can draw up to 15Amps from that socket when you take power out of that connector.
So charge into the battary is maxed at 5A and draw out of the batt can be up to 15A

 

For long term connection, the recommendation is to connect the charger to the boot socket. In that case. the charger's power goes via the car's power distribution computer that regulate power flow. For example, when you open the car door or audio system to make sure the draw from the charger is controlled.

 

The CS Charger's Internal batt can last for up to 1 hrs if you draw 5A from it. Not much as a long-term solution.
Also, if you plan to connect your charger to the battery under the hood, I am sure you are aware that the charger needs to connect to the separate red positive port (the BMS red connector) and not directly on the red positive of the actual battery.

 

Hey all, does anyone know if the OEM charger functions both as a charger and maintainer?

i dont think I would not drive the car up to the point where battery is drained but would prefer something that just charges (if required) and maintains the battery without providing a continuous charge all the time.

Would I be connecting it in the trunk if im just looking for maintenance?

 

Yes. Just plug it into the socket in the trunk. I am assuming that you are using the Mercedes-Benz provided charger.
I've been doing it that way since 2022 and I haven't had a problem.

 

ended up getting the oem charger since i havent been able to drive because the weather has been so crap here all week.

Do you have to remove that red cap from the 12v plug even though it doesnt really seem to click with or without?

 

This one? Just leave it on the plug. It will hold the plug tight in the trunk's 12V socket.

 

@untamedd You can do this. Since I'm sitting in an electric wheelchair I have to do it unsighted and with one hand. It takes a bit of force to push the plug into the socket.

 

yes sir all good. I was just afraid of breaking it initially as ive never really used one before but all good and in trickle mode now.

 

Good man!

 

Hey guys, hoping someone can clarify expected behaviour from the charger as ive used it twice and observed two different patterns:



1) first time i used it, the third light lit up solid orange indicating battery was charged 80%. Left it overnight and next morning fourth light was lit solid green indicating a full charge.

2) second time i used it, holding the reset button after plugging it in, the fourth light blinked indicating battery was fully charged but then when i let go of reset, no light would stay on.

from my first experience, i thought that even if battery was fully charged, the fourth light would still be a solid green or is the expectation that if battery is fully charged, no light would stay on the charger? Thanks.

 

Try unplugging it and plugging it all back in. Seems I've had mine do that before too and that fixed it.

 

I have the factory charger and the two yellow blouses for my totaled GT. Would anyone like to bid on them? I'm in Calabasas-Malibu area. (I'll throw in the unused cigarette holder/cup.) Exclusive of shipping.

 

I'm interested and in SoCal-OC. Sent you an emai and txt.