SL/R230: Adapting 12v accessory socket in trunk to work with trickle charger
12-28-2016, 09:08 PM
#1
Super Member
Thread Starter
Adapting 12v accessory socket in trunk to work with trickle charger
I recently acquired an MB labeled Ctek charger for use with my 2008 SL550. The MB version of the charger is supplied with two cables. One with alligator clips and the other with a plug that fits the 12v accessory socket.
It's a little inconvenient to lift the trunk floor to use the alligator clips. And since the 12v accessory socket is switched through the ignition it cannot be used to charge the battery.
I ordered a Ctek cable with eyelets that could be attached to the battery, but, the plug on this cable is not compatible with the MB version of the charger. So I ordered some after market accessory sockets to mount in the trunk. Unfortunately, the aftermarket sockets are not very good and don't hold the Ctek cigarette lighter plug in place very well. The OEM socket mounted in the trunk works perfectly with this plug.
So I decided to rewire the OEM socket directly to the battery. I used 7/64" slide on connectors to attach two wires to the prongs inside the OEM socket. Then I attached the other end to the battery. I used the cables that came with one of the aftermarket sockets. I just changed the 1/4" connectors to 7/64" connectors to use the cable. It came with a 2A inline fuse. I changed the fuse to a 6A one which should be adequate for use with the 3A charger. The cable appears to be 18 gauge and I am not sure if it can handle 15A which is the rating displayed on the cover to the accessory socket.
Down the road I will try the emergency air compressor and if it blows the fuse I may upgrade the cable to 14 or 16 gauge wire.
Warning: Don't remove the accessory socket from the rear plastic panel. It is very easy to damage the socket. I was able to repair it, but, it is better to just leave it in place.
It's a little inconvenient to lift the trunk floor to use the alligator clips. And since the 12v accessory socket is switched through the ignition it cannot be used to charge the battery.
I ordered a Ctek cable with eyelets that could be attached to the battery, but, the plug on this cable is not compatible with the MB version of the charger. So I ordered some after market accessory sockets to mount in the trunk. Unfortunately, the aftermarket sockets are not very good and don't hold the Ctek cigarette lighter plug in place very well. The OEM socket mounted in the trunk works perfectly with this plug.
So I decided to rewire the OEM socket directly to the battery. I used 7/64" slide on connectors to attach two wires to the prongs inside the OEM socket. Then I attached the other end to the battery. I used the cables that came with one of the aftermarket sockets. I just changed the 1/4" connectors to 7/64" connectors to use the cable. It came with a 2A inline fuse. I changed the fuse to a 6A one which should be adequate for use with the 3A charger. The cable appears to be 18 gauge and I am not sure if it can handle 15A which is the rating displayed on the cover to the accessory socket.
Down the road I will try the emergency air compressor and if it blows the fuse I may upgrade the cable to 14 or 16 gauge wire.
Warning: Don't remove the accessory socket from the rear plastic panel. It is very easy to damage the socket. I was able to repair it, but, it is better to just leave it in place.
Last edited by LAZARU5; 12-28-2016 at 09:12 PM.
The following 2 users liked this post by LAZARU5:
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03-19-2017, 05:40 PM
#4
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'95 s500
fgwinn: I think I understand the install BUT if you don't mind I have a few questions:
1.the connector change I get, the reuse of wire I understand but the inline fuse: is it in the trunk easily accessible or under a panel?
2.the original wire to the socket: you removed completely or disconnected from power point and taped it off?
a couple more pics(if not too much trouble would be greatly appreciated) but any help is welcomed.thankyou.
1.the connector change I get, the reuse of wire I understand but the inline fuse: is it in the trunk easily accessible or under a panel?
2.the original wire to the socket: you removed completely or disconnected from power point and taped it off?
a couple more pics(if not too much trouble would be greatly appreciated) but any help is welcomed.thankyou.
01-22-2018, 09:56 PM
#5
Super Member
Thread Starter
1) The inline fuse is under the trunk floor, easily accessed by lifting the floor.
2) I just tucked the original cable behind the plastic trim panel. So this modification can be completely reversed if the next owner chooses to do so.
2) I just tucked the original cable behind the plastic trim panel. So this modification can be completely reversed if the next owner chooses to do so.
fgwinn: I think I understand the install BUT if you don't mind I have a few questions:
1.the connector change I get, the reuse of wire I understand but the inline fuse: is it in the trunk easily accessible or under a panel?
2.the original wire to the socket: you removed completely or disconnected from power point and taped it off?
a couple more pics(if not too much trouble would be greatly appreciated) but any help is welcomed.thankyou.
1.the connector change I get, the reuse of wire I understand but the inline fuse: is it in the trunk easily accessible or under a panel?
2.the original wire to the socket: you removed completely or disconnected from power point and taped it off?
a couple more pics(if not too much trouble would be greatly appreciated) but any help is welcomed.thankyou.
