I have a 2012 E550 that will being going into a part use car. What are you using for a trickle charger? I would love to be able to use something that plugs into the cigarette lighter for ease of use for my wife, but I don't think the cigarette lighter is always on. What are my easy to use options?

 

most trickle chargers come with a set of ring terminals so you can connect to batter terminals and then run to somewhere convenient.
Opposite end has connector for output wires from charger.
locate this free end near grill with some wire clamps that you can easily get too.

then connect charger to it when you park car.
then you just show here where it is an how to connect.

 

There are terminals in the engine compartment for connecting a charger. The red terminal has a piece of sliding plastic to protect it. Only issue is that the engine bay will have to be slightly open to avoid crushing the cables.

 

Yes these, https://cimg2.ibsrv.net/gimg/www.mbw...82b6029552.jpg
Red being the positive and the bottom one is the ground.

 

I would like something where my wife does not have to raise the hood.

 

can user open the trunk?
If yes get charger hook-up wired to the trunk.

Battery connections can be hazardous with electrical short circuits. Not recommanded for casual users.

 

How about just starting the car and drive for a few miles every four or so weeks?

I have my 2010 E550 sitting very often for four weeks and it always starts like it was just driven. I have been tempted to leave it sit for 8 weeks to see if it still starts but if it fails it may open a can of worms to deal with so every four weeks I go drive for about 10 miles and no problems!

 

That is perhaps sadly not enough to charge the battery and you do drain the battery when you start it up, perhaps if you take it for a highway drive for 30-45 minutes it might help but a few miles might not be sufficient and depending on ambient temperature, the oil temperature might not reach the operating temperature either.

 

You don't want to have it constantly raised or raised once period? Asking because CTEK comes with two types of connections, one is the alligator clamp the other is those round (forgot what you call) that you just fit on the battery terminal like a hat. The latter of which you could possibly route the wires so the hood can be closed.

 

I don't like to use 12 V socket for some reason . CTEK can be plugged in directly into the wall . We use it this way if necessary The best method for me is just drive the car , it's also good for brakes , A/C and most likely even for the engine oil

 

Use a proper battery charger ie one where you can select the correct battery type eg AGM
Have a rotary timer (or digital version) like you use on lamps when you are not home
So you have say 30 mins charge every day and then it switches off
This one has little fingers that you press down to select the time that you want it to give power
Use the direct battery connection under the red slide
Use the earth post that is like a fat brass bolt
Use leads that are suitable for the current
Have a fuse in line with positive, just in case the charger craps itself and puts a short on the battery
You don't want things going up in flames when you are not around
Be careful because under the red slide is heaps of current that can short out

Teach her what to do, and how to be careful.

 

Is the car parked in a garage or outside in the drive way? In either case you dont want to connect the charger inside the car then you would have to leave a door or window open for the extension cord.

I recommend getting an inexpensive bluetooth battery monitor. You can easily see the condition of the battery from a cell phone without unlocking the car. Just stand next to it and see the battery voltage and ball park SOC. Then you can figure out how often you should charge the battery.

I have the Ancel BM200 battery monitor and have been using it to see how far I have to drive the car to have the battery fully charged. I dont put many miles on my W204.

I have a Noco Genius 5 battery charger also. I will connect it once in awhile in hopes it will "optimize battery for extended life", at least thats what the manufacturer claims. When i hook it up it appears to take around 3hrs to do its thing, for the lights to go from red all the way to single green flashing indicating its done charging and on maintenance mode. Its always around 3hrs for some reason.

I wanted to be able to charge the battery with the hood fully closed. Mercedes says to connect the charger to the jump start locations. This was not an option as i wouldnt be able to close the hood, at least easily. So next best option in my case was to hard wire the chargers adaper directly to the positive battery terminal and then connect the negative to the negative grounding point in the engine bay that the batteries negative cable is grounded to. This way the battery sensor can see the charging voltage.

When I want to charge the battery I place the charger in the engine bay behind the headlight and fish the extension cord thru the front grill which just barely fits.