[Dr. Indiana Jones]

Sadly, I don't drive my car much these days due to a disability, and the battery was always low/discharged, even though I didn't activate the alarm when parked in the garage. So, after reviewing a few videos online...

I just did a permanent CTEK MXS 5.0 battery charger/tender install on my 2017 M240i. The MXS 5.0 is the go-to model for decent functionality w/o breaking the bank (any lower model and you don't get temperature sensing adjustment and, in some cases, merely tender w/o full charging capability). Sorry no pics, but I will describe what I did...

You can use the wires with the clips (but I wanted a neater, more permanent solution, so use the o-ring wires). You want to install the +ve o-ring wire to the +ve battery terminal under the hood (no, never attach directly to the battery in the trunk, as it could fry sensitive electronics!). I was lucky that my terminal has a removable T-bolt, otherwise you'll have to find another way to make the connection. Then find somewhere nearby to attach the -ve 0-ring (I resorted to sliding the damn thing underneath a small bracket that bends over the edge of the engine body, and may need to solder it eventually, but any connection attached to the body will work). Also, luckily I had a small crease/crevice with which to tuck the -ve o-ring wire, so that it doesn't infringe with the plastic hood bonnet (otherwise you might have contact when closing the hood).

The wires all get covered with 10mm black auto flex tubing (optional and merely for cosmetic reasons). The lead wire gets fished through to the windshield wiper area (so you can close the hood w/o issue). You then simply tie-in from there to the unit, which gets plugged into a power outlet.

I purchased the CTEK extension wire but found I didn't need it. I intend to buy the CTEK plastic holder, so I can mount the unit on the garage wall, and avoid the need for this extension wire or any extension cords.

The total cost for the unit and materials was about $175-$200 CAD. This was a time consuming process simply because it was difficult to locate a suitable body/ground connection point, otherwise you can do it in 15 min. She works like a charm with the hood down, and alarm on! Just remember to lift up the driver's windshield wiper to remind you to unplug the damn thing before you drive off! Any questions; fire away.

[dradernh]

Thanks for the heads-up on the wall mounting bracket. I didn't know that CTEK offered that accessory.

[SW111]

Do you have any pictures of the install?

Thanks!

[John in VA]

You can see their mounting brackets here - https://www.ctek.com/uk/battery-char...2v-24v/add-ons

[Kernel Kurtz]

Originally Posted by Dr. Indiana Jones

Just remember to lift up the driver's windshield wiper to remind you to unplug the damn thing before you drive off!

No winter in Canada is complete without seeing people driving while dragging an extension cord or portion thereof behind them :-)

[dradernh]

Originally Posted by Kernel Kurtz

No winter in Canada is complete without seeing people driving while dragging an extension cord or portion thereof behind them :-)

Right. There's a reason the West Edmonton Mall has hookups at its parking spaces. That's a necessity at 53° North.

[Dr. Indiana Jones]

Originally Posted by SW111

Do you have any pictures of the install?

Thanks!

I have the mounting bracket on order, and once delivered on Dec 5, 2022, I will complete the installation and then take some pics to show the connections.

[Dr. Indiana Jones]

Originally Posted by SW111

Do you have any pictures of the install?

Thanks!

Here u go!

The CTEK unit's plastic holder mounts to any wall using wall plugs and screws (they don't tell you what size of drill bit to use, so you'll have to estimate, but error a little on the small side if you are drilling into concrete, since the hole will inevitably be a tad bigger than the bit size). I've mounted mine so that the CTEK unit's power cord just reaches the electrical outlet, and the other wire gets connected to the connector I've installed under the hood near the windshield wiper.

This connector under the hood comes equipped with it's own cap. Ideally the connector should be capped when not in use, especially when the car is being driven during inclement weather such as rain or snow, or you want to be able to operate the windshield washer w/o fear of the washer fluid contaminating/corroding the connector.

The only trouble I've had so far is trying to securely fasten the -ve o-ring wire terminal to the ground of the car. I've got it tucked under a metal sleeve that folds over the body, and I'm hesitant to solder it in place due to nearby wiring. Also, be careful not to fasten the -ve o-ring wire terminal too close to the windshield washer fluid intake, for fear that the connection might get wet/corroded when refilling the windshield washer fluid.

Since most if not all BMW batteries are AGM, I selected the car and AGM modes/options (although the unit can charge some AGM batteries w/o selecting the AGM option, I figured better to just select it anyway.). Read the instructions: the unit can take quite some time in certain/various stages of charging, so don't be alarmed if things are slow at first. Also, if the power LED is flashing (ahem, like mine was at one point), that likely means the -ve o-ring terminal isn't in good contact with the car body.

[Dr. Indiana Jones]

BTW, although the wall mount bracket holder is overpriced at ~$23 CAD for such a simple plastic part, I still recommend using it, so that the CTEK unit is portable (i.e., can be removed from the wall at any time). However, the CTEK unit does have two holes should you wish to use your own wall plugs and screws to permanently mount the unit directly to the wall w/o the holder.

[Dr. Indiana Jones]

BTW the below pic is reposted here to showcase the existing "small crease/crevice" within the plastic hood bonnet of most BMWs, that enables the -ve o-ring wire (furthest wire in the pic) to pass through so that it doesn't infringe with the hood when closed. In the pic, you'll see a kink in this wire (where I left the wire exposed w/o any flex tubing and wrapped it with a bit of tape to protect it, while it gets pushed down and squeezed into this crevice. I then put a piece of tape on top so that the wire won't slip out of this crevice.

Also, be aware that the CTEK unit comes equipped with it's own fuse (see fuse holder interjecting the +ve o-ring wire at the bottom left of the pic below). In the unlikely event that the CTEK unit gets overloaded or is mis-wired causing a short, it'll blow the fuse, and you'll need to replace the fuse. The unit is, however, polarity protected on the off chance you mix up the installation of the +ve and -ve wires.