C63 W205 - where is the battery?

[BJC]

Hello,

I appreciate the title may read like a stupid question, but please bear with me and read on! With the current lockdown, I've purchased a CTEK MXS 5.0 trickle charger for my W205 C63 as the battery was starting to throw some critical warnings.

Using the CTEK, I'm currently using the provided crocodile clips on the provided positive connection and the negative anchor point. It works great and took around two days to fully charge the battery. During my pre-purchase research, I watched a YouTube video of a W205 (not a C63 though) and they showed a car battery in the bonnet area, beneath some plastic trim and what I presume to be a cabin air filter. They then connected a CTEK "comfort" connection directly to the battery, providing them with a traffic light system to see the battery charge level.

Curiosity got the better of me, so I had a look there myself, only to find I don't actually have a battery there, but an empty space instead.

I'm guessing the video I watched was for a W205 diesel, rather than petrol, or the C63/C63S are different somehow? I have the CTEK comfort connector too (it was ~£10 from Amazon), but given the expected battery doesn't exist where I thought it would, and that the crocodile clips are just as quick-n-easy to use I'll stop being lazy and give the installation a miss for now.

Have any other W205 C63 owners bothered installing the CTEK comfort connector? Being electrical, and with cars being so technology-driven these days, I guess disconnecting the power by accident can have some "interesting" side effects? As stated above, for now, I'm staying away from it - "if it ain't broke, don't fix it" - but I'm still intrigued to know more. Any sensible thoughts are welcome!

Thanks, Ben

 

[ShaunB]

Don't know the answer to your question, but where did you purchase the charger from?
Did you then just connect the charger to the +/- points in your photo?

 

[jasonh]

In the W204 C63 the battery is in the boot under the boot floor.

 

[BJC]

Don't know the answer to your question, but where did you purchase the charger from?
Did you then just connect the charger to the +/- points in your photo?

I purchased it from Demon Tweaks as they were the cheapest at the time: CTEK MXS 5.0 Battery Charger

I think the price has gone up a few pounds since, so it would be worth checking a few places to get the best price available.

Connecting it is as easy via the slide covered red positive terminal, and the earthing point (just out of my original photo). Off the top of my head, I think it's detailed page 437 in the manual.

In the W204 C63 the battery is in the boot under the boot floor.

I'm sure I read or watched something stating you shouldn't go directly to the batter in the boot. I believe the W205 has two, one AGM for the start/stop functionality (which is the one that's been running low for me), then the usual auxiliary battery.*

* Disclaimer - I'm no mechanic or expert, so don't assume I'm right!

 

[Atavus]

Attach the comfort connect lead under the bonnet. It’s what I’ve done on my S63. Just drill the positive and attach the negative to the post.

 

[ShaunB]

I purchased it from Demon Tweaks as they were the cheapest at the time: CTEK MXS 5.0 Battery Charger

I think the price has gone up a few pounds since, so it would be worth checking a few places to get the best price available.

Connecting it is as easy via the slide covered red positive terminal, and the earthing point (just out of my original photo). Off the top of my head, I think it's detailed page 437 in the manual.



I'm sure I read or watched something stating you shouldn't go directly to the batter in the boot. I believe the W205 has two, one AGM for the start/stop functionality (which is the one that's been running low for me), then the usual auxiliary battery.*

* Disclaimer - I'm no mechanic or expert, so don't assume I'm right!

I could probably do with one of these, especially for my wife's A class Are they fool proof to use?

 

[540YMX]

I bought a CTEK at the start of the lockdown as well as the car doesn't like not being used and it works well.

Mine came with the additional connector which would be handy to fit directly to the battery in the boot, but these new fangled batteries look far to complicated to mess about with so abandoned that idea.


So just use it via the engine bay connectors.

 

[BJC]

I could probably do with one of these, especially for my wife's A class Are they fool proof to use?

I can use it, so yes, it's idiot-proof. It also has reverse polarity protection, so if for some reason I put the positive onto negative, it won't screw up the car or the CTEK unit.

 

[Atavus]

Get the drill out and you can fit the CTEK Comfort connect lead. It’s not meant to be attached to the battery on these stop/start cars.

 

[BJC]

Get the drill out and you can fit the CTEK Comfort connect lead. It’s not meant to be attached to the battery on these stop/start cars.
View attachment 95864View attachment 95865

Thanks, Atavus - I assume you're connecting the negative to the existing anchor point too? I read the same that connecting to the boot battery is not the correct way.

 

[Atavus]

Yes @BJC , the black wire with the green tape terminates at the existing point and I unbolted that to attach the CTEK lead.

 

[BJC]

Thanks for the info, I appreciate it.

 

[ShaunB]

I can use it, so yes, it's idiot-proof. It also has reverse polarity protection, so if for some reason I put the positive onto negative, it won't screw up the car or the CTEK unit.

Since you guys are using this on an S63 and a C63, it's bound to be good on my W213 E63.
Would I be ok to assume it would be grand on my wife's 2017 A220d?
It's a stop start car also.

 

[Steve84N]

It's fine on all normal cars.

 

[ShaunB]

It's fine on all normal cars.

Cheers

 

[ShaunB]

I can use it, so yes, it's idiot-proof. It also has reverse polarity protection, so if for some reason I put the positive onto negative, it won't screw up the car or the CTEK unit.

Did you have to purchase the ctek extension leads or anything?

 

[BJC]

Did you have to purchase the ctek extension leads or anything?

No extensions required, it works straight out of the box.

 

[ShaunB]

Just ordered one from Demon Tweeks, they seem to be offering the best price still

 

[ShaunB]

I've just received my MXS5.0 charger today.
I notice the instructions say that the normal car battery program says it will do many AGM batteries.

Do you guys just leave it on normal mode, or do you pick AGM?

 

[Steve84N]

Normal for me but if you have AGM then choose that. It uses slightly higher voltages for AGM.