Charging Battery CTEK

[farmer7]

Just wanted to check if it's OK to connect my CTEK trickle charger to my W213 E220d 2019? On the Mercedes app it's always showing as only partially charged.

I haven't looked into the battery location or types but am I right in thinking it's an AGM battery? And do I just connect directly to the battery? Or do I need to disconnect?

The car always starts OK but just wondered if I should try and charge it. Also should I put it on the Recondition programme or just a straight charge?

Sorry, I'm just a bit wary of a car with lots of electrics, I'm paranoid of frying something!

 

[Connoisseur]

Conditioning programme is best in my experience as it includes a series of tests of battery health. If yours is a AGM Battery then worth checking if your particular CTEK will work is magic as some CTEK are lead acid only. Your battery will have a label stating what type it is hth

 

[SpikyMikey]

If your E Class is like most other MB's it should have an arrangement like this under the bonnet for jump starting and charging:

 

[whitenemesis]

And do I just connect directly to the battery?

When my Mercedes dealership fitted a permanently attached CTEK charging lead, they connected directly to the battery terminals, as they do with factory fitted charging leads

 

[ALFAitalia]

Personally Id only be using the terminals to jump start....Id be charging direct to the battery posts. You shouldn't really jump start with the lead directly on the neg terminal.....

 

[chic0821]

My S63 & Range Rover is connected to Battery positive & a convenient bolt near the battery. Been like that for years. Told not to use battery negative

 

[Bobby Dazzler]

My S63 & Range Rover is connected to Battery positive & a convenient bolt near the battery. Been like that for years. Told not to use battery negative

I do the same. If I remember right the CTEK installation instructions tell you to do it that way too, rather than connect directly to the negative terminal of the battery.

 

[Bobby Dazzler]

Just wanted to check if it's OK to connect my CTEK trickle charger to my W213 E220d 2019? On the Mercedes app it's always showing as only partially charged.

I haven't looked into the battery location or types but am I right in thinking it's an AGM battery? And do I just connect directly to the battery? Or do I need to disconnect?

The car always starts OK but just wondered if I should try and charge it. Also should I put it on the Recondition programme or just a straight charge?

Sorry, I'm just a bit wary of a car with lots of electrics, I'm paranoid of frying something!

If you read you CTEK instructions you’ll see that you should not use Recon in AGM mode. even though it will allow you to select both options.

From memory, Recon increases the voltage to create bubbles which removes sulphur from the plates, but this can damage the glass mats in the AGM.

 

[Diesel Benz]

Just wanted to check if it's OK to connect my CTEK trickle charger to my W213 E220d 2019? On the Mercedes app it's always showing as only partially charged.

I haven't looked into the battery location or types but am I right in thinking it's an AGM battery? And do I just connect directly to the battery? Or do I need to disconnect?

The car always starts OK but just wondered if I should try and charge it. Also should I put it on the Recondition programme or just a straight charge?

Sorry, I'm just a bit wary of a car with lots of electrics, I'm paranoid of frying something!

Absolutely safe to use any CTEK charger. Connect it like Spiky showed, easiest and safest although not the only acceptable option.

If the charger does not support AGM batteries, it is still fine for your purpose. I just doesn't charge the AGM battery 100% full but no need either.

I often don't drive my car for several weeks and I also get the partially charged battery status frequently. My CTEK has the AGM mode but I often use the normal battery mode as I'm not aiming to absolute 100 % state of charge, just enough to make the Mercedes Me app happy (reports fully charged).

 

[OneForTheRoad]

If you connect directly to the battery ,the BMS won't see the charge and still think the battery is low , always use the jumper pegs. Or live to battery and earth before the battery pole.

 

[Diesel Benz]

If you connect directly to the battery ,the BMS won't see the charge and still think the battery is low , always use the jumper pegs. Or live to battery and earth before the battery pole.

This claim is popular but I still don't buy it. The point being the BMS is not alive more than a few minutes after ignition has been switched off. It would not continue monitoring the trickle charger output throughout the night. If it did, the car would keep consuming more current than a small trickle charger can give.

Depending on the MB model, the negative pole has the BMS current sensor which is there even if ignition was switched off but it only introduces a resistance of a fraction of an ohm (obviously, needs to pass the starter motor current without significant voltage drop). This does not make any real difference for the trickle charger voltage as measured on the battery poles.

This, I'd say "urban legend" comes from a real issue which is connecting consumers directly to the battery, specifically high current consumers like a powerful audio amplifier. BMS needs to see the current coming/going from the battery, not that current altered by the audio amplifier consumption. This all is active when the car is being driven and fools battery monitoring.

 

[OneForTheRoad]

This claim is popular but I still don't buy it. The point being the BMS is not alive more than a few minutes after ignition has been switched off. It would not continue monitoring the trickle charger output throughout the night. If it did, the car would keep consuming more current than a small trickle charger can give.

Depending on the MB model, the negative pole has the BMS current sensor which is there even if ignition was switched off but it only introduces a resistance of a fraction of an ohm (obviously, needs to pass the starter motor current without significant voltage drop). This does not make any real difference for the trickle charger voltage as measured on the battery poles.

This, I'd say "urban legend" comes from a real issue which is connecting consumers directly to the battery, specifically high current consumers like a powerful audio amplifier. BMS needs to see the current coming/going from the battery, not that current altered by the audio amplifier consumption. This all is active when the car is being driven and fools battery monitoring.

Thanks for your hindsight another point is having to remove covers to get at the battery poles, totally pointless and unnecessary. What your saying also voids the need for a BMS reset when a new battery is fitted.

 

[kcsun]

In my manual it says always connect to the terminals under the bonnet, not direct to the battery. Been fine for 5 years and quick and easy connection



kc