CTEK MXS 5.0 Modes

[Deleted member 134751]

I bought a CTEK MXS 5.0 and despite reading the manual and looking online, I don't really understand which mode I should be using on my car.

Obviously, I know to select the car mode, instead of the motorbike mode, but I have no idea whether to select car only, or car + AGM, or car + AGM + RECOND.

It says to use AGM mode in cold weather, but how cold is cold?

Any advice (in plain English) would be appreciated - thanks

 

[whitenemesis]

Must admit I only ever used the standard car only option on my CLS55, never had an issue and maintained the battery perfectly well.

 

[Deleted member 134751]

Must admit I only ever used the standard car only option on my CLS55, never had an issue and maintained the battery perfectly well.

Thanks - I think I will go with that option... unless anyone else chips in!

I'm guessing it's the quickest mode as well, and I only really want to fully charge the battery at this stage.

 

[flowrider]

Only use "AGM" mode if you have an AGM battery, only use "RECOND" mode if your battery is in need of a revitalisation due to age but NEVER use "RECOND" on an AGM battery.

 

[Deleted member 134751]

Only use "AGM" mode if you have an AGM battery, only use "RECOND" mode if your battery is in need of a revitalisation due to age but NEVER use "RECOND" on an AGM battery.

Thanks - but if that's the case, how come one of the modes you can select is "AGM + RECOND"?

 

[Muckypaps]

If it's cold you wear a coat when you go outside
If it's not cold you can wear a shirt outside and not feel cold.

 

[Srdl]

Thanks - but if that's the case, how come one of the modes you can select is "AGM + RECOND"?

You should use “Car + AGM” if you have AGM. I understood RECOND is only for a totally flat battery that needs brining back to life

 

[Deleted member 134751]

You should use “Car + AGM” if you have AGM. I understood RECOND is only for a totally flat battery that needs brining back to life

I've not got it to hand to check, but I'm pretty sure it says in the manual that AGM can also be used if it's "cold" outside, whatever that means.

 

[Deleted member 134751]

In case this helps others in the future - according to this video, AGM mode should be used if you have an AGM battery, and if your car has start/stop technology, you will have an AGM battery:

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[whitenemesis]

AGM batteries tend to be fitted where the battery is within the cabin or potentially could contact those in the cabin in the event of an accident/overturning..
My CLS55 had an AGM battery and I still used the standard mode, worked fine..

 

[Deleted member 134751]

So I was planning to use my new CTEK charger today but the 2.5m extension cable isn't quite long enough.

Is it ok (i.e. safe/not dangerous) to join two extension cables together, giving me 5 meters? This would allow me to keep the device itself in my house whilst in use (and safe from inevitable theft).

 

[Merc220cls]

Why not run the mains extension to the engine bay with the Cetek connected there.

 

[Deleted member 134751]

Why not run the mains extension to the engine bay with the Cetek connected there.

I did think about that but not sure if there will be space for it once the bonnet is closed and also worried it might get hot under there and cause problems....I am just going to buy another 2.5m cable and connect them both. I can't imagine anything catastrophic will happen.

 

[E55BOF]

Only use "AGM" mode if you have an AGM battery, only use "RECOND" mode if your battery is in need of a revitalisation due to age but NEVER use "RECOND" on an AGM battery.

It sounds as though you know something we don't. Do please tell us what it is.

 

[190]

It says to use AGM mode in cold weather, but how cold is cold?

The reason they are saying that is because a batteries internal resistance is higher when cold which requires a higher charging voltage to achieve any given charging current. The cars charging system will have a negative temperature coefficient built in to allow for this when the alternator is charging the battery. Prior to smart alternators when simple voltage regulators were used they were also temperature compensated to reduce the charging voltage a couple of tenths at higher temperatures.

As for how cold is cold, who knows precisely. If the car lives outside in the winter then The AGM mode would be appropriate at least initially when bringing a battery up from a partially discharged state. I wouldn't use the AGM mode on a standard battery when the charger is being left on for long periods.

The reason for not using reconditioning mode on AGM batteries is because they are less tolerant of overcharging. Although they are sealed they have a safety valve which will blow off in the event of over charging with the possible loss of electrolyte. Do that too often and the battery will fail prematurely.

 

[Atavus]

They don’t recommend using a two leads, due to voltage drop. I also don’t expect anything catastrophic, but keep an eye on it.

 

[E220Downer]

In case this helps others in the future - according to this video, AGM mode should be used if you have an AGM battery, and if your car has start/stop technology, you will have an AGM battery:

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Thanks for that. I’ve just brought an MXS 5 and this was a great help

 

[alzieboy]

I understand that CTEK do a charger specifically for Vehicles with Stop /Start function.

CTEK CT 5 .

 

[Atavus]

Good marketing.

 

[Notwen]

They don’t recommend using a two leads, due to voltage drop.

Totally agree.

The charger could potentially see the voltage drop as a discharged battery and stay in the Bulk charge mode.
Bulk can be 14.5 or 14.7 volts, which is above the gassing threshold of 14.25v, not only overcharging your battery, but if in an enclosed space a build up of gasses could be dangerous

I have two very old ctek 7.0 chargers, one of them I alternate between the C43 and Jayne's SLK.
When charging the SLK I use a long extension lead I made, but I will only use the supply voltage mode of 13.6 to avoid issues.