R230 Consumer Battery - How To Charge

[alexanderfoti]

As far I am aware AGM vs Flooded.

An AGM can take a higher charge rate and requires a slightly lower FLOAT voltage (end of charge) than flooded. (2.21-2.25 volts per cell vs 2.3 ish volts per cell).

However, you wont be able to get 15.7 volts during the bulk or absorption charge phase with a 5 amp charger on a 100ah + AGM battery so don't worry. You would need a 30+ amp charger to do that.

Also, the Ctek wont float charge any battery to 15.7 volts, it only uses high pulses of 15+ to waken "dead" batteries.

 

[Submariner1]

Hi

I have a new CTEK MXS5.

In the manual, Step 1 which is Desulphation shows as 15.8V for all types and sizes of battery - from small (which shows as a motorbike symbol) to normal (car symbol) to AGM and Recondition.

Quite a few people on here have used the CTEK and the recondition mode on their cars that have AGM batteries with no ill results.

Let us know what you find out.

Thanks good to know. This guy didnt say it would kill the battery just wreck its longevity and max performance.
I am interested to know if the Ctek Stop and go version designed for AGam batteries have the 15.8 V cycle.
Interestingly he says the MB oemed Ctek does NOT have the 15.8v cycle :-/
Maybe thats why mb say u can only use theirs ?

 

[Submariner1]

As far I am aware AGM vs Flooded.

An AGM can take a higher charge rate and requires a slightly lower FLOAT voltage (end of charge) than flooded. (2.21-2.25 volts per cell vs 2.3 ish volts per cell).

However, you wont be able to get 15.7 volts during the bulk or absorption charge phase with a 5 amp charger on a 100ah + AGM battery so don't worry. You would need a 30+ amp charger to do that.

Also, the Ctek wont float charge any battery to 15.7 volts, it only uses high pulses of 15+ to waken "dead" batteries.

Interesting this is all new to me, all I knew was AMG batteries needed slightly higher 14.7V as opposed to 14.4v absorbtion. But that was just heresay.
Out of interest why cant one get 15.8 v if the charger outputs that value?

 

[alexanderfoti]

Interesting this is all new to me, all I knew was AMG batteries needed slightly higher 14.7V as opposed to 14.4v absorbtion. But that was just heresay.

They don't need a higher absorption, but will take it happily because they have a lower internal resistance and can take a higher charge current.

Out of interest why cant one get 15.8 v if the charger outputs that value?

Because of ohms law. Current = voltage / Resistance. The internal resistance of a battery decreases as its charged, but only slightly.

If you have not got a 30+ amp charger then you aren't going to get 15.8v Volts. You can't just put 15.8v into the battery without the appropriate current, because again, Voltage = Current X resistance.

Without the current to back it up, the voltage will be pulled down by the battery.

As a result, the only time you will see 15.8 volts is during the float charge or if the battery is sulphated and trying to be "recovered". As mentioned, this high a float, will kill an AGM or boil a flooded lead acid unless its very very cold.

 

[Submariner1]

Well just got the response from CTEK Technical in Sweden, and their recommendations for Mercedes with complex electronics, VRLA, EFB and or AGM Batteries is the CT5 Stop Start 3.8A. Max V = 14.55V.
So basically its an MX5 limited to 3.8V and 14.55V it also does not have the high 15.8V check/desulphation cylce, but a 14.55V check/desulphation [to help AGM batteries] and doesnt have (as its harmful for AGM Batteries)the 15.8V Recondition Cycle.

Sounds logical, and also mirrors what VARTA technical say. I.e. Dont use the 15.8V cyle on AGMs. And as my good MB mechanic says under 4Amps removes a lot of risk if you make any mistakes. Also the original CTEK MB OEM charger does not have the 15.8V pre check cycle. Plus I like the limited 14.55V as you knever know what 15.8V being pulsed could do to any of the sensitive electronic boxes.
So ordered one.
Plus if all the cars go stop start in the future then its suitable too.

So hope that helps anyone thinking of getting one.
Is it the correct advice .... who knows but if MB and CTEK and Varta who make my original MB AGM battery all agree hopefully the research paid off.

Just glad I checked, as I was going to buy a MXS 5, purely because the litrature says its OK for AGM batteries ... which it is not!

Its a bit more expensive than the MXS 5 @ £58 m as opposed to the CT5 stop start one at £70. But as they say AGM batteries rarely get fully charged up by the alternator (due to their ability to go lower) and thus its a good idea to give them a periodic charge up .... seems worth the £12 Difference.

 

[flowrider]

Well just got the response from CTEK Technical in Sweden, and their recommendations for Mercedes with complex electronics, VRLA, EFB and or AGM Batteries is the CT5 Stop Start 3.8A. Max V = 14.55V.
So basically its an MX5 limited to 3.8V and 14.55V it also does not have the high 15.8V check/desulphation cylce, but a 14.55V check/desulphation [to help AGM batteries] and doesnt have (as its harmful for AGM Batteries)the 15.8V Recondition Cycle.

Sounds logical, and also mirrors what VARTA technical say. I.e. Dont use the 15.8V cyle on AGMs. And as my good MB mechanic says under 4Amps removes a lot of risk if you make any mistakes. Also the original CTEK MB OEM charger does not have the 15.8V pre check cycle. Plus I like the limited 14.55V as you knever know what 15.8V being pulsed could do to any of the sensitive electronic boxes.
So ordered one.
Plus if all the cars go stop start in the future then its suitable too.

So hope that helps anyone thinking of getting one.
Is it the correct advice .... who knows but if MB and CTEK and Varta who make my original MB AGM battery all agree hopefully the research paid off.

Just glad I checked, as I was going to buy a MXS 5, purely because the litrature says its OK for AGM batteries ... which it is not!

Its a bit more expensive than the MXS 5 @ £58 m as opposed to the CT5 stop start one at £70. But as they say AGM batteries rarely get fully charged up by the alternator (due to their ability to go lower) and thus its a good idea to give them a periodic charge up .... seems worth the £12 Difference.

None of that makes any sense. Why have an MXS5 that has an AGM and recondition option if it is not suitable. Surely it is the current that will harm electronics more that the voltage. The MXS5 at 15.8v is only 1.8A.

 

[rexemper]

None of that makes any sense. Why have an MXS5 that has an AGM and recondition option if it is not suitable. Surely it is the current that will harm electronics more that the voltage. The MXS5 at 15.8v is only 1.8A.

That's what I don't understand either. There is a specific AGM and AGM with recondition function on the MXS5.

 

[Submariner1]

None of that makes any sense. Why have an MXS5 that has an AGM and recondition option if it is not suitable. Surely it is the current that will harm electronics more that the voltage. The MXS5 at 15.8v is only 1.8A.

Just repeating what I was told.
Apparently the damage done to the battery is due to the high pulsing Volts, as this is used on flooded batteries to detach the sulphate, and also to get a wet battery to fizz a bit and therefore mix up the acid ( like stirring the acid ).
However it doesnt work on an AGM battery as the detached sulphate cant be dispersed. Varta said that caused problems, tbh it then went over my head, but I got the drift that the detached excess sulphate formed a sort of barrier or something like that. And That makes sense to me.

As for the higher voltage causing problems, that was just my view i.e. If one has intrinsictly a 12V battery, that is used to / designed to being charged by an alternator at 14.4-14.7V then 15.8 seemed quite high. I just guessed all 12V components must have some kind of tolerance, no?
Plus as I=V/R having a much higher current could give a component more current than it was designed to handle ?

 

[Submariner1]

That's what I don't understand either. There is a specific AGM and AGM with recondition function on the MXS5.

See above reply. And yes, I can fully appreciate your concern, why have this cycle and specifically for AGM batteries.
Did they make a huge gaff?

All I can say (as an ignorant layman, with knowledge only up to an A Level in Physics.) is if the battery manufacturer's technical department says its really bad news, and when challenged CTEK technical (and confirmed by CTEK UKs Sole Retail Distributor ) agree, its better not to have 15.8V going into an AGM battery for long term performance, and then they recommend a charger that does not have the 15.8V cycle .... sounds like its true.

If on the other hand CTEK's technical had disputed what VARTA said then that would have been a dilemmna.

Personally I too was just about to buy the MXS5, as on the surface seemed to do all and more than I needed, and was a lot cheaper. If ai had bought it I would have demanded that CTEK replace it with a Start Stop charger ( under fit for purpose).

Sounds to me like CTEK made a huge gaff, and then the battery MFG came across the negative effects of charging at 15.8V on their AGM range. Logically as the effect is not instant failure, its the sort of thing the battery manufacturer would have discovered first, over time.

Yet again, this isn't my theory, I am just passing on what I was told!

 

[rexemper]

See above reply. And yes, I can fully appreciate your concern, why have this cycle and specifically for AGM batteries.
Did they make a huge gaff?

All I can say (as an ignorant layman, with knowledge only up to an A Level in Physics.) is if the battery manufacturer's technical department says its really bad news, and when challenged CTEK technical (and confirmed by CTEK UKs Sole Retail Distributor ) agree, its better not to have 15.8V going into an AGM battery for long term performance, and then they recommend a charger that does not have the 15.8V cycle .... sounds like its true.

If on the other hand CTEK's technical had disputed what VARTA said then that would have been a dilemmna.

Personally I too was just about to buy the MXS5, as on the surface seemed to do all and more than I needed, and was a lot cheaper. If ai had bought it I would have demanded that CTEK replace it with a Start Stop charger ( under fit for purpose).

Sounds to me like CTEK made a huge gaff, and then the battery MFG came across the negative effects of charging at 15.8V on their AGM range. Logically as the effect is not instant failure, its the sort of thing the battery manufacturer would have discovered first, over time.

Yet again, this isn't my theory, I am just passing on what I was told!

You know more than me - I didn't do Physics at O level, let alone A level!

Well I've used it to recondition 2 batteries already so guess will have to just wait and see if anything untoward happens.

 

[flowrider]

Just got my consumer battery on charge again, the car has not been used for just over a week and the battery warning is on again. This is a pain in the neck!