[chavoush]

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Hi all, have a 2024 M2. From other threads, looks like the battery is an AGM. The manual says not to exceed 14.4v while charging but my CTEK charger goes to 14.7v for AGM batteries. Anyone have any insight. Please let me know if I'm off here. thanks.

[Tag]

Originally Posted by chavoush

Hi all, have a 2024 M2. From other threads, looks like the battery is an AGM. The manual says not to exceed 14.4v while charging but my CTEK charger goes to 14.7v for AGM batteries. Anyone have any insight. Please let me know if I'm off here. thanks.

Voltage depends on the program you select to charge the battery. What model CTEK do you have?

[chavoush]

Thanks, I have an MXS5. AGM mode it goes up to 14.7 in standard mode goes up to 14.4. If the M2 battery is an AGM, should I not be charging with the AGM mode on the charger since it goes to 14.7v and the M2 manual says keep it at 14.4v?

[Tag]

Originally Posted by chavoush

Thanks, I have an MXS5. AGM mode it goes up to 14.7 in standard mode goes up to 14.4. If the M2 battery is an AGM, should I not be charging with the AGM mode on the charger since it goes to 14.7v and the M2 manual says keep it at 14.4v?

I see that the manual says 14.4V which is odd, because BMW TIS says not to exceed 14.8V.

Warning! Do not charge the AGM battery with > 14.8 V. Do not use rapid-charging programs!
When charging removed batteries (so-called stand‐alone batteries), do not exceed the maximum charging voltage of 14.8 V at room temperature. Also, for charging via the external start connection point, the maximum charging voltage of 14.8 V at room temperature must not be exceeded. The battery can be damaged even if the AGM battery is only briefly charged with a charging voltage higher than 14.8 V. A charging voltage of more than 14.8 V is usually used in quick-charging routines.

See attached 'Notes on AGM battery.pdf'

Also see here for more info on the battery and charging.

If you're uncomfortable going to 14.7V then just select the standard car charging program. It's identical to the AGM program with the exception that it only goes up to 14.4V.

MXS_5.0-manual-low-UK-EN.pdf

[chavoush]

Thank you much, this is very helpful. I think the manual in some places is too generic. I wanted to make sure the M2 has an AMG, and if so, I'm not concerned. thanks again.

[Tag]

Originally Posted by chavoush

Thank you much, this is very helpful. I think the manual in some places is too generic. I wanted to make sure the M2 has an AMG, and if so, I'm not concerned. thanks again.

There are quite a few here that have been using CTEK with the AMG program without any issues. I wouldn't worry about it either, they are smart chargers and the best consumer grade ones on the market.

[aerobod]

The voltage used in most programs is also transitory unless the battery is at low charge state. For maintaining charge the voltage drops from the maximum quickly in pulse or low current mode.

For the G87 I just use the 0.8A CTEK which only uses 14.4V max for all battery types. As I have it plugged into a ceiling socket and hanging over the car, a nice light charger works better for easy connection and disconnection and low risk of damage if it falls on the car.

[Kevin_The_Clean1]

It's an AGM battery not an AMG guy. But I know what you mean & are trying to say. LOL For years I used the non-AGM / generic battery charging option on my C-Tek. Thinking that was best. But years later I come to find out that the AGM mode actually (keeps the unit cooler & charges the car battery faster). Because most if not all M cars now-a-days have that type of battery. It's there for a specific reason. So use it & don't be afraid to select the AGM button on your charger.

[vrooooom]

AGM batts apparently should be charged 14.7V which CTEK uses. Noco uses 14.8V for their AGM setting.

[Tag]

Update:

According to the latest Battery Charging Procedures and Parameters that was released today, the acceptable charging voltage range is between 14.4V to 14.8V. Only time it requires 14.8V is when the car is being worked on for mechanical and electrical repairs or programming. The CTEK AGM charging program which goes up to 14.7V is safe to use.

[Ravenseal]

I've been using a NOCO GENIUS2 on my RS5, M240i, and M2 without any issues.