Quote:
Originally Posted by Teutonic
Yes, that is true, confirmed as well by my tech and another tech here on the thread.
The problem is that this charging is fast but heats up the battery ...
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Also, the professional charger they use in the dealerships is able to adapt to the requirements of the vehicle and they have certain functions and they reduce the amount pushed based on a permanent battery reading, while the 25A off market chargesr are just pushing 25 A straight. Noco is a very good product as I own the 5 and the 10, but when I talked to them they confirmed that their 25-50 chargers are pushing that Ah straight. ...
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I have followed some of these threads and did some testing and measurements on my M440i MHEV. I have not had a need to charge my 12V battery so this was just testing out of interest (and i preparation to know what works if needed). Further, I don't have an outlet where I park but I have a "CTEK CS Free" that initially is capable of supplying up to 20A.
My guess is that the MHEV system in these cars does something funny for a while after connecting a charger while consuming a high current. I haven't measured the current to the 12V battery but the voltage at the charging posts stays normal so my conclusion is that the current to the battery is not too high. As can be seen in my voltage/current plot the current rise to 17.5A at the beginning but then reduces while the voltage increase to a normal charging voltage of 14.1V. A car charger which is specified to be used on a battery while still being connected to the car should be safe to use even with a high current rating because it will make sure that the voltage doesn't exceed 15V or so. No cycling of click noises was heard.
