How to charge battery?

[m.a.g]

Recently (probably because it is colder) I'm getting this "increased battery discharge" message whenever I start the car. Same thing was happening last winter season, and I took my 2014 X6 the the dealership and was told that battery is fine and holds the charge. I guess they must have charged it too, because message was gone for few months, till recently.

I don't drive long distances, just multiple short trips during the day, plus the car was sitting in the garage for 2 months while I was out of the country, so I figured I just need to charge the battery.
I referred to the manual, located terminal under the hood, hooked up the charger, and.... something weird happened.
At first, charger (black & decker brand) was showing that battery is only 25% charged, and battery got charged from 25 to 100% in less than 10 minutes. From that moment on it would not charge any more.
Still, I was getting "increased battery discharge" every time I started the car.
I figured it is not possible to charge the battery in just 10 minutes using crappy 15 amps black and decker charger, so I bought another charged on Amazon, NOCO Genius, fully computerized, automated, etc.
That one worked better - it was charging for about 20 minutes maybe (and initial state was less than 25% charge) - then it was showing that battery is full, and after a few seconds it was starting to charge it again - showing 25%, 50%, , 75%, and then 100% again, in cycles. I let it do it for 2 hours and that actually helped with "increased battery discharge".

But, from what I understand after battery was fully charged the charger should just maintain it at 100%, so I guess something is wrong, either with the charger, the way I use it or the battery. I never had this problem before.
Any ideas?

[MochiEater]

I believe your car, like my car, has AGM batteries. Sometimes they don't get along with regular battery chargers. I use CTEK chargers which specifically work with AGM batteries.

https://www.amazon.com/CTEK-56-864-A...70_&dpSrc=srch

[turboawd]

yeah, batteries are agm.
and you may have 2 batteries. not sure how they are wired exactly, and not sure if they both get charged direct when you connect under the hood.
maybe hook up charger direct to battery?

see this thread for location and pictures of the batteries.
http://f15.bimmerpost.com/forums/sho....php?t=1351415

[SCA]

Originally Posted by MochiEater

I believe your car, like my car, has AGM batteries. Sometimes they don't get along with regular battery chargers. I use CTEK chargers which specifically work with AGM batteries.

https://www.amazon.com/CTEK-56-864-A...70_&dpSrc=srch

I use the aforementioned CTEK battery charger on multiple BMWs. Highly recommend.

[deutsch100]

I have used the BMW branded charger on my last 4-5 BMWs, and it works great. If I know I will not be driving the car, and sometimes as a 1x month preventative measure, I hook my car up to the charger. My '17 X5 40e and now 35d have never displayed the Increased Battery Discharge warning, but our 2017 M6 does if it sits for days w/o use :-O

[MochiEater]

The BMW branded charger is made by CTEK.

[expidia]

Interesting thread for me. I never knew there are + and - hook up battery connections under the hood. Now I can top off my tires or blow up inflatable items, bike tires etc. with my compressor that uses alligator clips (instead of the cig lighter port) and hooks up directly to battery terminals.

[mijoed]

I’ve had the same "increased battery discharge" message on my E60 for several years. BMW have always maintained that there is no issue. I do mainly short trips. After a couple of longer journeys, the message goes away but quickly returns. I’ve never tried using a charger....