[bmw1&3seriesfan]

hello

i have a e93 335 2010 and have done approx 23k miles since new and was wondering how often i should charge my battery. i have recently purchased a ctek mx5.0 charger and charged it fully but since i dont drive the car often was wondering how to work out when to charge the battery. i do roughly 50/50 short journeys (a few miles) and long journeys (20miles+). would i do much damage if i charged it fully once a month or is that overkill ? also how often should i use the conditioning option or is that something not required for my kind of battery. i want to be cautious as i have been told because of efficient dynamics the battery is more sensitive to external charging than a standard battery. is this true or am i talking nonsense ?

any advice would be appreciated

[xenon]

I wouldn't charge it at all unless the IBC starts giving messages. Otherwise, leave well alone.

[bmw1&3seriesfan]

Originally Posted by xenon

I wouldn't charge it at all unless the IBC starts giving messages. Otherwise, leave well alone.

is the IBC in the middle of the instrument cluster (which gives warnings/info)

[G82Dude]

Let your car manage the charging. If you get warnings/battery low, then go for a long[er] drive!

[ukbeemerboy]

As above. If you charge it you'll kill the battery. The car looks after the battery condition itself.

[KM79]

AGM battery shouldn't be charged much more than 85% which is regulated by the cars electronics.I wouldn't be touching it with an external charger unless it gets barely used and you start getting battery warnings on Kombi

[xenon]

Originally Posted by bmw1&3seriesfan

is the IBC in the middle of the instrument cluster (which gives warnings/info)

IBC is Intelligent Battery Controller but it will give warning messages on the OBC (On-Board Computer)

[John320d]

kris m79. Please tell me where you got this info from. I had a replacement 12 months ago and I trickle charge charge it once a week. If I do not do this my auto/stop start will not work. I am old school, so to speak and always believed it is best to keep a battery fully charged. If you have further info about amg batteries please share.

[KM79]

Well for starters mate I work as a diagnostics tech for a BMW main dealer so I'm pretty knowledgable when it comes to vehicle electrics/electronics.
An AGM battery should never be fully chaffed to 100% as it will damage the cells.The IBS fitted to the battery constantly monitors charge/ draw/ output etc and adjusts the alternator output to suit.They generally like to sit at around 85-90% to operate best.An older non AGM can be charged fully without issue(non efficient dynamics ).
As regards to you're own car:You either have a very strange driving profile,or you're car has charging/current draw issues as you shouldn't be having to charge it that much.
Kris

[John320d]

Hi Kris, thanks for your enlightening reply. I obviously would not know that you are a bmw tech. I am always happy to learn something new. I suppose my very strange driving profile is pretty much like every other retired person. Kris I have a 9amp charger, do you think it would be better if I used that for the occasional top up?. I believe the 9amp charger does not fully charge the battery because when that clicks off I can put on the trickle charger and it carries on charging for a number of hours. Thanks John.

[Josh1a1h]

As my trips usually are no longer than 10 miles. I frequently get the battery low warning pop up. But it starts every time. I just do the odd long drive here and there to keep it topped up

[KM79]

No probs John,I'll help members the best I can.Ideally you need a Bmw approved charger or at least one that is AGM battery safe.As I said they can be damaged by charging to 100% and likewise by letting them discharge too much so bit of a viscous circle!
Kris