[jlmacd]

Hi all.
My battery is getting on in years and I want to charge it, in situ in the car. It has been reading around 60-65% charge of late. I have a 7-stage smart charger that is suitable for AGM batteries. I’m hoping this will recondition the battery back to a higher level of charge as I am suspecting the IBS may be restricting some functions at the moment.
Is it safe practice to charge the battery in the car - or is it better to remove it and charge externally and refit afterwards.

Question - if I use this to charge the battery whilst still in the car, once it the charging process is finished, do I need to Register the battery as if it has been swapped for a new one - or not? If so, am I correct in thinking that I just select ‘same as old one’ in Bimmertech registration operation.

Many thanks for any guidance that can be offered.

[Billfitz]

A charger does exactly the same thing when the engine isn't running as the alternator does when the engine is running.

[Tommy D]

Charge it in the car and no need to re-register it if the battery was already registered to the car years ago. How old is the battery? I usually get 7-8 years out of mine.

[jlmacd]

Good question.To be honest, I’m not entirely sure how old the battery is! I bought the car last summer (June 23) and this is the battery it came with. Car itself is 2014 (64 plate here in UK)
Battery make is Banner. Negative terminal is stamped ‘38 14’ which led me to think ‘September 2014’ but I read on Banner website these numbers are coded and not a true representation of the actual age?

BimmerLink shows the battery capacity 90AH and charge at 65% but strangely no mileage values regards registration. Mystery !

[Billfitz]

65% isn't bad. When it consistently goes below 50% and neither charging nor a long drive will bring it back up you need to replace it. https://www.aussiebatteries.com.au/a...website(1).jpg

As for age mine turns ten years old next month, it's still hanging in there.

[AspektUSA]

I read that as 38th week of 2014, based on the negative terminal.

Time to think about replacing it!

[jlmacd]

I agree - that’s what I read it as too. The manufacturer seems to not want people to believe this though.
If it is true then would prob be wise to replace it. 10 years 3 months is a fair run for it.
I think I will try charging it and see how it fares but looks like it’s time for a replacement.

Any ideas why there is no recorded mileage showing in the registration? I can only think maybe it is the original if the date is true.
Quite a feat if it is!

[AspektUSA]

Originally Posted by jlmacd

I agree - that’s what I read it as too. The manufacturer seems to not want people to believe this though.
If it is true then would prob be wise to replace it. 10 years 3 months is a fair run for it.
I think I will try charging it and see how it fares but looks like it’s time for a replacement.

Any ideas why there is no recorded mileage showing in the registration? I can only think maybe it is the original if the date is true.
Quite a feat if it is!

All of the evidence points to that as being the original battery.

BMW's OE AGM batteries are known to be long lived, I still have my original one from 2017 installed.

In terms of charging it, you don't need to do anything special - just connect the leads to the pos/neg posts in the engine bay. No need to register or mess with any settings.

[jlmacd]

Thank you - I appreciate the reassurance.

So, I have had the battery on the 7-stage charger all day today and it has just completed. It sat in the ‘reconditioning phase’ for a nice long period then proceeded eventually to the ‘Fully Charged’ final stage.

I popped BimmerLink on to review the outcome and it now reports the charge as ‘75%’. Having watched and monitored it go through the charging process, and to see the outcome, I am of the opinion that if a battery of this age can still achieve 75% charge and has been reconditioned (best as it can leastways for its years) then I am sufficiently confident that it isn’t on its last legs just yet.
It’s still my intention to replace it with a new one - which can only be for the best - but I must say I am quietly impressed how long it has endured.

First thing I noticed, after the BimmerTech diag check was done, was on starting the car the dreaded ‘SOS Call System Failure’ warning message didn’t rear its ugly head! From what I had read about the IBS monitoring and how it tries to optimise the delegation of power resources when the battery is beginning to wane, I suspected perhaps the SOS back up battery was not being given due charging attention, despite it being new, and was being flagged up as being defective. I could be wrong of course but, either way, it is now behaving itself.

Guess it’s time to shop for a new battery then ….

Thanks to all for your time, input and assistance. It is very much appreciated and I hope to be able to reciprocate in some way in the future. 😊

[Billfitz]

Make sure you have 4G. If you have 3G the SOS call system won't work anyway, there's no one at the other end to receive it.

[tjlees]

if you really want to recondition the battery, it needs to be disconnected and charged with a battery conditioner that can input atvleast 5a.

One of my chargers can offer up 40a at a set voltage, when the battery has been deep discharged to bring it back to life.

A battery tester will tell you more accurately whether or not the battery is OK - particularly when turning over. I've had batteries that are green on the conditioner but give a red on turn over.

All this means I'm over 10 years on the original battery, 170k miles and green on cranking power

[Billfitz]

He didn't recondition the battery, he merely charged it. You really can't recondition AGM batteries the way you can old style lead acid.

[Nickski06]

If I know my car is going to sit for more than several days, I throw a tender on it and keep it fully charged. My car is 2016 with the original battery and still fires right up easily in below freezing temps.