Battery charging issues

cgeaves · 03-31-2020, 11:30 AM

I had to replace the battery in my MY2014 M235i a couple of months ago and haven't driven it much since then. The new battery didn't come from BMW but is a direct equivalent replacement of an OEM from O'Reilly's. It was (unsurprisingly) dead when I tried to start it yesterday so.....no big deal, I'll throw a charger on it, right? I hooked up the charger and it would charge for about 20-25 seconds and then "click" and shut down. The click was coming from the battery charger and after being unhooked for about a minute it would click and "reset". I'm guessing it is an overload protector built into the charger. I assumed it was a problem with the charger however I disconnected both terminals on the battery and connected the charger again and it charges just fine when the battery is not hooked up to the car. The battery is fully charged now and I have no issues.

My question is this. Is there some special way I should be hooking up a charger to the battery in this car? I tried connecting the charger to the terminals in the engine bay and alternatively directly to the battery in the rear and had no luck either way. It was only when I actually unhooked the battery from the car that I was able to put a charge on the battery. Why? AND if I want to put a battery tender on this vehicle am I going to have the same issue?

Thanks for any help!

Dylan86 · 03-31-2020, 11:44 AM

Curious, did you go with an AGM battery?

cgeaves · 03-31-2020, 11:52 AM

Yes, I did

RoundelM3 · 04-01-2020, 08:22 AM

Just asking - did you code the intelligent charging system when you replaced the battery? If not, you might want to get that done first. Now - since your charger apparently thinks the battery is already fully charged, have you tried another charger or have you tested the battery itself to see whether it's actually fully discharged? It doesn't seem logical that something would draw it down in just one day. Did O'Reilly's put a tester on it when they sold it to you to make sure it was fully charged?

cgeaves · 04-01-2020, 09:02 AM

Yes, I had my mechanic do a reset after putting in the new battery. My understanding is that tells the computer there is a new battery so it won't overcharge and conversely as the battery ages it will gradually put more amps into the recharging process. As I mentioned in my original post when I unhooked both posts on the battery and then used my charger it charged the battery just as it is supposed to. I tested the battery....it was definitely down. It just needed charging from lack of use (not one day, but 3 weeks or so). It is charged up just fine now and everything is normal.

Update: I had a Deltran Battery Tender Plus (1.25 amp) that wasn't being used and hooked it up to the car. It put a top charge on the battery last night and seemed to work as it should. To repeat everything is working fine now but it just seems bizarre that my charger's overload protector would shut the unit off while the battery was still hooked up to the car and yet work perfectly when the terminals were removed. I need to hook it up to my wife's GMC and see if it does the same thing. Perhaps it is an anomaly with the charger and not a BMW thing.

03-31-2020, 11:30 AM	#1
cgeaves Enlisted Member 10 Rep 39 Posts Drives: M235i Join Date: Jan 2015 Location: Louisiana iTrader: (0)	Battery charging issues I had to replace the battery in my MY2014 M235i a couple of months ago and haven't driven it much since then. The new battery didn't come from BMW but is a direct equivalent replacement of an OEM from O'Reilly's. It was (unsurprisingly) dead when I tried to start it yesterday so.....no big deal, I'll throw a charger on it, right? I hooked up the charger and it would charge for about 20-25 seconds and then "click" and shut down. The click was coming from the battery charger and after being unhooked for about a minute it would click and "reset". I'm guessing it is an overload protector built into the charger. I assumed it was a problem with the charger however I disconnected both terminals on the battery and connected the charger again and it charges just fine when the battery is not hooked up to the car. The battery is fully charged now and I have no issues. My question is this. Is there some special way I should be hooking up a charger to the battery in this car? I tried connecting the charger to the terminals in the engine bay and alternatively directly to the battery in the rear and had no luck either way. It was only when I actually unhooked the battery from the car that I was able to put a charge on the battery. Why? AND if I want to put a battery tender on this vehicle am I going to have the same issue? Thanks for any help!
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03-31-2020, 11:44 AM	#2
Dylan86 Colonel 1330 Rep 2,214 Posts Drives: F15d msport, F22 m235i Join Date: Jan 2016 Location: GTA iTrader: (0)	Curious, did you go with an AGM battery? __________________ My F22 Road/Track Build
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03-31-2020, 11:52 AM	#3
cgeaves Enlisted Member 10 Rep 39 Posts Drives: M235i Join Date: Jan 2015 Location: Louisiana iTrader: (0)	Yes, I did
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04-01-2020, 08:22 AM	#4
RoundelM3 Major General 1834 Rep 6,989 Posts Drives: 15 F80 M3, 22 G01 X3 30i Join Date: Apr 2010 Location: Clayton, NC iTrader: (2) Garage List 2022 BMW X3 [9.83] 2015 BMW M3 [6.50]	Just asking - did you code the intelligent charging system when you replaced the battery? If not, you might want to get that done first. Now - since your charger apparently thinks the battery is already fully charged, have you tried another charger or have you tested the battery itself to see whether it's actually fully discharged? It doesn't seem logical that something would draw it down in just one day. Did O'Reilly's put a tester on it when they sold it to you to make sure it was fully charged? __________________ 2015 F80 ///M3 Sedan 7DCT Tanzanite, 2022 X3 sDrive30i 8AT Brooklyn Grey
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04-01-2020, 09:02 AM	#5
cgeaves Enlisted Member 10 Rep 39 Posts Drives: M235i Join Date: Jan 2015 Location: Louisiana iTrader: (0)	Yes, I had my mechanic do a reset after putting in the new battery. My understanding is that tells the computer there is a new battery so it won't overcharge and conversely as the battery ages it will gradually put more amps into the recharging process. As I mentioned in my original post when I unhooked both posts on the battery and then used my charger it charged the battery just as it is supposed to. I tested the battery....it was definitely down. It just needed charging from lack of use (not one day, but 3 weeks or so). It is charged up just fine now and everything is normal. Update: I had a Deltran Battery Tender Plus (1.25 amp) that wasn't being used and hooked it up to the car. It put a top charge on the battery last night and seemed to work as it should. To repeat everything is working fine now but it just seems bizarre that my charger's overload protector would shut the unit off while the battery was still hooked up to the car and yet work perfectly when the terminals were removed. I need to hook it up to my wife's GMC and see if it does the same thing. Perhaps it is an anomaly with the charger and not a BMW thing.
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