BMW R1200RT/R1250RT Forum

Sorry for another battery question.

My bike is a March 2019 R1250, I’ve no idea if it’s the original battery but I’m guessing it is. Both my battery chargers/ tenders tell me it’s in good order even after a week of not being used or on charge, here is yesterday’s scenario,

Bike starts fine in shed- I take it outside and stop the engine whilst I get geared up- bike starts fine again- ride 13mls to a garage and put some fuel in- press starter and bleh, just like a flat battery and only just caught up.

It has done this a few times over the last few months but I’m reluctant to put a new battery on just going into winter where I will rarely use the bike. It’s odd that both chargers tell me it’s in great shape.
Anyone else experiencing the odd start up that seems like an almost flat battery ?.

Thanks.

On the newer bikes there was a batch of batteries that would internally fail when warm, which meant they would start from cold every time but would struggle when the bikecwas warm. If you search the forum you will find the battery batch numbers.
Personal I'd just use the bike more if possible and see fit the fault clears after charging from the bike and fit a new battery in the new year if it persist .

michaelc2710 wrote: ↑Sun Nov 13, 2022 7:21 am On the newer bikes there was a batch of batteries that would internally fail when warm, which meant they would start from cold every time but would struggle when the bikecwas warm. If you search the forum you will find the battery batch numbers.
Personal I'd just use the bike more if possible and see fit the fault clears after charging from the bike and fit a new battery in the new year if it persist .

Thanks I hadn’t read that, sounds plausible!. I will get a replacement in the spring.

Yep, I had exactly the same situation with my '18 1250RT after I bought it earlier in the year. One day it's be fine, the next, or worse half way through a ride, you'd refuel and it'd seem the battery had gone flat. I suspected it was a battery issue as it had been laid up over the Winter without a tender before I bought it, but a trawl through the net showed it wasn't whilst I say a common issue, it certainly wasn't an unknown issue, worse still, no one had ever given a definitive answer to the problem. Meanwhile back home the multimeter read fine and the bike would start fine the next morning. So how did I fix it? A Li battery with a dirty great big CCA (Cold Cranking Amps). In other words more oomph.

5,000miles later and I haven't had a problem since.

I had a battery that when fully charged wasn't fully charged. What was happening was 2 of the cells were dead and these would not take any charge at all. To me, the volt meter showed 12.7 volts. Once i tried a drop test the problem showed up. Even a short ride would drain the battery to 10.03 volts.
All garages should have a battery drop tester and it only takes 20 seconds.