Sudden Flat Battery - then its ok?

[hawkeye]

About 18 months ago, I changed the battery on my 2019 R1250GS (at my own expense) as even though I hadn't had a battery failure with the OEM battery (as some others have experienced), I wished to avoid that. And to date have had absolutely no issues at all with starting, hot or cold. Bike has been kept on the BMW charger in the garage when not in use.

Was out on my bike virtually all day yesterday, and being a nice day, went out on it again this morning. Did about 30 miles and stopped for fuel. Came back to the bike, hit the starter, and it hardly turned over - it struggled. Left it 15 mins or so - same thing. Checked the battery terminals and they were both tight. Left it a further 30 mins and whilst the battery had rallied a bit and it tried to turn over (really slowly), it really did not want to know, loads of error messages coming up on the TFT (which kept going blank). Then if I hit the button again - nothing, dead as a dodo. In the end decided to call out BMW Assist, who indeed confirmed a flat battery, put a set of jump leads on, and it fired up straight away. They tested the charging circuit and all was good, showing 13.9v at tickover and 14.1 -14.3 when revved. Rather than carry on with my day out, decided to ride the 15 miles to home.

Checked the battery with a meter this evening and its happily showing that's it holding its charge ok. Bike starts on the button first time.

My gut feel is that perhaps there may be something amiss with the battery and for what it costs I'm going to put another on - but anyone any ideas why it should suddenly decide to go flat - and then be ok?

 

[Santa-2512]

What is the battery?

if you changed it to oem Lithium, you may have picked up a duff un

sounds like one cell is on its way out ..

If it's not a Lithium, but Gel/mat or lead acid it could be on it's way out ( sometimes they don't go for there 4/5 years)

as they say, it's only a matter of time

 

[bosnjo]

This problem has been discussed a lot. I personaly haven't expereinced any of those problems on my 2021 GS with OEM battery. But, I know that those that had that problem and decided to replace the battery, went with Yuasa YTX14H-BS as that one has some extra juice for starting.

 

[hawkeye]

This problem has been discussed a lot. I personaly haven't expereinced any of those problems on my 2021 GS with OEM battery. But, I know that those that had that problem and decided to replace the battery, went with Yuasa YTX14H-BS as that one has some extra juice for starting.

Which is exactly the battery I fitted 18 months ago! Indeed I think it is as @Santa-2512 suggested that one of the cells is going duff. I'm not blaming the battery (in fact I've just bought another Yuasa YTX14H-BS and will be fitting it today) as I've had Yuasa batteries on many bikes and they have always been excellent and given good service - hence why I've (yet again) bought another. I'm wondering whether the battery may have been somehow compromised when I was rear-ended last year, bike was on its side for some time with the SOS flashing on the TFT before the ignition was switched off, followed by 8 weeks awaiting repair in a dealers, so probably the charge ran down some whilst it awaited repair. Whether the shock of the rear ending caused some cell plates to loosen slightly or I've just been unlucky with this battery or the accident had some bearing - who knows? Either way, new Yuasa YTX14H-BS being fitted this morning and hopefully that's the end of it.

 

[BobT]

This problem has been discussed a lot. I personaly haven't expereinced any of those problems on my 2021 GS with OEM battery. But, I know that those that had that problem and decided to replace the battery, went with Yuasa YTX14H-BS as that one has some extra juice for starting.

What do you mean by extra juice for starting? Does it have higher CCA? I also have a Yuasa fitted by the dealer as a replacement after the BMW one dies at 14 months old.

 

[brianmaslen]

As a matter of interest what is the warranty period, I believe it may be 2 years? Worth a look.

 

[waterloo700]

I’ve had this exact same problem a few times now and I’m thinking it’s something connected to the starter circuit and not battery condition. I’ve tried oem Lithium and now Motorbatt and it still happens.
It’s effect is like trying to start the bike in gear - absolutely nothing at the switch.
Dealer couldn’t find any fault and of course it’s intermittent and therefore unpredictable.
One day it might fail completely and show up the cause but until then…..

 

[bosnjo]

What do you mean by extra juice for starting? Does it have higher CCA? I also have a Yuasa fitted by the dealer as a replacement after the BMW one dies at 14 months old.

Yes, it has higher ampers cold crank.

 

[knutk]

FWIW:

It may be a shot in the dark, however a charging voltage of 13.9 at tick-over and 14.1 while running seems a bit low.

I have only owned 2 LC's, and they both charged 14.4 - 14,5 at tickover as well as when running. Charging with 14.1 V will not drain the battery, but it will certainly not bring it to a full charge either..

 

[LFC09]

Possibly a faulty battery if circuit tests fine

 

[Scanners]

My 2017 did exactly the same a few weeks ago. Started it and moved it out. Got my kit on, went outside and nothing. Got it going with a starter pack and has been fine ever since.

 

[MIKE R]

I had exactly the same on my precious 1250GSA

Rode to the petrol station and the bike wouldn't start after refuelling. The bike was totally dead and the TFT screen went black after a few attempt to get it going.

Pushed it away from the pumps, tried again and still nothing. Decided to try one last time before I rang BMW assist and it fired up.

Rode the 2 miles home, switched off and the bike started again perfectly. I have more than one bike so I put it on the Optimate and went for a ride.

After about a month with no further issues I mentioned it to my dealer when the bike went in for a service. They changed the battery under warranty.

Traded the bike about 12 months later with no re-occurrence of the issue

Mike

 

[hawkeye]

FWIW:

It may be a shot in the dark, however a charging voltage of 13.9 at tick-over and 14.1 while running seems a bit low.

I have only owned 2 LC's, and they both charged 14.4 - 14,5 at tickover as well as when running. Charging with 14.1 V will not drain the battery, but it will certainly not bring it to a full charge either..

You make a good point @knutk - from memory it was charging at 14.4v recently, I'll check that out when I fit my new battery later (just on charge at present to make sure it has a full charge before fitting)

Only other thing I have wondered - and this is from memory - wasn't there something a while back about one of the valves causing over compression (being tight?) stopping the bike turning over or something like that? Its got its 12k service in another 1k miles, so hopefully when they check and adjust the valves that will sort that (if indeed it is an issue)

@waterloo77 - what has happened to you was exactly what happened to me yesterday. If I ever do get to the bottom of it I'll let you know. For the time being I'm going to carry one of those Nobo starter packs with me so if it happens again, I can give it a bit of a shot (hopefully with the new battery it won't but who knows?

 

[GB.]

FWIW:

It may be a shot in the dark, however a charging voltage of 13.9 at tick-over and 14.1 while running seems a bit low.

I have only owned 2 LC's, and they both charged 14.4 - 14,5 at tickover as well as when running. Charging with 14.1 V will not drain the battery, but it will certainly not bring it to a full charge either..

I agree, mine is never in the 13v range even at idle. Would have that charging system checked. I have a bmw charger and I think you can test the charging system with those, or you can with the old one I have.

 

[hawkeye]

I agree, mine is never in the 13v range even at idle. Would have that charging system checked. I have a bmw charger and I think you can test the charging system with those, or you can with the old one I have.

Fitted new battery this afternoon - now 14.4v at tickover and 14.5 when revved, so I think the charging system is ok, but I'll keep an eye on it for sure. I also have the BMW charger, wasn't aware you could test the charging system with it, I'll have a look at the manual this evening to see how one does that. But at present, with the new battery all is good, so I suspect that the old battery had a cell which was a bit suspect (and I'll test that as well)

Thanks all for your help and advice very much appreciated