Battery discharging while riding

[pants]

R1150GS issue. I was out for a lovely ride in the sun with some friends earlier this afternoon when I opened up the throttle and the bike cut out. I got it off the road and tried to start it but no joy the battery was flat.

I was brought home on a low loader, oh the shame of it

It is kept on a oximiser over night so the battery should have been healthy when we left. I have had this happen on a Honda VFR 800 before, the culprit for that was a regulator rectifier and the generator at the same time. Is this likely to be the cause here too?

I checked the battery posts and all seems ok, no loose wires. Any other ideas of where to look? There has been no electrical work done to the bike for at least a year.

 

[(RIP) Bin Ridin]

How old is the battery?

 

[pants]

Update, I have manage to put some charge in the battery with the oximiser. Tried to start it and it turned over but would not start.

 

[pants]

Don't know it was on the bike when I got it at 52,000

 

[MikeO]

What's the voltage across the terminals when the starter motor is running?

Also - stupid question - was your generator light on?

 

[Fanum]

It is kept on a oximiser over night so the battery should have been healthy when we left.

Nope, sorry.....

All it means is that the optimiser will have put as much charge into the battery as it could...that's all the green light means...."I've put as much as I can in so I've stopped charging" rather than "Your battery is fine and fully charged"

It happens a lot......using a trickle charger all the time just disguises the real state of the battery, often (as you've just found) leaving someone stranded out and about, having just had enough juice to start the bike and get you on the road.

I strongly suspect that your battery is fekked.

And in answer to your next question.....Motobatt MB51814 about 70 quid delivered from Ebay

 

[Black Rooster]

also have you checked the alt belt
and if your battery is fully charged after about an hour it should read about 12.8 volts

 

[dubster]

also have you checked the alt belt
and if your battery is fully charged after about an hour it should read about 12.8 volts

Wot he said. Check the volts on batt first to eliminate that, otherwise belt seems likely

 

[pants]

So I don't understand it but it seems it was the better as many of you rightly suggested. It was showing a good battery on a battery tester but when load tested it didn't want to play.