Good morning. I've just shot blast and painted the exhaust system on my '05 400. To cure the paint the engine had to be run at idle for 10 minutes, cool down 20 minutes then run for another 20 minutes at idle. Just at the end of the 20 minutes at idle the engine stopped, wouldn't start, solenoid just clicked. A flat battery was the obvious diagnosis. Checked the voltage, 12.5. So charged the battery and all is well.

Checked the charging system was working, ~13volts at idle rising to ~14.5+ from about 1800rpm.

I'm puzzled as to why running at idle for an extended period would flatten the battery, the regulator seems to balance the load at idle.

Any thoughts?

John

Cant see why your Burgman should flatten the battery on idle as the one I had charged even with the lights on at idle,
was the fan running when it stopped as they do take a fair bit of power but again I would not expect it to stop the engine,
one thing I do know is some Yamahas turn off the engine after 20 min on idle but I don't know if Suzuki do the same or
if that is what happened why did in not restart on the button. did you cycle the ignition or just press the starter as things
like this inc the tip over sensor require the ign to be cycled before it will restart.
If your on the org battery it's getting a bit long int tooth.

12.5 volts is not a flat battery. Did you measure it while trying to start? If the starter wouldn't turn at anything over 9 volts the fault is elsewhere. A bad battery when attempting to crank would probably show less than 6 volts. Were there any signs that the engine overheated? Rather than run the engine I used to cure VHT paint using a blow torch applied to each end of the silencer in turn. Also bear in mind that on a modern bike or scooter running for 15 minutes at idle might cause a reset on the closed loop fuel mapping data.

Thanks for the replies. Assuming the meter I used is accurate then I agree 12.5v is not flat, although significantly discharged.
I've measured the voltage again this morning, showing ~12.8v. ~12.6v turning the ignition on, ~10.3v cranking and starting the engine. This would suggest the (~4 year old) battery is OK.

No sign of overheating at idle, the fan was running, temperature gauge showing normal.

That all sounds perfectly good. Given the extreme conditions under which it happened I would be inclined to put it down to heat soak of some component that wouldn't happen in normal riding. So if the scooter continues to be reliable in everyday use I wouldn't worry about it.

Don't forget if your battery was already a little down, it doesn't take much to lower the charge on it when idling for a prolonged period. Your Burgman doesn't reach peak charge until at least 3000+rpm. Until then it's barely charging at all. So after starting your bike (it takes about two miles of normal running to put back the juice you used from the battery to do that), if the bike was idling it's not too uncommon for the battery to reach a discharged state. I encountered this many times during my time as a tech. Don't think you have anything to worry about, but keep an eye on it for a while.

I'm with Data on this. I've done about 300 miles since the "problem", the bikes running well. For the last ~100 miles I have had a voltmeter attached to the battery that confirms all is well. I suspect the battery is a bit past its best, an hour after a run the voltage drops a bit, possibly more than it should for what I think is a sealed (AGM?) battery.

Stumpy, yes it sounds as if your battery may be just a little past it's best, but it'll probably be ok for a good while yet if the bike is in regular use. You probably know it's normal for voltage to drop off after a period of time when riding as the bike doesn't need the higher rate of charge once the battery has attained it's optimal or near optimal state. That doesn't of course mean it doesn't need to receive charge, just not a higher rate of charge. If after being parked up for an hour or so it drops it's voltage a bit, then again, that's ok as long as it's still around 12.5v or thereabouts. So I suspect everything is fine with your bike. Enjoy!