Engine warning light after flat battery

[SteveL]

I installed heated handlebar grips a few weeks ago, and I suspect they might be draining the battery with a slight current even while off - they are connected directly to the battery as per manufacturer's recommendations. I intend to connect them to a switched circuit soon.

Anyway, I had a flat battery tonight and roll-started the bike, then drove for about 25 minutes through the city - traffic was light so I didn't stop much.

I left the bike running when I stopped at the other end for about 5 minutes, then headed home.

While stopped at the lights, the orange "check engine" warning light (not the oil warning light) came on briefly. When the lights changed I accelerated gently and the light went out. This happened again at another light.

At the same time I installed these grips I installed BikerDude's headlight mod, which involved removing the airbox.

So there are two possible causes that I can think of for this problem - electrical from the grips, or mechanical from the airbox not being reinstalled correctly. Unless of course it's something totally unrelated.

Any suggestions? How worried should I be about the engine warning light? My bike is the Australian 2004 model.

Thanks,
Steve

[Nelly]

I think you have answered your question mate. You have a battery drain problem. What type of grips did you fit?
I would uninstall the grips charge the battery and see if the problem persists under the same riding conditions.
Nelly

[reiobard]

Might have completely killed the battery when it went dead too. Often a car/bike battery can't recover from a full drain all the way so it might have make your batteries capacity too little now.

[SteveL]

Thanks guys, I think you might be right - my idle speed was a bit too low, which is probably why the light comes on while stopped, since the alternator isn't working hard enough to keep the voltage up.

I'll try charging the battery overnight and let you know if that doesn't resolve the problem.

[abacall]

Just a heads-up. I had this problem two days ago. Dead battery, had to push start. The bike rode home, but the engine light flickered twice.
Replaced the battery yesterday, the light is gone.

[SteveL]

Guys, the problem seemed to be the battery being too flat for the alternator to charge it.

Thanks for the assistance - I wasn't sure whether the engine warning light meant "I have a head-ache" or "call the coroner", but you've put my mind at ease.

Cheers,
Steve

[weswood151]

Not that it matters Steve, but I seem to have the same problem.

Except that I left the lights on too long and it wouldn't start. Roll started it and left it running in the garrage (door open) for 15 minutes.

Come out and "check engine" is on. I freek, (had te bike two weeks) and shut it off. When I returned the ignition to ON the light remained, and the bike would not start.

Picked up a battery minder and it is charging now.

Long story short, thanks for the post. I hope the charger works, and will post if it doesn't.

WesWood151

[SteveL]

Cool, I'm glad you seem to have got it sorted.

From what I've since learnt elsewhere on the forum, our bikes don't actually have an alternator but instead have a stator.

The difference is that the stator doesn't start charging immediately, but only beyond a certain RPM - or perhaps it's that the relationship between RPM and voltage isn't linear, and it only starts charging properly past a certain RPM.

Anyway the problem seems to be that if you have a flat battery and the idle speed is low, the engine warning light will show since the stator isn't generating enough voltage to keep things running properly. Revving the engine slightly, or driving off, seems to resolve the problem in this case at least.

It also seems that if the battery is flat beyond a certain point, the stator can't recharge it even after a long drive, so an external battery charger is required.

Note that this is just my experience, and the engine warning light might actually mean "warning" in some cases!

[wolfc70]

Originally Posted by SteveL

Cool, I'm glad you seem to have got it sorted.

From what I've since learnt elsewhere on the forum, our bikes don't actually have an alternator but instead have a stator.

The difference is that the stator doesn't start charging immediately, but only beyond a certain RPM - or perhaps it's that the relationship between RPM and voltage isn't linear, and it only starts charging properly past a certain RPM.

Anyway the problem seems to be that if you have a flat battery and the idle speed is low, the engine warning light will show since the stator isn't generating enough voltage to keep things running properly. Revving the engine slightly, or driving off, seems to resolve the problem in this case at least.

It also seems that if the battery is flat beyond a certain point, the stator can't recharge it even after a long drive, so an external battery charger is required.

Note that this is just my experience, and the engine warning light might actually mean "warning" in some cases!

Alternators have a stator too, it is the non moving windings. The rotor is the moving part, and is usually a magnet or electromagnet. Bike charging systems are more rpm dependent than cars, do to the fact that is is directly driven by the engine. In a car, the belt drives the alternator, and is set up to spin faster than the crankshaft speed. So if your car is idling at 800 rpm, the alternator may be spinning 2000 rpm. On bikes (most bikes, some have belt driven alternators) it is directly related to rpm, so you may not get full output until 5000 rpm. Versus in a car it will achieve max out put not far from idle.