Charging battery in idling?

Can anyone confirm for me: Does the engine, when running in idling mode, (ie standing in neutral) charge the battery, or does the motorcycle have to be in motion for a few miles before the battery will be charged? (put bike on lift, back wheel off ground, and put it gear and let run for half and hour?)
Regards

 

Your engine needs to be turning at about 2K rpm before the alternator is producing enough output to keep up with the demands of the motorcycle. Below that you're discharging the battery.

 

I think better than running it in gear on the stand you should buy a charger. $25.00 (us) or so for a basic one... and zero chance of the spinning wheel touching the ground and sqirting the bike foreward into... whatever is in front of it.

 

What about putting it at 2200 rpm's via choke in neutral? Does it charge then? I think I remember my light getting brighter when the engine takes off on the choke before I can pull it down, but maybe I'm just imagining it.

Is this all motorcycles? How much does this vary? And while we're on the topic, how much does this apply to cars, as well?

 

It doesn't matter how badly your engine runs, it's based on rpm. Above 2k rpm, the alternator is turning fast enough to keep up with current demands. Doesn't matter if it's combustion driving it, or an external motor. And you don't have to be in gear. Below 2k rpm, it can't meet demand, and draws from the battery.

You should put the battery on a tender in between any test or tuning runs that involve sitting at idle for extended periods of time, and consider disconnecting your headlight to reduce load. The battery can get you about 20 miles from home without being charged (I'm sure I'm not the only one who's figured that out the hard way ).

There are different ways to generate electricity from a combustion engine, but I think most cars use an alternator, and when the engine is idling, the engine computer can blip the throttle to make up for demand. Just sit in your idling car on a hot summer day with the a/c on, and you'll see it rev every few seconds. You can't do that with our carbs.

 

So leaving it on choke in neutral sitting above 2k is fine, then, right?

Following, long highway cruises should fully charge the battery, correct? When driving really long distance, is there anything to worry about batterywise, other than fluid level?

 

leaving the choke on and the engine over 2k rpm might produce enough current to not pull from the battery, but why? It's not an efficient way to charge you battery, and you'll just foul out your plugs and waste gas.

These bikes don't produce any usuable torque below 3k rpm, so it follows that ANY driving is keeping your charging system happy, as long as:
1. It's functioning properly. TEST your charging system
2. You don't add load. These alternators aren't all that powerful, and you can overload them with accessories.

In the winter, I keep my cheapo walmart battery on a tender, because it doesn't have the juice to start the bike after a week. But now, it's got no problem. Get yourself a tender.

 

Keeping th eengine running at 2000 rpm in your garage will probably get the engine rather hot. Outside on a cold and windy day it would be alright, but if it doesn't get all sooted up first it will generate quite a bit of heat.