Buyang 300cc Charging Problem
 

Battery is fully charged but after running for about 3 hours battery is dead and has to be put on charger to recharge. Any suggestions.

1) After your battery is recharged will the quad crank at normal speed and start up? If you turn on a kill switch (so the quad cannot start) and crank the starter for 30 seconds, does the battery hold out?. This tests your battery capacity to see if it capable of starting the quad.

2) Start up the quad, turn off the headlights and run at medium fast speed. Measure the DC battery voltage with a meter set to the 20 volt DC scale. What do you measure? It should be between 13.5 and 14.5 volts (but still tell me what you measure). This will determine if your charging system is working or not.

Your battery may or may not be up to the task. Your charging system is probably not working.

Does your quad look like this wiring diagram (from www.HighRPMRacer.com)? Do you know how to tell if this wiring diagram matches your quad?

Attachment 6600

Click on the thumbnail for a bigger picture...

Great minds think alike. I measured the voltage at 1400RPM 11.87v at 4000rpm 11.97v. It got worse as the temp went up. Probably the rectifier converter. Checked a different unit and got 12v and 12.8. At 5000rpm it was a respectible 13.5.

Thanks for the answer.

I think you should be getting 13.5 volts at your battery (headlights off) at 3000 RPM. This assumes a good (and fully charged) battery, since a bad battery, or a discharged one, can be a significant load on the stator and regulator.

If it were me, I'd charge up the battery overnight using a motorcycle battery charger (2A max), then start up the quad and see if the battery voltage reads between 13.5 and 14.5 volts at 3000 RPM with the headlights off. I'd then test the battery capacity by setting a kill switch so the quad won't start and crank the starter for 30 seconds.

Having to go to 5000 RPM on an unloaded charging system to get 13.5 volts doesn't sound right. It doesn't sound to me like you're out of the woods yet...;)

Charging Problem.
 

The test was done under a full load except for the auxiliary outlet. Flashers going, brake lights and high beams. With a minimum load the voltage was close to 14.5v. We did do a crank for about 30 seconds and it was fine. We had just put in a new batttery fully charged on the suspect unit. With everything off it read 12.?. As soon as we started it up and the idle smoothd out we get 11.87v and then as it warms up it goes down. Never able to get over 12v in a reasonable fashion. Suspect the rectifier/converter and may look into moving it to a spot where it won't get as hot. May not be necessary, but the cooler it is the higher the voltage coming out will be. I suggested a nitrogen cooling system for it but was overridden :lol:.

That's quite a different scenario. Yes, with this additional info I believe your quad charging system is working...:)