Hello I am a newbie looking for help.I just bought a go cart for the kids and I replaced the battery and they used it for a day and the battery was dead.I then charged it again and same outcome.I took a volt reading while the motor was running and the positive wire off and got a reading of 3 volts(is that normal?).I want to test to see what is wrong with it can anyone lead me in the right direction.The cart is a 250cc coolster with a chinese motor.ty

 

Welcome to the forum Hoseman28 !

I had a problem with the charging system on my Jetmoto 125. It turned out to be a loose wire connection...I would check those first... 3 volts isnt a good thing for sure...is it the same with the engine off? Is this cart new or used?

 

The way to check the charging system is to leave the battery hooked up, then measure the voltage across the battery with the engine running rev'ed up to mid range level.

The battery voltage should read 13.5 volts DC to 14.5 volts DC. Note that this voltage is higher than the 12.6 volts you get across the battery with the engine stopped. When the charging system raises the voltage above the battery's nominal 12.6 volt output, current flows backward through the battery, charging it up. The battery itself regulates the amount of charging (reverse) current. When the battery is low it draws a lot of current. When the battery is charged it draws a teeny amount of current. But note that the charging voltage doesn't change - it still stays in the range of 13.5 to 14.5 volts. So measure the voltage with the engine running at a fast clip - that's all you need to do.

If the charging system can't raise the battery voltage above 12.6 volts then the charging system isn't working. The stator produces the power for the charging system. On all the 250cc engines I've come across the stator puts out 3 phase AC voltage through three (usually yellow) wires to the voltage regulator/rectifier. The regulator/rectifier converts AC voltage to DC and then regulates it to the 13.5 to 14.5 volts DC to charge the battery.

Besides measuring the charging voltage across the battery terminals, can you verify that you have three yellow wires from the stator to the regulator? Can you unplug the stator wires from the regulator (engine running) and measure the *AC* voltage between each of the three wires to each other and also between each to engine ground? This will hopefully isolate the problem to the stator or to the regulator or wiring.

 

i just bought a new battery off of maxtrade.com for about $36.00 and the battery didnt go dead so thats what i woulds do.