Atv keeps killing battery
 

I have a 2008 raptor 250, and it keeps killing the battery to the point where its in chargeable. 2 brand new batteries in the machine both with same results. Could ride for a few hrs, and then no power at all but atv would be able to be bump started. A couple more hrs of riding and battery is so shot it wont even bump start. With a brand new battery and bike running there is 14.5 volts at 3/4 throttle doesnt change at full throttle. Who can steer me in the right direction?

When tested with a voltmeter across the battery, the charging rate should rise to 14.5v max at about 2500rpm then either stay there, or drop off slowly back to about 13v with increased revs. Disconnect one battery terminal, with ignition OFF, connect an ammeter between terminal and lead, there should be no amps showing, more than 0.03 of an amp, and you have a drain on the battery. Usually a faulty regulator, so disconnect it at the wiring plug and see if the drain goes away.

Whatever, the problem of a flat battery is usually caused by the regulator, but a high resistance in the wires between regulator and battery, or a faulty stator, which gives up charging when warm, can't be ruled out.

I also want to add that after this the battery is completely shot. Will not accept any kind of charge. Fortunately the shop I got the new battery from warrentied ot for me

Once a battery gets to low, most will never recharge again, your battery supplier is doing you a big favor by replacing it. He is seriously interested in keeping you as a customer, so support his business and tell others about him. You don't find to many people today willing to do the right thing, especially business people. You are lucky to have one in your area.