ATV (Honda Rancher TRX420TMD) Kills Battery while on in few seconds, then dies

[cervenakrava]

Hi,

New to ATV repair but willing to learn and get my hands dirty.

We start the atv and even with a good battery, it will drain it very quickly and eventually the atv shuts down. Checking the battery afterwards shows significant drain on it.

Would this be a shot alternator? Some electronics module?

Thank you kindly.  Just need to be pointed in the right direction and then with a repair manual will get to it.

Cheers

[Gwbarm]

The only thing I can think of that would pull that much juice that fast is an internally shorted starter. The stator may not be recharging the battery, you can check that with a volt meter while its running.

[Mech]

It sounds like a big drain to me, and if it doesn't make a big spark when you connect the battery lead, then the drain/short must be something controlled by the key. I'd pull all the fuses, and disconnect the voltage regulator, then turn the key on and watch the battery voltage if you have a volt gauge. If the voltage stays stable after a few seconds then I'd start refitting fuses and the regulator one at a time checking for a sudden voltage drop. If you have an amp gauge, you could disconnect a battery cable and fit the amp gauge in line and then start trying connecting things looking for a big drain.