Mowing Battery or alternator?

[calvin76]

My tractor wouldn't start.

I tried to jump the tractor (positive to positive, negative to frame) from my car, with the car off, and it was stone dead.

So instead, I just detached both wires from the battery and used the car battery to START the tractor, hooked up the battery while it was running, and cut the lawn for an hour and a half. After that, the battery would TRY to turn the engine over, but couldn稚 do it.

All of the above suggests the battery is no good, right?

However, I took the battery out and used a 12V laptop charger to trickle charge it for 7 hours. After that, it started the tractor 3 times. It started the tractor again two days later, and again a week after that.

I doubt the alternator went bad, and the battery is barely one year old.

Can I draw any definitive conclusions from the above?

 

[puckgrinder85]

The alternator on a tractor isn't very large, might not be enough to pickup a really dead battery. I would just take the battery out and go to a parts store or auto shop that can charge it fully and then load test it with a carbon pile type tester, this will give you a more accurate picture on your battery's health. One year old batteries aren't immune to issues, we replace year old walmart batteries at least weekly, they suck that bad.

 

[Wolfy]

The small batteries so common now can not take going dead for long. Usually a few times will cook them. I would check the ground connections, if they are okay then the battery is likely the culprit.

 

[jaotguy]

the jumpering with a car and it was dead ... points to bad/corroded connections ... car battery has more than enough juice to start a tractor AND boost a completely flat battery....

clean all connections ( grounds too ) ...

jumper the battery with a car , run the car for 15 minutes at fast idle ... ( tops off the tractor battery )

then use the tractor as normal , but hook up a multi meter to the battery and watch the voltage ... should stay above 13 volts when running ... anything less than that and the tractor is not charging ...

 

[Rocky Hoffler]

A quick way to determined if alt is charging while running if it can be done safely take a screwdriver either on pulley end or at other end of shaft touch screwdriver to spinning shaft and see if there is magnetic pull if there is no magnetic pull battery is fully charged not requiring alt or in most cases its not charging. I would hook trickle charger to battery and charge 24 hours and then have load tested also check for draw. remove neg cable from post and put test light from removed cable and neg post on battery if it lights with everything shut off you have a draw.

 

[calvin76]

Thank you, everyone, for your advice.

 

[94BULLITT]

Thank you, everyone, for your advice.

Do you have a voltmeter? How many volts are in the battery before you start it? How many volts are in the battery when you crank the tractor? Put the meter on the battery with the tractor running at a fast idle.