A charging problem

[Papa's Cub]

Since I don't have a working battery charger at the moment I thought I'd take the dead battery out of my 3000 ford and set it on the floor board of my cub and hook up the cables and let the cub alt charge it. I knew I would have to jump start the cub so it could do its job. The problem is when I disconnected the jumper cables the motor would run for maybe 30 seconds then die. The third try I increased the rpm's and it continued to run long enough for me to get about 75 yds. further away from the barn. I Don't understand why this wouldn't work. Any ideas other than purchase a new charger.

[beaconlight]

the way you describe it you have a really dead battery. do you have the battery wired into the circuit when running? When is the last time you were sure the alternator is working? Do you have a voltmeter you can use to check the voltage put out by the alternator?

[SONNY]

Alternators will not charge dead batteries!---generators will so you will have to get the dead ones at full charge then the alternator will maintain them at full charge!--- or so they tell me! LOL!!! thanks; sonny

[Eugene]

As I read the initial post. A battery was used to jump start the Cub with alternator. If the charging system/alternator were functioning, the battery used to start the Cub would have excited the alternator, started it charging.

Any way. $20- to $30- battery charger or borrow one from neighbor. Charge up the batteries. Then have batteries checked for condition.

Once batteries are charged and in good condition check the Cub's alternator out put as Beaconlight suggested.

Multimeter/volt meter inexpensive. I picked up two cheap ones from Harbor Freight for $3.99 each, for shop use. Local hardware store should have some for a few dollars more.