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Hey guys,

Here is my situation. New battery, has been verified by seller. Tractor runs fine after starting with a 50amp battery charger. Ground test from negative post to generator as 0. Have 14.6 volts coming from the alternator when tractor is running. When leaving the battery charger on overnight the appears to have a dead battery, but if I switch to the 50 amp boost, the tractor will start after 5 min of charging. I can then use it all day without turning off, but as soon as I do it will crank. Not sure what to check at this point. I can only surmise that I have a short somewhere. Has anyone run into something like this and suggest what I might check? Thanks for your help.:usa
 

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Not only will the load tester actually confirm the batteries ability to handle the load of a starter, it will also confirm the alternator charging rate. Very handy tool and the only way to actually test a battery. If the battery will permit the tractor to start after 5 mins of 50 amp charger, my money is on the battery isn't putting out the volts to start the tractor without the additional boost of the 50 amp charger.

The majority of the time, such issues are a bad battery. Not that the battery won't test at 12 volts plus, its a matter of the batteries ability to provide the power to actually start the machine under a load. Generally, its a bad plate or cell in the battery and once the tractor is running, the alternator output and the voltage of the battery will keep the engine running (which doesn't take much electricity for a diesel engine). Also, when strange things begin to happen and everything else works fine, its often the battery.

Make sure to clean the battery cables very well when replacing the battery and make sure they are tight on the new battery.

When you said the new battery is "verified by the seller" hopefully its a load test they are performing as anything else is largely meaningless.

If the new battery load tests fine and you are still having the issue, I would suspect either a bad ground or a bad battery cable. The reason why it takes the extra 50 amps to start the tractor IF THE BATTERY IS ACTUALLY GOOD, could also be

1. - the battery is undersized for the application and not meeting the 500 cranking amps needed.

2. - the ground is bad and the extra voltage (and amperage) is needed to achieve starting.

3. - the battery cables are internally corroded (touch them when on the battery charger to see if the cables are hot with the extra 50 amp charging load).

4. - make sure the positive battery cable is tight on the starter and that connection is clean.....

5. - when checking the ground, don't forget to check the battery ground cable end on the chassis or engine ground. Make sure its clean and tight and no sign of corrosion.

That's where I would start when the tractor won't without the 50 amp charger....
 

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Assuming the battery is, indeed, OK, I'd be more suspect of the battery cable connections, as Sulley mentioned.

When connecting the 50 amp boost charger, are you connecting directly at the battery post clamps or are you connecting the cables some place else, such as the engine block or starter motor? If connecting at the battery posts, then I'd be almost certain the issues is the connection between the posts and the cables. Even if they are not corroded, I've seen a black film develop on the posts that acts like an insulator. Make sure both the posts and the clamps are "shiny" clean utilizing a wire brush on the posts and a copper pipe fitting brushes on the cable clamps. I prefer these to a post/clamp cleaning brush as I found most of them do a poor job cleaning the cable clamps, especially the positive, as it is a larger diameter. I definitely do not care for the type with a blade that actually trims away a portion of the clamp/post. I purchase the fitting brushes at places like Harbor Freight by the handful as I also utilize them in my parts washer and other cleaning tasks.

If that checks OK, after charging the battery, disconnect it overnight. If it fails to start the machine, you have a defective battery.

If you're connecting the boost charge to other points other than the battery cable clamps, you could have a poor connection issue somewhere else. A common place for this occur is with replacement battery post cable clamps. These are the type where the cable is stripped back to expose the wire strands and the replacement post clamp is attached to the strands with a secondary clamp over the strands. Corrosion will develop between the wire strands and the clamp--often where you can't visually see it. I detest these type of clamps as at some point, they become problematic. I always replace a worn/damaged post clamp with a new cable/clamp assembly with the "molded on" post clamps, where corrosion elements cannot enter the connection.
 

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Glad you got it fixed.

Thanks for the update. :thumbup1gif:
 

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After going round and round checking all that was suggested, it turns out it was the battery. Took it back to AutoZone and they replaced it with no charge. Thanks again.
Glad you let us know and also glad you got the issue repaired. That's the main thing......:good2:

I would bet that 80% of the time or more when things are behaving as you described, its the battery. That's why owning your own battery load tester can save you a lot of time, plus you can use it on anything 12 volt. When the batteries load test as defective, they are unable to meet the machines needs 100% of the time......
 
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