Something is causing the battery to overcharge, I tried putting in a new alternator but still the same problem. What can cause this?

Is the a Kabota tractor, a UAZ Jeep or a Caterpillar grader?

What causes this is usually a bad votage regulator... most vehicles have those built into the alternator these days. Key word being most.

How many volts are you getting from the alternator? Also check your grounds as well as your field wire. Make sure they are clean and making good contact.

Regulated battery voltage should be 14 to 15 volts, with the engine running. If it's more than that, the voltage regulator is likely bad.

Yes, I agree with thee above poster, it may be bad voltage regulator when regulator in the alternator is not working properly and the other reason for overcharging can be heat.