charging on a 129 Cub Cadet

What should the voltage be on the charging system. Replaced the voltage regulator because it quit charging. Now I get 16.9 volts and you can smell the battery when running. Ammeter will hold steady at lower RPM bounces back and forth at higher RPM.
Have checked and cleaned connections. Will not charge if you disconnect field wire at generator.
Thanks for any help.

Ted

For the regulator to function properly there needs to be good grounding between the battery and the engine and the starter-generator and between the starter-generator and the voltage regulator. Paint and rust can interfere with that and if the regulator "frame" voltage rises above battery ground voltage overcharging will occur.

Regulators with rubber mounts at the base have a little braided ground cable that jumpers around the rubber mounts, if yours is rubber mounted check the little ground jumper.

A couple of other things... if you are using a digital meter they don't always read correctly around the "electrically noisy" engine charging and ignition systems, and failing batteries can "gas" and also make the charging system act "odd".

As to the ammeter "bouncing", mechanical voltage regulators don't control as precisely as the modern electronic units we are long accustomed to, and SOME ammeter movement is normal. Also, "back in the day" good quality ammeters were "damped" to hide some of the needle movement from the operator.

If all the above checks out and the system IS overcharging the voltage regulator can be adjusted to reduce charging rate.

If not done properly/carefully that can cause more problems or even let the smoke out of the charging system, so I'll avoid commenting any more on doing that at this time!

You mentioned that you had replaced the voltage regulator, look where it was made, I had problems with voltage regulators that were made in India, they were charging at a higher rate than 14.3 volts, I always had to add water to the battery, I replaced it with a good used one, my problems went away, very rarely do I have to add water to the battery, I would try a voltage regulator from a different source and not made in India, your problems will most likely go away, the way these are made, they are pretty much non-adjustable.