Thanks for the input. The problem is both batteries in series read 14 volts they should read 28. So I guess one battery is completely shot. it won't take the charge so the dumpload takes over at 28 volt input. I thought the dumpload didn't come on until the batteries reached 28 volts, not when the alternator reached 28 volts. If the mill isn't able to spin over the rpms needed for 28 volts, due to the resistance of the dumpload, how is it able to produce the amps needed to charge the batteries. There must be something I'm not understanding.