AC/DC issues with a Univolt

[Tabasco]

So I have replaced the rear section of floor in the 64 Tradewind and before the battery setup wasn't there to begin with. Inverter and polarity switch box present and hooked up but no actual battery. Hooked up a battery before running the shore power cord back in, fans and lights work great. Ran power cord in and hooked up everything as before and lights work but fans are mad.
I didn't unhook any wiring from the univolt to the polarity box so I didn't screw that up. The lights get brighter when the AC voltage comes on. The fan in the front which is still original may be spinning faster because it gets noisy. The Fantastic fan in the rear comes to a halt rather quickly and hums like it is burning up. under battery power it works beautifully. Even reversing the polarity at the fan makes no difference.
I have always heard that these old Univolts are the best and it seems to be working somewhat and I was under the impression that this was a complete pass or fail, no "sort of" or "Gray" area.

[TG Twinkie]

I am not sure what you mean by "polarity box".
If all items work on battery power alone. I would suspect the Univolt. They are known for boiling batteries etc.
I would bet if you checked the voltage out of the Univolt you will find it in the range of 16 volts or maybe higher.
Recommend getting rid of the old converter and installing a modern unit.

[Tabasco]

I am calling the switch box from city power/ battery power the polarity box only because I have no idea what to call it otherwise. I am pretty sure that the Univolt will be to blame but I really didn't see that causing the Fantastic fan to stop.

[68 TWind]

First,toss the Univolt, they make good boat anchors. Seriously, if you had done that much work on the trailer, spend the money on a modern 3 stage converter. You will be glad you did. Randy at Best Converters is nice guy and will steer you in the right direction on which converter you need. With a new converter and a good battery, you can then get the other electrical issues cleared up.

[Tabasco]

So it seems that Univolt converters have diodes which is what actually converts AC voltage to DC. Upon further testing my outputs from the Univolt are in fact 13 volts which is great, however it is AC form. The lighting system is fine since a bulb is merely a resistor. DC motors however are not so happy.
New converter it is I'm afraid.
Damn, really needed this together for next month.