8955 Converter Issue

[Wnellis]

Hello,

This is my first post. I recently bought a Revere 26' Trailer. It is a great unit in many ways, but I am having trouble with my power converter and it is frustrating because the techs at my dealership seem to think it is fine...

When plugged into shore power and the 40A fuses removed, I get the expected voltage reading of 13.6v. Once I add the Fuses, I get a reading of ~12.5v. As I add DC load, my measured voltage drops with increased load, going down to about 9v if all of the lights are on. If I disconnect the batteries, the 12v lights will run very dim before eventually going out.

So, If I have all of the 12v items off, my battery will charge, slowly. If I am running 12v items for any length of time, the battery is draining.

I took it to the dealership and they said that the system is working fine, although I suspect that they pulled the fuses, saw the expected voltage and called it a day. My unit is still under warranty. Any advice?

[Herk7769]

Originally Posted by Wnellis

Hello,

This is my first post. I recently bought a Revere 26' Trailer. It is a great unit in many ways, but I am having trouble with my power converter and it is frustrating because the techs at my dealership seem to think it is fine...

When plugged into shore power and the 40A fuses removed, I get the expected voltage reading of 13.6v. Once I add the Fuses, I get a reading of ~12.5v. As I add DC load, my measured voltage drops with increased load, going down to about 9v if all of the lights are on. If I disconnect the batteries, the 12v lights will run very dim before eventually going out.

So, If I have all of the 12v items off, my battery will charge, slowly. If I am running 12v items for any length of time, the battery is draining.

I took it to the dealership and they said that the system is working fine, although I suspect that they pulled the fuses, saw the expected voltage and called it a day. My unit is still under warranty. Any advice?

My guess is a faulty battery. Without the 40 amp reverse polarity fuses your battery is disconnected from the converter. When you plug the 40 amp fuses in the only thing you are doing is connecting the battery.

Today's converters are not designed to operate "stand alone" without a battery in the circuit. Your shorted battery is pulling down the voltage on the converter as it can not keep up the load trying to charge a bad battery and run your camper at the same time.

Your battery may be new, but a cracked plate can happen anytime.
Borrow a new one and see if it fixes it.

[Wnellis]

Thanks for the tip, Ill test the batteries tonight. I have two hooked in parallel right now, ill just try running off of each one individually to see if I get similar results on each.

[Herk7769]

Originally Posted by Wnellis

Thanks for the tip, Ill test the batteries tonight. I have two hooked in parallel right now, ill just try running off of each one individually to see if I get similar results on each.

Yep. Or you can have them load tested.

[Wnellis]

I just finished doing some tests, here's what I got.
I'm using 2 12v batteries in parallel.

Unhooked batteries. Both producing 12.5 V. Both passed on a load tester.

With shore power hooked up and batteries connected converter voltage (no load) 12.42v

Turned on one light - 12.04v
Two lights 11.68v
three lights 11.5v
Four lights 11.25v
Five lights 11.1
Six lights 11.0

With shore power connected but batteries disconnected (no load) tested converter voltage output 13.6v

Turned on one light. Very dim, converter voltage drops to 5.5v.

Turned on second light. Both lights get very bright, converter voltage jumps to 14.4, converter is letting out a high pitched whining sound. Must have entered bulk mode.

So, for some reason, when the converter is in standard run mode, it is losing voltage as soon as DC load is added. When the batteries are hooked up, they seem to offset the drop, but without batteries it is virtual free fall.

I'm guessing some kind of controller board problem. Thoughts?

[Herk7769]

Yes, I think you are right about it being a control board in the converter. Going into bulk mode fixes your output voltage is a big clue.