question

bishop avatar image
bishop asked

Multipluss II 2x120 not passing through enough power to run the air conditioning from the generator.

New install of a Multiplus II. Generator runs fine and the Multiplus charges the battery bank perfectly. When the air conditioning unit is turned on the multiplus will still run 80 amps from the charger (what it is set at) and the air conditioner for a few minutes. Then the generator shuts off. 5500 onan. It seems the multiplus is not diverting the charge power to run the air conditioning unit and the generator quits. One year old fifth wheel. Generator has never been an issue and was serviced 5 months ago. Am I missing a setting to force power to the load vs the charger?

Thank you.

green.png

Multiplus-IIGeneratoraircondition
green.png (56.0 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
tmac99 avatar image
tmac99 answered ·

I feel your pain, I am going through the same (or at least similar) issue with a Multiplus II 2x120 and an Onan 5500. Hopefully people smarter than me will chime in, but for now, what I can add that might clear things up for you a little is that assuming everything is wired normally, and you haven't changed any wiring in the RV's ATS, then the MPII will only be able to use 1 leg of the Onan output (so basically only 25 Amps). This is caused by the fact that the Onan puts out 2 legs of 120V power that are in-phase - for safety reasons the MP can not use these 2 in-phase legs of power, so it rejects the L2 input and only uses L1 so you only have half of your generator potential output as usable power. I think this is to do with the fact that if the MPII is seeing the same phase on L1 and L2, then it assumes that the power is actually being supplied by a 30 amp service with a 30 to 50 "dog bone" (that duplicates the 30 amp L1 onto L2) and it would blow the circuit if it tried to use both lines since it is really only 1 line split in half (hope that makes sense),


There are workarounds - if you search for Onan 5500 you will find some, but it basically requires you to jump both Onan power lines together at the ATS and then you will have the Onan's full output (about 46 amps) available for you on the MPII Line 1 and Line 2 goes unused when running on the generator.


Since I am new to this world, I would encourage you to search for the answer from other, wiser, MPII users, but I wanted to chime in here to give you a starting point.

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

bishop avatar image bishop commented ·
@TMac99 Thank you. Gets me pointed in the right direction. I had read this was an issue on a post from over a year ago. I had assumed it was corrected. This is also why i am only seeing on leg on the reporting from the VRM. Thank you.
0 Likes 0 ·