Dirty power stops fridge from working

We choose PDI on purpose for their reputation, but only replaced the converter section, so the 120 v section remains the same. Yes, the fridge is almost directly above the converter while the battery is 20 ft. away. The craziest thing was that the inside fridge illuminating light would not work when the Parallax converter was on but worked just fine otherwise. The control lamp did flash error codes at us when the Parallax was on, so we almost changed out the Norcold control board. Figured that the Parallax would go eventually, and that replacing with PDI was a good investment in the future. Remain disappointed in Norcold for a design that sensitive.

Items that require clean 12V DC (circuit boards and such) do NOT function very well on 'dirty 12V DC'.........AC ripple above .6v is dirty

A good charged battery supplies nothing but clean DC

When you plug into AC power.....converter is supplying the DC System even when battery is fully charged.

Ron3rd wrote:
Parallax has a reputation for being the biggest piece of junk ever put in a trailer, but mine worked fine for 10 years in my old trailer. Good that you found the problem.

Not quite but they purchased Magnetek which did.. I would give Parallex a high position on that chart though.

To the O/P.
A lot depends on how things are connected, The common Parallex 7300 is a combination device, 120vac Power center, 12 VDC power center and converter all in one box. This means the converter is INCHES from the distribution panel, where as the batteries can easily be 1.5 times the length of your RV (Depending on where everything is) So the batteries have a lot of wire between them and the converrter where as the fridge has only a few inches (from the fuse that feeds it)

I have a progressive Dynamics 9180 with wizard.. the filtering on that is nice.. I have some very sensitive hardware that can not tell if the batteries are connected or not,, works the same either way.

But then you know the PDI units are well built now don't you :) (Since you installed one.. Oh by the way, Good choice)

In 2005 when this house was new I did some serious research looking for a better converter than the one I have,,, This also applies to all the PDI units with wizard either built in or plugged in.

I failed to find a better one.. Total and absolute fail. Found some that are as good, but not one better.

Parallax has a reputation for being the biggest piece of junk ever put in a trailer, but mine worked fine for 10 years in my old trailer. Good that you found the problem.