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robval1987 · 08-05-2017, 05:49 AM

Well after a 2 week vacation in 95+ degree weather my mind was made up. I need a second a/c (preferably in the bedroom). Now we are talking about a Winnebago Vista 30t (30 Ft 3 slides) with one Coleman Mach 3 (15k a/c, heat pump) and at 98 degrees outside I could not cool down below low 80's. So I made up my mind to convert from 30 amp to 50 amp service, I also decided to swap out the 4kw Onan for a 5.5kw Onan that I took out of my 5th wheel prior to selling it. So it began, 1st thing I did was start with the transfer switch, then swapped out the breaker box w/converter, I the swapped out the shore power cord and the main line from the transfer switch to the now new breaker box as well as an external convert charger. So now I have a breaker box with two hot lines in (50 amp service achieved) now it was time to tackle the generators. The 4kw's mount was welded in (had to cut it out and grind it smooth, next was to order in the new mount for the 5.5kw. Had my frame reinforced and the new generator mount welded in (the shop that installed it, checked it by placing over 500 pounds of weight in mount). Next was to get the 5.5kw in the mount (placed it on a few wood blocks then backup over the generator so that it was under the RV below the mount) 3 friends and alot of wood blocks, floor jack and jack stands we finally got it into the mount and secured. Hooked up generator to the transfer switch and verified that it worked as it was suppose to. All wire to the transfer switch was 6 gauge wire, 8 gauge from the transfer switch to the breaker panel (ran numerous checks on eletric system, all is good). The last piece of this puzzle was not the hardest, but sure was the most nerve wracking as I had to cut a hole in my roof (14x14 same size as a vent). I then needed to get power to the new a/c through the Styrofoam roof insulation and over to the breaker box. I did get the wires all ran, 2nd thermostat and ducting setup the way I wanted (all the ducted vents forward of the front a/c work on front a/c and I blocked off the rear ducts, then installed duct tunnel from the rear a/c to the ducts to the rear of the front a/c allowing the rear a/c to use the ducts to the rear off the front a/c). I also installed Chill Grills on both front and rear a/c's. Now 98 degrees outside in Lawton Oklahoma about 55% humidity, it's a cool 70 degrees inside my rv. Pics or video to follow once I figure out how to resize.

mikebreeze · 08-05-2017, 06:04 AM

Congrats! It sounds like you have a good knowledge of electricity to get this done. I'd be curious how much you spent in materials to do this and how much one would expect someone else to do this conversion for them parts and labor wise.

trx430ex · 08-05-2017, 10:29 AM

Nice upgrade, like the can get it done attitude, safely, and on spec.
Mike, he salvaged much from the 5'er, nice way to do it. Find one that is wrecked, buy it for parts.Things crash everyday.

Redapple · 08-06-2017, 11:04 AM

Congrats! What you did is no small feat. Great job! Look forward to the pics!

trx430ex · 08-06-2017, 11:49 AM

robval1987 had my AC intake down to clean filter, and you made me dig a little deeper because the AC always sounded like it was fighting for flow. So low and behold I pull the cross plenum for output to the front and there is a decal on the top of it??? It was installed upside down!!! creating a 3/4 inch wall of foam on the bottom of that small plenum. Then also the foam between the two ducks was a flat wall air was running into. So I cut the roof foam into a v to deflect the air into the ducks more efficiently. What a difference! That and about 25 pieces of silver tape to seal the intake from the output. Then found leaks from where the 120 line comes in, sealed every little hole with silver tape. System runs 100% more air flow and sounds like it is not struggling.

System still would not have kept up with the heat you were in, but thanks, you made me dig a little deeper.

You may want to revisit the front unit and re-hab it for best flo.Cut the square wall roof foam into a v for more efficient flow.

dwaugh10 · 08-07-2017, 04:05 PM

robval1987, Great job! I'd love to see your pictures on this one. I have a Vista 27N and was considering doing exactly the same thing. Solved this one by buying a 30T with dual air conditioners yesterday

Btw, I'm very familiar with Lawton, I grew up there!

David
2013 Vista 27N, soon to be 2017 Sunstar 30T

hilgert · 08-10-2017, 09:29 AM

I did much the same thing this past weekend on a similarly-sized motorhome. Ripped out the 30A inlet, bypassed the existing 30A transfer switch, and removed the 30A wiring. Replaced with a 50A inlet, 50A transfer switch and ran the 50A cable from one side of the motorhome to the other (very small space to run it).

I also added a 50A Hughes Autoformer (for voltage boost in RV parks with low voltage issues...so pretty much all RV parks) and a Progressive Industries EMS-PT50X 50A EMS (after the autoformer). Both are plug-in units so that I can bypass if either fails.

New AC unit and induction cooktop will be the next big projects (when bank account recovers).

robval1987 · 09-01-2017, 10:13 AM

Here are the pics for my 30 to 50 amp conversion. I did use the same type of a/c just smaller version, 15,000 btu in living room, 13,500 in bedroom, vents in the living room run from that a/c, vents down the hall, bathroom and bedroom from that a/c, (I blocked off the vents to the rear from inside the living room plenum, small piece of sheet metal and hvac tape.

robval1987 · 09-01-2017, 10:53 AM

Here are photos of the generators, transfer switch (same switch, it's a dual 30 or 50 amp depending on wiring), breaker boxes, pics of the cutting of the roof and rear a/c install,

I have more pics if needed just PM me or email me for more info.

robval1987 · 09-01-2017, 01:57 PM

And yes if you'll look at the pic of the a/c plenum installed you can see the Styrofoam in the ceiling, I did go back an built a wooden fram 1x3.5 (I noticed as i tightened the a/c bolts it began to crush in the Styrofoam) I then covered everything in hvac tape. I did have to drill a hole for the power/thermostat wires as well as the 2x6 inch opening that I cut thru to the duct work for the rear a/c. I also used the new Coleman dump vent/ filter housings on both a/c's to keep the appearance the same and for the function to dump the a/c's directly down and cool off the coach quickly if needed. On my final test day it was 98 degrees outside with a feels like temperature of 111 degrees and I was able to cool the coach down to 70 degrees (the a/c's were actually cycling on and off as needed to keep that temperature, and that was using shore power and then running off the Generator.