YES: RV Solar/ Li/ and AC running full time

[Generis]

Update:
Finally got the Dicor EPDM coating on the roof yesterday, which was phase 2 of this project. Phase 1 was scraping off the old Dicor self-leveling sealant (23 years old!) around all the roof openings and applying new sealant.

I'll admit your roof looks good. Yes.
I did a strip and re-cover on my roof at 21 years of age (RV age) and I believe it was only one step different from yours... I think you could have reroofed for the same effort. I'm also guessing the price is similar. In any case I also hope the liquid will last! I'm glad you got it sealed up!

Now, did the liquid show off any reflecting properties? Was it cooler in the RV afterwards? How do you insulate your front bunk window?

 

[richard cabesa]

What help is that? Turning off the charge?
If I've got a 38a charge and a 24a draw isn't that still 60 amps? If I've got a 25 amp charge and zero consumption or charge on the meter, isn't that still a 25a load?

That’s fine as long as all the math is included but several I have read or seen have stated draw with solar on and left out gain
I like the idea of a shunt or meter on the AC circuit itself so we could see JUST what it is drawing.
Everyone’s inverter and balance of system is different with differing inefficiency

 

[cinergi]

When it's below 90F outside, I use about 18kWh for everything in the rig per day including A/C set to 72. That's with a well-insulated (something like 3" foam on roof, 2" on walls) 38' 5th wheel. When it's 100 like it is now and 75+ overnight, I can use upwards of 30kWh per day.
5-8kWh of that is for non-A/C usage.

 

[Short_Shot]

When it's below 90F outside, I use about 18kWh for everything in the rig per day including A/C set to 72. That's with a well-insulated (something like 3" foam on roof, 2" on walls) 38' 5th wheel. When it's 100 like it is now and 75+ overnight, I can use upwards of 30kWh per day.
5-8kWh of that is for non-A/C usage.

What model?

One been digging around and can't seem to find anything with insulation anywhere near that good.

 

[cinergi]

What model?

One been digging around and can't seem to find anything with insulation anywhere near that good.

New Horizons RV. Starting around 150k new.

 

[tazmann]

Well to give you an idea of power usage, My Giandel inverter has a digital display that toggles between DC volts in and watts out. The little window ac 8000btu pulls 750 watts in moderate temps and 840 watts when it's hot out, in eco mode if it cycles the fan stops, when not in eco mode fan keeps running and pulls 100 watts. The Colman roof air pulls 1600 watts in moderate temps and about 1750 when it's hot out this is with it on low, fan pulls 320 watts on low and 450 watts on high add about 10% to the watts for losses and you will be in the ballpark of what is coming from battery and or solar. Small microwave pulls 1150 watts, 3.1 CF dorm fridge 45 watts after settling in

 

[Lt.Dan]

When it's below 90F outside, I use about 18kWh for everything in the rig per day including A/C set to 72. That's with a well-insulated (something like 3" foam on roof, 2" on walls) 38' 5th wheel. When it's 100 like it is now and 75+ overnight, I can use upwards of 30kWh per day.
5-8kWh of that is for non-A/C usage.

Thats pretty good, im averaging 30-35kWh right now maintaining 76* in my rig, and its been ~95* outside this last week or so. When its 100+, I'm up to 45-50kWh and I only keep it at 80* inside. That 5 degrees makes a biiig difference.

 

[aangel]

I'll admit your roof looks good. Yes.
I did a strip and re-cover on my roof at 21 years of age (RV age) and I believe it was only one step different from yours... I think you could have reroofed for the same effort. I'm also guessing the price is similar. In any case I also hope the liquid will last! I'm glad you got it sealed up!

Now, did the liquid show off any reflecting properties? Was it cooler in the RV afterwards? How do you insulate your front bunk window?

It's possible that the cost of recaulking and applying the coating is close to a new roof but I keep telling myself that I'm still paying less ?

The coating does not have any reflective properties beyond it being a brilliant white i.e. it doesn't seem to have any metallic element to it. But I have to say it's really, really white. I'm not sure the RV will last 10 more years but the roof certainly will.

And unfortunately the temperature these last few days has varied enough that I don't think I could gauge whether it's helped reflect more heat away than when the roof was a dull grayish white.

However, I expect that when I put the solar panels on the roof and cover every square inch I can that that will cut down greatly on the heat coming in from the top.

 

[cinergi]

Thats pretty good, im averaging 30-35kWh right now maintaining 76* in my rig, and its been ~95* outside this last week or so. When its 100+, I'm up to 45-50kWh and I only keep it at 80* inside. That 5 degrees makes a biiig difference.

Keeping the sun off the windows was absolutely key. I wasn't able to maintain 70s inside until I did that (I just got awnings installed over the rest of my windows, and I plan to tint them (UV blocking), too)

 

[Lt.Dan]

Keeping the sun off the windows was absolutely key. I wasn't able to maintain 70s inside until I did that (I just got awnings installed over the rest of my windows, and I plan to tint them (UV blocking), too)

Do you have dual pane windows?

I also made the silly decision to park facing North so both sides of the rig get beat on by the sun all day. If I park facing West I feel it would do much better as well.

 

[cinergi]

Do you have dual pane windows?

I also made the silly decision to park facing North so both sides of the rig get beat on by the sun all day. If I park facing West I feel it would do much better as well.

Yes. Though note that dual pane RV windows are not low-e coated. So they're still very bad at insulating.

 

[Lt.Dan]

Yes. Though note that dual pane RV windows are not low-e coated. So they're still very bad at insulating.

Y'know I got dual panes on mine and all of our windows are the frameless kind that just kick open at the bottom, maybe 10-15 degrees. I noticed the fixed mounted glass is all dual pane, but the glass that opens is only single pane! I felt pretty taken after I noticed that lol.

I was thinking about adding the low e film too, maybe whenever I have some free time.

 

[aangel]

Looking at spectrally selective low e film, too. I used it at my sticks and bricks home 15 years ago and it made a big difference. I'm hoping the films have gotten even better since then.

I even got it priced out for my front windshield to help with the long, sunny driving days but wasn't into spending $300 at that exact moment. I think I can do it myself on the other flat windows but a big piece like the windshield might not turn out so well if I do that one. Maybe all I need is another set of hands?

 

[K8MEJ]

Awnings over the windows help a lot, especially with my single-pane windows. This weeks it's in the 90s again AND high humidity. That's a terrible combo over just heat alone. When it gets like this, I get relief from putting my solar panel awnings over the driver side of the camper and reflectix between the window shade and glass on the inside. It's dark as hell inside but it helps me keep the camper at 74 degrees with the mini-split running.

Once the sun goes down, even if it's still hot, the AC is able to keep the camper at 70 degrees. Right now it is 1:00pm EDT, 31 degrees C (88 F), and about 65% humidity. My total AC load is currently 458 watts, with the thermostat set to 74 degrees and all the window shades closed with reflectix in the window. There are only three AC loads at the moment: the air conditioner, an electric fan on medium, and a microwave clock. When the AC and fan are not running, the inverter shows 3 watts (mostly from the microwave on standby). I have a 12k BTU 120 volt mini-split made by LG. When I first start up the AC to cool the camper, it'll pull 600-700 watts until it backs off when the camper is cool and then runs between 150-400 watts to maintain it depending on the outside temp and time of day. My rooftop unit pulls between 1,400 and 1,600 watts when it's running. Total daily consumption without me living in the camper is 10kWh just with the mini-split and fan trying to keep the camper between 72-74 degrees. Right now the camper is sitting in my driveway while I'm monitoring consumption. Once cooled down, my 12v compressor fridge consumes about 65 watts on average all day if we're not living in the camper and about 90ish watts on average when we're camping.

Hopefully that provides some decent info for whoever asked about consumption.

 

[Short_Shot]

Awnings over the windows help a lot, especially with my single-pane windows. This weeks it's in the 90s again AND high humidity. That's a terrible combo over just heat alone. When it gets like this, I get relief from putting my solar panel awnings over the driver side of the camper and reflectix between the window shade and glass on the inside. It's dark as hell inside but it helps me keep the camper at 74 degrees with the mini-split running.

Once the sun goes down, even if it's still hot, the AC is able to keep the camper at 70 degrees. Right now it is 1:00pm EDT, 31 degrees C (88 F), and about 65% humidity. My total AC load is currently 458 watts, with the thermostat set to 74 degrees and all the window shades closed with reflectix in the window. There are only three AC loads at the moment: the air conditioner, an electric fan on medium, and a microwave clock. When the AC and fan are not running, the inverter shows 3 watts (mostly from the microwave on standby). I have a 12k BTU 120 volt mini-split made by LG. When I first start up the AC to cool the camper, it'll pull 600-700 watts until it backs off when the camper is cool and then runs between 150-400 watts to maintain it depending on the outside temp and time of day. My rooftop unit pulls between 1,400 and 1,600 watts when it's running. Total daily consumption without me living in the camper is 10kWh just with the mini-split and fan trying to keep the camper between 72-74 degrees. Right now the camper is sitting in my driveway while I'm monitoring consumption. Once cooled down, my 12v compressor fridge consumes about 65 watts on average all day if we're not living in the camper and about 90ish watts on average when we're camping.

Hopefully that provides some decent info for whoever asked about consumption.

How thick is the insulation and what are the dimensions of the space you're cooling?

 

[K8MEJ]

How thick is the insulation and what are the dimensions of the space you're cooling?

It's a 28 foot bunkhouse, so 28 feet x 8 feet x 6.5 feet to the ceiling. Here is info on how it's insulated: Grand Design Imagine . Just single pane windows.

 

[aangel]

How do you insulate your front bunk window?

I had custom heavy blackout curtains made.

 

[Short_Shot]

It's a 28 foot bunkhouse, so 28 feet x 8 feet x 6.5 feet to the ceiling. Here is info on how it's insulated: Grand Design Imagine . Just single pane windows.

That explains it.

R7 is pretty good as far as rvs go but definitely insufficient in my opinion for what we're trying to do here.
Drives me nuts that the industry skimps on insulation, though I understand why. That's about an inch and 3/8 of xps foam equivalent, and a rather large space to cool.

So I'd say you're doing pretty good with 10kwh.

I keep using different calculators for R12 for about half that volume and coming up with numbers that suggest I might be able to cool it with rather less than 4kwh/24 hours even on a hot 100f day. So that makes sense in comparison.

 

[aangel]

I have a 12k BTU 120 volt mini-split made by LG. When I first start up the AC to cool the camper, it'll pull 600-700 watts until it backs off when the camper is cool and then runs between 150-400 watts to maintain it depending on the outside temp and time of day. My rooftop unit pulls between 1,400 and 1,600 watts when it's running.
...
Hopefully that provides some decent info for whoever asked about consumption.

Very helpful. Looks similar to the numbers @Generis is getting. Gives me confidence that a 12K btu mini-split unit and 1300W of panels will easily be able to handle 100 degree F days. But I wouldn't risk a 9K btu unit.

 

[Lt.Dan]

It's a 28 foot bunkhouse, so 28 feet x 8 feet x 6.5 feet to the ceiling. Here is info on how it's insulated: Grand Design Imagine . Just single pane windows.

I never really looked around Grand Designs website, but I got to see the same construction tab for my Momentum and am pleasantly surprised its got R11 walls. Thanks for the link!