Solar and max fan upgrade to Big Blue

[Billscottsvalley]

After reporting on my a/c mishap last month I have got a lot of #59’s issues fixed. Using a tractor to remove the,(very heavy) a/c unit I was left with a 15”x25” hole. Using marine grade polymer sheet I covered the hole with butyl bedding and screws, then cut the 14”x14” hole.
Next I installed the max air 4500 with a remote control panel and a solar cable inlet port. Then sealed it all with self leveling rv sealant.
Using the 6 mounting points for the a/c I added 2 aluminum tubes to attach a 170watt sun power flex solar panel to the roof not adding any new holes. The end result is very sturdy and off the roof to aid in airflow.
I made a bracket to mount the mppt controler and ran the cables through where the cig lighter was.
I left all the a/c stuff in place, if someone down the road wants a 12v a/c it can easily be converted back to stock.
This system has the benefit of providing a bath exhaust fan, just open the high access over the door and crank it up.
some new wheel covers with benz inserts and big blue is ready to go. PS is old a/c unit has been claimed by another westy owner.

 

[Billscottsvalley]

 

[OldWest]

Thanks. Excellent info. If you have time, more specific info on brand/size/etc., on polymer sheet, alumin tubes, controller, etc., would be great.

Some additional info/thoughts:

1. Use of Aluminum Tubes. Very clever to reuse AC mounting points. Also, besides air cooling, the elevation allows clearance for the upper kitchen cabinet mushroom vent (replaced with lower profile?) And the pre-drilled mounting holes (plastic covers) are not covered (clearance space around holes too) so can add the kayak/surfboard brackets for whatever purpose.

Translift und Solar - James Cook Forum

forum.james-cook-freunde.de

Also allows easy replacement of solar panels in the future.

Idea: One could modify this set up for a portable one by using the same type tubes but using some type of easy to remove brackets. This would save wear and tear on the solar panels. A combination of sliding brackets and thumbscrews so can reach from skylight?

2. Sunpower 170 watt panel is 45.4" x 31.9" (confirm to be sure)--so you can see the size fit on the roof.

A more rigid backing would be used to reduce flex and cracking of solar panel on the aluminum tubes.

A matching voltage solar controller is needed as the 170 watt Sunpower panel is a higher voltage. Most controllers have ability to step down higher voltage panel to right charging voltage for 12 volt batteries.

 

[Billscottsvalley]

Thanks for the kind words. Being a retired building contractor I really enjoyed thinking through a completing this project. I figured the whole solar setup for a 5 year lifespan. (The warranty on the sun power 170w panel).

I mounted the max air fan on a 1/4” thick piece of starboard from taco marine, a polymer “plastic wood” that will outlast the van.

The aluminum tubes were hardware store items in a rack with different size and shapes, nothing special, 48” long. Stainless hardware and lexel sealant in the holes.
Attached to the rails is a piece of 3/8” ac plywood cut to exact size of panel, painted 2 coats exterior finish, attached with #12x1” sheet metal screws 4” on center. On top of ply is a piece of corrugated plastic from the sign shop then the panel. When I screwed down the ply I added a piece of closed cell pipe insulator on center to create a slight bow to pitch water to the sides. then I through bolted through the grommets in the panel.
next I wrapped it all together with rv sealant tape cut to 3” wide, this stuff is amazing, it really sticks. Then sealed the corners with self leveling rv sealant.

I canabalized the vent to make it flat. My first attempt was to stick the panel to the roof as described in the boss solar video. I didn’t like the way it looked so I went back to the raised method with the tubes. I found a vent that is low profile and it will be installed soon.

As for the controller I am happy with the rich solar 20amp mppt. Is is identical to the renogy model and a little cheaper. It came right up working with little programming. It has a very low self consumption rate and can handle an additional panel if I decide to add 100w to the nose cone.

I thought about a portable panel but I really liked the idea of the batteries always being topped off when the van is just sitting not being used, it now feels like I can forget about the whole thing an jump in and go.

 

[Billscottsvalley]

I can’t seem to get the photo thin down

 

[OldWest]

Thinking aloud.

Bill mounted his 170 watt solar panel crossways (45.4" x 31.9"). He also has extra vent.

Most 100-115 watt solar panels are about 22" wide to 46-50" long. So two of these solar panels could fit lengthwise in the area of the air conditioner (flattest roof area is about 44" wide x 50" long). That would be easier than doing transverse--crossways; if longer than Bill's 45.4" 170 watt Sunpower--otherwise, could do like Bill and mount two transversely).

So, rather than mounting the aluminum tubes lengthwise like Bill, do transversely so you'd use the existing 6 AC screw holes and mount 3 transverse rails (rather than Bill's two long rails).

Then, you'd put the two solar panels (with backing) on top of the three rails and have 3 places on each panel's long side to screw down/bolt down the solar panels (down the middle of Westy would be a gap).​

Otherwise, if did like Bill with long rails--tubes like a car rack, you'd have the long rails, plus cross members. So more height and weight.

The rails give you an air gap plus flexibility to change out the solar panels relatively easily.

If the cross rails are as wide as the roof, you could put some eyebolts are ends and use to hook a temporary solar panel on the side of van.

Just a thought. Please add more thoughts.

 

[Billscottsvalley]

Some good ideas here, I thought I would give a 4 month update on my solar update to big blue. originally I bought a 150w rigid panel that was 50” wide and installed it on the rails. I didn’t like the look of it hanging over the roofline and the tall alu frame Was not a clean look So back to Amazon. Photo shows how flex panel doesn’t protrude past the roof line and is thinner.
The idea of eye bolts to attach temp panels is cool, I would think about a way to attach semi permanent for an entire trip and remove when you get home. The access to to the roof is challenging, I am 6’6”” and need a 4’ ladder to get through the skylite to get to the panel.
After a few trips the setup is working great, I have 2 fresh agm batteries and they have plenty to run everything including the espar. I added a solar on/off switch that I turn off when driving because the alternator is charging, otherwise
it’s on all the time. Hauling firewood to Bodega bay.

 

[OldWest]

What kind of on/off switch do you have for the solar? Between the solar panels and controller?

I wondered if the solar panels with higher voltage charging setting would cause the alternator and/or the regular Westy charger to turn off, but that does not seem to be the case. The different charging sources just seem to add together but the highest voltage appears on the windshield central computer monitor. Don't know how that interaction works. Perhaps driven more by what the batteries can accept in amps?

 

[Billscottsvalley]

Yes, the switch is between the panel and the controller. The battery voltage is typically 13.6v with solar panel charging with sun and about the same when drIrving. This shows up on the solar charge controller screen and the central computer. When every charging source is off, it’s at 12.8v at full charge, 50% charge is about 12.0v. These are rough numbers but it is a pretty good way to determine the state of charge. I agree that current sources will add but I figure I don’t want any funky interactions between solar panel and the alternator voltage regulator so I switch off the panel when driving.
Ideally these old vans would be updated with modern systems, lots of lithium capacity, dc to dc converter, victron inverter, bms, and lots of solar panels. That is a huge commitment and expense and aside from battery powered air conditioning, it’s not necessary for occasional camping trips. If used for full timing thats another matter.