Project Report: Solar Install on a Fleet

[steelhead]

This post is intended to describe the recent installation of a 100w solar panel on a Yakima rack and a PWM charge controller in a FWC Fleet that is about a year old now. Since many posts on WtW were extremely helpful for this project, I thought conveying my experiences might be useful for anyone thinking about taking on a similar installation. I was really nervous about doing this project but it turned out to be much easier (for the most part) than I expected. The last section will be about what I might do differently if I were to do it again. Apologies too for the length of this post but i thought some of you might be interested in some of the details
.

A few important ‘Thank You’s’ to start. First, thanks to Leadsled9 for his detailed posts from 2010 about installing a panel on Yakima racks. Installing the panel on a Yakima system was my preference as I did not want to drill additional holes in the roof and had the rack already for carrying skis. It is not likely that I would have taken this project on by myself without the guidance in those posts. Mandatory reading for anyone thinking about installing on Yakima racks. Thanks also to Doug and Roger from AM Solar in Springfield Oregon for their advice on the components and the install. Thanks lastly to HandyBob for the information on his site – his articles can be tough to read but contain a ton of useful information.


About the components: we selected the GS100 panel from AM Solar. This is a 100w panel from Grape Solar. While it is a little more spendy than other 100w panels, it weighs in at about 14.5lbs which was, by far, the lightest weight panel we found for the wattage. Based on the recommendation from AM Solar, we went with the Sun Charger 30 (SC30) PWM charge controller from Blue Sky Energy. The decision was between the SC30 and the Morningstar Sunsaver 20l PWM. We chose the Blue Sky unit it because it has a digital readout of various data points and is programmable. A few comments about this choice will come later. We seriously considered an MPPT charge controller but were advised that it was not worth the extra money for a small system like ours. This was a tough decision because you want the system to perform as efficiently as possible but in the end decided to go with the PWM recommendation. There are definite pros and cons for both technologies that are widely debated on this and other forums so it is definitely worth some research to understand the differences and benefits.


Out Fleet has the FWC standard two AGM auxiliary battery configuration. We started with the charge controller since it was a wet weekend in Oregon. Our unit is configured with the side dinette so there is a small cabinet just above the battery compartment which is where we decided to install the controller (picture below). I thought the biggest problem would be making the cutout in the side of the cabinet because there is not much room for power tools in that part of the camper. I used a Ryobi plunge cutter and it worked really well. Running the wires was the difficult part. AM Solar recommended 8 gauge wire but that gauge wire turned out to be too difficult to use because there was not enough room to make a downward 90 degree turn to the battery compartment plus the tightening screws on the controller had a cross pattern so neither a Philips head or slot screw driver head worked well enough to tighten the 8 gauge wire. So, after a trip to Home Depot for some 10 gauge wire and a new tool, I was able to complete the battery connections. The hole in the bottom of the cabinet where the wires come out did not turn out very well because there is a metal screw or rod or something else right in the middle of it. Fortunately, the seat cushion is taller than the hole so you really do not see it or the wires.


The installation of the panel was uneventful. I had ordered the L shaped brackets that Leadsled9 used to support his panel from the bottom but the GS100 did not have flanges on the bottom on the panel ends, probably as a result of trying to save weight. Dave from AM Solar told me that I could drill a hole in the side wall of the panel so that is what we did and then attached the panel to the rack cross bars with a bolt and washers just like it was a typical Yakima attachment (picture below). If you are wondering why there is only 1 Yakima lock on the crossbar in the picture, it is because those things cost $17 apiece and it seemed like having just one lock on the front bar and one on the back would be a big enough theft deterrent . I am not crazy about how it looks though so may end up springing for two more locks.


As for performance, we have not had a chance to field test the setup yet. But we have been observing the panel output via the display on the charge controller and it seems to deliver decent amperage even on very cloudy, rainy days. We are very happy that we no longer need to plug the camper into auxiliary power every few weeks to top off the batteries.


So what would we do if we did this again? I am not sure I would choose the same charge controller. The battery compartment in the Fleet has a perfect location for the Morningstar controller, probably because that is what FWC provides with the solar option. HandyBob is a huge proponent of those controllers and I am not sure the geek factor of the Blue Sky product is worth the trouble of installing it. It is nice to see the data in the various displays but it does not tell us anything we could not get from the Trimetric 2025RV monitor that was installed last summer. It is likely that the appreciation of the data display will grow as the memory of the install fades but I wanted to point out that installing the Morningstar is much simpler and should be considered.


So that is our solar install story. The net of it is that we are happy with the way it turned out and are confident that the investment will be a real asset to our travels. Feel free to PM me with any questions. Thanks for reading!

-steelhead

 

[KILR0Y]

Wow, nice write-up steelhead. I've bookmarked it for future reference when I'm ready to install my solar. I also voted this topic up for adding to your reputation!

Well done...

Kilroy

 

[steelhead]

Thanks Kilroy. The write-up was my turn for some pay back for all the great guidance this forum has provided me over the past few years.

 

[takesiteasy]

x2 on the write-up. Very helpful looking ahead to solar. Thanks!

 

[ntsqd]

Nice report. We also have a Grape 100W panel on the roof with a Sunsaver Duo controller and a TriMetric monitor. On the install day when I pulled the towels & shirt off the panel after making the final connections the meter showed a 3.6A charge. I was extremely pleased with that!

I do think that the 8ga. suggestion should be revisited. With some time for it to soak in a solution may present itself. If not, be happy with what you have. As it happens we too don't have room for anything bigger than 10ga. due to where it passes thru the roof being limited in size and already being occupied by other wires. Those other wires may just get moved as part of an iteration of our rear tarp-awning and if they do I'll be looking to replace the 10 with 8.

 

[ski3pin]

Steelhead, thanks for the helpful detailed report on your install. Keep us updated on your results, please. There is nothing like harvesting the sun and keeping those expensive batteries topped off!

 

[steelhead]

Thanks for the replies everyone. After re-reading my post, I realized that I left out 1 key item - we had the Fleet pre-wired for solar by FWC when we purchased it.

The reason for bringing this up is the point about wiring mentioned by ntsqd. If the wiring from the panel to the charge controller is 10 gauge, is there any benefit to having the wire from the controller to the battery be 8 gauge? In our case, the run is less than 3 feet. Opinions would be appreciated - thanks.

 

[Bwht4x4]

Do you have a picture of where you mounted the Trimetric battery monitor? I'm about to pull the trigger on one and cannot figure out where to mount it.

Right now I'm thinking that I may remove the hot water heater switch and put it there, which is above the programmable thermostat. I would then relocate the hot water heater switch to the spot where FWC put the exterior LED sidelights switch (in front of and a bit to the right of the sink) and group both of these switches into the same gang. I think it would look a lot cleaner than having multiple switches all over the place and a thermostat and a Trimetric and the FWC water/battery monitor.

 

[ETAV8R]

Nice write up. I finally got my battery and controller under my hood. Now comes the fun part of wiring it all up.

 

[steelhead]

Bwht4x4 - picture of the 2025 is below. I think our cabinet configurations are slightly different in that I have more surface area on the upper right side because the drawer is further to the left than yours. I can provide a wider angle picture if that would help. The location you suggested could be a good one because it should be fairly easy to run the wire to the batteries from there.

 

[Bwht4x4]

Steel,

Can you do me a favor and measure from the center of each mounting screw hole for the 2025? I know what the unit size is, but having the center to center measurement will help my in my planning.

Thanks

 

[steelhead]

Bwht4x4 - i can definitely take those measurements but I am curious about why you want them. Are you considering a flush mount? If not, all you need to do is drill a hole for the wire coming from the batteries - no other cutout is required. I thought about the flush mount but in the end decided it was not worth the trouble because the unit does not protrude very far out from the cabinet.

 

[Bwht4x4]

No I'm going to go with the same model you did, but I want to be sure that the entire unit from mounting screw-to-mounting screw will fit where I want it to go. I don't have much room. I think I have about 5.5 inches total.

 

[ntsqd]

Thanks for the replies everyone. After re-reading my post, I realized that I left out 1 key item - we had the Fleet pre-wired for solar by FWC when we purchased it.

The reason for bringing this up is the point about wiring mentioned by ntsqd. If the wiring from the panel to the charge controller is 10 gauge, is there any benefit to having the wire from the controller to the battery be 8 gauge? In our case, the run is less than 3 feet. Opinions would be appreciated - thanks.

This is a volts vs. amps thing. Power (Watts), minus whatever tiny losses there are in the controller, is the same. If the volts are high, then for the same total watts the current is low. The math: Volts (V) * Amps (I) = Watts (P), since P is the same V*I on the panel side is = to V*I on the battery side, or: V1*I1 = V2*I2

With V2 being low and I2 being high there is a resulting heating of the wire. Backing up a bit just in case it's not clear, Volts is the rough equivalent to water pressure (psi), and current is roughly water flow (gph). You can have a lot of psi (volts) with no flow (current) and not much will happen to the conductor. Bring up the current, even if you drop the voltage, and the conductor starts to get hot. This is "Voltage drop" and as the conductor gets hot it's resistance increases, which causes it to get hotter, which..... until an equilibrium state is reached. The problem with this is that the heat produced is Power that should have gone to charging the battery. When you're not dealing with much to start with, every little loss is not so little and is significant.

This is a long winded way of saying that while not ideal, the 10ga. between the panel and the controller is the best place to have small wire if you have to have it at all. The worst place is between the controller and the battery because the controller has taken in a high(er) voltage, low(er) current Power and converted it to a low(er) voltage, higher(er) current Power. So any loss from too small of a wire is more likely to happen here because of the higher current's potential for heating the wire.

There are some caveats to keep in mind. The biggest one is the length of the wire in question. A short piece of wire that is borderline too small for the application won't have much resistance because there isn't a lot of it there in the first place. This is actually exploited by the OE's in using "Fusible Links" to protect large current circuits. These are intentionally too small of a wire (~2 gauges smaller than needed), but only a short piece of it, with a special, non-flammable insulation. The idea is that normal loads will heat the wire but otherwise things will work as needed. They can afford this because of the alternator. Have some sort of major short and the wire burns up. The OE's are willing to give up some power to heat in this wire, but in solar battery charging you can't afford this loss because the power isn't great and the time that it is available is limited.

All of that to say if the wire from the controller to the batteries can be changed to bigger then it will be worth the trouble and expense in the long term. If it can not be done then don't fret over it. When you're in the camper it's supposed to be a vacation, so enjoy it!

We also have the surface mount TriMetric and I went looking for a pic of it and then realized that with a different brand camper it wouldn't mean much to the question. I've looked at other solar controllers and concluded that with this meter any other displays would be redundant and possibly confusing.

 

[steelhead]

Bwht4x4 - I will take the measurements this afternoon and get them posted for you.


ntsdq - wow, sincere thanks for taking the time to write such a thorough explanation. It confirms what I suspected but understanding why it matters is helpful. Now the tough decision is whether to take it all apart and try it again with 8 gauge......

 

[steelhead]

Bwht4x4 -

On the 2025, the center to center distances for the screw holes are as follows:

Horizontal holes: 2 and 7/16 inches
Vertical: 3 and 5/8 inches

Let me know if you need anything else. Good luck with your installation.

 

[DavidO]

Bwht4x4-
I installed my Tri-metric-RV as you can see in this photo. The case measured outside to outside is 4.25" by 3" the tabs on the top and bottom are an additional .5" each. You could remove these tabs by cutting them off as the back is solid without even a hole for the wire to go through. The meter is 1.375" deep which is just a hair more than the White-Rodgers thermostat.

I also sprung for the meter to shunt cable which made installation a breeze. I put in the 100A shunt instead of the usual 500A shunt. I choose this shunt because I have a small system that uses less than 70 amps maximum (charging or discharging) though there is a warning that the shunt will become too HOT if you use a 1000 watt inverter. I have no inverter and upon checking P-15 on the tri-metric the most amps I've seen is 30.2. The advantage in the 100A shunt is it reads currents as low as 1/100 amp instead of 1/10 amp the 500A shunt reads.
I think that Four Wheel Camper should offer this or any similar meter as an option. Our batteries are so important to us especially with a two way fridge. It sure is nice to see just how much each any everything is affecting our batteries. Do you know how many amps your truck provides your batteries? Do you know how many amps the Iota charger provides your batteries and what about if you add a IQ4 charge controller to it. Do you know the draw of your hot water heater? If you add a Tri-Metric you will know or at least you can find out. The tri-metric on it's most basic setting tells you three things 1) voltage at the battery 2) how many amps you are drawing or adding right now and 3) what % charge is left in your battery. If you hold the select button down until it flashes AH and release it tells you the number of Amp-hours discharged from a full battery. It can tell you a bunch of historical data also.

 

[Bwht4x4]

Thanks for the info DavidO and Steel.

It looks like you have a newer model FWC too. My setup looks just like yours, minus the 2025. Like I said I think I'm going to remove the hot water heater switch and relocate it and put the 2025 there. Right now I'm thinking of having two custom labeled switches done by Otrattw (http://www.otrattw.net/home.php) that will read "Water Heater" and another that reads "Exterior Side." I will then put both of them where this single switch is now.

 

[steelhead]

Bwht4x4 - I think I had a serious brain freeze when taking the measurements yesterday. For some unknown reason, I thought you wanted the distances between the screw holes on the face plate, not the mounting plate. If you like, I will measure the holes on the flange. But I expect that the dimensions would be about 3/8 inch longer on each end than the vertical distance I posted yesterday. As DavidO points out though, if you are really cramped for space, you can trim the mounting flanges off and simply screw the mounting plate onto the cabinet from behind the face plate. I actually thought about doing it that way for a cleaner look but decided it was not worth the trouble. Apologies for the incorrect data yesterday.

 

[Bwht4x4]

Thanks Steel.

If there is a way to screw the plate to the cabinets without using the flanges I might do that so it looks cleaner.

Thanks again and no problem.