I wanted to toss some build info on here regarding my rig in the hopes that it might be useful for someone else down the road be it someone with a newer Chevy Colorado or someone looking for solar/battery details which, of course, is very frequent on WTW. I know that for myself, despite this being my second overlanding rig, I still relied on this forum heavily for the build. I put this in the Truck Campers section because most of the info is about the truck suspension and solar/electrical, not info specific to FWCs.
Vehicle and Camper Info
2015 Chevy Colorado Crew Cab with Long Box, Z71, 3.6L V6 4WD
This truck has been great so far. 269 lb-ft torque at 4000 rpm, 305 hp, 18/26 mpg. Seems to have no issue with the camper on despite being fairly close if not a little over the vehicle’s GVWR of 6,000 lbs; base payload ticks in at 1520 lbs. I’ve driven into the Rocky Mountains and back on several occasions still getting around 16-17 mpg with the camper and cab fully loaded. That will, of course, start taking bigger hits in the wind and at high speeds.
2015 FWC Fleet
I bought a used Fleet that had barely seen any use and was fully loaded: Fridge, heater, water heater, sink, stove, dual fans, awning, exterior lights, folder over couch floor plan, silver spur. Love it.
As I knew would be the case, the camper was a little much for the truck’s stock suspension. This is also my daily driver and the camper is not on full time. After doing quite a bit of research, I decided to add airbags, see how they worked, and go from their if additional help was needed. I opted for the Ride Rite airbags and the Airlift dual, wireless compressor. Love the setup. The compressor and wireless receiver fit nicely in the engine compartment near the battery. The wireless controller is easy to use and has two programmable presets which work nicely for camper-on/camper-off. Because each side can be controller separately, this setup can be used for additional leveling and I wired it to work even when the key is not in the ignition. So far, even on normal four-wheel trails, I haven’t felt the need to add anything else. I barely notice the airbags when the camper is off, even when left inflated to their minimum recommended (5 or 10 psi, can’t remember). I did also add a 2” leveling kit to the front because the stock Colorado has a rake on the front end. This leveled it out and added some clearance which I think makes it look and perform quite a bit better.
The Colorado has significantly higher bed rails than the Tacoma so I had to build a platform to boost the camper high enough out of the bed for the wings to clear the rails. Another gotcha with the Colorado is that the rails are raked and the bed isn’t. Another words, the rails are higher at one end than the other. Not wanting to mess with raking the platform, I just made sure the entire platform allowed for the wings to clear even at the deepest part. It was pretty straight forward. I used two 2X4s stacked to create cross supports. Four of these run east to west so to speak under a 1/2” thick piece of sanded ply (or 5/8”, I can’t remember). I then coated with heavy duty outdoor paint, threw it on some sawhorses, lowered the camper lightly onto it, and mounted it directly to the bottom of the camper.
Next up was the battery and solar setup. I like to go off the grid. Indefinitely! Because of this, rather than upgrading the componentry for charging from the alternator while driving, I opted to put a beefy solar array in place. So I left the stock wire run and isolator in place. Often, I don’t even bother plugging the camper into the truck. It’s just not necessary.
To size, I began with the battery sizing spreadsheet floating around this forum. The default numbers weren’t very accurate so I modified those to reflect the gear in a modern FWC and then split total amps into two seasons so I could get a realistic idea of what cold vs hot weather camping would look like in amp hours. This is where I wound up for my estimated usage and needs:
I wanted to be able to go off grid for two full days without any charging whatsoever as a base. That would equate to a ~120 ah usable battery solution. I began considering the following variables: size of my battery compartment, the fact that they would be located inside without exterior ventilation, and weight among other things (quality, price, lifecycles, etc). After thoroughly exploring various combinations of AGMs I was considering pulling the trigger on a nice Lifeline solution when I began bumping into LiFePO4 solutions here and there. I stumbled across a sub $1k Lithium with a battery management system built in and added it to my short list:
I decided to go with the LiFePO4 for several reasons:
· I can use nearly all of the battery’s ah capacity without damaging it
· It should last for several thousand of cycles rather hundreds
· Faster charging
· You won’t damage it by using it before it is fully recharged
· The built in BMS guarantees you won’t accidentally damage it
· 3 year warranty
· I like cool new tech
· And most importantly, it only weighs 29 lbs! (weight being important to me in my mid-sized truck)
I figured 100 ah usable once I added robust solar would be sufficient especially since I was probably overkill in my energy requirements to begin with. The one drawback that should be considered with LiFePO4 is that the BMS will automatically turn off charging somewhere in the 20-30 degree F range. I don’t think this will be an issue for me because while the battery won’t charge when its that cold, it will still operate. I should be able to fire up the furnace and run it for much longer than I will need to warm the inside environment back up to acceptable charging temps.
A little side note, the battery I went with was from a company called Battle Born Batteries out of Nevada. Not only did they give me a discount when I called to order one, but they chatted with me on several occasions and answered a ton of questions which was very helpful. Good people, solid offering.
Next I had to decide how much solar to add. This can be kind of tricky. I decided to poll some people on the forum as well as estimate the amount I would need based on the average solar radiation per day that exists in the general areas I’ll be spending the majority of time in. Fortunately, around the Rocky Mountains we don’t have really high temps or high humidity, which are both major hindrances to solar efficiency. I looked at weight, power, and cost for this. I estimated somewhere between 200-300 watts of solar and then began looking at my options. It appeared to minimize weight and maximize output, 24v panels would be best if I were to go with rigid, traditional panels. That way I could get a single panel and not have to have multiple.
But the more I poked around I kept finding very good deals on flexible panels that weighed practically nothing. The only negative thing I had heard about them was heat problems. More on that later.
So with two Solar Cynergy flexible panels I’m getting 240 watts, virtually no additional weight at all, and they are backed by a 10 year warranty. After measuring up the panels and looking at where the pre-installed SAE plug on my Fleet was, I realized that I could easy fit a 3rd, smaller HQST in the setup and add an additional 50 watts for only $95 extra. Why not potentially oversize for such small cost? So that would be 290 watts total. Now to see if the math checks out.
Having that panel solution in mind my calculations went something like this: I looked at the average solar radiation for Denver, my baseline for the areas this rig will camp most. (UT, WY, CO). It's 5.54 kWh per square meter. Multiplied by my panel kW (.29) I get 1.6066 kWh per day, or 1606.6 Wh per day. Divide by 12.8v for 126 amp hours per day, per square meter. I’ll have ~.99 square meter of panel. So if I'm doing all of this math right, 126/.99 means I can expect to generate ~125 ah a day as a daily average in any season. But of course that's assuming I get my theoretical maximum amount of power, which of course, I won't. Considering my bad math, what other people have measured with similar setups in real life, less than ideal panel location in the morning and evening, shading from parking under trees, etc, bad weather, the ~%70 efficiency of panels to begin with, and fudge factor in general, I opted to go with ~50% of that number. So hopefully I'm still around ~60 ah per day which is more than enough to meet my likely 50 ah a day energy needs.
After all of that, Rando commented with this link: http://pvwatts.nrel.gov/pvwatts.php which of course made life a lot easier. But it also confirmed I was in the right ball park.
Wired in parallel, I’m looking at 30 amps @ 12v. Wired in series, I’m looking at 10 amps @ 36v. I decided I wanted to be able to deploy both options. Series was the front runner for several reasons:
· Easier to wire
· Won’t be pushing the limits on the wiring (stock 10awg and even an 12awg SAE adapter)
· More optimal for the controller
The one downside to series is that shade on one panel decreases the efficiency of the entire array, not just that specific panel.
I decided after only a little research that Victron was the way to go based on quality, cost, and for me, the ability to interface to my phone with Bluetooth. In my last rig I didn’t have the insight into the system that I would have liked and it proved difficult to troubleshoot because of this.
An interesting thing about solar panels is they generate quite a bit more voltage than they’re rated for and this changes with temperature (think resistance). After crunching the numbers, if a 12v panel can exceed 25v in the right conditions and I wired three of them in series, it could easily exceed the Victron 75/15. If I wire in parallel, the 30 amps would smoke that as well. So I opted for the Victron MPPT 100/30.
I saw some mention in my research that MPPT wasn't as effective with LiFePO4. I can't see how that is true because the MPPT specifically provides a boost during bulk, and LiFePO4 batteries charge to nearly 99% in bulk. MPPT seems more advantageous for lithium than for LA considering this. Also, the Victron algorithm is fully programmable which is important considering my battery's different chemistry (although with the built in BMS the manufacturer says 14.2v bulk and 13.5v float is ideal which is very typical in many LA configurations).
Lastly, I want to know what is happening within this setup. I need good data! Already on board with the Victron gear and having heard nothing but good things about their battery monitor, I went with the BMV700. It also interfaces with the phone via Bluetooth so I figure I can start with one dongle, switch back and forth between the solar controller and battery monitor, and if I decide to add a second dongle down the road I can.
Purchase and Installation
So I pulled the trigger and ended up spending about $1600 all told (battery, panels, controller, monitor, etc).
The controller and the shunt fit perfectly in the existing battery compartment which made wiring very easy.
The installation of the shunt was very straightforward. The trickiest part was where I wanted to mount the lcd readout. It made sense to put it where everything else was which is on the opposite side of the camper from the battery. It turned out to be pretty straightforward to run the cable under the panel that covers the water tank, through the cabinet with the water heater, and then into a spot between two drawers very near the other switches and gauges. All it required was a 2” hole bit. Looks great and is in a very usable place. The programming was ridiculously easy as well. Just tell it how many amp hours the battery’s capacity is and boom, you’re done.
The panels were a bit trickier. As I eluded to earlier, I didn’t want to run into any of the heat issues many had mentioned with flat panels glued or mounted directly to the aluminum roof. Also, if a panel did blow out or needed to be replaced, it would be handy if it was removable. And finally, I always prefer not to penetrate the roof if possible.
After combing the forums and vacillating between a bunch of possible ideas, I ended up using Weld Mount studs to create bolts without drilling into the roof. I then added a plastic/air/plastic barrier between the roof that consisted of 8mm thick clear Twinwall Polycarbonate and bolted the panels through their eyelets to the roof with polycarbonate in between. Finally, I used the remainder of the Weld Mount adhesive to glue down a nice cable management system that concluded with a Renology MC4 to SAE adaptor. Why they don’t sell these with a 90 degree angle in them in curious – I certainly couldn’t find one.
Interesting thing about that Renology adaptor - I finish installing, wiring, etc and feel like Chevy Chase in Xmas Vacation as I’m about to plug the PV wires into the controller. Boom, nothing happens. It just blinks that it doesn’t have enough juice to do any charging. I use the app and interface with the device – 0 watts, 0 volts. What the? Then, out of a cob web ridden, dark corner of my brain I remember an Amazon comment about that adapter having come with its polarity reversed. The controller instructions read that reversed PV polarity will not damage it, so… I switch the wires. Boom!
Electrical system results
I’ve been monitoring the system with the app and everything looks great. Interestingly it charges at over 9 amps even in my imperfect parking spot in my driveway (there is a large tree in the way for a lot of the day but it is not heavily leaved this early in the season). I suspect that has to do with the MPPT boost. The rig is not parked east to west either. Also interesting, in fairly mild temps (not even below freezing), the panel voltage hit 75.8v – already exceeding the limit of the 75/15 controller that I didn’t go with. I’ll be glad to have the 100/30 when the temps get truly cold. So far the highest yield I’ve produced with the array in a day has been 680 Wh. Divide that by 12.8v and you get 53 ah - gotta love research/math validation! Works for me, I think I’m set!
Also, it turns out the readout from the LCD is plenty sufficient for the battery monitor and the Bluetooth works great for the solar controller, so I’ll probably stick with single dongle for the foreseeable future.
Hitting Colorado, Utah, Idaho, and Wyoming for a nice leisurely climbing trip in about a week. If anything notable pops up I’ll be sure to update. If I can lend a hand or if anyone would like more detail on something, feel free to comment or PM me. And a big thanks to everyone on the forums that lent their brains and experience to my newest build!
Edited by Esus, 25 May 2017 - 02:27 PM.