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Old 12-28-2016, 02:02 PM   #1
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PV Solar for the Heap

Hi everyone,

After much research, I am finally putting solar in my rig, something I should have done from the beginning. Figured I'd post my plan for criticism / ideas for others. It will be a budget build for sure, but I think in sunny Colorado, it should work just fine.

First off, I have pretty low electrical demands. All my lights are LED, my inverter maxes out at 1000 watts, and when we dry camp, we usually bring a cooler. Not really counting on running the fridge with this setup, though the fridge is incredibly energy efficient.

As of right now, I have six batteries in the bus total - two 12v in parallel for starting, and four 6v 225ah golf cart batteries for the house. These two banks are isolated / joined manually via one of these:



I wired the battery bank on the side of the road in a few hours, so this switch is in the storage compartment where the aux batteries are. Really inconvenient and I am going to move the switch to inside the bus by all the other electrical business in the back.

I picked up one of these solar charge controllers:

https://www.amazon.com/Solar-Boost-3.../dp/B0179V9JQI

It is a very compact unit, very intelligent, with many settings, and several uses, AND cost-effective. Crazy, right? It allows you to program different float voltages and settings for different types of batteries. What drew me most, however, is that you can either use 12-volt designed panels, or the higher voltage, higher efficiency 60-cell panels like you'd find on a house for grid tie systems, which operate at 24-36 volts. This unit is capable of reducing that panel voltage to whatever is the optimal charging voltage for your batteries at that time. It is much more efficient than a PWM controller as far as putting the juice from your panels to work.

In addition to this, it has an input for an optional battery temperature sensor, which you'd put near the batteries, so the computer knows what charging voltages are optimal at whatever temperature the batteries are at, increasing charging efficiency.

It ALSO has a 12 volt, 2 amp charging output for starting batteries.If you are parked for a long period of time and want the house and starting batteries disconnected, this unit will trickle charge them separately, given that there is enough sunlight. Excellent for me, since the bus is stored in a spot where it gets 8+ hours of sunlight per day.

I was planning on coupling this system with one 260 watt 60-cell panel from the following seller in Denver:

260 watt Solar Panels - New!!

Priced nicely at $160 each. I will build some sort of mounting system for them that allows me to pivot them if I want, but also to keep secure at highway speeds. The 260 watt panel should keep me safely under the maximum for the charge controller.

I will feed the wires through the roof with this plate:

https://www.amazon.com/gp/product/B0...A2X8N6V4HT8DJJ

And a few more goodies:

Fuse box (in and out style, no bus bar) - https://www.amazon.com/gp/product/B0...A2WCR1L7XCIL9L

ANL High-amp fuse holder for inverter and large 12 volt loads - https://www.amazon.com/gp/product/B0...A130UJC6EIIOR0

DC Circuit breaker for panel disconnect / protection (I might want to go with a lower-amp one...) - https://www.amazon.com/gp/product/B0...=A6AY1HFZHO49U

10 gauge cables with MC4 connectors (pretty standard for solar) to run through roof to charge controller - https://www.amazon.com/gp/product/B0...A2TN19FHI2Z5KL

I will be mounting the solar panel and charge controller at the back of the bus, across from my fridge (directly over the drivers side rear wheel) as there are already 2/0 lines to the battery banks there for the inverter, and mounting it there would be the shortest run, and would use existing runs. All I need to do is drill a few more holes for a couple more wires to relocate my battery selector switch, hole in the roof for the lines from the solar panel, and some smaller gauge wires to the starting batteries for the maintainer function from the charge controller. I don't currently have the battery temperature monitor, but I think I will get one, and run that as well.

I will draw up some amateur wiring diagrams shortly and make sure all my plans make sense.
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Old 01-12-2017, 01:04 PM   #2
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Picked up my panel from a seller in Denver, $160 for a 60-cell panel, like you'd put on a house. It is 39" wide and 65" long. 260 watt maximum, which should put us safely under the controller's 290 watt maximum.





Waiting on warmer weather for installation! I came up with a pretty simple way to make a mount that will allow this panel to be tilted in four different directions, using door hinges. I'll have to get up on the roof to adjust it, but it should work. I was also thinking about adding some cross bracing in the center of the panel, since this thing isn't designed for use on a vehicle.

More updates to come!
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Old 01-12-2017, 04:43 PM   #3
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Nice snag... the trouble I'm having right now is the only way I can get a decent price on panels is to buy a whole pallet of them... Nobody around here likes to sell single panels for any kind of reasonable price...
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Old 01-12-2017, 04:58 PM   #4
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Originally Posted by slaughridge85 View Post
Nice snag... the trouble I'm having right now is the only way I can get a decent price on panels is to buy a whole pallet of them... Nobody around here likes to sell single panels for any kind of reasonable price...
That's exactly what this guy in denver did. He buys them by the pallet and marks them up a bit, but they're still substantially cheaper than buying one and having freight shipping. He is just some honest dude who is into solar and wants to help people out. Try searchtempest.com, it searches Craigslist in a certain radius and you might find more Craigslist sellers. Where in kansas are you? CO isnt that far!
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Old 01-12-2017, 05:05 PM   #5
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I'm in eastern ks. I wouldn't think twice about hopping in my honda and zipping out to CO for some decent priced panels... except that the transmission just went out and my other options are a f150 that gets ~13mpg or a 72 nova that gets ~14mpg or the bus that gets 10... There is a guy in KC, he just never has any panels when I have the money and then after I drop a couple g's on my kids college tuition he has LOTS available...

I'll be interested to see how that particular panel works out for you. It's a brand and model I've been considering for a while.
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Old 01-12-2017, 05:46 PM   #6
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Check out this guy too: Sunelec.com

Prices as low as 38 cents per watt. He is generally THE lowest price anywhere. He has some amazing prices on "B" grade panels, ie, panels with tiny cosmetic blems that do not alter either the power output or the warrantee. Warehouses in Los Angeles, Phoenix, and Miami. Read his blog too. The guy is a trip! Even has free panels (shingles, really) that are recycled and yours for the asking.
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Old 01-12-2017, 08:03 PM   #7
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I just got 6 250 watt panels delivered to my door for 1300.00 from ebay. it was a drop ship from ca. 30 year warranty . I paid over 5 bucks a watt for my first panels 15 years ago.
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Old 01-13-2017, 12:14 AM   #8
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So-called "Grid-tie" panels with 60 cells are the cheapest way to buy PV. Another benefit is that most manufacturers make them, all at about the same power, so if one breaks you can easily find a replacement with similar Vmp and Isc, even if it's from a different company. I suggest mounting your panels inside support frames to reduce the load on the panels' own frames, then if you want to get fancy and tilt them you attach the tilting mounts and support struts to the support frames - this way you don't need to attach any hardware to the panels themselves. I've got eight Grade B Sharp grid-tie panels set up this way, and they're working well (except in this lousy rain!).

John
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Old 01-14-2017, 02:59 PM   #9
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Quote:
Originally Posted by slaughridge85 View Post
Nice snag... the trouble I'm having right now is the only way I can get a decent price on panels is to buy a whole pallet of them... Nobody around here likes to sell single panels for any kind of reasonable price...

Freight is very high on panels so try to find local. Plus if they are damaged in shipping you will have to fight with both delivery and company.

We finally found local that would break up pallet. Just ask if they will sell a couple. Keep looking and good luck.
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Old 01-14-2017, 03:05 PM   #10
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Originally Posted by slaughridge85 View Post
Nice snag... the trouble I'm having right now is the only way I can get a decent price on panels is to buy a whole pallet of them... Nobody around here likes to sell single panels for any kind of reasonable price...

Also try Loews or Home Depot. They sell panels so does Costco. We bought a solar kit from Home Depot last year but sent it back till Florida bill passed for DIY private solar. Now we went al lout to put on a utility trailor we've had for 15 or so yr.s.

https://youtu.be/WfH4fnBNjSE
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Old 01-16-2017, 05:39 PM   #11
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Quote:
Originally Posted by slaughridge85 View Post
I'm in eastern ks. I wouldn't think twice about hopping in my honda and zipping out to CO for some decent priced panels... except that the transmission just went out and my other options are a f150 that gets ~13mpg or a 72 nova that gets ~14mpg or the bus that gets 10... There is a guy in KC, he just never has any panels when I have the money and then after I drop a couple g's on my kids college tuition he has LOTS available...

I'll be interested to see how that particular panel works out for you. It's a brand and model I've been considering for a while.
I can send you the dude's contact info if you want. I bought the last panel he had for a while, he said 2-3 months before he had more in. That should give you time to sort the trans on the honda.
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Old 01-16-2017, 05:42 PM   #12
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Quote:
Originally Posted by Iceni John View Post
So-called "Grid-tie" panels with 60 cells are the cheapest way to buy PV. Another benefit is that most manufacturers make them, all at about the same power, so if one breaks you can easily find a replacement with similar Vmp and Isc, even if it's from a different company. I suggest mounting your panels inside support frames to reduce the load on the panels' own frames, then if you want to get fancy and tilt them you attach the tilting mounts and support struts to the support frames - this way you don't need to attach any hardware to the panels themselves. I've got eight Grade B Sharp grid-tie panels set up this way, and they're working well (except in this lousy rain!).

John
Yeah that's why i went this route. Also that higher voltage paired with an MPPT controller is apparently much more effective than an entirely 12 volt system.

Whats the matter with attaching hardware right to the panel frame? Too much stress on a moving vehicle you think?
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Old 01-16-2017, 11:19 PM   #13
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@GreyCoyote

Have you ever done business with that person? I've seen that site, but something about it... i don't know, seemed too good to be true?
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Old 01-18-2017, 06:22 PM   #14
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Quote:
Originally Posted by porkchopsandwiches View Post
Also that higher voltage paired with an MPPT controller is apparently much more effective than an entirely 12 volt system.
That seems to be the general consensus. I've noticed that the price per watt for panels is definitely better for the higher voltage ones targeted toward grid tie systems. You also don't have as many issues with trying to prevent power losses over longer wire runs when you work with higher voltages. Your transmission wires running down into the bus can be lighter gauge with fewer losses.


Quote:
Originally Posted by porkchopsandwiches View Post
Whats the matter with attaching hardware right to the panel frame? Too much stress on a moving vehicle you think?
Just too much stress on the panel in general. I rarely see systems of any size that don't have support frames with the panels mounted inside of them. I imagine it could also cause issues if you had to replace mounting hardware or remove panels for maintenance at some point in the future. That's a lot simpler to do if they aren't mounted directly to the roof.

Lucas
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Old 02-06-2017, 12:44 AM   #15
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Cross-posted to my build thread, but figured I'd post it here because it is relevant to the area.

So this weekend I started and finished my solar installation.

Step one was to run fatter wire between the battery banks, inverter and selector switch, and to move the selector switch inside the bus. It was previously underneath the bus near the battery bank, as I hastily wired the battery bank in a few hours in the summer of 2015 before a trip.



It isn't pretty, but it works. I need to put a cover over this whole deal. I upgraded everything from 2 AWG to 2/0 AWG, except the one smaller 2 gauge wire seen, which runs to the front of the bus for aux battery bank loads.



Got the panel mounted up, on the back of the bus. I reinforced the panel with riveted-on corner brackets and aluminum pieces that run across the back of it. Probably unnecessary, but I figured since the panels were not meant for vehicular use, it wouldn't hurt.

I mounted them as such:



Riveted door hinges on all 4 corners. This way, the panel can tilt in 4 directions to face the sun, by undoing bolts on the side you want to raise. When you're tilting it not in the direction of the hinge, just loosen the bolt on the side that stays down, and the panel will pivot on the the bolt. I don't yet have anything to prop it up, but I am planning on using uni-strut or something similar and having a short piece of square aluminum tube to prop it up, with bolts.

Please excuse the sloppy sealant, time was of the essence. I am taking 18 credit hours, working part time and trying to build this thing





I bought the through-roof plate on Amazon:



When I hooked everything up, it all worked, which was nice. This was about 1:30 pm, probably about prime sunlight this time of year. Was reading 13 volts at the time:



And 14 amps output to the batteries at the time (indicated by the small dot on the screen, flashing dot means amps input from the panel).



Not sure what the amps input from the panel was, but since the panel operates at 30-35 volts, the amps would be lower. 14 amps x 13 volts is 182 watts of output, which isn't bad. Panel is rated at 260 watts. I was able to start my refrigerator on the inverter without a hiccup, something that I never used to be able to do on batteries.

Final installed product. Voltage is low because I had been running tools and the sun had gone behind the mountains:



The circuit breaker to the right also doubles as a cutoff switch for the solar power.

Fuse box for 1) 10 amp fuse on the starting battery trickle charge output from the MPPT controller and 2) 30 amp fuse from MPPT to batteries:



Current inverter / other electrical setup. Yeah, I break rules and mix colors for wiring. At least this time I marked it with tape. The MPPT controller is on the other side of the cabinet of this inverter. Instead of running wire from the MPPT to the batteries in a dedicated line, I ran them to the 2/0 gauge going to the inverter. The charger output from the 120 volt breaker panel charges the batteries through there as well. I didn't see any harm in setting it up this way, other than possibly under load, the MPPT controller might see a lower voltage than the batteries actually are.

Also, the MPPT controller has a battery temp sensor for optimal charging voltages.

Let me know if you have any questions / need a diagram of how I did this. I did it all in my head

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