MOST solar/batteries capacity

[Kwest364]

What's the biggest capacity rig you've seen? I personally know of Derek from @Sunnytheskoolie, has 3600W of panels and 24,960ah of battery capacity (520ah @ 48V).

Anybody know of any rigs with more? I'd like to see their setup. Links to videos/pics would be great.

[Rucker]

Use the search function in the upper right of the forum to find 'maximum solar' and you will be rewarded with several high-quality discussions.

[DeMac]

Sasquatters built an insane deck with slide-out solar panels, which provide additional square footage to the factory bus roof.



Photos & details here:
www.skoolie.net/insane-rooftop-deck

[rossvtaylor]

I recently did a roof raise and installed 10 450W panels on a bus. That's the most I've done so far.

For batteries, it's got 28,800Wh of battery capacity (six 100Ah at 48V).

[TucsonAZ]

I have 12 panels, 435 watts each going on my roof, currently have 19kWh of LifePO4 but thinking about adding to that. That doesn't include the 1,250 I have on my enclosed trailer.



I'm also giving some serious thought to adding vertical panels, maybe another 2,000 watts of cheap panels on the sides of the bus.

[kazetsukai]

My current battery bank is 840Ah @ 48V (52V nominal), or 43kWh.

3150W up top, with another 1800W on the ground for now.

Originally Posted by DeMac

Sasquatters built an insane deck with slide-out solar panels, which provide additional square footage to the factory bus roof.

This is what I wanted to do on this build, but now will likely do the next one. Man that's a nice, clean job. Don't need the deck, just more room for panels.


I think 6000W is the sweet spot for us, might enable us to do solar heat through the winter with a little LP here and there.

[HamSkoolie]

WOW
We thought we were going over kill with 10ea 290W panels for 2,900W and 10kWh of lithium with room for another 10kWh in the battery rack.


I do know of several builds with 24kWh of lithium from Nissan Leaf batteries that were reconfigured. The two I know are Juan and his family and the Broccoli bus. Juan's rig has large panels down the top of the roof with a second set of panels below and an actuator mechanism to deploy them.

The Broccoli bus has had some issues at RV parks that charge for electricity when the meter showed no power used and they accused him of hooking into a different power post. He literally doesn't have to plug in.


After extensive calculations our 10kWh should be enough but got a rack capable of doubling it should the real world provide more days of low solar than the initial bank can deal with.

[Rock-N-Ruth]

Originally Posted by Kwest364

What's the biggest capacity rig you've seen? I personally know of Derek from @Sunnytheskoolie, has 3600W of panels and 24,960ah of battery capacity (520ah @ 48V).

Anybody know of any rigs with more? I'd like to see their setup. Links to videos/pics would be great.

We've got 12 327w panels on the roof and four more on a trailer. Our battery bank is 6 24V BYD 220ah in a 6P configuration. We are about to reconfigure to a 2S3P for our new EG4 split phase 48V hybrid inverter. And adding an additional 304ah 48v battery.


We live in it full time and love autonomy. We like it hot when it's cold and cold when it's hot.

[HamSkoolie]

Originally Posted by Rock-N-Ruth

We've got 12 327w panels on the roof and four more on a trailer. Our battery bank is 6 24V BYD 220ah in a 6P configuration. We are about to reconfigure to a 2S3P for our new EG4 split phase 48V hybrid inverter. And adding an additional 304ah 48v battery.


We live in it full time and love autonomy. We like it hot when it's cold and cold when it's hot.

We were going to go with the Victron 24v 3000W MultiPlus until we saw that EG4 had the EG4 6.5kW for several hundred less and included a larger battery charger, two built in charge controllers, and the monitoring/settings control was detachable for remote location (thus saving several thousand dollars in additional components -- two charge controllers at $325ea, display and display "driver" at about 8 or 9 hundred, etc.). Plus it is fully compatible with our 2 EG4 24v (will be in series) batteries with 10.24kWh of lithium. If we need to expand, Signature Solar assured us that we can then parallel a single 48v or two 24v in series additional EG4 batteries if we find we need more storage capacity.

[Rock-N-Ruth]

Originally Posted by HamSkoolie

We were going to go with the Victron 24v 3000W MultiPlus until we saw that EG4 had the EG4 6.5kW for several hundred less and included a larger battery charger, two built in charge controllers, and the monitoring/settings control was detachable for remote location (thus saving several thousand dollars in additional components -- two charge controllers at $325ea, display and display "driver" at about 8 or 9 hundred, etc.). Plus it is fully compatible with our 2 EG4 24v (will be in series) batteries with 10.24kWh of lithium. If we need to expand, Signature Solar assured us that we can then parallel a single 48v or two 24v in series additional EG4 batteries if we find we need more storage capacity.

That is the new addition to our system. With it's 500V pv input capacity I can run all 12 panels into one hybrid controller inverter unit.
It's a heavy beast. Be ready to build a strong mounting point.

[HamSkoolie]

Originally Posted by Rock-N-Ruth

That is the new addition to our system. With it's 500V pv input capacity I can run all 12 panels into one hybrid controller inverter unit.
It's a heavy beast. Be ready to build a strong mounting point.

Yes the PV controller input capacity will handle our 10 panels at 290W each saving us over $650 just in Victron charge controllers.
The sending unit and display for remote monitoring and control was going to cost another $800 or more with Victron. With the EG4 6.5 having a relocatable control panel with just a single standard cable we save that as well.
Toss in more than DOUBLE the capacity, a 13kW surge capability, and a battery charger with 50A more than the Victron at over $200 less AND CERTIFIED.....
It was a no brainer change from Victron for us.


It is rather heavy but it will be mounted on top of the 1394 pound (rather a specific spec) capacity battery rack to minimize and simplify the wiring between it and the rack. I will likely mount heavy duty angle iron to the rear uprights of the battery rack, run flat or angle across at the inverter mounting points and then pay a sheet of 3/4 ply over that for attaching other components (disconnects, fuses, shunt, etc.) The entire assy will then be secured to the deck, outside wall, and side walls with damping material and grade 5 bolts ensuring it will stay where it belongs.

[Iceni John]

I sometimes wonder how much actual power is produced by these large arrays of flat-mounted panels when the sun is low, i.e. at the beginning and end of each day, or in winter, or at more northern latitudes? This article convinced me that a smaller quantity of tiltable panels may be better than a greater quantity of flat panels: Optimum Tilt of Solar Panels

John

[Rucker]

Originally Posted by Iceni John

I sometimes wonder how much actual power is produced by these large arrays of flat-mounted panels when the sun is low, i.e. at the beginning and end of each day, or in winter, or at more northern latitudes? This article convinced me that a smaller quantity of tiltable panels may be better than a greater quantity of flat panels: Optimum Tilt of Solar Panels

John

Very good article. Some time back there was a similar discussion and I noted (as the data from your article similarly shows) that the efficiencies gained from adjustable panels are meaningful above 40 degrees latitude, or roughly north of Interstate 80. Below that, the gains diminish rapidly.

[HamSkoolie]

Originally Posted by Iceni John

I sometimes wonder how much actual power is produced by these large arrays of flat-mounted panels when the sun is low, i.e. at the beginning and end of each day, or in winter, or at more northern latitudes? This article convinced me that a smaller quantity of tiltable panels may be better than a greater quantity of flat panels: Optimum Tilt of Solar Panels

John

We will be mounting our panels on a fixed rack with the inboard edges 2 1/2 inches higher than the outboard. The 2 1/2 inch difference will allow rain to wash the panels without our input while not having much of an impact.
We decided on fixed mounts because we've read accounts of people with tilt mounts and in the real world, they simply don't go out and tilt them because it's a hassle.
So we went with a maximum coverage setup of 10 panels on an elevated rack which will shade the roof and has a theoretical production of 2900W of which we'll be happy to get 2000W for 2 hours with rise and drop on either side for a total of 8kW per day. We will adjust from there.

[Rock-N-Ruth]

Originally Posted by HamSkoolie

We will be mounting our panels on a fixed rack with the inboard edges 2 1/2 inches higher than the outboard. The 2 1/2 inch difference will allow rain to wash the panels without our input while not having much of an impact.
We decided on fixed mounts because we've read accounts of people with tilt mounts and in the real world, they simply don't go out and tilt them because it's a hassle.
So we went with a maximum coverage setup of 10 panels on an elevated rack which will shade the roof and has a theoretical production of 2900W of which we'll be happy to get 2000W for 2 hours with rise and drop on either side for a total of 8kW per day. We will adjust from there.

The shade gains in the southwest are eaten by the heat radiated towards the roof by the panels. We thought the same thing when we installed our panels in 2018. We were expecting it to help cool the bus by shading the roof. What we soon realized is that the panels absorb heat from the sun and radiate it towards the roof. Having some insulation on the roof between the panels and you helps. Allowing an air gap for convection helps as well.

Your plan to include a little rise for water runoff is a great idea.

The only time we ever would get a noticeable gain from a tilt in our panels here in New Mexico, is late in December for a few days. This is what our four 327W panels on the trailer are for. We can tilt them and swig them south for the soltice sun.

We love solar living and now we are becoming solar gluttons.

Just a note for those looking to DIY batteries, 18650batterystore.com is a USA distributor with both grade A and grade B cells. Great customer service and quick response times. They have a great selection of EVE and Gafang cells at good prices, shipping from Georgia.

We just closed a deal with them for cells in a 69KW battery bank at just .14/watt

[HamSkoolie]

Originally Posted by Rock-N-Ruth

The shade gains in the southwest are eaten by the heat radiated towards the roof by the panels. We thought the same thing when we installed our panels in 2018. We were expecting it to help cool the bus by shading the roof. What we soon realized is that the panels absorb heat from the sun and radiate it towards the roof. Having some insulation on the roof between the panels and you helps. Allowing an air gap for convection helps as well.

Well there are going to be big black solar panels up on the roof so they're going to absorb heat. However, with a 4-6" stand off and the 2 1/2" inboard edge being higher than the outboard edge, heat should tend to rise the the center and escape.

Along the center of the bus will also be a wooden walkway between the panels. That walkway will have gaps between each 2x4 or 2x6 board for heat escape.
And if things don't work out in the real world as we planned..... we will adjust and modify. Perhaps a higher air gap.

[Veloc]

A thin aluminum panel attached under each solar panel with a 1 inch standoff will help as well. The idea would be solar panel, airgap, aluminum panel, airgap, bus roof. Cars use a thin heat shield between the car body and the 900+ degree catalytic converter and it does a great job of keeping that heat out of the cabin while just a couple of inches underneath. A few grooves in each panel will keep them from flexing in the wind.

[Rock-N-Ruth]

Originally Posted by HamSkoolie

Well there are going to be big black solar panels up on the roof so they're going to absorb heat. However, with a 4-6" stand off and the 2 1/2" inboard edge being higher than the outboard edge, heat should tend to rise the the center and escape.

Along the center of the bus will also be a wooden walkway between the panels. That walkway will have gaps between each 2x4 or 2x6 board for heat escape.
And if things don't work out in the real world as we planned..... we will adjust and modify. Perhaps a higher air gap.

Up in Oregon the radiant heat from direct sunlight will not be as bad as in New Mexico. Here, the sun literally bakes the paint off of cars, drys and destroys sitting tires, eats plastic lawn furniture and turns people to raisins. The large air gap you are planing will indeed allow convection to occur. Air heated by the hot undersides of the solar panels will rise drawing air over the roof.

Just one note. Heat, of itself, does not rise. Hot air rises because it is lighter than cold air.

Here is a link to a pretty good article about how heat transfers work.

"Misconceptions of Thermodynamics: Does Heat Really Rise?" https://www.wondriumdaily.com/miscon...t-really-rise/

Someone once suggested to me to pack XPS foam on the backside of the solar panels. While this would greatly reduce the radiation of heat towards your roof, it would greatly reduce the ability of the solar panels to shed heat. I think this would reduce the life of the panels and also their efficiency.

[HamSkoolie]

Originally Posted by Rock-N-Ruth

Up in Oregon the radiant heat from direct sunlight will not be as bad as in New Mexico. Here, the sun literally bakes the paint off of cars, drys and destroys sitting tires, eats plastic lawn furniture and turns people to raisins.

Well being a retired Marine, I've spent some time in the desert. 4 1/2 years stationed in Barstow and you know those reserve recruiting ads about "just two weeks in the summer".... well the reservists do two weeks.... we active duty types were 6 to 12 weeks as the reservists were rotated through for their two weeks.
Anyway, I know what the desert will do. Thus we also have a 12000 btu air conditioner in the front and a 9000 btu air conditioner in the back.

[Iceni John]

Originally Posted by HamSkoolie

Along the center of the bus will also be a wooden walkway between the panels. That walkway will have gaps between each 2x4 or 2x6 board for heat escape.
And if things don't work out in the real world as we planned..... we will adjust and modify. Perhaps a higher air gap.

That's exactly, sort-of more or less, what I did. After painting the roof, I made a 26ft-long walkway between my two roof hatches from 6061 angle and 3003 diamond-plate. Each of my eight panels sits inside a support frame made from 6063 angle, four on each side of the walkway, hinged to the walkway and with telescoping stainless struts on their outer edges. I can easily raise or lower the panels by hand, but during the summer they'll probably mostly remain in their stowed position if I can recharge my battery banks without raising them. Yes, it was a lot more work to do all this, but on dull winter days when I need to maximize solar harvest I think I'll be happy that I can tilt the panels towards a wan sun. Even when stowed down for travel, the panels have enough air gap under them to avoid heating the roof; in the summer the interior is noticeably cooler (OK, less hot) under where the panels shade the roof.

In addition, I provided water on the roof so I can easily and safely wash the panels: there are two quick-connect water outlets under hinged sections of diamond-plate, so I need only bring a washdown brush with a short curly hose up onto the roof, and all water flows away from me while I'm doing the ablutions there. Easy!

John