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Old 08-06-2020, 01:45 PM   #1
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Setting up my solar system

I'm in the planning stages of adding solar to my travel trailer. I was on the fence about it, but after starting a thread here, I've decided to move forward with it.

I currently have a battery bank of two 6V flooded lead acid GC batteries in series that is 215 Ah 12 volts. I am planning on adding two more of the same batteries in series-parallel for a 430 Ah 12 volts (215 Ah usable) battery bank. I then plan to add 800 watts of solar. Right now I'm leaning toward using four of the Renogy 200 watt panels.

I plan to wire in parallel, as from what I've read, if I'll be camping in shaded/partial shaded spots, which I usually do, parallel gives better output in these conditions. However, if the panels have internal diodes, does this make this line of reasoning not applicable?

I'll then combine these at a combiner box. Is a combiner box necessary? Or can I just do a T-branch coupler, assuming the amp rating is high enough? And when run in parallel, am I correct in assuming I'll need a fuse/breaker at each positive cable from each individual panel? And if so, is there a combiner box that also has breakers?

From the combiner box, I believe I also need to have a properly rated breaker/fuse to the charge controller, right? And I am planning on a 60 amp MPPT charge controller, that should be correct for 800 watts panels, right?

From the charge controller, I'd need a final breaker/fuse between the controller and the battery, right?

And I'd be using proper gauged wire, based on run length and amperage at each station, probably 10 ga --> 4 ga --> 6 ga. I'd have to measure distances and consult an ampacity chart.

I'm planning on putting the charge controller in the front underneath storage compartment of my Grey Wolf 22MKSE, as this is the closest covered compartment to the batteries. I'm thinking actual line length would be about 5-7 feet from the charge controller to the battery. I don't know where the best place to put the combiner box. I'm thinking having it right next to the controller would be best, in order to cut down line length.

I'm pretty comfortable with electrical in general, but this will be my first go at solar, so please critique my plans and add any advice, it will be appreciated.

Thanks!

EDIT: I should add that the trailer came with a factory installed 50 watt panel with a piddly charge controller. I'll be completely removing this from the system entirely.

EDIT AGAIN: Oh, and what do I do about the AC-DC converter. Will the solar charge controller work seamlessly with this?

And I don't need an inverter at this time. The only thing I really need that is AC when I'm not plugged in is the air conditioning, which I would only use if I had shore or a generator.
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Old 08-06-2020, 02:17 PM   #2
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Not sure why you would use a combiner box on this small of a system. You can easily run these in parallel without the combiner. Just my thoughts.
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Old 08-06-2020, 03:41 PM   #3
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Not sure why you would use a combiner box on this small of a system. You can easily run these in parallel without the combiner. Just my thoughts.
Okay, good. I was hoping this would be the case. One less expense, and less bulk as well. So If I just use some sort of spice/T-junction, etc., would it be okay to do that on the roof so I only had to fish one wire down to the controller? Or would it still make sense to make that run as short as possible and keep the lower amperage wires longer? If I did it on the roof, the line from the combiner to the controller would be 6-8 feet. Or maybe just go with a larger wire...
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Old 08-06-2020, 09:33 PM   #4
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I connected mine on the roof.
Here is a link to the connectors I used. https://www.amazon.com/dp/B07DJ5PHSB...1-686a582cf1a7

You are going to install 4 200 watt panelsso you would need 4 of them and a set of these https://www.amazon.com/BougeRV-Conne...s%2C164&sr=8-5
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Old 08-08-2020, 08:14 PM   #5
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Renogy Panels

When I was putting my system in I was on the phone with Renogy numerous times.
They were very helpful and took time to answer all of my questions.
You might give them a call just for a second opinion.
Of course this was pre Covid. I do not know how their staffing is right now.
I have had very good luck and zero issues with their products.
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Old 08-09-2020, 07:19 PM   #6
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I found this youtube channel very helpful when I installed mine,
https://www.youtube.com/channel/UCoj...q8kmJme-5dnN0Q
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Old 08-09-2020, 11:41 PM   #7
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Quote:
Originally Posted by GravelRider View Post

From the charge controller, I'd need a final breaker/fuse between the controller and the battery, right?
Since you need a way to disconnect the solar controller from the battery and from the panels, you need a switching device on both input and output. Circuit breakers that can be switched would work well on both sides and provide short-circuit protection.
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Old 08-09-2020, 11:57 PM   #8
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I'm planning my system, as well, and hope to benefit from your plans and experience.
Quote:
Originally Posted by GravelRider View Post
... Right now I'm leaning toward using four of the Renogy 200 watt panels.

I plan to wire in parallel, as from what I've read, if I'll be camping in shaded/partial shaded spots, which I usually do, parallel gives better output in these conditions. However, if the panels have internal diodes, does this make this line of reasoning not applicable? ...
Having 4 panels, would 2S2P not offer some benefit in shady conditions? What size SCC do you plan to use?
Quote:
And I'd be using proper gauged wire, based on run length and amperage at each station, probably 10 ga --> 4 ga --> 6 ga. I'd have to measure distances and consult an ampacity chart. ...
Can you elaborate on the locations of the various gauges of wire?
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Old 08-10-2020, 12:45 AM   #9
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Quote:
Originally Posted by GravelRider View Post
I'm in the planning stages of adding solar to my travel trailer. I was on the fence about it, but after starting a thread here, I've decided to move forward with it.

I currently have a battery bank of two 6V flooded lead acid GC batteries in series that is 215 Ah 12 volts. I am planning on adding two more of the same batteries in series-parallel for a 430 Ah 12 volts (215 Ah usable) battery bank. I then plan to add 800 watts of solar. Right now I'm leaning toward using four of the Renogy 200 watt panels.

I plan to wire in parallel, as from what I've read, if I'll be camping in shaded/partial shaded spots, which I usually do, parallel gives better output in these conditions. However, if the panels have internal diodes, does this make this line of reasoning not applicable?

I'll then combine these at a combiner box. Is a combiner box necessary? Or can I just do a T-branch coupler, assuming the amp rating is high enough? And when run in parallel, am I correct in assuming I'll need a fuse/breaker at each positive cable from each individual panel? And if so, is there a combiner box that also has breakers?

From the combiner box, I believe I also need to have a properly rated breaker/fuse to the charge controller, right? And I am planning on a 60 amp MPPT charge controller, that should be correct for 800 watts panels, right?

From the charge controller, I'd need a final breaker/fuse between the controller and the battery, right?

And I'd be using proper gauged wire, based on run length and amperage at each station, probably 10 ga --> 4 ga --> 6 ga. I'd have to measure distances and consult an ampacity chart.

I'm planning on putting the charge controller in the front underneath storage compartment of my Grey Wolf 22MKSE, as this is the closest covered compartment to the batteries. I'm thinking actual line length would be about 5-7 feet from the charge controller to the battery. I don't know where the best place to put the combiner box. I'm thinking having it right next to the controller would be best, in order to cut down line length.

I'm pretty comfortable with electrical in general, but this will be my first go at solar, so please critique my plans and add any advice, it will be appreciated.

Thanks!

EDIT: I should add that the trailer came with a factory installed 50 watt panel with a piddly charge controller. I'll be completely removing this from the system entirely.

EDIT AGAIN: Oh, and what do I do about the AC-DC converter. Will the solar charge controller work seamlessly with this?

And I don't need an inverter at this time. The only thing I really need that is AC when I'm not plugged in is the air conditioning, which I would only use if I had shore or a generator.
I have ten Renogy 100 watt panels in parallel with a 50 amp MPPT.


I ran two pairs of 10 awg solar cables to the roof with 60 amp circuit breaker at the MPPT controller. I will not climb up on the roof to tilt, so I oversized the solar array. I get a max output of about 700 watts, but I get 250 watts when it is cloudy.

Click image for larger version

Name:	MPPT Screenshot_20200808-214254.jpg
Views:	68
Size:	154.9 KB
ID:	236200

See: Solar panel over sizing for rigid roof mount



BougeRV 30 Feet 10AWG Solar Extension Cable


Distribution Block 4 Gauge in to (4) 8/10 Gauge Out
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Old 08-10-2020, 12:23 PM   #10
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Originally Posted by rk06382 View Post
Very helpful. And one can do his own very precise comparison with the NREL PVWatts database. And do it for specific locations.

This tool was in development over 20 years ago and has been tuned and fine tuned ever since. The solar data base is huge. You can choose a location down to a few miles. It predicted my 13,500 kWH home array to closer than 50 kWH.

You can compare a fixed array with a ground array (a two-axis tracking array if adjusted angle and direction. Or you can interpolate if you won't adjust the ground panels every 10 minutes.

Do look at the list of losses, some do not apply to us. Also, the shade estimate is probably better estimated by hand. I use 7% for losses and consider shade separately. Converter losses are listed separately (4% is the default).

Best of all, typical inclement weather for each location is included so you can look at cloudy days for whatever location and season you want to zero in on.

Unfortunately for us, the program only provides monthly or hourly data, not daily data. I have a spread sheet that extracts daily data from the hourly data if you have a spreadsheet program (Google Sheets or Excel or similar) I'll send it to you.

https://pvwatts.nrel.gov/pvwatts.php

Here's an example. Denver. Scary but in most locations the solar energy is not not so variable from day to day. I can generate this plot for specific locations (it's easy) for anyone wishing to have one. This one is for a 100W panel but can be scaled to any array wattage. Axes are Watthours vs days of the year. Divide Watthours by battery voltage to get amp hours.

Click image for larger version

Name:	Denver 100W.jpg
Views:	47
Size:	141.4 KB
ID:	236243
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Old 08-10-2020, 12:28 PM   #11
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Quartsite; much better place to camp than Denver for solar users. This is for a 1000W array but can be scaled.

Click image for larger version

Name:	Quarsite 1000W Panel Array.jpg
Views:	56
Size:	111.5 KB
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Old 08-10-2020, 03:21 PM   #12
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Quote:
Originally Posted by Hclarkx View Post
Very helpful. And one can do his own very precise comparison with the NREL PVWatts database. And do it for specific locations.

This tool was in development over 20 years ago and has been tuned and fine tuned ever since. The solar data base is huge. You can choose a location down to a few miles. It predicted my 13,500 kWH home array to closer than 50 kWH.

You can compare a fixed array with a ground array (a two-axis tracking array if adjusted angle and direction. Or you can interpolate if you won't adjust the ground panels every 10 minutes.

Do look at the list of losses, some do not apply to us. Also, the shade estimate is probably better estimated by hand. I use 7% for losses and consider shade separately. Converter losses are listed separately (4% is the default).

Best of all, typical inclement weather for each location is included so you can look at cloudy days for whatever location and season you want to zero in on.

Unfortunately for us, the program only provides monthly or hourly data, not daily data. I have a spread sheet that extracts daily data from the hourly data if you have a spreadsheet program (Google Sheets or Excel or similar) I'll send it to you.

https://pvwatts.nrel.gov/pvwatts.php
I ran the numbers it came back that I can generate $190 of electricity per year with my array.

In June I saw 4 kwh per day. For August I see about 3 kwh per day. But I only use the array when I boondock & the 3 kwh is priceless.
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Old 08-10-2020, 07:05 PM   #13
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Quote:
Originally Posted by rk06382 View Post
I ran the numbers it came back that I can generate $190 of electricity per year with my array.

In June I saw 4 kwh per day. For August I see about 3 kwh per day. But I only use the array when I boondock & the 3 kwh is priceless.
Yes! It's a kick seeing the battery topped off mid-day. But also a kick getting through a few cloudy days without starting the generator.

Down the results page a ways is a link to export the results in either a monthly or hourly tabulation (*.csv files) that load into any spreadsheet. I don't know why they don't provide daily output. The help line is very responsive so I may call them about that. I crunch the 8760 hours down into 365 days with a pivot table. One can then look where and when they travel and look at the cloudy days (often two or three in a row) and decide how much battery/solar to have.

Anyone wanting to do this, PM me and I'll send a spreadsheet that does the above and a few other things.
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Old 08-10-2020, 09:00 PM   #14
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GravelRider , have you drawn up a rough schematic yet? Lets see it !
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Old 08-11-2020, 09:34 AM   #15
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Thanks for all the replies everyone. I've been also considering using 3 larger Renogy 275 watt 24 volt panels instead, and running them in series. On another forum a few members had mentioned having a system at least partially in series will bring the voltage up and help with harvesting low angle morning and evening wattage. I figure if I just get 24 volt panels, I can still stick with running them in parallel and get the best of both worlds.

Quote:
Originally Posted by chriscowles View Post
I'm planning my system, as well, and hope to benefit from your plans and experience.Having 4 panels, would 2S2P not offer some benefit in shady conditions? What size SCC do you plan to use?Can you elaborate on the locations of the various gauges of wire?
I'm planning to use a 60 amp controller.

I may have to adjust the numbers based on the specific panels and number I use, but I was planning 10 ga from panels to combiner box, then 4 ga to controller, and probably just use the same 4 ga to the battery bank.


Quote:
Originally Posted by rk06382 View Post
I have ten Renogy 100 watt panels in parallel with a 50 amp MPPT.


I ran two pairs of 10 awg solar cables to the roof with 60 amp circuit breaker at the MPPT controller. I will not climb up on the roof to tilt, so I oversized the solar array. I get a max output of about 700 watts, but I get 250 watts when it is cloudy.

Attachment 236200

See: Solar panel over sizing for rigid roof mount



BougeRV 30 Feet 10AWG Solar Extension Cable


Distribution Block 4 Gauge in to (4) 8/10 Gauge Out
Awesome solar setup! I'll have to read through your thread you linked, as it looks to have a lot of pertinent discussion. I also will not be climbing on the roof to tilt my panels, so maybe I'll oversize a bit as well. Though, I don't have a big trailer, so roof space will be my limiting factor I think.

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GravelRider , have you drawn up a rough schematic yet? Lets see it !
I haven't. I usually just keep these things in my head. If I do sketch something up I'll post it.
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Old 08-11-2020, 11:48 AM   #16
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Quote:
Originally Posted by GravelRider View Post
Thanks for all the replies everyone. I've been also considering using 3 larger Renogy 275 watt 24 volt panels instead, and running them in series. On another forum a few members had mentioned having a system at least partially in series will bring the voltage up and help with harvesting low angle morning and evening wattage. I figure if I just get 24 volt panels, I can still stick with running them in parallel and get the best of both worlds.

My suggestion...don't use 100W panels. Get the largest panels that will fit. You have less panels that way so less mounting and less wiring. Your plan of the 3 270W is good.


Figure 70% loss if they are flat mounted. Depending on where you are, figure 5 hours equivalent sun. What that means is that for every 100W instead of 7A you will get 5A and with 5 equivalent sun hours that means 25AH for every 100W. Then double it if you travel in the winter.


I have 200AH of lithium and 700W of solar.


I have a whole write-up I did for another person and I can email it if you want.


Use a quality crimper to make your cables. Don't use a hammer crimper. Use voltage drop calculators to size all your cables and shoot for 2% drop.


Don't use any circuit breaker or distribution block that uses set screws to hold the cables. Use crimped ring connections only.
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Old 08-11-2020, 04:50 PM   #17
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Originally Posted by rk06382 View Post
I ran the numbers it came back that I can generate $190 of electricity per year with my array.

In June I saw 4 kwh per day. For August I see about 3 kwh per day. But I only use the array when I boondock & the 3 kwh is priceless.
Yesterday was cloudy and raining, I only got 1.75 kwh.

Click image for larger version

Name:	Solar MPPT Screenshot_20200811-133905.jpg
Views:	37
Size:	150.6 KB
ID:	236404

Today and the day before I was plugged into shore power at home. The fridge is on 120v all the time. The only time I switch the fridge to propane is when the SOC is below 50%.
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Old 08-11-2020, 08:49 PM   #18
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Some other things to think about when planning your system. I have my inverter hardwired into an auto transfer switch along with shore power. My line out goes into a hard mount surge protector that has a remote display. I like that I can see the amps I am using from my inverter and shore power.
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Old 08-11-2020, 08:55 PM   #19
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This is the crimper I use.

IBOSAD Hydraulic Cable Lug Crimper Crimping Tool 6 AWG to 600 MCM Electrical Battery Terminal Cable Wire Tool Kit Wire,marked with AWG https://www.amazon.com/dp/B07VK9V6YJ..._PT0mFbZ8QHM62
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Old 08-11-2020, 10:46 PM   #20
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This is the crimper I use.

IBOSAD Hydraulic Cable Lug Crimper Crimping Tool 6 AWG to 600 MCM Electrical Battery Terminal Cable Wire Tool Kit Wire,marked with AWG https://www.amazon.com/dp/B07VK9V6YJ..._PT0mFbZ8QHM62
The problem with these types of crimpers is that they are really metric dies with AWG sizes stamped on them to KINDA match the equivalent metric one. Not accurate at all.


This isn't the one I have but it is the one I recommend. Mine is quite a bit more money. Make sure you use the suggested crimps that are thick walled.

Read this before buying a crimper
https://marinehowto.com/making-your-own-battery-cables/







https://www.amazon.com/Correctos-Cri...NsaWNrPXRydWU=
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