400w Solar for RV - Critique my initial blue print

[Deanm]

-Please critique my first draft blue print
-Disclaimer -Not the awsum Photoshop image that I wish I could do . Will clarify as needed. My goal is to avoid starting the 4k Onan generator when boondocking as much as possible and this is my gateway solar project.
-Ive purchased 4 HQST 100w panels so far, waiting to pull the trigger on everything else pending opinions, ( very hard to do ha ha !! )
-Daily usage when boondocking = 60AH max / 110AH battery storage ( I already have 2-220ah 6v Full River AGMs in series with a Victron BMV 712 on RV tongue )
Thanks for any help

[nayther]

why series/parallel for the panels? If you're charge controller will handle the higher voltage of all in series I'd do it that way, less wire loss at higher voltage. Other than that it appears to be a solid plan. Not sure what you're powering with a little 600 watt inverter, one that small can be wired in anywhere.

[hobienick]

That looks reasonable to me. For a really good overview of a solar install (possibly a bit overkill) check out Mortons on the Move on YT. He has a 3 part solar series that I really liked. He also has a video on his hybrid inverter/charger. Well worth the 70 min total to watch all 4 videos.

[hobienick]

nayther,

Series will be more affected by partial shading than parallel. The S/P combo is a bit of a hedge.

[nayther]

Originally Posted by hobienick

nayther,

Series will be more affected by partial shading than parallel. The S/P combo is a bit of a hedge.

Good point, didn't think of that. I only have 3 panels and most of my RV'g is in the desert without shade so never gave it much thought.


I will say, I too overthought the crap out of solar. Then pulled the plug and did it and it was so freakin' simple and effective.



My advice is GO FOR IT!

[rk06382]

Originally Posted by Deanm

-Please critique my first draft blue print
-Disclaimer -Not the awsum Photoshop image that I wish I could do . Will clarify as needed. My goal is to avoid starting the 4k Onan generator when boondocking as much as possible and this is my gateway solar project.
-Ive purchased 4 HQST 100w panels so far, waiting to pull the trigger on everything else pending opinions, ( very hard to do ha ha !! )
-Daily usage when boondocking = 60AH max / 110AH battery storage ( I already have 2-220ah 6v Full River AGMs in series with a Victron BMV 712 on RV tongue )
Thanks for any help

You need to have a circuit breaker on both sides of the MPPT.
This is how I did mine:

[Deanm]

Thanks for the replies !
-Yes, S/P to negate shading effect ( at least that's what the internet says )
-Inverter to power a 30" TV 35w, apple TV , Macbook pro 85w, maybe a few usb's. Possible a nutribullet if I can swing it, but nothing that heats or anything with a heavy draw.
-WHat do you'all think about an added MC4 just before the SCC for a PV disconnect?


I overthink like mad all the time ha ha !!!! thnx for the advice !

[Deanm]

Originally Posted by rk06382

You need to have a circuit breaker on both sides of the MPPT.
This is how I did mine:

Awsum ! What Brand/type are those breakers?

[boondocking]

They do look like this type of circuit breaker, which are used quite often in solar set ups.

[rk06382]

Originally Posted by Deanm

Awsum ! What Brand/type are those breakers?

Amazon: 50A Inline Circuit Breaker



The Circuit Breakers brand I purchased from Amazon is no longer free shipping. Go figure?

[hobienick]

Upstream of the SCC should have a breaker as already mentioned. Unless you foresee a common need to disconnect the SCC a fuse between it and the battery will suffice and save $$.

I really like Blue Seas products for mobile electrical applications. They are not inexpensive but are very well made. I used them on both of my sailboats, my popup, and now my Roo. They will have breakers, fuse blocks, terminal strips, etc. for anything you will run into.

[Bama Rambler]

If it were me, I'd up the gauge of all the wires except the #2 awg at least one size, Especially if you plan on adding more panels. It's pretty cheap to do it now as opposed to later.

[Dragonmaster]

Originally Posted by Bama Rambler

If it were me, I'd up the gauge of all the wires except the #2 awg at least one size, Especially if you plan on adding more panels. It's pretty cheap to do it now as opposed to later.

Agreed, min 8awg from the solar to the controller. If you are putting panels in series, why not purchase the cheaper 250w 36v panels in lieu of the 100w in series?

[ependydad]

Disclaimer: I have no usable knowledge on the subject- so I'm not saying it should or shouldn't. More just asking the question.

Does the 100amp fuse need to be on the other side of the bus bar, closer to the inverter?

[Deanm]

Thanks for the replies ! Just keeping the conversation going with my answers here. Not saying Im right ha ha !!

Originally Posted by Bama Rambler

If it were me, I'd up the gauge of all the wires except the #2 awg at least one size, Especially if you plan on adding more panels. It's pretty cheap to do it now as opposed to later.

I was just using this wire chart https://assets.bluesea.com/files/res...on_chartlg.jpg
A 50A SCC with a 60A breaker and wires <6' long ( 6AWG is good up 70A ), correct?

Originally Posted by Dragonmaster

Agreed, min 8awg from the solar to the controller. If you are putting panels in series, why not purchase the cheaper 250w 36v panels in lieu of the 100w in series?

I considered 8 AWG but There are 10AWG wires already installed ( "Wired for Solar" !! ha ha ) and it seemed logical to just use them. So before I drill another hole from the roof I was going to see if I had much voltage loss with the 10AWG since it would be the same amount of work. The Wire chart says Im good up to 30' with the 10A rating and currently with 400w array my max current is 11A. The run is prolly 20-23 feet. If I use the 20A rating on the chart 20 feet is max length. Are these reasonable assumtions?
Question on MC4 connectors and 8AWG. Do the standard MC4 connectors work with 8AWG? All of the crimping tools say they only work up to 10AWG ???

Ive already purchased and received 4 HQST 100w at $78 / panel. I figured they are light 16# , and the 2S/2P configuration is more conducive for battling shading on a RV roof.

Panels seem nice, and I when I tested them it was complete overcast , all registered ~18.8v open circuit

[Dragonmaster]

Originally Posted by Deanm

Thanks for the replies ! Just keeping the conversation going with my answers here. Not saying Im right ha ha !!


I was just using this wire chart https://assets.bluesea.com/files/res...on_chartlg.jpg
A 50A SCC with a 60A breaker and wires <6' long ( 6AWG is good up 70A ), correct?


I considered 8 AWG but There are 10AWG wires already installed ( "Wired for Solar" !! ha ha ) and it seemed logical to just use them. So before I drill another hole from the roof I was going to see if I had much voltage loss with the 10AWG since it would be the same amount of work. The Wire chart says Im good up to 30' with the 10A rating and currently with 400w array my max current is 11A. The run is prolly 20-23 feet. If I use the 20A rating on the chart 20 feet is max length. Are these reasonable assumtions?
Question on MC4 connectors and 8AWG. Do the standard MC4 connectors work with 8AWG? All of the crimping tools say they only work up to 10AWG ???

Ive already purchased and received 4 HQST 100w at $78 / panel. I figured they are light 16# , and the 2S/2P configuration is more conducive for battling shading on a RV roof.

Panels seem nice, and I when I tested them it was complete overcast , all registered ~18.8v open circuit

If the 10AWG is there use it if voltage drop is minimal. I have MC4 connectors on 8AWG no problem at the roof level, can't recall if they I ordered special as it was almost 6 years ago. Used ring terminals on my, breaker, bus bar and panel disconnects in the trailer for the 8 AWG and then upsized to #4AWG from the MPPT controller to the batteries.

[Bama Rambler]

I agree with the Master. I didn't realize the wiring was already in place. Since that's the case just use it. You can change it later if voltage drop becomes and issue.

[hobienick]

If you do decide to change the wire to larger gauge just use the current wires to pull the new ones through

[GoneSouth10]

Originally Posted by hobienick

If you do decide to change the wire to larger gauge just use the current wires to pull the new ones through

I had thought the same thing, but has anyone tried this - in a "non-RV" setting the cabling/wiring would probably have been secured/harnessed at various points along the run, but who knows in the RV world!?!? (I'm assuming that they had open access to the cable run, or at least some part of it, during construction, but maybe that's not always the case). Also, I guess I'm just assuming that if the cabling is secured/harnessed, it would be difficult if not impossible to use the existing wires to pull through the new wiring - but I'm open to learning if there is an technique that works . . .
Maybe the fact that the RV world doesn't care about securing their wiring is finally the bright side of all those "the assembly plant is a nightmare" comments!

[Deanm]

Originally Posted by hobienick

If you do decide to change the wire to larger gauge just use the current wires to pull the new ones through

Originally Posted by GoneSouth10

I had thought the same thing, but has anyone tried this - in a "non-RV" setting the cabling/wiring would probably have been secured/harnessed at various points along the run, but who knows in the RV world!?!? (I'm assuming that they had open access to the cable run, or at least some part of it, during construction, but maybe that's not always the case). Also, I guess I'm just assuming that if the cabling is secured/harnessed, it would be difficult if not impossible to use the existing wires to pull through the new wiring - but I'm open to learning if there is an technique that works . . .
Maybe the fact that the RV world doesn't care about securing their wiring is finally the bright side of all those "the assembly plant is a nightmare" comments!

One thing this project is doing is getting me familiar with my RV. Im new to all things RV,( I researched for a year and made my first RV purchase Jan 2019 ) Nothing is harnessed, secured, tightened down, or made the least bit organized ha ha !!!!

If I end up using 8AWG, Id just drill a new hole in the roof and take a much more direct route to the storage area where this solar circuit panel will go right behind the battery box on the tongue.