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  • Spring Project Solar Install Momentum 21G

    It's finally time to start the intimidating solar install on out small Momentum 21G. All pieces have arrived, plans have been drawn, all that's left is to put it all together.

    By posting here I am obligated to finish. I'll try to detail as much as I can (good and bad) and hope it is helpful to somebody.

    This will be installed in multiple stages over about 2 months. I'll try to chronical the thought behind decisions, what worked, what didn't work and what I would change if I did it again.

    Some of this project has already been completed. Much more is yet to be completed. I'll start from the beginning. This will be a long read.

    Stage 1: Determine what I wanted from a solar system-or why I wanted a solar system on the trailer (maybe I don't even need one). After the great blackout of February 2021 in Texas, I knew I wanted something I could use if/when the "system broke". I didn't want to invest $60K + on a home system without understanding what I actually needed. I knew I didn't want to rely on a generator (needs fuel), so the idea was to build a good solar system on the trailer as "practice" and as a learning activity. This told me a large system was what I wanted.

    Stage 2: Energy audit. At this point I needed to know how much energy we consumed each day to determine the size of the battery bank, which will determine the size of the solar array. After calculating daily average usage, I came up with about 3000WH per day. That's about (3) 100AH lithium 12V batteries. But, you should have enough energy for 2 or 3 days in case the skies are overcast or you are under a tree. I decided on 3 days or 9000WH of storage. This came out to about (8) 100AH lithium 12V batteries (assuming 12.8V each battery). This also told me I could use about 1500W solar array. With this size system, many recommendations suggested a 24V system will save money.

    It was decided, a 10KWH battery bank, 1600W solar array and 24V system.

    Stage 3: Design system. Original plan was to have 1600W solar array consisting of (8) 200W panels. They will fit on the 21G roof, however it leaves no space for anything else. Listening to my wife's "recommendation", I scaled down the system to 960W with 6 smaller panels and added a secondary solar charge controller for up to 400W of additional suitcase panels if needed. We will try this out for a year. If it is not sufficient, I will switch out panels and increase to 1200W on roof with the additional 400W suitcase panels.

    Because I had already bought the 24V multiplus, I decided to stay with the 24V system. Overall I saved money going with the 24V system over a 12V system. Savings came from wiring and batteries. Still undecided if this was a good decision or if I should have gone to a 12V system.

    Stage 4: Make money and purchase equipment. Because we are a one income family and have 7 kids, this isn't as easy as I would have liked. In the end it took a little over a year to save up the money and purchase the equipment needed. Wife isn't overjoyed with the cost - ouch. This better impress her somehow.

    Stage 5: Build Batteries. Originally planned to purchase SOK batteries. Then I learned about Big Batteries and liked them...but they were never on stock. Watching Will Prowse one day and he reviewed some batteries from Signature Solar. 755 of the cost of both SOK and Big Battery. Sold. Well, every time I went to buy one of the 24V 200AH batteries, they were out of stock. It was frustrating. One day I checked thier site and noticed they started selling 8 cell 100AH 24V packs (no BMS, no case...just the cells strapped together with terminals welded to plates). They were on stock and so were the Overkill BMS's. I bought 4 of the packs and 4 BMS's from Overkill Solar. the way I had imagined the build, I really didn't need a case around the batteries, so this worked. Overall I saved almost $500 over purchasing (2) of the $1500 EG4 batteries and got a superior BMS ( in my opinion). Total cost of 10.2KWH of batteries was about $2800. If I would have gone with Battle Born, it would have been around $5800. SOK would have been about $4300 and Big Battery would have been about $4300 had they been in stock. One win for me.

    Stage 6: Rebuild the exterior storage/master closet area. This is my current stage and it is the most intimidating for me. I want it to look nice and be structurally sound to support the 300#-400# of equipment that will be installed. I have some preliminary designs drawn up that I think will work...I hope will work.

    Stage 7: Wiring. This is the second most intimidating stage for me. Mostly because I have a few challenges to address.

    Challenge 1: How to run wiring from the rear of the trailer (where solar array penetrate roof) to the front of the trailer (where solar charge controller will be)? Currently there is a 10awg wire from the rear of the trailer to the front area. I need at least 8awg and am thinking about 6awg for future considerations. 2 options: keep 10awg in place, use for panels at rear. Add another box for panels in center and front. OR: try to run another wire through entire attic area to front. I plant to drop the ceiling in the master bed anyway to help with other wiring so TBD.

    Challenge 2: How to run wiring from front storage area to control center in center of trailer. I think dropping the master ceiling will help a lot to accomplish this.

    Challenge 3: Where to place GX Touch screen. Master bedroom or control center? Any suggestions are appreciated here.

    Challenge 4: I am replacing the main panel with a 30/50 Amp split phase panel (without converter/charger). This gives me more DC circuits, and sets my up for phase 2 (If I ever get there) of converting to a split phase 50 amp trailer with additional 30 amp output for another trailer to connect).

    Stage 8: installing equipment. Tedious, careful work. Don't' want to blow up anything...already over budget as is. One challenge is heat dissipation for the equipment. I bought a bunch of 12V DC fans and some temp control boxes to automatically turn on/off the fans at preset temperatures. I do need to decide where the fans will be placed and do I need more vent holes on the out side of the trailer??

    Stage 9: setup. This is slightly intimidating as I am going with All Victron components. Proper setup seems to be a little complicated and involved. Need to take my time here. Again any suggestions are welcome.

    Stage 10: Enjoy. IT will be nice when it is complete


    Last edited by acoleman43; 03-26-2022, 02:54 PM.
    Allen

    2021 Momentum 21G

  • #2
    Stage 3 Solar diagram below. Any critiques are welcome

    Click image for larger version  Name:	Solar diagram.jpg Views:	0 Size:	74.6 KB ID:	80276
    Attached Files
    Allen

    2021 Momentum 21G

    Comment


    • #3
      Stage 5 Build batteries.


      Batteries as they came from Signature Solar (3 of 4 shown....ran out of $$ after 3. Had to wait another month for 4th).
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      BMS's came unboxing

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      Finished batteries. The (2) 8awg black wires go to negative busbar of Lynx distributor. The small circuit board attached to the BMS's are Bluetooth modules. I also have USB modules and a remote on/off switch if I want to attach those to the BMS as well.

      With the Bluetooth modules I can connect and configure each BMS using Bluetooth on my phone. I'm using Xiaoxiang app for this. This will be the only non-Victron component of the system.

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      Allen

      2021 Momentum 21G

      Comment


      • #4
        Stage 6: redesign and rebuild exterior storage/master closet area. Preliminary drawing of area below.

        We have a trip in 2 weeks so this stage is on hold until we get back. This is the next step, and it's raising my anxiety level slightly.


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        Allen

        2021 Momentum 21G

        Comment


        • #5
          Going to enjoy watching your build! I don't think I could use that much power if I tried!!! Good luck!
          2022 Momentum 21G with factory 300w solar and generator
          2022 F-350 Lariat 6.7 PSD
          x2 206ah SOK LiFePO4 batteries

          Comment


          • #6
            acoleman43

            A couple of things jump out at me while reviewing the schematic. (Can you post a higher resolution PDF, please?)

            1) install PV shutoffs between the panels and MPPT inputs. Trust me there will be times you'll want to remove PV from the MPPT inputs and it is required prior to battery connection or disconnection. I used an external circuit breaker for the MPPT-to-battery connection so I can turn it off as desired, too. (Consider external shutoff switches for both MPPTs, but especially the one that will be used for the external panels.)

            Example of the PV shutoff from my system diagram below (see my Comprehensive thread if you don't already have the full PDF--it has an attachment you can download).

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            2) The fuse for the Multiplus (145A?) is too small. The manual shows 300A is the right size for a 24V system. If you look at the specs on the Multiplus' datasheet, it is capable of a 6000W peak power (for a short duration) before it will shut down due to an overload. That's 250A of 24vDC . That's why the fuse is spec'd at 300A. The screenshot below is from the Multiplus' manual.

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            3) I think we discussed this in a different thread, but how exactly will the solar array be wired? I couldn't quite make it out from the description or drawing. The 24V system begs for more panels in series than what others might do since you'll need a much higher PV value for the MPPTs to kick in and start charging the batteries. If you can provide your layout in detail that would be helpful if you'd like feedback.

            4) I completely agree that the physical installation will take the most time. Took me a long time to figure out the best layout that fit in the space available. Like any project, double the time estimate (and costs, too).

            Probably more here to discuss but I've got to get back to a project I'm in the middle of working on. If you can upload that higher resolution PDF or JPG and the solar layout it will be helpful to review the schematic closer.

            Howard
            Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

            2017 Ford F-350 DRW, '19 315RLTSPlus

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            • #7
              howson thank you for your feedback. Appreciate any help I can get

              A couple of things jump out at me while reviewing the schematic. (Can you post a higher resolution PDF, please?)
              I tried multiple times but I keeps giving me a database error. :(

              1) install PV shutoffs between the panels and MPPT inputs. Trust me there will be times you'll want to remove PV from the MPPT inputs and it is required prior to battery connection or disconnection. I used an external circuit breaker for the MPPT-to-battery connection so I can turn it off as desired, too. (Consider external shutoff switches for both MPPTs, but especially the one that will be used for the external panels.)
              I agree. Forgot to add that to the diagram. I will have one for each solar charge controller (They are on the preliminary sketch...2 squares just below the solar charge controllers).

              2) The fuse for the Multiplus (145A?) is too small. The manual shows 300A is the right size for a 24V system. If you look at the specs on the Multiplus' datasheet, it is capable of a 6000W peak power (for a short duration) before it will shut down due to an overload. That's 250A of 24vDC . That's why the fuse is spec'd at 300A. The screenshot below is from the Multiplus' manual.
              Ahh.....yeah, I knew that. Forgot to make the change. Glad you caught it.

              3) I think we discussed this in a different thread, but how exactly will the solar array be wired? I couldn't quite make it out from the description or drawing. The 24V system begs for more panels in series than what others might do since you'll need a much higher PV value for the MPPTs to kick in and start charging the batteries. If you can provide your layout in detail that would be helpful if you'd like feedback.
              I'm going to have 3 pairs of series panels wired in parallel (did I say that right??). basically, each pair will be wired in series (to increase voltage for the multiplus), then the three pairs will be wired in parallel. In series each pair of Newpowa 160W panels Voc will be 39.66V. If that isn't enough, my backup plan is switch to 200W Rich solar 24V panels. Voc for those is 45.4V each. In that case I would like to connect all in parallel..

              4) I completely agree that the physical installation will take the most time. Took me a long time to figure out the best layout that fit in the space available. Like any project, double the time estimate (and costs, too).
              Yeah.....I'm starting to figure that one out........

              Again, I appreciate your input. Keep it coming.
              Allen

              2021 Momentum 21G

              Comment


              • #8
                I would disregard the factory solar roof port and create your own in an area that is more user friendly, you will want a larger wire from the roof to the controllers. You might be better off to have a combiner box above the cabinet where all of your goodies are located, then you can just drop the wire right down where it is needed.

                Instead of removing the ceiling panels why do you not go down under and remove the coroplast and pull your wires to the power panel from the bottom?

                This is surely going to be a well watched project, mine was way easier than this. You will do fine, take the time to do each task as it needs done and most important keep the wife happy, don't forget to get the kids to help, great experience for them as well.

                Brian
                Brian & Michelle
                2018 Reflection 29RS
                2022 Chevy 3500HD

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                • #9
                  Originally posted by Country Campers View Post
                  I would disregard the factory solar roof port and create your own in an area that is more user friendly, you will want a larger wire from the roof to the controllers. You might be better off to have a combiner box above the cabinet where all of your goodies are located, then you can just drop the wire right down where it is needed.
                  Thanks for the suggestion. That would save money on wiring as well.

                  Instead of removing the ceiling panels why do you not go down under and remove the coroplast and pull your wires to the power panel from the bottom?
                  I thought about that. But I think the gray tank is in the way. I want to re-do some of the ceiling anyway...some things about it really bug me.

                  This is surely going to be a well watched project
                  That makes me a little nervous. I was hesitant to post about it. Thanks for the encouragement!



                  Allen

                  2021 Momentum 21G

                  Comment


                  • #10
                    Originally posted by acoleman43 View Post
                    I tried multiple times but I keeps giving me a database error. :(
                    Sent you a PM.

                    Originally posted by acoleman43 View Post
                    ...my backup plan is switch to 200W Rich solar 24V panels. Voc for those is 45.4V each.
                    For clarity as this thread will probably be read by many members, the only time a "24V" (or 12V or 48V for that matter) panel is needed is when using a PWM controller with a corresponding battery voltage. In other words, a "12V" panel must be matched with a 12V system that has a 12V PWM controller. Same logic for 24V and 48V.

                    The nominal panel voltage is NOT a concern when using an MPPT. With an MPPT make sure none of the three criteria are exceeded (Voltage, Amperage, and total Wattage) and it will be fine--use whatever panels are best. (That's why mine are wired as they are in my system. Couldn't have that panel configuration with a PWM controller.)

                    Finally, going over and over and over the plan and verifying what you're installing is a really good idea IMO. Hopefully Will won't mind me quoting from his book as I think what he's saying here is exactly what I'm trying to convey:

                    So what I like to say is that if you have a 100 watt solar panel on your roof, you only have 50 watts of usable power. This only applies if you have a properly designed system. If you use cheap parts, small wires, or have bad connections, you will not have much power at all. I would not be surprised to see a 100 watt panel producing only 20 watts on a badly designed system. No matter how perfect your math is in planning your system, you will always have losses and you will need to create a system that is slightly larger than what you need. When you design a system, do it right from the beginning and you will save yourself from months of frustration and problems. -Will Prowse from his book Mobile Power Made Easy!

                    Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                    2017 Ford F-350 DRW, '19 315RLTSPlus

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                    • #11
                      Attached is a PDF with a higher resolution for those who want to do a review.

                      Attached Files
                      Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                      2017 Ford F-350 DRW, '19 315RLTSPlus

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                      • #12
                        acoleman43 -- a couple of more quick thoughts this morning.

                        1) Consider inserting a hard-wired EMS between shore power and the transfer switch. The following is from Progressive Industries FAQ page on their website:

                        Q: Should a Hardwired EMS be installed before or after the transfer switch?

                        A: A hardwired EMS should be installed prior to the transfer switch. The reason for this is most RV generators already have built-in voltage and frequency protection. If the EMS is installed after the transfer switch, this leaves the transfer switch vulnerable to power problems.

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                        2) The smaller MPPT is a BlueSolar or is that just an errant picture? I'd want the bluetooth dongle to can see how the panels are performing and allow "fine tune positioning" of the portable panels. Also, I don't see that small MPPT tied into the Cerbo (no comm cable)?

                        3) What junction box are you using with the solar panels-to-MPPT? If you don't have one selected yet, consider AMSolar's "Roof C-Box". https://amsolar.com/rv-combiner-box/20-roof



                        4) The 8 AWG from where the panels combine to the MPPT -- suggest increasing the wire size. You don't want to lose PV here (solar power). Very easy to induce losses even with the relatively small resistance difference from 8 to 2 AWG wire.


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                        Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                        2017 Ford F-350 DRW, '19 315RLTSPlus

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                        • #13
                          acoleman43

                          Hope this is not overwhelming...but a few concerns about the solar setup.

                          Is this the panel being used? https://www.newpowa.com/products/160...2v-solar-panel

                          If so, below are the specs. What I'd like to discuss is the VMP and VOC. (VMP is where the MPPT will operate. VOC is the maximum "open" voltage of the panel.)

                          Click image for larger version  Name:	160W specs.JPG Views:	0 Size:	59.9 KB ID:	80335

                          I need to caveat here that what is written below and shown in the video is to the best of my knowledge with what I know as of today. Solar is an incredibly complex topic--I'm still learning and make no claim to being "all knowing". Please--if a reader catches something that's incorrect below set me straight.

                          From an earlier post the plan is to wire two of the panels in series (effectively becoming a 320W panel). The series configuration doubles VMP and VOC, so 33.54v and 39.66v. This is a fine setup for a 12V battery system, but I'm not sure about a 24V system. Key point to consider: an MPPT will operate at the VMP of the panels.

                          The Battle Born "12V" batteries I use are, as I type this, at 13.3V (86% State of Charge, or SOC). Assuming a "24V" system is double, that would be 26.6V.

                          So now consider a few numbers. I'm going to drop decimal points to make this easier to read. The VMP is 33v, the batteries are at 26. The MPPT will not start charging the batteries until the input is 5V above the battery voltage, so that's 31v! The panels will have to be operating at near peak proficiency to do anything to charge the batteries since the "window" is only 31-33v.

                          For your setup, consider 2 strings of three panels in series and then those two strings in parallel. What that does is raise the VMP to 50.31, so now there is a much wider operating range as the MPPT will start charging at 31V (earlier and later in the day).

                          Below is a quick video showing an example of what I'm trying to type out using my system. Note when I say "2 amps" it really is only .2 amps. (Sorry the SD quality makes the numbers on the video hard to read.)



                          But...there's no free lunch here. Putting three panels in series raises the VOC to almost 60V. Double-check the shutoff switch's specs to ensure it is rated for 60V. Having the panels in series also increases the loss when one of the panels is hit by shade.

                          The same VMP issue will apply to the 400W portable panel wiring configuration which is not discussed in the thread (yet).
                          Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

                          2017 Ford F-350 DRW, '19 315RLTSPlus

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                          • #14
                            howson Thanks for taking time to look at this. Glad to get this feedback before install than after install.

                            1) Consider inserting a hard-wired EMS between shore power and the transfer switch. The following is from Progressive Industries FAQ page on their website:
                            I thought about that and wanted to do it, but I don't think that is in the budget now...why?? Se below :(

                            2) The smaller MPPT is a BlueSolar or is that just an errant picture? I'd want the bluetooth dongle to can see how the panels are performing and allow "fine tune positioning" of the portable panels. Also, I don't see that small MPPT tied into the Cerbo (no comm cable)?
                            It's the BlueSolar. It does have the Ve.Direct connection, Does that not connect to the Cerbo GX?

                            3) What junction box are you using with the solar panels-to-MPPT? If you don't have one selected yet, consider AMSolar's "Roof C-Box". https://amsolar.com/rv-combiner-box/20-roof
                            That is the junction box I will be using. I stole the idea from your install

                            4) The 8 AWG from where the panels combine to the MPPT -- suggest increasing the wire size. You don't want to lose PV here (solar power). Very easy to induce losses even with the relatively small resistance difference from 8 to 2 AWG wire.
                            I think 8awg should work...particularly now that I have made changes (below). Wire length from junction box to MPPT will be about 12' to 15'.

                            Is this the panel being used? https://www.newpowa.com/products/160...2v-solar-panel

                            If so, below are the specs. What I'd like to discuss is the VMP and VOC. (VMP is where the MPPT will operate. VOC is the maximum "open" voltage of the panel.)
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                            The VMP is 33v, the batteries are at 26. The MPPT will not start charging the batteries until the input is 5V above the battery voltage, so that's 31v! The panels will have to be operating at near peak proficiency to do anything to charge the batteries since the "window" is only 31-33v.
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                            Sigh....Yeah, I think you're right. I also think I'm sleeping on the couch for a few months. Looks like a panel change needs to happen. With the 2 panels below in mind, which method would you recommend? Wiring all 6 panels in parallel, or wiring panel pairs in series and the 3 pairs in parallel?

                            RIch solar

                            Newpowa

                            The same VMP issue will apply to the 400W portable panel wiring configuration which is not discussed in the thread (yet).
                            Yet to be determined. I was thinking about putting a piano hinge on a couple of the Newpowa 60W 24V panels in series to have a 120W panel to create a "suitcase". Rig up a system to hold them up. They are small and relatively cheap. A few of those might work out.


                            Lesson learned: My first instincts were to go with the larger 24V panels. But I thought I'd save some money and go the "cheap" route. Bottom line, I now have some panels I won't be using and will have to spend more money for correct panels. Don't take cheap shortcuts.




                            Allen

                            2021 Momentum 21G

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                            • #15
                              acoleman43 -- I hope you don't mind if I re-emphasize you're NOT limited to panels that are identified as "24V". This is only important (critical, actually) when using a PWM controller. You can choose practically any panel with an MPPT.

                              I only repeat stating this because when I opened both links to the panels in the previous post both showed they were "24V" panels. If you are limiting your choices based on that criteria there's no reason for it. I can elaborate further if need be...
                              Last edited by howson; 03-27-2022, 07:29 PM.
                              Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

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