Spring Project Solar Install Momentum 21G

[howson]

acoleman43 -- instead of buying all new panels, why not just buy three more of the 165W panels you already have? 165*9=1485W That's a decent system. I assume, of course, that you've done the due diligence to ensure everything is going to fit on the roof. Review my lengthy thread on how I went through the decision process if need be--hopefully it helps. https://gdrvowners.com/forum/solar/1...n-2019-315rlts

What I'm suggesting is three strings of three panels and then put the three strings in parallel. As previously documented, three of the 165W panels in series gives a VMP of 50.31V. That's enough of a spread (IMO) between the 31V minimum previously calculated. Sell the 400W panels and you won't have to spend as much time on the couch.

The reason I keep harping on this is because of the previous post's question about putting all the proposed 24V panels in parallel. The VMP of the Newpowa panel is "only" 33.54V. If all of the panels were in parallel you'd have the exact same problem with very little "head room" between where the MPPT starts charging and where the panel likes to operate.

Some readers may be very confused at this point and I understand. If we could all gather around a monitor and watch in real time the actual power going to the battery with various configurations there'd be instant clarity on why having some range between the MPPT's starting voltage and the VMP is beneficial. Especially on marginal solar days where there's considerable overcast or in the winter with no ability to tilt and aim the panels at the low-in-sky sun.

Let me beat this point to death with the example of my system. The Renogy's Vmp is 17.7V. I wired two in series so they now should operate at 35.4V -- an excellent spread from my nominal battery voltage of 13.3V and MPPT starting voltage of 18.3V.

Below is an actual graph of my system's performance. You probably know by now that I have six two-panel strings (2 100W panels in series and then six of those strings in parallel). The dips in the middle were probably due to clouds passing over the camper. The key is the MPPT tried to keep the voltage at the Vmp of the panels. Wire panels in series and the target Vmp voltage of the MPPT increases.

I hope this helps...

[acoleman43]

acoleman43 -- instead of buying all new panels, why not just buy three more of the 165W panels you already have? 165*9=1485W That's a decent system. I assume, of course, that you've done the due diligence to ensure everything is going to fit on the roof. Review my lengthy thread on how I went through the decision process if need be--hopefully it helps. https://gdrvowners.com/forum/solar/1...n-2019-315rlts

What I'm suggesting is three strings of three panels and then put the three strings in parallel. As previously documented, three of the 165W panels in series gives a VMP of 50.31V. That's enough of a spread (IMO) between the 31V minimum previously calculated. Sell the 400W panels and you won't have to spend as much time on the couch.

The reason I keep harping on this is because of the previous post's question about putting all the proposed 24V panels in parallel. The VMP of the Newpowa panel is "only" 33.54V. If all of the panels were in parallel you'd have the exact same problem with very little "head room" between where the MPPT starts charging and where the panel likes to operate.

Some readers may be very confused at this point and I understand. If we could all gather around a monitor and watch in real time the actual power going to the battery with various configurations there'd be instant clarity on why having some range between the MPPT's starting voltage and the VMP is beneficial. Especially on marginal solar days where there's considerable overcast or in the winter with no ability to tilt and aim the panels at the low-in-sky sun.

Let me beat this point to death with the example of my system. The Renogy's Vmp is 17.7V. I wired two in series so they now should operate at 35.4V -- an excellent spread from my nominal battery voltage of 13.3V and MPPT starting voltage of 18.3V.

Below is an actual graph of my system's performance. You probably know by now that I have six two-panel strings (2 100W panels in series and then six of those strings in parallel). The dips in the middle were probably due to clouds passing over the camper. The key is the MPPT tried to keep the voltage at the Vmp of the panels. Wire panels in series and the target Vmp voltage of the MPPT increases.

I hope this helps...

Thanks Howard the graph is very helpful.

I could probably Squeeze 3 more 160W panels on the roof, but wouldn't have any room to walk. I need to limit to 6 total panels to keep the space my wife wants panel free (She's the one that does the roof/gutter/slideout cleaning).

The 210W Newpowa panels are about 15" longer than the 160W panels, but will work (barely). The Rich Solar 200W panels are only 10" longer than the 160W Newpowa panels which would give me a little extra space. But I've contacted Newpowa to see if they will accept the 160W panels as a return as they haven't even been unpackaged yet, and purchasing the 210W panels from them might be in my favor with a return.....plus I like Newpowa.

The reason I keep looking at 24V panels is because they have twice the voltage (and half the amperage) of similar 12V panels, and, it's becoming obvious, voltage is what I need. For example, the Newpowa 210W 12V panel Vmp is 16.77V and Imp is 12.48A. The 210W 24V panel Vmp is 33.54V (double the 12V panel) and Imp is 6.24A (half the 12V panel). I'm not concerned about the label "12V", or "24V" but like the 100% greater voltage of the 24V panels, and half the amperage reduces recommended wire size.

Based on your real life graph above, I think I'll get the 210W Newpowa 24V panels and wire pairs in series, then the 3 pairs in parallel giving me 3 panels pairs with Vmp of 67.08V and Imp of just 18.72A (making 8awg wiring work just fine). Based on what I am seeing and you are saying, I think this is what will perform best for me.

The root of my problem was looking at Voc instead of Vmp. With Voc being higher than Vmp I justified my selection of the 160W panels. Lesson learned....nobody make this same mistake

Again, thanks Howard for the info and making me spend more money

[howson]

acoleman43 -- the good news is the 150-100 MPPT should be fine with the two 210W panels in series. VOC will be 39.66 * 2 = ~79.32. That's less than the 150 rating of the MPPT. (Yea!) Garret (AMSolar) uses the equation (Total Wattage * .9 ) / battery voltage for the amperage, so that's (210*6) * .9 / 24 = 47A. This is also well below the 100A spec of the MPPT so all is good!

I hope you can send back the other panels.

Please remember to check the spec on the PV shutoff switch...I doubt the standard red ON/OFF switch is spec'd to 80V

Edited to show numbers with 2 panels in series not three! (Oops)

[Jlawles2]

Looking at you cabinet layout. Any reason to not put the batteries at floor level? Immediate thoughts are: decrease net COG of trailer by keeping weight low, and reduces the amount of bracing (again weight) needed to carry the batteries.

[acoleman43]

Looking at you cabinet layout. Any reason to not put the batteries at floor level? Immediate thoughts are: decrease net COG of trailer by keeping weight low, and reduces the amount of bracing (again weight) needed to carry the batteries.

Good question. What I don't show is a heating duct that runs through the back and a mess of wires that run up through the bottom of the floor. I had to keep the batteries almost 12" off the floor and the distributor/shunt as far forward as I can to avoid this.

Original plan was to have the batteries at the top for easy access from the closet floor in case I needed to repair or remove them. But I felt it was better to have access to the Lynx Distributor (batter bank busbar) in case a fuse blew. I am assuming a blown fuse is more likely than a blown battery.

[acoleman43]

acoleman43 -- the good news is the 150-100 MPPT should be fine with the two 210W panels in series. VOC will be 39.66 * 2 = ~79.32. That's less than the 150 rating of the MPPT. (Yea!) Garret (AMSolar) uses the equation (Total Wattage * .9 ) / battery voltage for the amperage, so that's (210*6) * .9 / 24 = 47A. This is also well below the 100A spec of the MPPT so all is good!

I hope you can send back the other panels.

Please remember to check the spec on the PV shutoff switch...I doubt the standard red ON/OFF switch is spec'd to 80V

Edited to show numbers with 2 panels in series not three! (Oops)

Thanks for the approval

I did find some 250V, 63A single pole circuit breakers for a 35mm DIN rail. Those SHOULD work and they were cheap.

Honestly I had a difficult time finding a suitable main shutoff switch. With a possible 500amps from the battery bank (4x125amp fuses), it was difficult to find something that wouldn't fry. I ended up with e Blu Sea heavy duty 600 amp switch. Those aren't cheap.

[acoleman43]

Update: Newpowa accepted the 160W panels as a return and will apply the difference to the 210W panels. That's a win. Great customer service.

I updated the preliminary drawing slightly (below) and started laying out the batteries and distributor/shunt. I'm hoping I have enough cable (especially the 4/0....that is expensive).

A few things I forgot: Straps to hold down batteries, main ground busbar, a couple power posts, cables to connect Cerbo GX to multiplus, MPPT chargers, GX Touch and Shunt.

We are off to the coast next week so the official teardown in about 2 or 3 weeks.



Laying out batteries and distributor/shunt. Wanting to fit two distributors and the shunt in a small space, but don't think it will work. Will have to separate them which means longer cables ($$)



batteries look good? Anybody smarter than me: what is acceptable cell voltage difference (acceptable delta)?

[Subfreq111]

acoleman43 I am just wrapping up a similar sized system on our 2020 21G. We went with a 12kwh unit from big battery, and a 48v renogy inverter/charger/solar controller/transfer switch unit in a box. 6 175w panels in series for a Voc of 144v, just under the 150 max. I aim to keep voltage as high as allowable to reduce voltage drop and wire size requirements. All ac power from the built in transfer switch on the Wfco passes through the renogy box and then back to the main breaker in the wfco. This allows us to charge the big battery with shore power or gen if solar is insufficient. Mounted the renogy remote switch in the bedroom. If you’re set on installing your own roof penetration up front, I would recommend doing it just inboard of the bathroom fan. I’m just using the Factory Jaboni port and coming up through the floor. Pull the inner tray to the shower skylight and a wire can be fished forward through the trusses to the ceiling of the storage area. We did this to add another 15amp circuit for a bidet. We just did it all this week so it’s all pretty fresh if you have any questions. Ps, removing the heater duct below the closet was a big help in feeding wires from the storage area to the wfco.

[acoleman43]

acoleman43 I am just wrapping up a similar sized system on our 2020 21G. We went with a 12kwh unit from big battery, and a 48v renogy inverter/charger/solar controller/transfer switch unit in a box. 6 175w panels in series for a Voc of 144v, just under the 150 max. I aim to keep voltage as high as allowable to reduce voltage drop and wire size requirements. All ac power from the built in transfer switch on the Wfco passes through the renogy box and then back to the main breaker in the wfco. This allows us to charge the big battery with shore power or gen if solar is insufficient. Mounted the renogy remote switch in the bedroom. If you’re set on installing your own roof penetration up front, I would recommend doing it just inboard of the bathroom fan. I’m just using the Factory Jaboni port and coming up through the floor. Pull the inner tray to the shower skylight and a wire can be fished forward through the trusses to the ceiling of the storage area. We did this to add another 15amp circuit for a bidet. We just did it all this week so it’s all pretty fresh if you have any questions. Ps, removing the heater duct below the closet was a big help in feeding wires from the storage area to the wfco.

Thanks! This is great. A couple questions:

-Can you provide a little more detail about how you ran your wiring from your panels? Where is the factory Jaboni junction box located on your trailer?
-When you removed the skylight inner tray, are the 10 awg wires from the solar panels visible?
-I'm a little confused about how you're using the factory Jaboni port and coming up through the floor. Can you explain that a little more?

Again, thanks. This is great!

[Subfreq111]

Thanks! This is great. A couple questions:

-Can you provide a little more detail about how you ran your wiring from your panels? Where is the factory Jaboni junction box located on your trailer?
-When you removed the skylight inner tray, are the 10 awg wires from the solar panels visible?
-I'm a little confused about how you're using the factory Jaboni port and coming up through the floor. Can you explain that a little more?

Again, thanks. This is great!

Sure, panels will go in on Sunday but here is the plan. Our camper has a small black box near the right rear corner of the roof. (Top left of picture below.) Removing the pop off black plastic cover revealed a male and female mc4 connector. From there, the wires lead to a bundle of wire under the trailer, right below the front right storage area. Lay on your back and look up under the front right corner and we have a 6” loop of bundled white wire, labeled “Solar Inv.” Since this is directly below the storage, I will drill and caulk a hole through the floor and connect directly to a switch and then the charge controller. Removing the skylight tray revealed no wires originally, it just provided access to fish wires forward, as all the roof above the storage is the front fiberglass cap of the trailer which I don’t think you would want to drill through. The bottom end of the fan also comes out easily, this just helps for attic access.

[Subfreq111]

Here’s where I found the other end of the wires.

[Country Campers]

Subfreq111

Are you sure that the connectors in the roof port are MC4?

If this is a Furrion port it should have the Furrion connectors that only will accept Furrion panels or connectors. If if is Furrion and truly MC4 then that is a real change that we are not aware of. Many here that have tried to use the Furrion port have found that MC4 does not connect and they have either removed the Furrion port or made a set of connectors that went from the Furrion to MC4.

Brian

[acoleman43]

Sure, panels will go in on Sunday but here is the plan. Our camper has a small black box near the right rear corner of the roof. (Top left of picture below.) Removing the pop off black plastic cover revealed a male and female mc4 connector. From there, the wires lead to a bundle of wire under the trailer, right below the front right storage area. Lay on your back and look up under the front right corner and we have a 6” loop of bundled white wire, labeled “Solar Inv.” Since this is directly below the storage, I will drill and caulk a hole through the floor and connect directly to a switch and then the charge controller. Removing the skylight tray revealed no wires originally, it just provided access to fish wires forward, as all the roof above the storage is the front fiberglass cap of the trailer which I don’t think you would want to drill through. The bottom end of the fan also comes out easily, this just helps for attic access.

Gotcha, thanks. My solar panel, MMPT charger and inverter were already installed so the wires are not in the same area as yours...but it makes sense.

I think I'm going to seal up the Jaboni box, then put a junction box next to the antenna. Fish the wires through the trusses into the front storage area. At the same time I'm going to run wires to the vent opening in the main room so I can install a fan and wires into the bedroom for a future fan. While on the roof I'm going to install a new antenna, and a soft start for the AC.

[Subfreq111]

Country Campers its definitely mc4, plugged a panel in today. Not furrion though, it’s Jaboni

[acoleman43]

It begins. Removal of front storage/bedroom closet area.

First step is to disconnect and remove the batteries. After I removed the 2 battery boxes, I found major corrosion between the boxes and the metal angles holding the battery boxes. A lot of water was found which resulted in the rusty mess on the concrete below the trailer tongue. Glad to have those removed and gone forever.




Front storage/bedroom closet Before: