I am putting together a 3000 watt system for a small RV. Looking to purchase the EG4 3kw along with EG Lifepowered 4 rack battery 48 v 100 amp hour. I will probably just place the solar panels outside and not worry about attaching to the roof. The number and type of solar panels is pretty overwhelming, any recommendations. Live in the Southern USA. The diysolar site provides lots of recommendations, but not sure how to down select.
Good solar panels for RV
- Thread starter gman1958
- Start date
sunshine_eggo
Victron's little biatch
Good. 3000W on a "small RV" roof is going to be tricky unless you have no roof protrusions or intend to rack above everything.
Need more info. Is this a one time deployment onto a ground mount? Are you going to transport the panels to and fro?
Hybrid
The RV is parked on my land for now so I am thinking I can put a permeant structure, but I would like also like to have a portable solar array I can put in my truck when I pull the RV to a camp ground. As I understand it the EG has a minimum voltage requirement from the solar array to operate.
sunshine_eggo
Victron's little biatch
Hybrid
Yep, and a maximum PV input current it can use.
the 120V minimum is Vmp, not Voc, and you need to allow for some margin due to panel heating, i.e., when panels are heated in the sun even in mild ambien conditions, their voltages drop about 8%, so you'll want to shoot for a minimum of 140Vmp on the array.
The 18A limit is the maximum the MPPT can draw from the array, so putting parallel strings on the MPPT can be limiting.
Something else to consider - HV PV input isn't great for RV rooftop due to the high voltage requirement and pervasive partial panel shading due to roof protrusions. Shading/partial shading can decimate PV production. Shading even a single cell of a typical 60 or 72 cell panel will cut production by 33%. Shading a single row of cells with the panel in portrait orientation will take production to 0%.
This unit:
Growatt 3kW Stackable Off-Grid Inverter | SPF 3000TL LVM-48P
The Growatt 48V 3kW 150VDC Stackable Off-Grid Inverter delivers efficient and scalable power for off-grid systems, ensuring reliable energy independence and versatility. Available now at Signature Solar.
signaturesolar.com
Has a 145Voc limit and only needs about 66Vmp to be able to charge a 48V battery, but it's also limited to 145Voc. This means you're limited to 2S 24V panels (45Voc each) or 3S 60 cell panels (36Voc); however you can parallel the crap out of them as the only real limit is the 80A MPPT output rating - generally speaking, when you don't have a published limit, you use that one.
Your proposed hybrid config would maximize RV-only PV performance with the Growatt as you could place fewers panels in series and more in parallel to address partial shading performance.
When combining the two arrays, you need to match the array Vmp within about 10% (closer is better) to ensure they will perform well with each other.
While not a big fan of Renogy, they do make a high performance panel for shaded conditions:
Renogy 200W ShadowFlux™ Anti-Shading N-Type Solar Panel
The Renogy 200W ShadowFlux Solar Panel is a revolutionary off-grid power solution. It is 7% smaller and 10% lighter than traditional rigid solar panels. Featuring N-Type solar cells and 16BB technology.
www.renogy.com
They appear to perform as though they have a bypass diode on each cell such that the % shaded correlates to the % reduction in performance.
They are essentially equivalent to 60 cell panels, and 3SXP would work nicely on your RV rooftop.
You could the build a 3SXP ground array of 60 cells panels and parallel it to the growatt PV input with the rooftop array and perform well.
3SXP means 3 panels in series with X strings in parallel. 6 panels would be 2 strings of 3 in series in parallel, or 3S2P.
To accomplish the same on the EG4, you would need both arrays to have a Imp of < 10A, and they would have to be the same Vmp. This may be very limiting to the ground array.
For a portable array, fixed frame panels are heavy. A typical 300W panel is going to be around 50#. While heavy, they may not be heavy enough to stay put in windy conditions. Unless you plan to spend long periods of time in a location, a big "portable" array is something of a headache.
For maximum portability, lightweight and ability to stake into the ground, lightweight flexible panels mounted in PVC frames might be more practical:
I've probably given you enough input to confuse you.
@chrisski has a 5th wheel with rooftop PV, and he deploys significant supplemental ground arrays. He might have some suggestions.
chrisski
Solar Boondocker
My build is in my signature block. Also run a 3 kW inverter which I push to 2 kW for hours.
I like the portable array and makes so much more power throughout the day than a roof array, but there are limits mostly because of winds blowing them away and how much you trust your neighbors.
These are the ground mount panels I deploy:
I can not make a quality panel cheaper than lion energy sells them for.. it’s basically two 50 watt panels hinged together with two spring locks to hold shut and metal foldable legs. The last few I bought came with a case to carry. I store them in the box they came in.
I deploy 9 of these. They withstand minor winds OK, which a flexible panel with PVC legs won’t. These lion energy panels even though being 25 lbs each, will still blow away in strong winds.
Winds are an issue as most places I stay at least part of the year will come out of nowhere and gust to 15 knots and above.
I have found no practical way of dealing with winds except to lay the panels flat, and then when winds get strong enough, put them away.
I also put the panels away each night, and not so much for them being stolen about I’ve had to walk a bit to collect one the wind blew away and then rivet it back together.
I use 9 of these things, and they take the back seat of my pickup when I drive.
I’ve got lots of good suggestions that may work to secure the panels if you have one or two panels, but with a larger array to power a 3 kW inverter, filling 18 sandbags with hard packed dirt for a three day trip just not worth it. Same thing with driving anchors.
I like the portable array and makes so much more power throughout the day than a roof array, but there are limits mostly because of winds blowing them away and how much you trust your neighbors.
These are the ground mount panels I deploy:
I can not make a quality panel cheaper than lion energy sells them for.. it’s basically two 50 watt panels hinged together with two spring locks to hold shut and metal foldable legs. The last few I bought came with a case to carry. I store them in the box they came in.
I deploy 9 of these. They withstand minor winds OK, which a flexible panel with PVC legs won’t. These lion energy panels even though being 25 lbs each, will still blow away in strong winds.
Winds are an issue as most places I stay at least part of the year will come out of nowhere and gust to 15 knots and above.
I have found no practical way of dealing with winds except to lay the panels flat, and then when winds get strong enough, put them away.
I also put the panels away each night, and not so much for them being stolen about I’ve had to walk a bit to collect one the wind blew away and then rivet it back together.
I use 9 of these things, and they take the back seat of my pickup when I drive.
I’ve got lots of good suggestions that may work to secure the panels if you have one or two panels, but with a larger array to power a 3 kW inverter, filling 18 sandbags with hard packed dirt for a three day trip just not worth it. Same thing with driving anchors.
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Just saw some HT panels for sale nearby on FB specs "550 watt solar panel. Max 688 watts with bifacial gain. Dimensions are 89. 724 x 44.645 x 1.377 inches" $200 a piece They will be too big to load in truck but I could possibly use these on a permeant structure.
Is this because you don't think I will get enough solar on the roof to drive the EG4 or growatt. Still in the design phase. Also do you run shore power directly int the EG4, will these systems work as a transfer switch between the grid and solar?
Good stuff, thanks for the detailed response. Do you hook the Growatt or EG4 directly to shore power. Will these units act as a transfer switch for grid power.View attachment 293221
Yep, and a maximum PV input current it can use.
the 120V minimum is Vmp, not Voc, and you need to allow for some margin due to panel heating, i.e., when panels are heated in the sun even in mild ambien conditions, their voltages drop about 8%, so you'll want to shoot for a minimum of 140Vmp on the array.
The 18A limit is the maximum the MPPT can draw from the array, so putting parallel strings on the MPPT can be limiting.
Something else to consider - HV PV input isn't great for RV rooftop due to the high voltage requirement and pervasive partial panel shading due to roof protrusions. Shading/partial shading can decimate PV production. Shading even a single cell of a typical 60 or 72 cell panel will cut production by 33%. Shading a single row of cells with the panel in portrait orientation will take production to 0%.
This unit:
Growatt 3kW Stackable Off-Grid Inverter | SPF 3000TL LVM-48P
The Growatt 48V 3kW 150VDC Stackable Off-Grid Inverter delivers efficient and scalable power for off-grid systems, ensuring reliable energy independence and versatility. Available now at Signature Solar.
Has a 145Voc limit and only needs about 66Vmp to be able to charge a 48V battery, but it's also limited to 145Voc. This means you're limited to 2S 24V panels (45Voc each) or 3S 60 cell panels (36Voc); however you can parallel the crap out of them as the only real limit is the 80A MPPT output rating - generally speaking, when you don't have a published limit, you use that one.
View attachment 293225
Your proposed hybrid config would maximize RV-only PV performance with the Growatt as you could place fewers panels in series and more in parallel to address partial shading performance.
When combining the two arrays, you need to match the array Vmp within about 10% (closer is better) to ensure they will perform well with each other.
While not a big fan of Renogy, they do make a high performance panel for shaded conditions:
Renogy 200W ShadowFlux™ Anti-Shading N-Type Solar Panel
The Renogy 200W ShadowFlux Solar Panel is a revolutionary off-grid power solution. It is 7% smaller and 10% lighter than traditional rigid solar panels. Featuring N-Type solar cells and 16BB technology.
They appear to perform as though they have a bypass diode on each cell such that the % shaded correlates to the % reduction in performance.
They are essentially equivalent to 60 cell panels, and 3SXP would work nicely on your RV rooftop.
You could the build a 3SXP ground array of 60 cells panels and parallel it to the growatt PV input with the rooftop array and perform well.
3SXP means 3 panels in series with X strings in parallel. 6 panels would be 2 strings of 3 in series in parallel, or 3S2P.
To accomplish the same on the EG4, you would need both arrays to have a Imp of < 10A, and they would have to be the same Vmp. This may be very limiting to the ground array.
For a portable array, fixed frame panels are heavy. A typical 300W panel is going to be around 50#. While heavy, they may not be heavy enough to stay put in windy conditions. Unless you plan to spend long periods of time in a location, a big "portable" array is something of a headache.
For maximum portability, lightweight and ability to stake into the ground, lightweight flexible panels mounted in PVC frames might be more practical:
I've probably given you enough input to confuse you.
@chrisski has a 5th wheel with rooftop PV, and he deploys significant supplemental ground arrays. He might have some suggestions.
sunshine_eggo
Victron's little biatch
They both have AC chargers. Both can be configured as a "UPS" passing through grid while keeping the batteries topped off, or they can use grid as backup.
What state are you in? Do you have neighbors to deal with?
Mississippi. No Neighbors.
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