Motorhome with LG Neon R 440W

[GlenC]

I'm looking at putting 4 LG440QAC-A6, 440W High Efficiency LG NeON® R Solar Panel ( https://www.lg.com/us/business/neon-r/lg-lg440qac-a6 ) with 66 Cells (6 x 11), Module Efficiency: 22.1%, Connector Type: MC4 on my motorhome. Also looking at 600Ah LiFePO4 batteries and Multiplus 3000VA. Most usage will be boondocking with A/C, refrigerator, lights, microwave, Vitamix, etc.

I assume the best configuration of charge controllers, for overall performance, is using 4 Victron SmartSolar MPPT 100/50, one for each panel as opposed to pairing panels in series or parallel and using 2 - 150/85 charge controllers.

 

[HRTKD]

Any time you want an opinion on components, you need to provide the full specifications or a link to the specifications, with the former being preferred. One reason you have received no responses is that you didn't provide enough information.

LG440QAC-A6

ELECTRICAL PROPERTIES (STC*)​

• • Model
  • TBD
  • Maximum Power (Pmax) [W]
  • 440
• • MPP Voltage (Vmpp) [V]
  • 41.4
  • MPP Current (Impp) [A]
  • 10.64
• • Open Circuit Voltage (Voc, 5%) [V]
  • 48.2
  • Short Circuit Current (Isc, 5%) [A]
  • 11.20
• • Module Efficiency [%]
  • 22.1
  • Power Tolerance [%]
  • 0 ~ +3

Before you order these panels, make sure you can actually fit them on your roof. Often, arranging panels on the roof of an RV is like playing Tetris. It can be very difficult unless you have a lot of wide open space. Also, don't forget to take into account the space needed for mounting brackets.

If you arranged the panels in a 2s2p configuration, I think you could get by with a single Victron 150/100 solar charge controller. You would still be over-paneled by 150 watts @ 12v, but that's nothing. There is the potential to leave about 33 amps of PV power on the table, but that's only if you achieve the very best optimal charging from the panels. You could step up to a bigger Victron solar charge controller to ensure you don't leave any power on the table.

You may be able to run the air conditioner for a while, but probably not all day. If you have a very efficient air conditioner like a mini-split then that's a different situation.

 

[GlenC]

Size and mounting is not an issue and the A/C is a mini-split 12K BTU.

From the info I have ( https://www.explorist.life/solar-charge-controller-calculator/ ), the 440W panels could produce ~100V/5.32A or 532W ea
1= 100V/5.32A ... 532W, 2S= 100V/10.64A ... 1064W, 2S2P= 100V/21.28V ... 2128W
My charge controller Options:

1. 4-100/20 ( 2/$632) @24V PV 580W ea. Charging 4x20A
2. 2-100/30 ( 2/$450) @24V PV 880W ea. Charging 2x30A
3. 2-100/50 ( 2/$650) @24V PV 1400W ea. Charging 2x50A
4. 1-150/70 ($540) @24V PV 2000W Charging 70A
5. 1- 150/85 ($697) @24V PV 2400W Charging 85A
6. 1-150/100 ($785) @24V PV 2900W Charging 100A

Max charging will be less some internal losses. Since these will be mounted flat on the roof of a motorhome, I may only see full output performance during mid day in summer months. However shading from trees is a big concern and this has me looking more at option 1

The photo is a similar installation

 

[HRTKD]

How do you figure that you're going to get 532 watts out of a 440 watt panel? Those panels are rated at 48.2 Voc.

 

[GlenC]

that 48.2V is at 77F/25C as the temp drops output increases.

 

[HRTKD]

You sure aren't going to see 100v out of a panel rated for 48Voc. That's just fantasy.

 

[wolfinstl]

I'm looking at using two of the same panels for a TruckCamper with an additional two to use freestanding so am watching this thread. I'd be interested to see where you ended up getting them and what controller you went with.

 

[GlenC]

I'm thinking of using 4 Victron 100/30 charge controllers to maximize panel efficiency. If one is shaded by a tree, the others can still charge 100%

 

[HRTKD]

I'm thinking of using 4 Victron 100/50 charge controllers to maximize panel efficiency. If one is shaded by a tree, the others can still charge 100%

If you're that worried about it then wire the panels in parallel. No need for four controllers.

 

[wolfinstl]

Won't the unshaded cells on these panels still produce power and the charge controller compensate? I thought panel and charge controller technology has advanced beyond a performance hit because some cells are shaded.

 

[HRTKD]

Won't the unshaded cells on these panels still produce power and the charge controller compensate? I thought panel and charge controller technology has advanced beyond a performance hit because some cells are shaded.

This is true, but only to an extent. I wired mine in series. I live in the Rocky Mountains and do mostly boondocking, which allows me to pick where the trailer is parked. So I can avoid shade fairly easily.

 

[GlenC]

AFAIK, with a single charge controller, it will only perform to the level of the lowest performing panel in the array. So if one panel is shaded and producing 30%, then the entire system is at 30%. Additionally, I'm seeing 4 - 100/30 is cheaper than a single 250/100 (as recommended by Victron calculator) I would be limited to 30A charging from each panel total 120A, however the 250/100 limits to 100A.

 

[HRTKD]

If you're that paranoid about shading, put two panels in parallel and wired into a single controller. You'll need a bigger controller to handle that potential 73 amps (880 watts / 12 volts). The Victron 150/70 is about the right size ($589 x 2). I see the Victron 100/30 sold for $221. The Victron 250/100 is $932. Four 100/30 would be $884.

Either way, it is unlikely that your panels will produce at the STC. You'll get a lower output. Assuming you did produce at STC, the 100/30 x 4 would leave 36 amps on the table. The 250/100 would leave 46 amps on the table. I'm not sure you would notice the missing 10 amps.

The cost for wiring and circuit breakers of four solar charge controllers would likely even out the cost and may make the 100/30 units MORE expensive than the 250/100. The panel configuration of the 250/100 would be 2s2p, which may get by with the same size wire as one of the 100/30 units. (I didn't run the numbers on the required wire gauge) I sure wouldn't want to run eight wires when I could get by with just two.

If shade is such a worry, consider deploying panels on the ground instead.

 

[eXodus]

If you're that worried about it then wire the panels in parallel. No need for four controllers.

Aside of not being the most economic solution, having one charge controller per panel is the way to go.

AFAIK, with a single charge controller, it will only perform to the level of the lowest performing panel in the array.

Very common in residential applications to have one microinverter per panel - so the next logical step is having one charge controller per panel.

It is currently not the most cost effective way of wiring a panel, but it gives you the ability to milk the last bit of efficiency out of each panel.
I had a setup like this in my VAN - 2x low end MPPT charge controllers for two panels.

For mobile solar where roof real estate is the limiting factor - this not a bad idea. I don't think you need to go High end like Victron when you are only doing one per panel.

One downside I see - every MPPT has a standby consumption. So read the datasheets - this is an optimization problem. How much you gain in efficiency vs what you loose in standby.

 

[GlenC]

One downside I see - every MPPT has a standby consumption. So read the datasheets - this is an optimization problem. How much you gain in efficiency vs what you loose in standby.

The way I see it is about 30W consumption per day for 4 MPPTs ...
On one 440W panel, assuming I average 300W for 6 hours, that's less than 2% and shade on one panel can do that in minutes, especially if it affects multiple panels.

Panels laying flat are not optimal and not knowing location and time of year for boondocking, I'm not sure how many watts to expect. Just getting as much as possible from the available space.

 

[eXodus]

The way I see it is about 30W consumption per day for 4 MPPTs ...

Watt(W) or Watt hours (WH) ?

Here begins the hunt for data - 30W * 24h would be 720wh - so you would need to produce almost 1kwh from solar just to satisfiers the standby need. A MPPT is always on.

If it's 30WH for 24hrs or 1 day that would be good.

Your 4 panels would be producing 300w * 6h *4 pieces = 7200wh per day.

 

[GlenC]

Watt(W) or Watt hours (WH) ?

Here begins the hunt for data - 30W * 24h would be 720wh - so you would need to produce almost 1kwh from solar just to satisfiers the standby need. A MPPT is always on.

If it's 30WH for 24hrs or 1 day that would be good.

Your 4 panels would be producing 300w * 6h *4 pieces = 7200wh per day.

Yes, the self consumption @12V is .03A ....
12V×0.03A=0.36W
.036W×4×24hr=34.56Wh

 

[eXodus]

Yes, the self consumption @12V is .03A ....
12V×0.03A=0.36W
.036W×4×24hr=34.56Wh

you did you research. One high efficiency low standby loss MPPT per panel should be a great solution.

Build it and report back how it goes!

 

[GlenC]

Started getting equipment....
Black Friday deal on a Multiplus 2 12/3000 with free Cerbo GX and Touch 50.

Yesterday I had a deal for 20% off so l ordered 4 -Victron SmartSolar MPPT 100/30, SmartShunt and 4- Linux Power In and a Multiplus 12/3000 for my Airstream.

I figured I can add the fuse holder bolts to the Lynx Power In and connect my 6 or 8 lithium batteries individually with fuses directly to the lynx bussbar only needing 6ga cables. 2 - Lynx will connect together providing 8 connections.
The other 2 Lynx (distribution) will provide connections to inverter, 12V system and the 4 MPPT. Might consider adding an Orion 30A (or two) for alternator charging.

 

[drifty325i]

I’m excited for you mate, i’ve gone for 1x 100/50 for my 4 330w trina’s. I’m still tossing if i’ll wire them in series parallel or just parallel. I can always play with the setup after in terms of the wiring.

So far from my limited testing (on an AC200P in the RV) there hasn’t been any major shading issues. The performance has been really good even in winter. I also prefer not to have a huge bunch of wires coming down from the roof if i’m honest (i’ve got two charge controllers one for the front flex panels)

However I’m sure your multiple charge controller setup is going to be the best in terms of pure performance

I was going to use larger panels like you but didn’t want the panels overhanging the side of the GMC and spoil the looks. Are you concerned about this? not say they will spoil them but they are about 8 inches wider than mine i think