I'd like to use a LG 300w residential panel for my sprinter camper; advice?

[Abe Froman]

Is there any reason why I'd want multiple (at least 2) 100 watt 12v panels (flex or renology or grape) vs one residential panel?
I'd like to only deal with one set of mc4 connectors and not need a C box and all that extra stuff to secure on the roof vs. One panel and one penetration.
Total system costs seem to be less with a 60cell panel and A proper controller than multiple cheap 100w panels and controller. Batteries would be the same.


My research led me to the lg panels.
I can pick one up locally (no truck freight$) and around $350 to $400.
The specs:
Lg neon solar panel
Dimensions 64.57" x 39.37" x 1.38"
Weight 36.96 lbs

Watts (STC) 290 W
Max Power Voltage (VMPP) 31.8 V
Max Power Current (IMPP) 9.19 A
Open Circuit Voltage (VOC) 39.2 V
Short Circuit Current (ISC) 9.80 A
Max System Voltage DC 600 V

It weighs and costs less than three rigid 100 w panels.

Any recommendation for a user friendly charge controller than can drop the volts down? The blue sky stuff seems pretty good as far as price and features go.

Battery bank with be two 6v agm batteries to start.

Only draw to start will be an arb 50q and some led lights and USB charge ports.

I'd like to be able to build from this, but would really just like to get the fridge running independent of the vehicle charge system.

Vehicle is a sprinter with a SMB power pop-top rated at 150lbs for the electric lifting motor.

I only know what I have read about solar on RVs, so I have no firsthand experience and am open to advice good or bad.

 

[Haf-E]

It's what I would do. I've had two kyocera pv modules on my sprinter for 10 years no problem.

Only concern would be the strength of the frame - might want to add a cross piece on the back if there is any frame flex to prevent problems in high winds. Most modules require attachment at 25 and 75% points along the long edge - but additional attachment is worth considering on a vehicle application.

 

[rayra]

the large size solves as many issues as it creates, so I'd call that a wash. The deal killer for me would be the 32V output. I'd rather my vehicle panel(s) be 12V -native so I can wire it directly to my battery if necessary, say if the controller failed while I was out in the middle of nowhere.

 

[Joe917]

I am running 2x315watt panels on our truck. No added re-enforcing, mounted at 6 points per panel. The higher voltage is very helpful as it greatly reduces voltage drop. As for charge controller: Morningstar.
What I saved by going with the large capacity panels paid for the charge controller.

 

[LeishaShannon]

The LG Neons are great panels and will produce 10-30% more power per rated watt than standard "rv" panels. They're much better in low light conditions, early in the morning / late in the afternoon as they're a double sided cell that generates using light reflected from the rear. They also suffer less LID (light induced degradation) so they'll keep pumping out more power for longer than standard rv panels. We have 4 of the 300W on our roof and yesterday generated just over 6kWh in the middle of winter and in summer we can do close to 10kWh. Controller wise I like Victron MPPT mainly because they're programmable for any battery type you may use in the future.

If you can fit them on the roof, LG Neon or Sunpower X21 are miles ahead of RV stuff.

 

[228B]

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It weighs and costs less than three rigid 100 w panels.

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I may cost less, but three 100W panels (decent ones, @ $149. a pop) connected in series would net you a nominal 36V and with an MPPT controller, far more amperage (in this case +/- 25%). But max amps is just a number; there's more to charge profile for your batteries than amperage alone.
.
However, as an example, two 100W monocrystalline panels when connected in parallel to my Morningstar SunSaver MPPT 15L (you will need a bigger controller) send nearly 12 amps to the battery. When these two panels are connected in series (nominal 24V) they produce between 30 to 40 volts (depending on the panels' amp load) and the controller will send well over 12 amps to my single 100 amp-hour AGM battery. One of the benefits of an MPPT, or, Maximum Power Point (of the panels) Tracking controller algorithm is that more power is harvested... then used by the controller to charge and/or run accessory loads.

 

[Abe Froman]

Thanks for all the info.
Solar is pretty confusing with multiple approaches and solutions.
Looks like this simple charge controller will meet my needs with a 300w 60cell panel.
http://www.thesolarbiz.com/OutBack-...rge-Controller?sc=7&category=136404#gsc.tab=0

228B:I am still looking into the multiple 100w panel approach vs one big one.
wired in series does a shadow on one panel cause issue with the others?
What panels do you consider good quality?

 

[228B]

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I can only enthusiastically endorse Morningstar or Trimetric charge controllers. If I were to start from scratch today, I'd use all Bogart Engineering's Trimetric hardware; their meter (which I can still use and plan to install in the near future) and their new charge controller. These people have listened to mobile off-grid boondockers, done their testing, and produced what might be the best rec vehicle/small county cabin controller available anywhere).
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wired in series does a shadow on one panel cause issue with the others?
What panels do you consider good quality?

I take this stuff in it's worst-case scenario: a partially-shaded panel is worthless, and is effectively shut off for the duration. Wired in series? That is a very good question and since one panel's output effectively passes through the other(s) in the series' string... the outcome doesn't look good for any real output.
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I'm only a new consumer of solar, mind you, but from what I understand, the silicon "slices" that make up each cell within a photovoltaic panel are available from different quality grades of silicon billet, with monocrystalline being the "best". Renogy, Grape Solar, etc; any major supplier of off-grid (not grid-tie) panels will sell their version of a monocrystalline panel.
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[Edit:] LeishaShannon's recommended LG Neon PV panel bears looking into...

 

[4x4junkie]

228B:I am still looking into the multiple 100w panel approach vs one big one.
wired in series does a shadow on one panel cause issue with the others?

Pretty sure most panels nowadays have two or more shunt diodes within the junction box that are connected at the mid-point of the panel's circuit (my chinese UL Solar panels have these diodes anyway). This makes it so that if a panel is partially shaded (depending where it's shaded), only half the panel's output will be lost.

Keep in mind though, that if you do lose half the panel's output in a parallel setup, that entire panel will effectively be put offline because the remaining voltage will be well below that of your battery = no charge current. In a series circuit however, the voltage of 1½ panels is still well above your battery voltage, so with your MPPT charge controller, the system will have lost only 25% of it's capacity (not 50% as would be the case in a two-panel parallel setup).

So, IMO, if the opportunity is there (you have a MPPT controller), definitely wire them up in series. Additionally you won't have to use quite as heavy gauge wire between the panels & controller as well.

 

[228B]

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I sure like 4x4junkie's reply! a lot better than my worst-case scenario... lol. And, as noted in a prior post of mine, this is how I've connected my two panels. Thanks for the reply! junkie.
.

 

[4x4junkie]

No prob, Glad to help.

To be safe though, I'd say pop open the junction box on the rear of one of your panels and check just to be absolutely sure they do infact have the diodes (I'm mostly going on the assumption bigger-name panels would have them too since my chinese ones do). Without diodes, a shaded cell on one panel would instead take out the whole entire string of panels in series.

 

[228B]

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Yessir. One reason I liked your reply was that last month sometime I had already determined that the Renogy 100W monocrystalline PV panels do in fact have two "bypass" diodes in each panel box. Before ordering some MC4 connectors from Renogy so I could make some 10 ga. extension cables, I called them and got tech on the line, asking about panel diodes. I was able to score two spare diodes, just to have on hand should one ever fail. Now that I have them, Murphy says I'll never need them, see... but, hey; what can you do.

 

[LeishaShannon]

Using panels in series without bypass diodes is a neat way of destroying panels too.



Shade in the wrong spot can turn a cell into a heater

 

[Abe Froman]

http://www.solarpanelstore.com/sola...ems.rv-upgrade-series.160w-rv-kit.info.1.html

I have been re-thinking the large panel.
I used CAD (cardboard aided design) the space out different panel sizes and placement, and I think I can get this (160w) panel on my roof and then add either a fixed or movable flexible panel so I can retain roof usage and possibly have a panel that could be set in sun when van is camped in shade?
The big lg panel is pretty big.
I honestly don't even know if I need more than the 160 watts and a decent 12 agm battery.
Ideally, I get something set-up to use this summer and then explore additional needs, etc.
I'd hate to do something half assed, but hate to get all overkill on it too.
Thanks for all the responses.

 

[Bbasso]

that sounds like a lot of $ for that...

I keep hearing good things about Grape Solar.
How about this panel: http://www.homedepot.com/p/Grape-So...ystems-GS-S-160-Fab8/202959994#specifications
And a mid-range controller like: http://www.amazon.com/Sunforce-60032-Digital-Charge-Controller/dp/B000FIWKQE

then a few cables and wires to complete your system... ?