DIY solar installation

[Ivan K]

5 hours ago, W7BE_Bob said:

Voc increases with decreasing temperature. My panels are about 8% higher at 32F. .

 

 

 

Bob, is it 8% over the rated Voc? Do you know at what temp the panels supposed to be tested or is there no standard?

[W7BE_Bob]

Yes, as the temperature drops Voc increases, check the temperature coefficient values for the panel. Standard Test Condition (STC)  is 25C or 77F. 

The Monrningstar string calculator will do the math. You can select a panel or enter yours, tempeature etc. You must use one of their controllers but that doesn't change the panel output values.

 

[Ivan K]

Thanks for the info, Bob.

[waterskier_1]

23 hours ago, W7BE_Bob said:

Rick - Some Comments

Voc increases with decreasing temperature. My panels are about 8% higher at 32F. A controller with a 100V limit would not be wise for your example of 4 panels in series. I agree that output voltage increases with a decrease in temperature, but I have never disconnected my panels in freezing weather and connected a high impedance voltmeter to see how much.  I'll take you word for the 8% (see high) increase.  But, we must remember that Voc is open circuit - that means no load - no current being drawn from the panel.  As soon as a load is connected, the voltage decreases as current increases, so it is highly unlikely that a Voc condition would ever exist in real life.  Second, Voc is the maximum Voltage that could ever possibly exist in any circumstances.  That would mean a clear sky, with the sun at 90 degrees perpendicular to the face of the panel.  and that would only occur for seconds, unless you had the panel on a tracking mount.  I think the 5% safety factor I used is sufficient. If you don't think so, then purchase a controller with a higher Voc rating.  

 For bulk and abosrb charging Imp is used. I concur.

The controller may default to Isc for absorb charging. I'm not sure how controllers default to a input voltage.  They do not control the input voltage (other than what might occur if you exceed the max). I brought up Isc only as the worst case current condition, not that I would ever expect to see it, because at Isc, the voltage would be zero (theoretically)

Your text is referring to bypass diodes not blocking diodes. You are correct.  I used the wrong word.

All controllers prevent panel drain at night which was the purpose of blocking diodes. I though the diodes played a part in shadowing one panel when in series.  It's been a while since I researched it.  I remember that I was going to purchase a bunch of diodes and then called Grape (the manufacturer I used for panels on my old coach) and they were the ones that told me all manufactures built them into their panels for a long time. 

Lots of good information in your post.  Thank you.

My 3 series panels have 62' (includes panel pigtails) of 10ga UV wiring. On my current coach, I suspect my runs are about the same.  I didn't measure them, other than to use a 100' run of UV wire that I cut in half and ran from the pigtails to the controller.  It wasn't a full 50 foot, so I used the cutoff to extend one of the pigtails since I was wiring in series and the ending panel was further away.  I used 10 gauge also, but that run is only series panels, so max current would never exceed 10 Amps.

Wiring is held in place with dabs of Dicor. I did the same.

Monacos inside cabinet panels are cosmetic, connected with brads and glue. This comment threw me for a loop.  It wasn't until I was responding that I realized that we changed the subject for solar panels to wood cabinet panels.  LOL  I mounted mine on the side panel of a bay.  I didn't analyze the construction, but it seems more than rigid and sturdy enough for two solar controllers. 

 I removed some to run the vertical solar wires and reattached with some screws - Out of sight. Again, I missed the context.  I thought you were talking about the basement bay separation panels.  I did not need to do that, since I had a PVC pipe from the roof to the bay.  I can't take credit for that.  The PO did that when he installed the first 1000 Watts Solar.  He had the foresight to not only use a larger than necessary pipes so I had room for more wires, but he even left a pull string to tie onto to pull the new wires through the pipe.  

 The wires got to a A/C 240V disconnect switch and then the controller. I used 150 VDC Circuit Breakers in a small breaker box (One 20 Amp for the PVA to the controller and one 60 Amp from the controller to the batteries). I read that AC breakers are not acceptable for solar, but I didn't read far enough to find out why.  The cost difference was insignificant so I selected DC breakers.

The controller has a short run of 4ga wire to the inverter which has a long run of 4/O wire to the batteries another poor electrical choice by Monaco. Mine is similar. 

 

 

 

 

[waterskier_1]

22 hours ago, Jim McGarvie said:

22 hours ago, Jim McGarvie said:

 

 

22 hours ago, Jim McGarvie said:

I would agree. But I wasn't planning on doing that; I was planning on two sets of two, series/parallel. Unless my calculations are wrong the four 200W panels wired that way would only be 20A. Even if I add another parallel string of two in series, that would be only 30A. Right?  - That is correct.

22 hours ago, Jim McGarvie said:

The top controller on my list (so far; I am still open to suggestions) is the Epever Tracer 6415AN, a 60A controller with a max input of 138V, so that would easily run 4 or 5 in series.  I am not familiar with that specific controller, but it looks like all you need is covered.  I'm not sure how much the "add on's" like remote meter, and if you want historical info, and maybe advanced setup features, you'll need Bluetooth or WiFi module.  But that is pretty much true with any advanced controller.  The one you reference is set up for Lithium batteries, but says it has custom parameters too so that is good.

Sounds like you have most of this sorted.  I used Grape Solar Panels on my old Dynasty, and the tilt-able ones I installed on my Exec.  The primary driver for those was Home Depot sells them with free shipping to the store. I found that shipping is a major cost, up to 50% of the price of the panel, depending on where you buy.  Many wanted to wood crate and freight ship the panels, which made their quite reasonable panels much more expensive in the end.  

 Looking forward to Quartzsite, as is Dad.

 

 

[Jim McGarvie]

5 hours ago, waterskier_1 said:

Sounds like you have most of this sorted.  I used Grape Solar Panels on my old Dynasty, and the tilt-able ones I installed on my Exec.  The primary driver for those was Home Depot sells them with free shipping to the store. I found that shipping is a major cost, up to 50% of the price of the panel, depending on where you buy.  Many wanted to wood crate and freight ship the panels, which made their quite reasonable panels much more expensive in the end.  

You told me at Quartzsite about the solar panels from Home Depot, but I forgot about it. Thanks for mentioning it again. I just ordered four Grape 200W panels for pick up at our local store, and saved a bunch of money.

[jreich888]

On 8/24/2020 at 3:40 PM, Jim McGarvie said:

You told me at Quartzsite about the solar panels from Home Depot, but I forgot about it. Thanks for mentioning it again. I just ordered four Grape 200W panels for pick up at our local store, and saved a bunch of money.

Sorry to resurrect an old thread, but can you share more about the cost and deal you've got?  I look online and they're similar prices, and don't actually list a 200W panel (and the pickup price is about the same).  Is this a deal from one of the in-store solar guys?

[wamcneil]

Grape solar panels are marketed as 190w. I bought 4 last year, but mine are 4-bussbar and were marketed as 180w at that time. From the pictures looks like they've gone to 5-bussbar, but it's not stated in the datasheet. Drop-shipped from manufacturer and packing was OK. Slight damage in shipment and 2 of the panel corners were dinged, but not bad enough to return them. The nice thing about HD is if you don't like them or if delivered damaged you can just return to a store.

https://www.homedepot.com/p/Grape-Solar-190-Watt-Monocrystalline-PV-Solar-Panel-for-Cabins-RV-s-and-Back-Up-Power-Systems-GS-STAR-190W-US/313629211?mtc=Shopping-VF-F_D27E-G-D27E-27_31_CONTROL-MULTI-NA-Feed-PLA-NA-NA-CONTROL_OtherControl&cm_mmc=Shopping-VF-F_D27E-G-D27E-27_31_CONTROL-MULTI-NA-Feed-PLA-NA-NA-CONTROL_OtherControl-71700000053528212-58700005127833923-92700048704113429&gclid=Cj0KCQjwv7L6BRDxARIsAGj-34rH5YnCGpPxEu3P1I1VKYEg2G5sE2sqt0-y716kcQaH_csTiehLDecaAnstEALw_wcB&gclsrc=aw.ds

The hightec solar panels on ebay are very similar, 5-bussbar and almost identical to Grape Solar dimensions and construction (maybe 1/4" wider). Search ebay for "hightec solar", seller ID is fred480v. Looks like he doesn't have single "200w" panels listed right now, but might be able to message him on ebay and ask to post them. 

https://www.ebay.com/itm/25-200-Watt-12-Volt-Battery-Charger-Solar-Panel-Off-Grid-RV-Boat-FACTORY-PALLET/273487915033?hash=item3fad266819:g:y5wAAOSwwZtacRkO

I've got 2 of these. They're almost identical to the grape solar panels, but they come without the additional home depot retail markup ($232 at that time: $70 less per panel). The hightec packing is pretty bad though and one was damaged in shipment. I refused the first shipment and had to wait for a 2nd batch to be sent. He didn't fuss about the return and turned around the new shipment as soon as he received the return. While I do like these panels, I wouldn't base my purchasing decision on the claim of higher output than other brands that appear to all use the same cell wafers. 

Cheers,

Walter

 

Edited August 31, 2020 by wamcneil

[Jim McGarvie]

1 hour ago, jreich888 said:

Sorry to resurrect an old thread, but can you share more about the cost and deal you've got?  I look online and they're similar prices, and don't actually list a 200W panel (and the pickup price is about the same).  Is this a deal from one of the in-store solar guys?

No apologies necessary, Jason. This thread is still pretty active!

Here is the link to the panels I bought from Home Depot: https://www.homedepot.com/p/Grape-Solar-200-Watt-Off-Grid-Solar-Panel-Expansion-Kit-GS-200-EXP/314393965?cm_mmc=ecc-_-THD_SHIP_CONFIRMATION_STS-_-V1_M1_CA-_-Product_URL&ecc_ord=WM15907545. I expect to pick them up today.

[waterskier_1]

1 hour ago, jreich888 said:

Sorry to resurrect an old thread, but can you share more about the cost and deal you've got?  I look online and they're similar prices, and don't actually list a 200W panel (and the pickup price is about the same).  Is this a deal from one of the in-store solar guys?

Jason, the Grape Solar Panels at Home Depot are 190 Watt, not 200.  When I first bought them in 2013, they were 160 Watt, when I bought them in 2019 they were 180 Watt, now they are 190 Watt.  As mentioned, the reason I got them was because they are shipped FREE to your local Home Depot.  If you don't have a local Home Depot, this is not such a great deal.  I see others mentioned on eBay as cheaper, but not available.  Also, it looks like they charge freight shipping, but I don't know how much.  The last time I looked, 2019, all the "good deals" I found were no longer good after you added in the packaging and shipping.  This may no longer be true today.  I offer it only as a suggestion that I found.

3 minutes ago, Jim McGarvie said:

No apologies necessary, Jason. This thread is still pretty active!

Here is the link to the panels I bought from Home Depot: https://www.homedepot.com/p/Grape-Solar-200-Watt-Off-Grid-Solar-Panel-Expansion-Kit-GS-200-EXP/314393965?cm_mmc=ecc-_-THD_SHIP_CONFIRMATION_STS-_-V1_M1_CA-_-Product_URL&ecc_ord=WM15907545. I expect to pick them up today.

That is a different product than I purchased.  I got these:  https://www.homedepot.com/p/Grape-Solar-190-Watt-Monocrystalline-PV-Solar-Panel-for-Cabins-RV-s-and-Back-Up-Power-Systems-GS-STAR-190W-US/313629211

I had to purchase the extras you got separately, but since I was designing my own system, I wasn't sure a "package extension" would save me money.

 

[wamcneil]

1 hour ago, waterskier_1 said:

....  As mentioned, the reason I got them was because they are shipped FREE to your local Home Depot.  If you don't have a local Home Depot, this is not such a great deal.  I see others mentioned on eBay as cheaper, but not available.  Also, it looks like they charge freight shipping, but I don't know how much. ...

 

Hmmm. Mine were shipped free to home last year. And the free home-shipping option shows up on the HD product page for me now. I wonder why you're not getting the free shipping! The hightec panels from ebay were also free shipping.

That being said... If I had HD close by, I would have had them shipped to the store. That way you could thoroughly inspect for damage before leaving the store and make them order more if dinged in shipment.

Walter

1 hour ago, Jim McGarvie said:

No apologies necessary, Jason. This thread is still pretty active!

Here is the link to the panels I bought from Home Depot: https://www.homedepot.com/p/Grape-Solar-200-Watt-Off-Grid-Solar-Panel-Expansion-Kit-GS-200-EXP/314393965?cm_mmc=ecc-_-THD_SHIP_CONFIRMATION_STS-_-V1_M1_CA-_-Product_URL&ecc_ord=WM15907545. I expect to pick them up today.

Interesting... the GS-STAR-200W panel doesn't show up on Grape Solar's website.

Sure looks like the 190 panel but it has a separate datasheet and the dimensions are somewhat bigger. Comes with some extras, and it costs $25 less!

Edited August 31, 2020 by wamcneil

[waterskier_1]

6 hours ago, wamcneil said:

Hmmm. Mine were shipped free to home last year. And the free home-shipping option shows up on the HD product page for me now. I wonder why you're not getting the free shipping! The hightec panels from ebay were also free shipping.

That being said... If I had HD close by, I would have had them shipped to the store. That way you could thoroughly inspect for damage before leaving the store and make them order more if dinged in shipment.

Walter

Interesting... the GS-STAR-200W panel doesn't show up on Grape Solar's website.

Sure looks like the 190 panel but it has a separate datasheet and the dimensions are somewhat bigger. Comes with some extras, and it costs $25 less!

Maybe we're getting wires crossed.  I DID get free shipping from HD.  The link to the panels you said you got (but not the quantity), shows additional Freight Shipping.  I did not search eBay for panels, because I wanted to inspect, and did send one back, before accepting them.  As long as we're happy, that's all that counts.  

 

[jreich888]

The cost of the Grape solar panels had me confused; when you said they were a better deal ordering to the store I thought there was some further discount.  Right now they show on the HD website as deliver to home and to store as the same price, and the overall price is higher (for the 190w panel) than comparable panels elsewhere.  The 200w expansion panel does look a bit better, though. 

When I bought my Hightec panels from Continuous Resources 2.5 years ago, they shipped 4x175w panels for $25 (and they arrived in perfect condition).  Now their website says 4 panels will ship with UPS ground or Fedex ground for free.  

I think I'll stick with Continuous Resources for my next order (which now looks to be pretty soon, though they have a 1-2 week lead time on new panels), but I am now considering the GS-200-EXP option.  Thanks for the info.

[W7BE_Bob]

Solar panels are large, heavy, breakable and hence expensive to ship a few. They are not "free" to ship for the seller so the cost of free shipping to the consumer is included in the price. 12 volt panels are also popular for RVs and they cost more per watt.

[Jim McGarvie]

You will all be delighted, I'm sure, to hear I have yet another question about my install:

I plan to install the charge controller--an Epever Tracer 60A--in the rear curbside compartment along with the inverter/charger. That compartment is adjacent to the battery compartment. The inverter/charger compartment is not ventilated, except maybe for a little leakage around the door seal. As long as I install the controller with the specified clearance around it (6" in this case) do I need to worry about heat? Have any of you provided any extra ventilation in your controller compartment?

Thanks.

[Ivan K]

I have raised the controller from it's mounting surface a couple of inches and installed a 12v flat fan controlled by a little temp controller with sensor between the cooling fins.

Both are fed from the load terminals of the controller.

[Jim McGarvie]

34 minutes ago, Ivan K said:

I have raised the controller from it's mounting surface a couple of inches and installed a 12v flat fan controlled by a little temp controller with sensor between the cooling fins.

Both are fed from the load terminals of the controller.

Thanks, Ivan. I think I would feel more comfortable if I did something similar. Any details on where I can find the fan and controller?

[Ivan K]

I got both the fan and controller from amazon. First cheap controller failed pretty soon so now I have one that's rated up to 30v.

[Jim McGarvie]

Just now, Ivan K said:

I got both the fan and controller from amazon. First cheap controller failed pretty soon so now I have one that's rated up to 30v.

 

 

 

Perfect! Thanks Ivan!

[quick_tox]

Jim, what is the current status of your install? If your still looking for a path from rooftop to battery compartment, I wanted to chime in that on my Knight 32PBD I pulled my cables through the electrical trough in the rear AC and fished the cables through the ceiling to drop into the rear tv cabinet. I put the boost controller nearby and exited the boost controller down the back bulkhead area and over to the battery compartment. 

[Jim McGarvie]

10 minutes ago, quick_tox said:

Jim, what is the current status of your install? If your still looking for a path from rooftop to battery compartment, I wanted to chime in that on my Knight 32PBD I pulled my cables through the electrical trough in the rear AC and fished the cables through the ceiling to drop into the rear tv cabinet. I put the boost controller nearby and exited the boost controller down the back bulkhead area and over to the battery compartment. 

Interesting thought, Robert. I have been leaning toward going down through the rear cap, but hadn't considered the route you chose. I will look closely at that. Thanks.

[Jim McGarvie]

This forum has proven to be a tremendous resource for my project. I am ready to begin the install, and have a couple more questions:

1. I've decided to wire my four 200W panels in series. The easy way, using the least wire, would be to go from one panel to the next, finally to the combiner box. But if I do that, it seems it wouldn't be easy to check individual panel voltage in case of an issue. I would have to try to reach the connectors under the panel(s). Alternatively, I could run both wires from each panel all the way to the combiner box, but that would take almost twice the wire. Is it common to need to check individual panel voltage?

2. I bought a battery disconnect switch to put between the panels and the charge controller. Is there any reason to add a second switch between the controller and the batteries (in my case, the inverter/charger)?

Thanks For any suggestions.

Jim

[waterskier_1]

33 minutes ago, Jim McGarvie said:

This forum has proven to be a tremendous resource for my project. I am ready to begin the install, and have a couple more questions:

1. I've decided to wire my four 200W panels in series. The easy way, using the least wire, would be to go from one panel to the next, finally to the combiner box. But if I do that, it seems it wouldn't be easy to check individual panel voltage in case of an issue. I would have to try to reach the connectors under the panel(s). Alternatively, I could run both wires from each panel all the way to the combiner box, but that would take almost twice the wire. Is it common to need to check individual panel voltage?

2. I bought a battery disconnect switch to put between the panels and the charge controller. Is there any reason to add a second switch between the controller and the batteries (in my case, the inverter/charger)?

Thanks For any suggestions.

Jim

Jim,

1. You pretty much defeat the purpose of running them in series if you run each panel to the combiner box.  I've never needed to check an individual panel.  But if you did, you'd be up on the roof anyway.  Run from each panel to the next.  Most of my connections are not actually under the panels.  They came with 4ft-5ft pigtails and I needed the length to run from one panel to the next, but I wasn't able to mount my panels adjacent to each other.

2. I recommend having some sort of protection and cutoff for both the input to the controller and from the controller to the batteries.  You want to protect the output of the controller in case the wires become sorted or for some unforeseen reason it attempts to draw too much current.  Also, there may be times you want to be able to disconnect the solar system from the batteries.  Most installations the solar controller output goes directly to the batteries (not through the battery cutoff switch).  Many, like both my old Dynasty and my current Exec, tie into the Inverter feed.  That also does not go through the battery cutoff switch.  If you wanted to replace batteries or do some other maintenance, you want to be able to remove all voltage sources from the batteries.  

3.  Are you guys planning on going to Q-Site again this January?  Dad is wanted to go, and I plan unless prohibited, but still need to consider him flying home.  

  -Rick 

 

[Jim McGarvie]

3 minutes ago, waterskier_1 said:

Jim,

1. You pretty much defeat the purpose of running them in series if you run each panel to the combiner box.  I've never needed to check an individual panel.  But if you did, you'd be up on the roof anyway.  Run from each panel to the next.  Most of my connections are not actually under the panels.  They came with 4ft-5ft pigtails and I needed the length to run from one panel to the next, but I wasn't able to mount my panels adjacent to each other.

I can wire them in series within the combiner box, but you are probably right that it is unlikely to need to check them individually. I will make sure my connections are accessible, just in case.

2. I recommend having some sort of protection and cutoff for both the input to the controller and from the controller to the batteries.  You want to protect the output of the controller in case the wires become sorted or for some unforeseen reason it attempts to draw too much current.  Also, there may be times you want to be able to disconnect the solar system from the batteries.  Most installations the solar controller output goes directly to the batteries (not through the battery cutoff switch).  Many, like both my old Dynasty and my current Exec, tie into the Inverter feed.  That also does not go through the battery cutoff switch.  If you wanted to replace batteries or do some other maintenance, you want to be able to remove all voltage sources from the batteries.  

Thanks.

3.  Are you guys planning on going to Q-Site again this January?  Dad is wanted to go, and I plan unless prohibited, but still need to consider him flying home.  

Yes, we are, even if there isn't an RV show this year.

  -Rick 

 

 

[wamcneil]

58 minutes ago, Jim McGarvie said:

2. ...Is there any reason to add a second switch between the controller and the batteries (in my case, the inverter/charger)?

Thanks For any suggestions.

Jim

Yes, this needs a disconnect, but more importantly the wire needs overcurrent protection. A high-capacity DC circuit breaker on the inverter end of the cable serves both purposes. 
Cheers

Walter