Log In | Register
Skip to main content
Topic: Solar Wiring Questions From A Newbie (Read 40 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.
Solar Wiring Questions From A Newbie
Yahoo Message Number: 157629
In the spring, my wife and I purchased a gently used 2011 24' front dinette Lazy Daze. It came with the one original solar panel. As we are more the boondockers type of people and perhaps being naively ambitious and after several months of research, I ordered three 100 watt solar panels with tilt bars, a Sky Blue SB3000i controller and a wire harness (which has an 8 gage wire from the combiner box/junction box to the controller) from AM Solar. I plan to add additional batteries in the future. I've spent many an evening searching our groups Lazy Daze website for tips and information to help with this upgrade process. However, I am embarrassed to say that I tend to get a bit lost or find myself chasing an interesting tangent when trying to search for related posts. Anyway, I'd like to replace the original roof mount metal solar junction box with an AM Solar combiner box in order to take advantage of the pre-exiting hole in the roof to run the upgraded 8 gage wire harness to the solar controller. I'd be interested in hearing any suggestions & tips  from those that may have tackled this task. I'd also like to know others thoughts on whether or not I need to upgrade the wiring from the solar controller to the battery with a heavier gage and if so, how difficult that might be. When upgrading my converter, I found what appears to be a channel under the coach floor leading to my dinette bench seats for the solar controller wire to the battery. It would seem that one would be able to fish replacement wire through this channel. I will apologize in advance as this most likely been covered in previous posts but, being Yahoo Groups challenged, I've not been too successful in locating related posts.  Even if someone can point me in the right direction or provide me related previous post #'s, I'd be most appreciative. We (my wife and our two dogs) love our "Desert Rose" Lazy Daze. Thanks from a newbie.

Curtis
Re: Solar Wiring Questions From A Newbie
Reply #1 –
Yahoo Message Number: 157631
Curtis

Our 2003 23.5' FL has the same solar wiring configuration as your 2011 LD.
 The solar was upgraded last year with the addition of a 160-watt solar panel. bringing the total to 400-watts.
The stock 10-gauge wiring, leading to the controller and down to the Power Center was much too small and was replaced with 6-gauge wire.

I used a large exterior electrical junction box (from Home Depot), on the roof, to combine the four panel's wiring. A Blue Seas terminal block was installed inside.
The original, 10-gauge wiring was not difficult to remove. I did have to upsize the waterproof conduct from 1/2" to 3/4"( from the junction box to the roof entry). to provide room for the larger wiring.

The hardest part is getting the new wiring from the controller down to the Power Center or battery. The stock wiring is run inside the wall and is not accessible or removable.
I bypassed it and ran the new wiring outside of the upper cabinet, down the back corner of the sink, to  the lower cabinet. The charge wires, along with several other wires and cables, are covered with while split plastic covering, as shown in the photos.
From the controller's output, the wire runs to a panel mounted Buss 30-amp switchable breaker and then down to the battery cable.
Not long after the upgrade, the HPV-22B controller died and was replaced with a Sky Blue 3000i.
https://www.flickr.com/photos/lwade/albums/72157661711994929
 I don't have many photos as I didn't think it was a unique project, with the exception the new controller.

If you have questions, ask.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Solar Wiring Questions From A Newbie
Reply #2 –
Yahoo Message Number: 157632
"I'd like to replace the original roof mount metal solar junction box with an AM Solar combiner box"

One piece of advice: don't use the AM Solar combiner box that mounts on the refrigerator vent. It's made of cheap, thin plastic that is vulnerable to UV-caused deterioration. After a few years, it's as brittle as a potato chip. AM Solar does offer a larger, more substantial combiner box, but I haven't tried that one so I don't know how durable it is.

Second piece of advice: if you use the common method of running your wires down the fridge vent, be very careful of how you route them. The fins on the back of the fridge are sharp and they run hot! When I inspected my solar wiring last year, my downleads turned out to have notches in their insulation from rubbing against those fins. I replaced the wiring with AWG 2 (appropriate for my run lengths and panel setup) and rerouted the cables so that instead of passing through the fridge compartment, they enter it and then immediately turn sideways and pass through my upper kitchen cabinets.

Third piece of advice: watch your voltage drops, and in particular, remember that to calculate the voltage drops in your solar wiring you need to add the lengths of all the cables between the panels PLUS the cables to the combiner box PLUS the cable from the box to the solar controller... and then separately calculate the voltage drop in the cable from the controller to the batteries. Add these all together and you'll know how much solar power is being wasted.

To figure out all the voltage drops, I use this calculator. If you do this exercise, I can almost guarantee you'll be unpleasantly surprised. I aim for less than 1% voltage drop end to end. My solar power system as installed had many times that, so I rewired it from top to bottom. I get noticeably more power now.

Andy Baird
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Solar Wiring Questions From A Newbie
Reply #3 –
Yahoo Message Number: 157649
Larry, Thank you for your reply and information. I really appreciate your help. Just a few questions.
1.) It appears that you encased all of your rooftop solar related wiring in waterproof conduit. Is there a waterproof fitting where the wire from the panel enters? If so, what is it and did you also pick it up at Home Depot?
2.) What is the name/type of the waterproof fitting that you used to cover the hole on the roof in order to run your wire into the interior?
3.) It sounds like you were able to fish your new 6 gage wire from your roof mounted junction box to your solar controller. Was this very difficult?
4.) Speaking of solar controllers, have you noticed any performance or efficiency improvement going from your original HPV-22B and going to the Sky Blue 3000i?
5.) I can see that replacing the wire run from the solar controller to the Power Center is challenging. As best as I can see from the photos on Flickr , did you drill a hole through your countertop to get your run to the Power Center? If not, where was your access point?
6.) I had forgotten about the 10 amp fuse at the converter for the solar panels which certainly would blow. Thanks for mentioning the upgraded switchable breaker.
7.) Did you also replace and increase the wire gage for  run from the converter to your battery? If so, how difficult was it to fish the wire through the channel under the floor?
8.) I see that you installed a P.I. surge protector which  I too had planned on installing while replacing my converter. But, due to the confined area where the shore power line comes in and seemingly lack of solid surfaces I couldn't see any clear area where to screw or bolt the unit to. I was considering just using a significant amount of Scotch "Extreme" 20lb double sided tape and sticking it to some of the ΒΌ" paneling by the Power Center. I figure that if it's good enough for attaching the solar panels to the roof, it should be able to secure the surge protector. Is this a poor idea?
 I apologize for all of the questions. However, though I consider myself handy, I am a measure 10 times and cut once type of guy. I don't want to unnecessarily mar the beauty of our home on wheels.
By chance, are you located anywhere near or occasionally travel through the San Diego area? I am intrigued and motivated by themodifications depicted in your photos on Flickr and if you're willing, I'd thoroughly enjoy meeting you and seeing your modifications in person.

Curtis "By endurance we conquer" Ernest Shackelton
Re: Solar Wiring Questions From A Newbie
Reply #4 –
Yahoo Message Number: 157650
Andy, Thank you for your reply and information. I really appreciate your help. I ended up ordering AM Solar's roof mount combiner box unit rather than their fridge vent mounted combiner box. I'll inspect the roof mount unit to see how sturdy it is and if it can accommodate the larger gage wiring. If I have any doubts, I'llreturn the combiner box and use the same type of junction box as Larry's as that seems sturdy and probably less expensive than AM Solar's combiner box. I am hoping to use the same rooftop hole that Lazy Daze used when installing the original solar panelin order to get my wire to the interior. By your comments I assume that even your runs from the panels to the combiner box are 2 gage. I am trying to split up my dumb questions between both you and Larry so as not to be a burden to either one of youor take undue advantage of your gracious offer of advice. So, here are just a few questions:
1.) Did you use "welding" wire for your runs? If so, did you just pick that up off of Amazon. Com?
2.) Is your battery bank on the same side of the coach as your converter? If not, did you have to run your wire from your converter to battery via a channel under the coach floor? If so, any tips or suggestions that you may have to make the process easier would be most welcomed.
3.) I presently have two 6 volt batteries, can I add just one more 6 volt battery to my bank? Or, do I have to add two batteries in order to arrive at the 12 volts needed for the coach?  This, as I see that I easily can make room for one more battery. However, adding two more batteries will be challenging. Unless, I can rig up a system like Larry's which, I like as that frees up the battery bay.
4.) Are charging amps shown on my current HPV-22B solar controller merely the amps coming in from the solar panel and not necessarily what is actually making it to my battery due to any voltage drop between my solar controller to theconverter and then finally to my batteries?

Curtis "By endurance we conquer" Ernest Shackelton
As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Solar Wiring Questions From A Newbie
Reply #5 –
Yahoo Message Number: 157664
Curtis

1  The rooftop conducts and fittings are all weather proof, bought at from Home Depot.

2  I used a big electric cover plate with a 3/4" 90 degree fitting screwed and sealed in to it, It was screwed to the roof, along with lots of polyurethane sealant.
It is exact copy of the Factory installation, except for the change from a 1/2" to 3/4' fitting.

3 Changing to larger wiring is a chore but wasn't  too difficult, The pathway isn't hard to follow.

4  Can't make a good comparison between the HPV-22B and the 3000i, not having much camping time on it yet.

5 The wire run from the controller down below is the difficult part. The wiring exit the controller's box, goes into the area behind the microwave, A hole was drilled from this cabinet into the driver's side overhead cabinet, allowing the wire to enter the overhead cabinet. another hole is drill in the bottom of the cabinet to allow the solar and other wiring and cable to exit downward. This wiring is enclosed in the white split plastic covering. Shown here.
https://www.flickr.com/photos/lwade/23767225476/in/album-72157661711994929/ The wiring continues down and then enters the lower kitchen cabinet, through a new hole.
https://www.flickr.com/photos/lwade/23710894521/in/album-72157661711994929/

7  The wiring was upgrade from the controller to the battery cable. The cover under the rear barrel chair is the path.  While in the area, check the hidden circuit breaker or replace it. They often develop internal resistance and voltage drop.

8  Mount the surge protecter where you can and run wire to it. Just don't expect any double side tape tape to work indefinitely. it will fail eventually IMO.

I rarely get to SD, hating the drive south.
I do go to many of the LD CaravanCubs outings and do put on the Yahoo West GTG at Morro Bay, every March.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Solar Wiring Questions From A Newbie
Reply #6 –
Yahoo Message Number: 157668
"By your comments I assume that even your runs from the panels to the combiner box are 2 gage."

No, the runs between my panels are 6 gauge... but that doesn't mean that's the right size for anyone else. My wires were all sized for my panels' wattage, the lengths of the cables, the fact that all five panels are connected in parallel, and how much voltage drop I was willing to tolerate. You'll need to do those calculations for your own setup, using the online calculator I mentioned in an earlier post. (Note that if you have an even number of panels, you can connect them in series-parallel and use smaller cable to get the same voltage drop. That's assuming your solar controller will handle the doubled voltage--typically 36 V.)

"Did you use 'welding' wire for your runs?"

No, I used Ancor brand tinned marine-grade cable, purchased from Amazon, Fisheries Supply, and other marine vendors--whoever had the best price on the sizes I was buying. Tinning is not mandatory, but it ensures there will be little or no corrosion. I've seen copper wire that had oxidized so black, it could not even be soldered to... and it's a safe bet that wire in that condition is not making good contact at the ends, whether soldered or crimped. With the wire I used, each strand is tinned from end to end, so that won't happen.

Where appropriate, wires were terminated with FTZ brand heavy-duty lugs, crimped multiple times and covered with adhesive-lined heat shrink tubing, which not only shrinks but provides an airtight/watertight seal.

"Is your battery bank on the same side of the coach as your converter?"

Yes. In my midbath, two of my four Group 31XT 12 V AGM batteries are located in the normal (outside) battery compartment, while the other two are in the inside compartment under the refrigerator. That compartment backs up to the outside battery compartment, and I've cut away enough of the back to allow cables to pass through. (All batteries are connected in parallel with AWG 00 cable, because when I'm using my inverter, the batteries may see drains of up to 160 amps., and when charging, may see inputs of over 100 amps.

The "converter" in my case is a PROsine 2.0 2,000 W inverter/charger. I have completely replaced the factory-installed Parallax 7345 converter/automatic transfer switch/breaker box/DC fusebox "power center"--the big brown box--with marine-grade parts, mostly from Blue Sea Systems.

Please bear in mind that what I've just described is a much more powerful electrical system than most people have any need for, so don't assume that if your system is less powerful, it's inadequate. I'm just answering your questions literally. :-)

"I presently have two 6 volt batteries, can I add just one more 6 volt battery to my bank?"

No. Your two 6 V batteries are connected in series to yield 12 V, which is what your electrical system needs to see. If you want more batteries, you will either have to switch to 12 V batteries, in which case you could have three in parallel, or use an even number of 6 V batteries and wire them in series-parallel to obtain 12 V.

Note that when adding batteries, flooded-cell types such as the Trojan T-105s used in most Lazy Dazes MUST be vented to the exterior so that flammable gases won't enter the coach. That's why most people with more than two batteries (Larry excepted) use AGMs, which can be mounted anywhere with no venting.

"Are charging amps shown on my current HPV-22B solar controller merely the amps coming in from the solar panel and not necessarily what is actually making it to my battery due to any voltage drop between my solar controller to the converter and then finally to my batteries?"

Your converter is not involved here--its only job is to change 120 VAC into 12 VDC when you're plugged in.

To answer your question: as far as I know, the HPV-22 has no way to tell how much juice actually makes it into your batteries vs. how much is being lost to voltage drop and--more important--how much is being siphoned off by lights, your appliances, propane detector, etc. Only an amp-counter type battery monitor, such as a LinkPro or Victron BMV-700, can do that. The HPV-22 just knows how much is present at its output terminals.

The HPV-22 is able to tell you both how many amps are coming in from the panels and how many amps are going to the batteries (generally more, due to MPPT boosting). The slide switch labeled "Battery Voltage/Array Amps/Charging Amps" lets you choose.

Andy Baird
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Solar Wiring Questions From A Newbie - In praise of marine elect
Reply #7 –
Yahoo Message Number: 157687
Last summer I had a chance to get a good look at Andy's LD remodeled electrical system.

Wow! is all I can say.
The entire electrical system has been replaced with all marine-grade electrical, the same stuff I have been recommending for years.  It's looks and works as good as the electrical in a multi-million dollar yacht.

Andy has spent hundred of hours replacing the stock electrical with the best marine grade parts available and in return is enjoying greater efficiency of all of the electrical systems.
The entire electrical system can be monitored by one master panel, creatively built into a swing-out door, mounted on the end the kitchen cabinet, it's really very well done.

The only downside to someone reproducing this masterpiece is the time and cost.  Professionally done. it is probably in the $30,000 +range.
Sounds like a lot but for a dedicated fulltimer/boondocker, who plans on keeping his RV for very long time, it's worth it. Being able to do it yourself brings the cost back down to earth.

I have many years of experience working with low voltage equipment, in marine environments, and the cost of marine-grade tinned wire and other components have proven their worth in the lack of developing problems.
It's what I use when working on an RV's primary wiring (solar, battery and charging systems).
Learning to calculate voltage drop is also essential in getting the maximum output from battery charging system.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Solar Wiring Questions From A Newbie
Reply #8 –
Yahoo Message Number: 157699
Andy & Larry, Thank you for sharing your recommendations and tips. You've given me a lot to think about in preparation of improving our solar capabilities.

Curtis "By endurance we conquer" Ernest Shackelton
Re: Solar Wiring Questions From A Newbie
Reply #9 –
Yahoo Message Number: 157703
I wrote something last week that needs correcting:

"if you have an even number of panels, you can connect them in series-parallel and use smaller cable to get the same voltage drop. That's assuming your solar controller will handle the doubled voltage--typically 36 V." [emphasis added]

That number is actually a potentially dangerous oversimplification. The reason is that when cold, solar panels can put out voltages substantially higher than their ratings--in some situations, high enough to damage a solar charging controller.

For example, with the temperature at freezing, a typical solar panel with a nominal output (Vmp) of 18 V and an open-circuit voltage (Voc) of 22.5 V will actually put out more like 25 V, and at colder temperatures, you could see up to 28.13 V. Put a couple of those panels in series, and you're up to 56+ volts!

And--this is crucial--that high voltage will hit your solar controller first thing in the morning, when the panels produce full voltage (albeit low amperage), but the controller has not yet applied a load. That scenario could fry your controller.

The chart on this page gives Voc correction factors for various temperatures. Be sure to read the note at the bottom of the page, which explains how ignoring this factor could damage your controller. You may also want to use this calculator to determine how many panels can be put in series, based on temperatures.

Andy Baird
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Solar Wiring Questions From A Newbie
Reply #10 –
Yahoo Message Number: 157711
Andy, Thank you. As this is all rather new to me, I appreciate your taking the time as well as your efforts to pass on information to this of us much less experienced and knowledgable.

Curtis "By endurance we conquer" Sir Ernest Shackelton
 
Solar Wiring Questions From A Newbie
Reply #11 –
Yahoo Message Number: 159563
Larry,

Thanks again for all of the information previously shared. I finally have some time off in which to embark upon my solar project. I am going to use the same type of roof top solar junction box setup as yourself. However, I don't seem to be able to locate the Blue Sea two terminal junction block similar as to what is depicted in your photo. Would you happen to know or have a part number for the Blue Sea two terminal junction block that you used?

Thank you, Curtis