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Tino643 · 01-14-2016, 08:40 AM

OK! What is the next step?

I have a 2015 Airstream International 30 feet. I installed 3 Pannels solars on the roof and the junction box. I found the pre instal solar 10 AWG wire ( I decide to keep this wire). Now I have to drill a hole in the roof and connect the wire in the junction box.

Now that's done, what do i do afterwards?
1- Where the 10 AWG is going?
2- Do I have to connect the Bus Bar?
3- Where do I install the controller?
4- What wire should go to the controller?
5- The panel installation in parallèle or series?

So if some one whit exp. tell me the next step.

Ps. sorry for my english....

Thanks.

dznf0g · 01-14-2016, 08:42 AM

Where in the ceiling did you find the panel end of the (green and Yellow??) wires? Did you find the other ends of those 2 wires? (Near the electrical center??????)

alano · 01-14-2016, 10:21 AM

Tino,

When you have three panels, you're only solution is to install them in parallel. You can install four panels in a series/parallel arrangement. However with three parallel panels you will exceed 3% losses if you use the solar pre-wiring, so the recommendation is for you to run your own wires, #8 or #6, down to your solar controller.

Did you already install the three panels or are you planning to install the three panels? You haven't said what type of panels or what type of controller you're intending to use.

Also, if you can get a four panel on the roof like I did then you can re-use the existing solar pre-wiring and keep your losses at less than 3%.

Tino643 · 01-14-2016, 01:10 PM

Alano,

I don't want to change the wire. So i will buy a fouth panel and do the same set up you have. I am waiting for the controler. Is the same like you. My problem is all the wirering! Where the 10 AWG wire ends. Where I plug it and what do i plug in the controler....

alano · 01-14-2016, 01:50 PM

Ok, four panels will work well in a series/parallel arrangement. I'll draw up a schematic for you in a later post.

I mounted my solar controller in back of the couch next to the battery disconnect relay. I first prepared a plywood board to mount to the skin of the AS at the back of the couch and then mounted the controller and disconnect switch on the plywood. The controller sat perhaps 6 to 12" above the floor. It was necessary to remount the couch away from the front wall 1 to 2" to make sure there was some room in front on the controller for good air circulation.

You'll need to get a 50A rotary switch that you'll wire in series with the positive connection from the panels to the controller. This switch allows you to disconnect solar power if you need to do maintenance on the controller. You'll also need to buy a 40A fuse that connects from the solar controller directly to the batteries. I bought both the switch and fuse at my local auto parts store.

Have you read through the installation manual for the Blue Sky 3024 manual? Did you also purchase the IPN pro remote and shunt?

dznf0g · 01-14-2016, 02:05 PM

Al, let me ask a question.....I've read several times about the switch thing....why is it "needed"? If you have to disconnect the solar for some reason, why not just remove the solar connectors from the controller...if they're readily accessible. I ask, because I am half way through my install, but weather delayed. I don't plan on a cutoff switch, but my controller is easily accessible.

alano · 01-14-2016, 02:35 PM

I have four panels on the roof and the MC4 connectors are not readily accessible, so I decided to add the switch. Since I also have a series/parallel arrangement, my open-circuit voltage is near 50 V so I was confortable connecting my controller with the panels disconnected.

dznf0g · 01-14-2016, 03:25 PM

Ok, I see.

alano · 01-14-2016, 09:03 PM

Drawings1.pdf

Tino,

Here's some drawings to help you get started. You should probably read over them and then ask questions.

Tino643 · 01-15-2016, 07:47 AM

I am waiting for my 4 panel. The drawing will help me very much... I give some news went everything is set....Thanks

switz · 01-15-2016, 08:22 AM

We have a 50 amp solar panel isolation switch in the refrigerator area where the wires come down from the roof on both the 23D and the Classic. This allows one to work on the solar charge controller without input power interfering. There is also a similar switch in the wiring coming out of the solar charge controller to the battery array so the controller can be totally isolated.

youngpeck · 01-15-2016, 08:43 AM

Quote:

Originally Posted by switz

We have a 50 amp solar panel isolation switch in the refrigerator area where the wires come down from the roof on both the 23D and the Classic. This allows one to work on the solar charge controller without input power interfering. There is also a similar switch in the wiring coming out of the solar charge controller to the battery array so the controller can be totally isolated.

Any chance you could post some pictures of your setup? Or, if you have in the past, point us toward the appropriate thread? Thanks much.

WayneG · 01-15-2016, 09:01 AM

My setup is different and I used a 7.5 amp aircraft circuit breaker for each of my panels. That way if one shorts, the breaker should pop allowing the remainder to function. It also allows me to individually see how much each panel is putting out.

dznf0g · 01-15-2016, 09:58 AM

Quote:

Originally Posted by WayneG

My setup is different and I used a 7.5 amp aircraft circuit breaker for each of my panels. That way if one shorts, the breaker should pop allowing the remainder to function. It also allows me to individually see how much each panel is putting out.

I looked into fusing each leg and found that most all panels (quality) have diodes in them that prevent back-feeding to a shorted panel...so I was told that fusing the legs was unnecessary. I believe it was Lewster who said AM solar does no fusing between the controller and the panels. Lew, jump in and school me, if I misunderstood.

alano · 01-15-2016, 10:23 AM

Fusing each individual panel is unnecessary since most panels, Renology and Grape among others, include blocking and bypass diodes. Even if you were to apply a direct short to the panel at the output, the output current in the case of a Renology 100 W panel would be only 5.75 A - so it wouldn't trip the breaker.

Now, replacing each fuse with a SPST switch might be interesting to know each panels contribution to power. That's one feature I could play around with from time-to-time!

dznf0g · 01-15-2016, 10:54 AM

The problem here is....every "unnecessary" mechanical connection (Fuses, breakers, switches) introduces resistance to the circuit and cumulatively decreases efficiency of the system.

WayneG · 01-16-2016, 05:46 AM

It is true, a fuse, switch, circuit breaker, undersized wire and even excessive connectors in the wiring to the controller will increase the resistance and reduce your total voltage at the controller.
I picked Klixon 2TC2 aircraft breakers because they have a low voltage drop, (about .25 volt at full current, less drop on lower currents)
I know any voltage drop is a red flag for solar but with panels that provide more voltage than the controller needs, it works for me and I can see 20 amps into the controller from 4 panels in good sun. (Yes it will be much less in poor sun)

This is page 3 of my write-up showing my estimated losses in my system
(Whoops, I just realized that I did not add in losses for the breakers in those figures)

My theory on the need for circuit breakers or fuses is; It is true that if one panel shorts it will not trip its own circuit breaker, it is the other panels tied in parallel to the shorted panel that will trip the breaker to the shorted one, allowing the remaining panels to keep supplying current.
If my 4 panels put out their nominal rated current of 5.25 amps each (going through my 7.5 amp breakers) for a total of 21 amps, and one of the panels shorts out, the breaker to that panel is going to see 15.75 amps from the remaining panels and its breaker will pop. If I had more panels without any breakers and exceeded the amp capacity of the wiring, the current coming from the good panels could burn wiring going back to the bad panel.

I may have over-engineered my system, but it works for me, and being able to pull a breaker allows me to isolate the panels one by one for maintenance or to see how they are performing.
That came in handy when 2 of my panels went bad. Vibrations from a road trip opened up some bad solder joints in the panel diode junction boxes.

I was able to determine which panels were bad inside the vehicle by pulling breakers and checking outputs of each panel. Then I pulled the bad panels and re-soldered the connection and I was back up and running in a day.

alano · 01-16-2016, 10:52 AM

Wayne. Kudos for you! You designed, purchased and installed and tested your system yourself. That's a great accomplishment and you did it in a way that teachers other DIYers, so you should be congratulated!

The engineering of these systems isn't trivial and I suspect the difficultly level prevents many folks from doing it themselves. I'm all in favor of teaching and helping folks these things.

Again, nice job!

switz · 01-17-2016, 02:37 AM

The first photo is of the disconnect switch behind the Classic's refrigerator. We have the same switch mounted behind the refrigerator of the 23D. The 80 amp switch in the second photo (nine 100 watt GS-100 panels on the roof) is in the Classic when the four Lifeline batteries we started with were outside on the trailer tongue. There is more equipment in that space after the lithium battery replaced the Lifeline batteries.

The third photo shows we used a 30 amp switch on the 23D as it has five 100 watt panels plus the red automatic disconnect switch system from AM Solar to protect the 300 amp-hour lithium battery. A similar switch system was added to the Classic with a 600 amp-hour battery. Note that all the new electrical (both Solar and 120Vac) system is installed under the street side sofa and dinette seat with no loss of storage under those two cabinets or loss of use of the sofa slide out shelf for bed use.