Seneca solar install

[Mustang65]

Originally Posted by NorCal Eagle

Beautiful install! Looks great. Super clean.

It looks like the panels are wired in series? That would make sense for the mppt controller. I'm curious because it looks like you have a disconnect switch for the panels but in series it should be about 72volts coming in from the 4 panels. Almost all of the standard disconnect switches I've looked at are only rated to 48v max or less.

Wired in parallel it would be fine. I'm working on a wiring diagram for my install and the disconnect switch for the panels is tripping me up at the moment.

The only time you would want your SOLAR panels wired in SERIES is when you have "0%" possibility of shade. When wired in PARALLEL, only the shaded panel will have its output affected, all the rest will produce at their max (provided there is sunshine).

If you have your panels wired in SERIES and only one panel gets a little shade on it, the output of ALL the other panels will be affected.

For your drawing, the SOLAR panel disconnect switch will be located between the combiner box and the SOLAR charge controller, and of course the 2nd disconnect switch will be mounted between the SOLAR charge controller and the batteries.


Don

My Registry

RVing with SOLAR

[PlayersZ28]

Originally Posted by NorCal Eagle

Beautiful install! Looks great. Super clean.

It looks like the panels are wired in series? That would make sense for the mppt controller. I'm curious because it looks like you have a disconnect switch for the panels but in series it should be about 72volts coming in from the 4 panels. Almost all of the standard disconnect switches I've looked at are only rated to 48v max or less.

Wired in parallel it would be fine. I'm working on a wiring diagram for my install and the disconnect switch for the panels is tripping me up at the moment.

I have 4 panels configured as 2 series pairs that are paralleled at the combiner box on the roof. I use a DC breaker (BlueSky) on either side of the CC for protection and disconnect purposes.

[NorCal Eagle]

Originally Posted by Mustang65

The only time you would want your SOLAR panels wired in SERIES is when you have "0%" possibility of shade. When wired in PARALLEL, only the shaded panel will have its output affected, all the rest will produce at their max (provided there is sunshine).

If you have your panels wired in SERIES and only one panel gets a little shade on it, the output of ALL the other panels will be affected.

For your drawing, the SOLAR panel disconnect switch will be located between the combiner box and the SOLAR charge controller, and of course the 2nd disconnect switch will be mounted between the SOLAR charge controller and the batteries.

Not wanting to hijack this thread, but just a quick follow up to to your point (and I appreciate your experience in this area as I'm just learning all of this). How does shade impact the output if the panels have bypass diodes? I know there will be a drop in output but it is as much of a drop as your graphic indicates?

I have more questions but I'll post over in the solar group.

[Mustang65]

Originally Posted by NorCal Eagle

Not wanting to hijack this thread, but just a quick follow up to to your point (and I appreciate your experience in this area as I'm just learning all of this). How does shade impact the output if the panels have bypass diodes? I know there will be a drop in output but it is as much of a drop as your graphic indicates?

I have more questions but I'll post over in the solar group.

The answer to which is better Series or Parallel, is in the design of your SOLAR panel. Many of the lower output and inexpensive SOLAR panels do not include bypass diodes and some only include a blocking diode. Each person would have to check with the manufacturer as to what their product has.

As for my SOLAR panel, I have 2 bypass diodes incorporated into the panel. Each one cares for 30 cells, half the panel. If one of the sub-strings is shaded and bypassing, I will only see about 18 volts from the panel. If your panel (36 volts) has 3 bypass diodes, the voltage would be about 24ish volts (one sub-string shaded). In the case where there are NO bypass diodes, well the drawing is totally correct.

So if I had two SOLAR panels (which I do not need), and based on the fact that it does have 2 bypass diodes, then the panels can be connected in SERIES. The panel that is 1/2 shaded will provide 18 volts to the other panel's 36 volts (total 54 volts) there by adding voltage/power to the series string. I believe that there is a formula for calculating the numbers, but that is if you are producing 100% on panel #1 and 50% on panel #2, which of course is not going to happen in my case.

The short answer is, if you have bypass diodes in your panels, go ahead and install them in series. If you do not have bypass diodes in your panels, connect them in parallel. The one thing to remember is that when the panels are connected in parallel, the maximum difference in voltage between the output of the 2 panels should be less than 10%.

Do your panels have bypass diodes?

Hope that helps.

Don

My Registry

RVing with SOLAR

[Rustynuts]

Here are the specs on the panels I used....The instruction that came with the kit from Renogy specifically said to wire in series and came with a wiring diagram.

Monocrystalline panels come with high-efficiency cells that help increase module efficiency. Module efficiency: Eclipse 100W Monocrystalline: 18.35%
Bypass diodes minimize power drop caused by shade and ensure excellent performance in low-light environments

[Mustang65]

I forgot to mention in my previous post that if you go with the SERIAL panel connections you need to go with an MPPT SOLAR charge controller, as the PWM charge controller ignores any thing over 12 volts (battery voltage). Although some of the newer models are now claiming to handle higher panel voltages. May have to research those claims.

Don

My Registry

RVing with SOLAR

[tjbroussard]

Good Morning and Happy Thanksgiving all.

I really appreciated this thread and the details. Great documentation.

I'm looking at doing similar down the road. I have debated over roof top vs relocatable panels just to get started. Seems much like my satellite, when parked under shade trees, no TV.

Any experience with power generation under trees at the campgrounds? Thoughts?

Thank you!

[PlayersZ28]

Panel output will be degraded based on the amount of shade. If you plan to series the panels then make sure they have bypass diodes if you expect to be shaded.

If you will be shaded a lot then the portable would be better but more hassle and not feasible for a lot of wattage.

[Rino]

Rusty that is a really nice job on the solar install and charge control board you made. I am going to install a solar system on my Seneca this weekend. I am new to solar on an rv and I had a question about how often you run the system. We probably camp 50% full hook up and 50% boondock. Do you run the solar system all the time even when plugged in full hook up camping or do you turn off the system when plugged in or driving etc?

[Rustynuts]

I store the Seneca in a pole building so its off during storage. When I bring it up to the house I turn it on so I dont need to plug it in while we are packing and usually drive with it on. We Boondock probably 80% of the time but when we have full hookups I leave it off.

[PlayersZ28]

My is active all the time, even when the trailer is just sitting. On hookups I let it handle the 12v stuff and leave the converter turned off (assuming there is sun on the panels). The sun doesn't charge me for 12v power, the campground does.

[Rustynuts]

So I am in the process of insulating pipes and adding a heat duct into the wet bay compartment on our Seneca and I remove the panel under the bed to access the heat ducts and this is what I find......every time I open up an access panel I find some thing that just makes me shake my head.....these exposed wires are the solar panel wires that were twisted together but never capped and laying just above a metallic foil covered duct. Got the wires fixed but also found out why we had low heat flow to the rear bath, a smashed heat duct.

[RVermont]

Good catch. That was a high potential for dead short. One big bump on the highway and snap. Hopefully only a blown fuse but it sure would have been a pain to trouble shoot.
Did you cut out some of the extra wiring they put in there. I cut out about 100 feet of extra wire all laid out like spaghetti.

Must have been lunch break it would have taken 15 seconds to finish.

[Gunfighter]

I now will have to take a look very scary. Curious about your design on adding some heat to wet bay. I am planning trip next fall in northern climate and may get caught in a freeze zone. Would appreciate it if you share your design and approach. I haven't tested the temp in the general storage area in a cold climate so not sure if heat needed for grey and black tanks. I have a 37K with two black tanks. Front 1/2 bath tank is long and shallow and I think would freeze easy. Appreciate your thoughts.

[Stargazerandu]

On our shakedown, I kept hearing a metallic rustling sound when the heater kicked on. The next morning I removed the big drawer underneath the range top and what did I find....a bad attempt to plug an unused heat duct hole. As soon as I got home, I plugged it with a piece of metal. This being my 5th rodeo, first thing I did was tighten all the plumbing connections and look at all the wiring, picking up extra screws and tightening the obvious loose ones. I also look at the trim and caulking, recaulking when necessary and cleaning up sloppy caulking. Oh yes, I have seen horrific builds but I must say, this has been one of the better ones. The wiring is neatly bundled, caulking is not too bad, trim is holding up, plumbing needed tightening but not overly. Yes, this is one of the better builds I've seen.. I also keep reminding myself that this house on wheels shakes, rattles and rolls with each trip we take, why I always reinspect everything.


Happy Trails to all!!!

[Rustynuts]

Originally Posted by Gunfighter

I now will have to take a look very scary. Curious about your design on adding some heat to wet bay. I am planning trip next fall in northern climate and may get caught in a freeze zone. Would appreciate it if you share your design and approach. I haven't tested the temp in the general storage area in a cold climate so not sure if heat needed for grey and black tanks. I have a 37K with two black tanks. Front 1/2 bath tank is long and shallow and I think would freeze easy. Appreciate your thoughts.

I will be doing a thread on what I did, did lots of different things as one thing let to another. Our RB has the same bathroom and tank layout as your K model. We have been out several times when the temps got down to 26 degrees several time and we were caught off guard by it and had no issues at all with the way it was from the factory. We are wanting to boondock while snowmobiling so I am taking extra precautions. We upgraded the Truma to the comfort model so we are good there now. Since you bath layout is the same, look in the compartment, behind the carpeted panel above the propane tank. Towards the front of the compartment we had a 6” hole in the floor that the linoleum covered, I cut the linoleum out and tee’d off the duct and connected it to an under eave style dryer vent. Pretty easy to do and guessing they used to heat this bay through that hole....don’t know what else it would be for.

[Gunfighter]

Thanks Rusty. I will look tomorrow for the hole. Dryer vent makes sense. I definitely plan on adding some heat down below. Spend time in South Dakota every year in late October and it has some pretty dramatic swings in temps. This site has lots of good information. So far I have been very pleased with my Seneca. Moved up from a Class C which I spent a lot of time and money improving the handling. The Freightliner chassis is a pleasure to drive.
Cheers

[Stargazerandu]

Originally Posted by Rustynuts

I will be doing a thread on what I did, did lots of different things as one thing let to another. Our RB has the same bathroom and tank layout as your K model. We have been out several times when the temps got down to 26 degrees several time and we were caught off guard by it and had no issues at all with the way it was from the factory. We are wanting to boondock while snowmobiling so I am taking extra precautions. We upgraded the Truma to the comfort model so we are good there now. Since you bath layout is the same, look in the compartment, behind the carpeted panel above the propane tank. Towards the front of the compartment we had a 6” hole in the floor that the linoleum covered, I cut the linoleum out and tee’d off the duct and connected it to an under eave style dryer vent. Pretty easy to do and guessing they used to heat this bay through that hole....don’t know what else it would be for.

Well, I was wondering how to get heat to the basement and now I know. My hubby is going to disconnect the internet as I am always getting ideas for upgrades and then getting him to help me execute them.....lol....

[Rustynuts]

Originally Posted by Stargazerandu

Well, I was wondering how to get heat to the basement and now I know. My hubby is going to disconnect the internet as I am always getting ideas for upgrades and then getting him to help me execute them.....lol....

Before I discovered the hole I was going to bore one in the floor under the bed as there were heat ducts there. I requested a floor structural drawing from Jayco and they supplied one but found one already there once I started looking around. It may be there in other floor plans and there may not. I think the wet bay runs across under the bed area in most floor plans.

[Rustynuts]

I forgot to post this pic, but it shows the hole location.