Jayco customer service was no help:
"Those are the wires that go to the charge controller."
Yes, but which go to what?
"Oh, you're gonna have to send a picture so we know what you're talking about."
Seriously? No one can tell me what wires you provide to that junction?
So off to solve it...
I thought I had indicated in the original post that there was 1 roof connection. You had asked if there were 3. Sorry for the confusion. Yes. 1 roof entry point.
There was a gopower solar brochure and a PWM panel sticker in the pack. I read somewhere that it's common to have the panel sticker somewhere in the coach because that's where the wires are for the solar, but since the panel sticker wasn't put on and panel wires ran to the Bay, it doesn't apply...
System is 12v, 4 Panel 100W, 18v-21.6v, 5.5A-6.11A. 2 Series, 2 Parallel.
Apparently rule of thumb is to size it to be 2/3 max output. 400W / 14.4 Volts = 27.8A. If it's sized at 2/3, that would require a 41A output. I think 40 would be close enough.
However, Victron's calculator says to use...
I've read it in more than one place, and I've definitely seen the add 25% for environmental spikes. Here's the last place I read that 2/3 rule:
https://www.thesolarbiz.com/blog/how-big-of-a-charge-controller-do-i-need.html
In this circumstance, it's a roof preparation. It's a dual MC4 connection (1 Male & 1 Female) gland on the roof. There are no Zamp or Gopower ports on the side.
I didn't have the 2/3 rule backwards. I posted where I found that rule. It's also apparently from a reputable source. There are companies and installers recommending this. This is directly from the link I posted:
What Size Controller to Get
Add up the total watts of solar panels and divide by...
I'm building an 8 cell (3.2v 100ah) 12v pack as a "drop-in" replacement for my current lead acid setup. My intention is to make 2 sets of 4, then run them in parallel. Based on mobile-solarpower.com, i'm looking at this BMS:
https://overkillsolar.com/product/bms-120a-4s-lifepo4/
It's designed...
This is somewhat of a continuation of
https://diysolarforum.com/threads/emergency-starting.9618/#post-104557
Understanding that the Solenoid automatically connects the house battery to the alternator upon startup, it would seem that in order to facilitate charging the house battery with the...
https://www.mobile-solarpower.com/the-classic-400-watt-rvs-vans-buses.html
This also recommends 40A for a 400W 2S2P setup. Doesn't cite the 2/3 sizing, but I figured that's why 40A was selected.
Thanks for all the great information and reasoning. I really appreciated the over-paneling posts...
I posted this in the DIY LiFePO4 Forum, but thought it might be better here.
This is somewhat of a continuation of
https://diysolarforum.com/threads/emergency-starting.9618/#post-104557
Understanding that the Solenoid automatically connects the house battery to the alternator upon startup, it...
Thanks for the info. I think what I'm going to do is put a connector between the solenoid control wires so that if I need to connect them to start the engine, I can do that, then just disconnect them after the engine starts. Do you see any downsides to this?
Your solution is pretty elegant too...
Correct. It makes sense that if there is a connection to the DC side that it would have some type of breaker, or even that it was led to the DC fuse panel. I'm gonna have to look. That could be it. Maybe it's wired with no breaker or fuse and you have to populate it with the size of your system...
Hello, DIY Sleuths and Experts!
I have a 2021 Jayco Alante that has Solar Ready Wiring from the roof to the battery bay. There is nothing in the literature that came with my RV that explains this wiring. There was a junction box mounted to the inside of the bay marked "SOLAR PREP" that has six...
I don't feel so bad asking the question now. Lots of opinions on the matter.
After reading the replys, I believe 2 BMS is the way to go. If 1 BMS dies, you still have another "battery". You can "see" each individual cell. Smaller 30lb batteries (3.3kg * 4 * 2.2 + BMS & Connections). Easier...
I'm glad this forum exists. This can be kind of frustrating for a newbie.
It seems there is no clear answer here. I would imagine that if its an NEC code, then manufacturers would push to comply. Especially if it pushes someone to a larger more expensive product. Also places that cite a "rule"...