Solar Disconnect Question

[theguyoverthere]

I'm adding Solar to my 2016 Jayco Jayflight 287BHSW. I wanted to double check a couple of things with my thinking and need help knowing the right size Solar Disconnect to get. As a side note, I upgraded my internal trailer converter to the WFCO WF-8735-AD, it has auto detect and can properly charge Lithium. We did that before we decided to add solar.

I'm going with a Renogy system. I've pretty much purchased everything but the disconnect at this point. Here are main components:

-2x Renogy 175 W flexible solar panels
- Renogy 40A MPPT Charge Controller
-x2 Renogy 100 12v 100 AH Smart Lithium Iron Phosphate battery with self heating
-Renogy 2000W Inverter

I'm following their electrical schematic, attached image. I want to put an electrical disconnect between the Solar panels and the Charge Controller. I'm pretty sure I've figured out I need a 30A to 32A disconnect (9.5A Isc X 2 X 1.56 = 29.64), but not sure what size voltage to get for it. I will be running the panels in parallel. So here are my questions.

1. I assume I need to turn the panels off, using the disconnect, when towing the trailer as the car will be charging the batteries?
2. I also assume I need to turn the panels off when I'm connected to Shore Power, again using the disconnect?
3. Do I have the correct idea on Amps for the disconnect, and what about the voltage capability for the disconnect do I need to get?

Thanks for any help you can provide. I've been researching this for days and just want to make sure I install the correct disconnect.

[JimD]

I have 400 watts of solar running through a Renology 30 amp MPPT controller and love it. Have had this for many years and never disconnect while driving or connected to shore power. No problems encountered.

My panel and controller disconnects consist of the inline blade fuses. If I am working on the batteries or whatever and want to disconnect the panels I simply pull the fuse. Easy peasy. I thought of putting in a wireless panel disconnect but decided to just keep going with what I have. I don't believe the batteries will take in more than what they require.

I forget the fuse value I used but it was whatever Renology recommended. Think it was 30 amp, maqybe 20. The max current I have observed through my controller has been just over 16 amps.

Am interested to see what others are doing.

[ARoamer]

Fuses are likely a better {easier} way to go. My 2 -320W panels, 9.5A, 40V, are in series and can produce 80V @ 10A (on a perfect day, which never happens). I was using a chineesium 12VDC 20A breaker for a disconnect and kept having mystery trips which I attribute to the breaker being 12v and not liking 80v passing through. Found a 20A 80VDC breaker on flea bay for $13, so far no trips.

Since your panels are in parallel you'd likely be fine with a 20A fuse that's easily accessible.

Really no need to disconnect panels at any time, the controller will sense voltage and simply stop supplying when it sees a full charge, and your lithium batteries will disconnect themselves when they have had their fill. You're gonna like the lithiums!

[theguyoverthere]

I do have the two 15A fuses for the positive side of the panels, one for each panel. We switched to lithium so my wife could use her CPAP, but then realized none of the outlets worked once installed. So then I bought a power converter, at that point we realized we we almost had everything we needed for solar and decided to just complete the set-up.

Do I need to still turn off the trailer converter breaker with this set-up? Essentially I have two chargers, the solar charger and the trailer converter/charger.

[Dbunke]

Here is my controller setup with 400 watts. 30 amp reset able fuse. So far have not had the need to disconnect for a year. Shore power or not. I love this solar. We boondock 90 percent of the time and hardly ever have to run the generator any more..

[RogerR]

Per Renogy always disconnect solar before disconnecting battery, do not connect solar if a battery is not connected or mppt will be damaged, period.
Renogy says mppt is smart enough to charge batteries or let AC or truck do work if they charge at a higher voltage, no solar available, etc.

No need to do anything unless battery is being disconnected for some reason.

[ARoamer]

Originally Posted by theguyoverthere

I do have the two 15A fuses for the positive side of the panels, one for each panel. We switched to lithium so my wife could use her CPAP, but then realized none of the outlets worked once installed. So then I bought a power converter, at that point we realized we we almost had everything we needed for solar and decided to just complete the set-up.

Do I need to still turn off the trailer converter breaker with this set-up? Essentially I have two chargers, the solar charger and the trailer converter/charger.

Ideally you should have a easily accessible solar panel disconnect of some type. Most solar controllers should have a battery connected before connecting or disconnecting the solar panels.
From your schematic I'm assuming the inverter is free standing and not connected to your RV's 120VAC wiring. No need to turn off the converter breaker UNLESS you have a 12VDC INVERTER powering your entire RV's 120VAC circuits.

[TaftCoach]

I have fuses everywhere in the circuit. For now I just pull the fuse between the panels and the controller. It was what I had on hand and seems to work.

My cheap Renogy controller was fried when someone stole my battery. At first I thought it just went bad after three years in the southern heat.

[theguyoverthere]

Originally Posted by ARoamer

Ideally you should have a easily accessible solar panel disconnect of some type. Most solar controllers should have a battery connected before connecting or disconnecting the solar panels.
From your schematic I'm assuming the inverter is free standing and not connected to your RV's 120VAC wiring. No need to turn off the converter breaker UNLESS you have a 12VDC INVERTER powering your entire RV's 120VAC circuits.

I'm adding a 30A outlet on the outside of my trailer tied to the converter so that I can power the outlets inside the trailer. So when we don't have shore power, I'll plug the shore power plug into the converter outlet. The entire purpose for me even starting this was so that my wife can use her CPAP when we dry camp.

[ARoamer]

Originally Posted by theguyoverthere

I'm adding a 30A outlet on the outside of my trailer tied to the converter so that I can power the outlets inside the trailer. So when we don't have shore power, I'll plug the shore power plug into the converter outlet. The entire purpose for me even starting this was so that my wife can use her CPAP when we dry camp.

If I'm following correctly, then yes, your converter (battery charger) breaker should be turned off, otherwise you'd be trying to charge your batteries with the inverter drawing power from the batteries. Other high draw load breakers should be off, or switched to LP if applicable such as electric hot water, RV electric fridge, and AC.

[theguyoverthere]

Thanks for everyone's help and advice. Much appreciated. I'll take some pictures once it's set-up.

[ChiToones]

I have a 15A inline fuse for each of my two 200W panels: https://www.amazon.com/Renogy-15-Wat...s%2C139&sr=8-1

Then have a battery selector switch to isolate the panels from the controller: https://www.amazon.com/Perko-8501DP-...s%2C142&sr=8-2
I have my roof mounted panels on one switch position and wiring for portable panels connected to the other position.

As was previously mentioned, make sure to disconnect the panels from the controller before disconnecting the battery(s) from the controller to avoid damaging the controller.

If you connect your 30A cord to an inverter, be sure to turn off the breaker to you converter. Failing to do so would create a loop.

Depending on the type of CPAP used, you might be able connect it to your 12v system. I use this: https://www.amazon.com/DreamStation-.../dp/B07N45FSNY

[retroboy1989]

I went with some DC breakers for my 400w Renogy setup. Amazon screenshot below. Double pole on the PV side. Single pole for the positive battery side. It makes disconnecting so easy and quick. Always open the PV breaker first. Always close the battery breaker first.

Also, I turned my converter off at the AC panel after the install last year. My converter hasnt seen shore power since that time.

I use my trailer every 3-4 weeks over the summer. I just let the mppt babysit the batteries between uses. 2x 6v golf cart batteries from Sam's Club.

[Johnynorthland]

I have a PV breaker for the panels and a the same breaker as Dbunk on the battery side. Easy enough to switch off both for maintenance and no sun storage.

[theguyoverthere]

The trip was a success. Everything worked great. I still need to do some cable management. I'm assuming it was required, so I'd say the biggest pain for me was trying to work with the two different Shortstop breakers on the chasis. I had hoped to put all the wiring in the trailer storage, but due to those, I had to run the wire to the front of the trailer and back.