Solar cut off switch/breaker

[WBB]

Has anyone installed a cut off switch to disconnect the solar panels from the charge controller? If so, what switch did you use and where did you install it? Pics please.

It sure would be nice to be able to turn the solar "off" in order to test or change the batteries, work with the 12V system (e.g. install a shunt) etc. With everything off, the batteries do not discharge very quickly and it would be nice for storage too.

Appreciate your thoughts.

-Bill

[uncle_bob]

Hi

A lot depends on how much current your solar puts out. If you have a 1,200 W solar setup, that's going to be up around 100A. If you only have a 200W setup things are a bit less crazy.

The same disconnect switches (Blue Sea) that work for battery disconnect work fine for solar, pretty much regardless of how much you have.

Since there is no "standard" way of wiring the solar to here or there, the location of the switch will be a "that depends" sort of thing. Best guess, it will go somewhere close to the floor / on a cabinet. That means kicking it on a pretty regular basis (don't ask how I now this ... also don't ask the dogs how often they hav kicked it .... ).

Fun !!!

Bob

[Spartanfam]

https://www.airforums.com/forums/f44...ct-249003.html

If I pasted this correctly, it’s a link to another discussion on solar panel breakers switches.

[3OnOurWay]

SpartaFam
Good suggestion on that link for photos, though it may cause some confusion because that’s a trailer and the motorhomes set ups have a huge space limitation and wiring hurdles. To leap .

[StogieMan]

If you don’t want to go through all the trouble of installing a switch - you can always cover your solar panels either with a dark thick blanket or some cardboard whenever you’re going to do some work.

The second option of not too much work is to put a resettable breaker on the roof as the wires will be exposed. Put a 40A Blue Seas resettable breaker on the positive wire as it comes into the van on the roof. They have some waterproof ones. You’ll just need to climb up there every time you want to do some work and turn it off. Pretty convenient if you’re not always going to be doing work.

If you want to get down and dirty then you’ll need to find your solar wire coming from the roof. It’s usually marked and for your unit according to your diagram it’s a 8 Ga yellow wire. You can first find your charge controller and work back from there. I would again use a Blue Seas breaker right before the solar charge controller. Since you have 300 watts of solar going to your house batteries, I would install a Blue Seas system 40A resettable breaker which I have linked below but usually 10 to 15A’s per panel. To confirm, look up your panel information in order to determine the total amperage per panel to determine the fuse/breaker size. Keep in mind that these are not true solar cutoff switches but 200-300 watts is really not much. When you start getting up there then you should really be using a true solar cutoff switch.

Another option is to place the 40A Blue Seas breaker right before it enters the Airstream installed Thermal Fuse Busbar. I have attached a sketched up diagram on where I would put it. Both diagrams are for your build year. You can put the cutoff switch wherever it’s convenient for you by just running a longer wire to your desired location. Keep in mind to use the same wire size that is being used if you decide to extend the wiring.

Below I’ve attached a link to my thread and at various points that I have done, redone, changed my minded, expanded, removed and so on solar work on our rig. It’s always a work in progress but I have plenty of pictures and install information that you might find useful. I installed a true solar cutoff switch that I use to shut down both our roof and ground array which are both tied to it.

Solar info found on post #’s 32, 33, 34, 35, 39, 41, 42, 55, 119, 121, 122, 155, 176, 177, 178, 179, 180 & 181 - happy reading.

https://www.airforums.com/forums/f24...-234941-2.html



Blue Seas system 40A resettable fuse.
https://www.amazon.com/Blue-Sea-Syst...19&sr=8-1&th=1

[Kkeogh]

Can’t you pull 30amp fuse by controller

[3OnOurWay]

The Blue Sea resettable are simpler to install, safe, and easy to open / reset where space is already a premium inside of the AI GL/GT cabinet. I would vote those. Second, bluetooth MPPT has software to shut off via app. Unsure on the nonBT version installed by factory.

[WBB]

Stogieman,

This is awesome. Thanks.

PS - I had overlooked the house solar panels, charge controller on this wiring diagram - you made me realize I have more places to check for a loose connection.

[WBB]

Originally Posted by 3OnOurWay

The Blue Sea resettable are simpler to install, safe, and easy to open / reset where space is already a premium inside of the AI GL/GT cabinet. I would vote those. Second, bluetooth MPPT has software to shut off via app. Unsure on the nonBT version installed by factory.

I can't find any instructions in the manual for turning off the non-Bluetooth MPPT. For $185 a BT MPPT would be a great upgrade, it's just going to be a major pain to get inside the enclosed cabinet swap them out. If I move forward, I might put a cut off breaker/switch in as well.

-Bill

[WBB]

Originally Posted by Kkeogh

Can’t you pull 30amp fuse by controller

Thanks for the thought.

I am very envious of the space in trailers for things like this. Unfortunately, in my van the fuse is located on the battery in an enclosure under the van.

[PhilipRay]

Just a warning - do not hook up panels to a charge controller without batteries connected. That can fry your controller. To that end, just covering the panels may be a bad idea.

[StogieMan]

Originally Posted by PhilipRay

Just a warning - do not hook up panels to a charge controller without batteries connected.

I agree with this comment.

Originally Posted by PhilipRay

To that end, just covering the panels may be a bad idea.

But, I don't agree with this one.

We're talking about a van with a couple hundred watts of solar and not a home solar array with couple thousand KW's where I wouldn't recommend anyone trying it. The van though - I have done many times.

[Silverminer]

Well you can get on the roof and disconnect them. I've done that before.

[3OnOurWay]

Originally Posted by Silverminer

Well you can get on the roof and disconnect them. I've done that before.

Very easy and very safe to disconnect each of the solar connections on the ladder either panels individually to make sure the connection are good there or the whole array

on the GL it is not hard to reach in and change out the Bluetooth controller the front wood panel with the displays pops right off toward you held by magnetic catches. The space there gave me enough room to hot swap The MPPT with 10 minutes worth of work.

To me the disconnects on roof and the software on the new BT solar controller allow me to isolate each side. After this week, :-) I would be interested to place resettable fuses on the batteries to isolate them for testing in case they go to sleep or need to be jumped and trickle charged. ( maybe it’s a one off problem I had )

[JeffKim]

My understanding from Explorist/Nate is that this needs to be a two pole since the negative can be different potential than the ground on the trailer and its code (not sure what code). I know there are specialty 2-pole switches like the one referred to above, but I used a simple 25A DIN breaker for $14 on Amazon and mounted it in the hatch under the twin bed next to where the batteries are located. Mr. Nate mounts his DIN breaker in a big waterproof box but I didn't think that was necessary. In a van this might not be possible.

[StogieMan]

Again, we’re talking about a 12v and not a 48v system. If it was a 48v system or a 12v system with something in the 1k + solar range with that much solar - then yes a double pole disconnect is recommended. I mentioned it in my above post that if you have a bigger solar array - then yes, add a true disconnect. If you have the space then yes also add it as it’s not that much more money to buy one and a piece of mind. However, as everyone knows space is at a premium where we can install all these gadgets in our vans.

I’m at 920 watts total between both of my solar arrays and the reason why I added a double pole solar disconnect.

Another reason why installed it was as folks know that I’m a big proponent of planning ahead and knew that I was going to add more solar so I didn’t want to have to rewire everything and glad that I installed it. I’m also planning to build a dedicated permanent bigger ground array for our rig to charge at home while it sits idle and take it off shore power. To boot, I redid our whole system and ran new 6 Ga wires from my combiner box on the roof all the way to the both solar charge controllers. Easier for me and a cleaner look over all as I have two sets of wires. If I was just going to leave the 400 watts on the roof, then I would be fine with just adding a Blue Seas breaker on the positive side 100% but that’s just me.

Now to get technical:

In our vans we already have a common negative going directly the van frame chassis ground. Our battery banks are also negative grounded so in turn the solar charge controller(s) are not isolated from the solar array(s) to the battery bank nor is the solar array floating but grounded. Besides if your ground is energized then you need to find out why as that is a bigger problem with your wiring.

How many folks have a double pole breaker master disconnect switch on their battery bank? I have 600Ah’s of lithium and I don’t but just on the positive side. What has more power 300 watts of solar or a battery bank? I do a lot of reading and my thinking has also morphed along the way.

This is another subject of debate on many forums just like how many amps you can safely be taking from your alternator. Varying opinions on both subjects. Me, I have no problem charging at a 100A’s from our 220A alternator or just using a resettable breaker on either the positive coming from the panels or the positive going to battery from the solar charge controller.

Do what makes you feel better as long as you wire it the right way along with proper gauge wire and quality breakers and fuses. Lastly, please do your own research as this only is my opinion from a guy on the internet.

[Boxster1971]

Originally Posted by JeffKim

My understanding from Explorist/Nate is that this needs to be a two pole since the negative can be different potential than the ground on the trailer and its code (not sure what code). I know there are specialty 2-pole switches like the one referred to above, but I used a simple 25A DIN breaker for $14 on Amazon and mounted it in the hatch under the twin bed next to where the batteries are located. Mr. Nate mounts his DIN breaker in a big waterproof box but I didn't think that was necessary. In a van this might not be possible.

I also follow Explorist.life and once asked Nate why he recommneded the 2-pole shutoff switches when most in RV world just switch off the positive lead from solar panels. He just said it was the "code". Yes, the National Electric Code for residential and commercial applications from NFPA.
https://www.nfpa.org/news-blogs-and-...-all-50-states

[uncle_bob]

Hi

In an RV, a single pole switch is *plenty* good enough. Your battery is a *much* bigger hazard. How many folks disconnect it with a two pole approach? .... pretty much nobody / ever.

Bob

[StogieMan]

Originally Posted by 3OnOurWay

V After this week, :-) I would be interested to place resettable fuses on the batteries to isolate them for testing in case they go to sleep or need to be jumped and trickle charged. ( maybe it’s a one off problem I had )

No, you don’t want to use those as a battery disconnect. This is where you need a beefy battery disconnect switch like the ones linked below and again - stay away from the cheaper Amazon Chinese made ones. You only need one coming from the main positive battery cable. Since your batteries are underneath, I wouldn’t install it under the van as it has to be protected from the elements, water and road debris.

Airstream drops the ball here and doesn’t add one of these for convenience. Not sure why they don’t do it and if the newer vans come with one.


12v Victron Master Battery Disconnect switch
https://www.amazon.com/Victron-Energ...s%2C130&sr=8-2


or a Blue Seas Switch
https://www.amazon.com/Blue-Sea-Syst...ps%2C94&sr=8-3


or this one:
https://www.amazon.com/Blue-Sea-Syst...ps%2C94&sr=8-4

[uncle_bob]

Originally Posted by StogieMan

No, you don’t want to use those as a battery disconnect. This is where you need a beefy battery disconnect switch like the ones linked below and again - stay away from the cheaper Amazon Chinese made ones. You only need one coming from the main positive battery cable. Since your batteries are underneath, I wouldn’t install it under the van as it has to be protected from the elements, water and road debris.

Airstream drops the ball here and doesn’t add one of these for convenience. Not sure why they don’t do it and if the newer vans come with one.


12v Victron Master Battery Disconnect switch
https://www.amazon.com/Victron-Energ...s%2C130&sr=8-2


or a Blue Seas Switch
https://www.amazon.com/Blue-Sea-Syst...ps%2C94&sr=8-3


or this one:
https://www.amazon.com/Blue-Sea-Syst...ps%2C94&sr=8-4

Hi

The reason they don't come stock is that a full disconnect shuts down stuff like the propane detector. The legal eagles don't like you "defeating safety features" that way.

Bob