Solar Panel Disconnect Switch

[glennco]

In reading documentation on this forum and the Furrion MPPT manual, it seems there should be a disconnect switch between the solar panels and the MPPT.

What switch are people running for this use case. Most switches I see online are 12-48 volt switches. I’m assuming your switch should be sized to support max Line Open Voltage which could fairly easily go above 48v.

what switch have others used? Do I need to worry about LOV?

thanks for all the help,
Paul

[Country Campers]

This is what I use Amazon.com: Ampper Battery Switch, 12-48 V Battery Power Cut Master Switch Disconnect Isolator for Car, Vehicle, RV and Boat (On/Off) : Automotive , there are plenty of others as well.

Brian

[howson]

glennco
-- I installed what AMSolar included in the "kit" I bought from them. It's a common Blue Sea 6006 mini-switch. https://amsolar.com/rv-battery-accessories/93s-mini

[David Frederick]

Both of these are available from amazon.

https://www.amazon.com/Awclub-Transp...7S75TV3V&psc=1

https://a.co/d/egeCfMM

[stvaughn]

Both of these are available from amazon.

https://www.amazon.com/Awclub-Transp...7S75TV3V&psc=1

https://a.co/d/egeCfMM

Get the switch that David recommend. You must disconnect both wires simultaneously and it must be rated to handle OC voltage. The red battery disconnect switch is not suitable for solar disconnect.

[howson]

Get the switch that David recommend. You must disconnect both wires simultaneously and it must be rated to handle OC voltage. The red battery disconnect switch is not suitable for solar disconnect.

stvaughn,
Since that was your first post and your background/expertise is unknown to this forum's members, can you expand on your statement that the red switch is "not suitable for solar"? The red switch I posted was recommended by AMSolar, specifically by Garret Towne, a licensed electrical engineer who runs a business that installs these switches in units all day every day. Why would the switch be suitable to disconnect power to what could be considered an unconstrained power source (a battery) but not a constrained power source (solar panels).

Please understand I'm asking from a technical perspective, not a "my opinion is better than your opinion"--we don't all have to agree on this forum and a technical discussion on the merits of a given stance are always welcome (even if at the end of the discussion there is an agreement to disagree).

Howard

[Country Campers]

Get the switch that David recommend. You must disconnect both wires simultaneously and it must be rated to handle OC voltage. The red battery disconnect switch is not suitable for solar disconnect.

I only have the positive from my solar panels going thru a disconnect. Could you tell me the reason that both positive and negative need to be disconnected? I am still learning so this will be helpful.

Brian

[ncitro]

I only have the positive from my solar panels going thru a disconnect. Could you tell me the reason that both positive and negative need to be disconnected? I am still learning so this will be helpful.

Brian

I believe thats a requirement in home solar by the NEC. It is an ongoing debate if that applies to RVs or not.

[howson]

I believe thats a requirement in home solar by the NEC. It is an ongoing debate if that applies to RVs or not.

A home solar setup going to a PV Inverter (a completely different device than what we normally use in an RV as a PV Inverter directly generates 120vAC from the PV solar input from the panels) connected to the grid...maybe one of our electrician's can explain the need to disconnect both the negative and positive inputs from the solar panel. For the comparatively low power / low voltage systems in a RV that is connected to a solar controller to charge a battery--if it was a code requirement to have a switch GD would have to install them in their factory-provided systems. Since GD doesn't install anything, it leads me to believe they don't have to (i.e. there's no "code requirement").

Howard

[stvaughn]

stvaughn,
Since that was your first post and your background/expertise is unknown to this forum's members, can you expand on your statement that the red switch is "not suitable for solar"? The red switch I posted was recommended by AMSolar, specifically by Garret Towne, a licensed electrical engineer who runs a business that installs these switches in units all day every day. Why would the switch be suitable to disconnect power to what could be considered an unconstrained power source (a battery) but not a constrained power source (solar panels).

Please understand I'm asking from a technical perspective, not a "my opinion is better than your opinion"--we don't all have to agree on this forum and a technical discussion on the merits of a given stance are always welcome (even if at the end of the discussion there is an agreement to disagree).

Howard

Howard, if you will look at the specifications of the switch you referenced it will say maximum voltage 48Vdc. Voc on one 100 watt panel is usually around 24 volts so two in series will be the max that switch can safely handle. The double pole DC breaker David recommend is rated 250 Volt DC 63 amps which gives plenty of room for future expansion if desired.

As for my background, I am a retired master electrician working in the commercial and industrial electrical industry. I have no formal training in DC and/or solar systems but have spent a great deal of time studying the systems so I could properly install in my Solitude. As for the discussion that some mentioned about whether or not the NEC applies to RV’s my opinion is that the NEC is best practices and following their guidelines will give you the safest and most efficient system.

I certainly don’t pretend to know everything about DC/solar and am always trying to lean from those that have more knowledge than me. That’s what makes forums such as this one so good.

BTW this Solitude is my first GD product. We have only had the opportunity to make two short trips and we really like it.

Steve

[stvaughn]

I only have the positive from my solar panels going thru a disconnect. Could you tell me the reason that both positive and negative need to be disconnected? I am still learning so this will be helpful.

Brian

Breaking the circuit on either AC or DC systems creates an arc. AC systems by nature self extinguish, DC systems do not. Since solar panels wired in series add voltages, the voltages can get quite high and since DC arcs are hard to extinguish DC breakers are specifically designed to handle the current and voltage potential the panels produce. Opening both circuits simultaneously allows for a more efficient design.

[TucsonJim]

As for the discussion that some mentioned about whether or not the NEC applies to RV’s my opinion is that the NEC is best practices and following their guidelines will give you the safest and most efficient system.

Steve

Hi Steve - Welcome to the forum, and thanks for contributing to the conversation.

This response is for standards that are applicable to the RV industry. RV manufacturers get their requirements from the Recreational Vehicle Industry Association (RVIA). Several owners have expressed their dissatisfaction with the RVIA, but these are the requirements that GDRV complies with. The link below identifies all the standards adopted by the RVIA. The National Electrical Code (NEC) 2020 Edition is the current standard adopted for 120V/240V systems. Article 551 provisions cover RVs. It's important to note that if there is a conflict between residential requirements and the requirements in Article 551, the provisions of 551 take priority.

https://www.rvia.org/node/associatio...pted-standards

Jim

[TucsonJim]

My solar array generates an open circuit voltage of 86 volts and a short circuit current of 12.4 amps. I selected a breaker to use as the switch. It's rated for 150VDC, and 16 amps. It's perfect for my needs. Unfortunately, that model is no longer available on Amazon, but there are other alternatives that work well with higher voltage DC circuits.

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

Jim

[howson]

Howard, if you will look at the specifications of the switch you referenced it will say maximum voltage 48Vdc. Voc on one 100 watt panel is usually around 24 volts so two in series will be the max that switch can safely handle.

That explains why the switch I'm using in my system should be OK as the total is 1200W configured in 6 parallel sets of 2 100W series panels in series, so maximum voltage will stay within the limits.

Thanks for the thoughtful reply and if I haven't written it yet--welcome to the forum, Steve.

Howard

[stvaughn]

That explains why the switch I'm using in my system should be OK as the total is 1200W configured in 6 parallel sets of 2 100W series panels in series, so maximum voltage will stay within the limits.

Thanks for the thoughtful reply and if I haven't written it yet--welcome to the forum, Steve.

Howard

Thanks for the welcome Howard. I don’t spend a lot of time on forums but I certainly appreciate the time and energy you mods put into keeping things up and running.

There is no right or wrong when it comes to series vs. parallel panel layouts. Each person has to decide what will work best for their particular needs. I chose a 3s2p 600 watt layout to begin with and the room to expand up to a 4s3p 1200 watt system if I want to. This of course requires the higher capacity switch. I just completed the system yesterday so it hasn’t even seen the sunshine yet. Maybe tomorrow.

Steve