2 Different Solar Arrays - Would a Switch work?

jkjenn · December 2018

I have been mulling the idea of adding solar to the T@b, permanently ( I like the new factory install.) I would also like to have the option of using my existing solar array (4, 50w Renogy rigid panels) for those times when the T@b is in the shade.

Am I thinking about this, right? Could I utilize a marine 2 battery switch and wire each solar array to a different battery input on the switch? In other words, could I connect the on roof solar to battery 1 and the portable array to battery 2 and then use the switch to choose which array I use?

I do not think that the arrays would not be similar enough to run in parallel.

Edited for picture sizing.

DougH · December 2018

That's gonna be a lot of power!

I've read it's typical to use dual MPPT controllers wired in parallel to charge a battery bank. No switches necessary, but you could route the collective output from the two solar controllers into a switch to charge one or the other if the batteries are not connected.

I'm in a somewhat similar boat, in that we have one battery up front charged by a portable panel, and bank of several batteries in the back charged by permanent panels with an inverter that can pretend to be shore power. We can just use the tub battery for lights, Alde, etc. but when we need lots of AC power we can turn on the inverter and use any spare juice to charge tub battery.

But I think it's more standard to collect all the batteries into a single bank and feed it from multiple MPPT controllers each of which can be fed from different power solar panel arrays.

jkjenn · December 2018

I guess the other option is rig quick connects for both to the solar controller and simply plug in the set up that I am using.

Awca12a · December 2018

So long as its 1 and 2 and not 1+2 then the switch would be isolating the feed from the solar arrays from each other.
Not sure why you’d bother trying to get them working together for the few rare times you’d need or want that much juice at the same time.

ScottG · December 2018

jkjenn said:

I guess the other option is rig quick connects for both to the solar controller and simply plug in the set up that I am using.

Along the same line, why not just incorporate a switch instead of quick connects?

I'm not sure if you would have to disconnect both legs from the unused array, or if you could retain a common (-) lead and just switch the (+). Even if you had to disconnect both, there's gotta be a switch device out there somewhere that can do that.

Sharon_is_SAM · December 2018

Jenn, I think an inside mounted controller and a switch between the portable and installed panels would work. You would need wires for the portable panels with quick connects coming from the switch box out to the front of the TaB. Call Renogy!

jkjenn · January 2019

Awca12a said:

So long as its 1 and 2 and not 1+2 then the switch would be isolating the feed from the solar arrays from each other.
Not sure why you’d bother trying to get them working together for the few rare times you’d need or want that much juice at the same time.

Agreed...I would not want them to work together.

Sharon_is_SAM said:

Jenn, I think an inside mounted controller and a switch between the portable and installed panels would work. You would need wires for the portable panels with quick connects coming from the switch box out to the front of the TaB. Call Renogy!

And I think an appointment with Austin for late winter/early spring will be in order.

Photomom · January 2019

A related question - if you have solar panels on the T@B that charge your battery as you drive, do you need to disconnect the charge line from your vehicle’s battery that comes through the 7 way connector?

jcfaber1 · January 2019

I would use separate controllers for the two arrays. I think you are using Victron controller and meter? You would only need to add the second controller. I will be doing the same thing with our Lance. I will add 440 watts on top with 50 amp controller and a second 30 amp controller for my 200 watt suitcase. I ordered the controllers and meter through Northern Arizona Wind and Sun. Their tech support is great. Apparently Victron can manage as a network.

I have the camper in storage but hope to start in February. I am going to use Merlin Solar flexible panels. More expensive but you get what you pay for.
John

Normfun · January 2019

@Jenn. Yes the switch will work great. That’s the same method I have used on both of my t@bs. Nothing will blow up if you do have it in 1+2 it will simply use the controller with the highest voltage, causing the other to float. Same with vehicle charging, the solar may shut off if the vehicle voltage is high enough.

jkjenn · January 2019

Normfun said:

@Jenn. Yes the switch will work great. That’s the same method I have used on both of my t@bs. Nothing will blow up if you do have it in 1+2 it will simply use the controller with the highest voltage, causing the other to float. Same with vehicle charging, the solar may shut off if the vehicle voltage is high enough.

Thanks!

jkjenn · January 2019

jcfaber1 said:

I would use separate controllers for the two arrays. I think you are using Victron controller and meter? You would only need to add the second controller. I will be doing the same thing with our Lance. I will add 440 watts on top with 50 amp controller and a second 30 amp controller for my 200 watt suitcase. I ordered the controllers and meter through Northern Arizona Wind and Sun. Their tech support is great. Apparently Victron can manage as a network. I have the camper in storage but hope to start in February. I am going to use Merlin Solar flexible panels. More expensive but you get what you pay for.
John

Cool, good to know! Yes, Victron can manage as a network.

The new panels the factory is using have an excellent design and I am very optimistic about their longevity. https://www.pv-magazine.com/2017/01/05/sunflare-unveils-sticky-flexible-solar-panels-at-ces-2017/

jcfaber1 · January 2019

Interesting article. You are correct with the longevity concern especially with hail impact. I paid $3.3 per watt. They are made in California and are supposed to stand up to the elements. They are being used in military and in trucking industry applications. These are also self adhesive. They seem to have a full metal backing. They are much better than the Renogy flexible PV in my suitcase.
John

2 Different Solar Arrays - Would a Switch work?

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