Mixing Solar Panel Sizes???

[RogerD]

I have an extended chevy express.

I can get (6) 200-watt panels on the roof.

I would ideally like a fan which would turn that into 5 panels.

On each side of the fan, I could fit a 50-watt panel.

Also, I could mount (2) 100-watt flexible panels at the rear under the main panels on a slide and pull them out when parked.

5 - 200 watt
2 - 50 watt
2 - 100 watt

Thoughts?

 

[Moxadox]

Just curious....what do you plan to run with your power plant?

The Dire Wolfess

 

[RogerD]

Just curious....what do you plan to run with your power plant?  

The Dire Wolfess

An air conditioner is the main objective.

 

[AuricTech]

Where on your roof do you plan to install the fan? I ask because shading will become an issue.

I would ditch the idea of adding 50W panels on the sides of the fan, due to shade making them not cost-effective. As for where to install the fan, if you can routinely park on a north-south axis, I'd put the fan on one end of your van, then always park with that end facing away from the Equator. That would keep the fan from shading your panels, no matter the time of day.

 

[Seminole Wind]

i would highly recommend running separate solar charge controllers for the different banks of panels

 

[jimindenver]

What type of charge controller are you thinking of?

 

[RogerD]

What type of charge controller are you thinking of?

I was thinking of one of the 100 amp Victron SmartSolar MPPT controllers.

 

[jimindenver]

That being the case, do not mix the panels. You can either run 6 panels in 3 sets of two, 5 panels in series or 4 panels in 2 sets of two. Running them all in parallel would require at least 8 gauge to bring the power down and I do not know of a branch connector that can take 6 leads and handle more than 50 amps. There is a 5 place branch connector that will do 50 amps but really you want 5 volts or more difference between the battery charging voltage and the working voltage of the panels for the controller to do its thing. Those panels will have a working voltage of 18v which is too low when the battery is at absorb rates.

I know the panels you speak of and suggest them often for vans. at roughly 27 by 58 six would require 162 inches if mounted on a rack. Two 300 watt mono's end to end would need 130 inches, leave room for a fan and cost much less. I had a source for those here at $195 each, it's just too bad I don't have the room to buy some up and bring them with me. You might check craigslist in your area because even two panels in the 350 watt range will take as much room as 6 200 watt panels. (39x154)

 

[RogerD]

That being the case, do not mix the panels. You can either run 6 panels in 3 sets of two, 5 panels in series or 4 panels in 2 sets of two. 

So you are saying just run the 6 panels or I will need 2 charge controllers?

As far as the cost of the panels. I would rather stuff as much as I can on top of the roof and pay more than only have 700 watts and pay much less.

So if I run 5 (200 watt) in series on one controller. Can I mix (2) 50 watt and (2) 100 watt on another controller?

 

[MrNoodly]

Bob's previous van had the panels mounted high enough to clear his open vents (which also had covers). And, really, I don't think there's a noticeable difference between a vent open all the way versus open just enough for the fan to come on, so an over-the-vents rack wouldn't need to be all that high.

 

[RogerD]

I plan to make the panels be able to be tilted.

So I'm not concerned about the fan blocking them.

I plan to build a rear partition to house an AC.

Worst case scenario I will also install a fan as this guy did in the partition instead of the roof.

 

[jonyjoe303]

I have 3 roof vents in the roof and never use them, but they got in the way of installing my 240 watt solar panel. I recommend side vents which I wish I had done originally. I get better airflow from those side vents then I ever got from roof vents, and with side vents you can use flexible ducting to get the air where you need it. 

In the video that guy has his side vent in the back near near his bed, With flexible ducting you can have the side vent in the side of the van and just bring the air to you.


side vents


roof vents, without those vents the panel would have been almost flushed with the roof. And now I got a leak on the roof when it rains which I haven't been able to track down. I thought I did a good job on the vent installation using rv butyl putty tape, but 5 years later it sprung a leak.

 

[jimindenver]

jonyjoe

I see Dicor on the screw heads but not the edge of the flange.

 

[jimindenver]

So you are saying just run the 6 panels or I will need 2 charge controllers?

As far as the cost of the panels. I would rather stuff as much as I can on top of the roof and pay more than only have 700 watts and pay much less.

So if I run 5 (200 watt) in series on one controller. Can I mix (2) 50 watt and (2) 100 watt on another controller?

Yes but again you are mixing panels on the second controller. You can do it with a PWM controller.

 

[highdesertranger]

by looking at those roof vents I can see why you have a leak. highdesertranger

 

[RogerD]

Yes but again you are mixing panels on the second controller. You can do it with a PWM controller.

So I would need 3 MPPT controllers.

For the 2 different sets that are only (2) 100w and (2) 50w, is a cheap MPPT better than PWM.

 

[highdesertranger]

you can mix with a PWM. I do it. highdesertranger

 

[jimindenver]

You are going to end up with a rats nest of wires, fuses, switches and controllers. That stuff all takes up room to mount.

A MPPT controller on the two sliding 100 watt panels will produce almost as much as those and the two 50 watt panels combined on a PWM controller. Honestly the two 50 watts will only produce 5 or so amps and not really worthy of the expense or effort when you will have as much as you will already. The two 100's will produce maybe 11-12 amps, but you still need a MPPT controller that can be set like the big one.