Solar Panel Selection/Fit Help

[cygvan]

i spoke to arizona wind and sun when i was researching what pv panel i was going to use and i recall "steve" telling me that the mc4 connector version was all i needed if it were the only panel i was installing. i would need that and an mc4 extension cable (which would be cut in half) to wire to my next device, typically an mppt controller.

the junction box version works too but was more convenient if additional panels were going to be used as the junction box serves as a combiner box. the current cost is an immaterial $7 difference.

[cygvan]

Originally Posted by daveb

Yes and some panels use light diffusers to minimize the effect. You’ll see both of these in many of the marine panels that have to deal with shadowing from sails and rigging. The Solara panels were designed that way. Like I posted, I’m not sure about each manufacture. I went with Kyrocera because SMB was using them, they carry a warrantee for RV use, and the rack that Aluminess made was designed around that size panel (135w).

actually i used the wrong term, i was referring to a bypass diode. the blocking diode prevents battery discharge at night. i didnt know that manufacturers did anything different for the marine applications. that makes sense on a sailboat for sure.

everyone ive spoken to recommended the kyocera panels without reservation really so i chose that same 135w panel. i changed my mind between that and the 185 panel a few times before i got real lucky and i was given a solar world 245 as a gift.

here is an excerpt from the kyocera installation manual for the kd series panels:

9. BLOCKING DIODES
In systems utilizing a battery, blocking diodes are typically
placed between the battery and PV module output to
prevent battery from discharging at night. KDxxxGX-LPx
series modules are made of polycrystalline cells with high
electrical “back flow” resistance to nighttime battery
discharging. As a result, KDxxxGX-LPx series modules do
not contain a blocking diode when shipped from the factory.
Most PV charge regulators and inverters incorporate
nighttime disconnect feature.

10. BYPASS DIODES
Partial shading of an individual module in a source circuit
string (i.e. two or more modules connected in series) can
cause a reverse voltage across the shaded cells within the
module. Module output current is then forced through the
shaded area by the remaining illuminated cells and other
PV modules in series with the partially shaded module(s).
The current forced through the shaded cells within PV
module (or modules) causes additional module heating and
severe loss of power. All KDxxxGX-LPx series modules are
supplied with factory installed (non user serviceable)
bypass diodes.
The purpose of bypass diodes is to provide a low-resistance
current path around the shaded cells, thereby minimizing
PV module heating and array current losses.
PV modules employ bypass diodes that have:
? Rated Average Forward Current [IF(AV)] Above
maximum system current at highest PV module
operating temperature.
? Rated Repetitive Peak Reverse Voltage [VRRM] Above

[sdwindansea]

Thanks for all the help everyone. I ordered the Kyocera KD135SX-UPU from Northern Arizona Wind & Sun. This is the model with the junction box to keep it simple. It will have a slight overhang on the penthouse top, but not nearly as much as I imagined.

I'm getting it installed on September 19 at SMB Fresno. I may have to rig up a temporary connection before then just to verify that it actually works.

[cygvan]

have you decided on a charge controller?

[jage]

Hope this is relevant:
viewtopic.php?f=14&t=7644

[ANZAC]

Ok, so slung under the roof racks, not my best idea.

On the other hand, no real plans for my roof racks, may as well mount on top of them. Any issues with doing that? (ie wind getting under it while driving?) any pictures of how to do this? Could still use the Yakima H4 or V4 or whatever clamps?

How does the solar panel wiring work with the PH top? Down through a grommet and then down with the existing PH power cable for lights in the corner?

[Ford_6L_E350]

Originally Posted by ANZAC

Ok, so slung under the roof racks, not my best idea.

On the other hand, no real plans for my roof racks, may as well mount on top of them. Any issues with doing that? (ie wind getting under it while driving?) any pictures of how to do this? Could still use the Yakima H4 or V4 or whatever clamps?

How does the solar panel wiring work with the PH top? Down through a grommet and then down with the existing PH power cable for lights in the corner?

Mounted on top of the roof racks is not a bad idea. It is good to have some air under the panel to allow for cooling.

I ran my solar wiring down the rear corner opposite the factory PH wiring. Same idea, different place.

Just come through the fiberglass top outside of the canvas, then up and over the canvas to the inside wiring for no leaks.

Mike

[ANZAC]

Originally Posted by Ford_6L_E350

Mounted on top of the roof racks is not a bad idea. It is good to have some air under the panel to allow for cooling.

I ran my solar wiring down the rear corner opposite the factory PH wiring. Same idea, different place.

Just come through the fiberglass top outside of the canvas, then up and over the canvas to the inside wiring for no leaks.

Mike

Got it. I still have the issue of the vent/fan in the middle of my roof... And how to arrange around that. Maybe two smaller panels slung across two rails...

[BroncoHauler]

Originally Posted by ANZAC

Got it. I still have the issue of the vent/fan in the middle of my roof... And how to arrange around that. Maybe two smaller panels slung across two rails...

How tall is your roof vent? Mount the solar panels on a roof rack OVER the vent. Rain protection for the vent too.


Herb

[ANZAC]

Very tall, it pops open on a hinge up to almost 90deg angle. Pretty much have to avoid it. SMB did warn me that solar+roof vent was annoying.