[RE-wrenches] crystalline VS uni-solar

Larry Crutcher larry at starlightsolar.com
Fri Oct 31 18:08:52 PDT 2008


Geoff,

When you mentioned "plenty of partial shading", that settled the issue  
for me. Every cell in Uni-Solar modules have a bypass diode allowing  
them to handle shading better than any other module I know of. For  
potentially shaded areas or high ambient temperatures, it is our  
module of choice. After 6 years of selling and installing Uni-Solar,  
we have only had one failure. Their performance here in our very hot  
climate is outstanding.

As for the mismatching module sizes, the 68 is half the voltage of the  
136 but the same current. They both use the same cells. If you are  
only using a single string the MPPT controller will simple adjust for  
the Vmp of that circuit. However, as with any array, if you have  
multiple strings with mismatched string voltages, the controller will  
"see" a lower average and you will, at the least, be wasting power.  
The bypass diodes have nothing to do with mismatched strings.

If you are comparing arrays with different angle of incidence and  
without shading, the one most perpendicular to the sun will perform  
the best.

Kindest Regards,

Larry Crutcher
Starlight Solar
11279 S. Glenwood Ave #11114
Yuma, AZ 85367
(928) 941-1660

larry at starlightsolar.com
www.starlightsolar.com


On Oct 31, 2008, at 8:08 AM, Geoff Greenfield wrote:

> As a follow up to my uni-solar post (and thanks to all who provided  
> feedback),  I have a second request:
>
> Any references to recent side-by side "shoot-outs" between Unisolar  
> and conventional crystaline PV?  Scientific studies?  Your own  
> wrench thoughts?
>
> I am more and more often encountering confused customers that are  
> considering unisolar systems at zero-tilt (we are at 40 degrees N),  
> with plenty of partial shading, after getting a pitch about all  
> sorts of advantages of Uni-Solar.  I think that this product has  
> it's role and I occasionally sell it... But I am frustrated when I  
> truly believe I can deliver a better net energy production with a  
> tilted crystalline solution (avoiding the shaded areas).
> For a brighter energy future,
>
> Geoff Greenfield
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