Sanyo HIT panels in off grid app [RE-wrenches]

[Ron Young]

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Okay so here's where I'm getting mired down. The Sanyo 195 has a Voc  
of 68.1. I'm using a temp correction factor of .170 per degree C  
(ref. the chart in Home Power #121) and potential low temps around  
-14 degrees C. in my locale. Based on the 25 degree STC ref. temp  
that works out to 39 x .170 = 27.3 volt correction factor. This  
results in an effective Voc of 68.1 + 27.3 = 95.4 which seems  
unreasonable to me, have I miscalculated? Is the temp correction  
factor only relevant for NEC compliance which doesn't apply in my off- 
grid situation?

Earlier in this discussion I was using a temp. correction factor of  
1.25 which gave me Voc of 68.1 x 1.25 = 85.12.

In either case a series connection of two modules will be impossible  
with an MX60, exceeding the maximum output voltage of ~ 140 V.

Ron Young
earthRight Solar


> From: Ryan Mayfield <ryan_mayfield at earthlink.net>
>
>
> There is a great PV reference chart in the last Home Power, #121. From
> that info, the Sanyo 190 has a Voc temperature correction factor of
> -0.169V per degree C.
>
> Ryan

On 2-Nov-07, at 9:15 AM, Jay Peltz, Peltz Power wrote:

>
> Hi Larry,
>
> The 190s are 67.5v, so x 2 = 135VOC
> which give around 15v to play with.
>
> I don't have their voltage adjustment figures in front of me, but  
> when I did the calculations given our
> record lows, it was close but the numbers did work out OK for the 2  
> in series.
>
> jay
>
> peltz power
>


> From: William Miller <wrmiller at charter.net>
>
> Ron:
>
> When calculating total Voc there are two considerations:  legal and  
> technical.
>
> The NEC compliance has only come into relevance for my projects  
> when the total VOC as corrected by NEC correction factors exceeds  
> 600 VDC.
>
> In this case, the only limit is the manufacturer's design  
> limitations in the charge controller.  Using NEC correction factors  
> is irrelevant here.  Instead, the module manufacturer's or the  
> industries correction factors must be applied.  I don't use them  
> often and don't have them handy, but I am certain someone else on  
> the lists does.
>
> William Miller
>
>


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