Alt-BEAM Archive
Message #01048
To: beam@corp.sgi.com
From: TurtleTek@aol.com
Date: Fri, 26 Feb 1999 21:02:06 EST
Subject: [alt-beam] Re: ARG, stupid 'vore! + V vs A
Greetings,
> > I used a 22x33 sunceram solar cell from SB.
>
> Afaik there is a 6-cell 24x22 panel (BP-242221) and a 5-cell 24x33
> which has much larger cells. I'm not aware of a 22x33. What's the
> number of cells?
>
I'm sorry, I meant 24x22. I don't use the "BP-xxxxxx" to identify them because
I've been too lazy to memorize them.
> > First of all, it doesn't trigger at 2.7 like it's supposed to.
>
> The J triggers somewhere between 2.6V and 2.9V. Don't count on
> every J to have exactly the same trigger point. For those trying to
> help you, it would be more interesting to know at what voltage it
> does trigger, if at all.
It triggers between 3.2v-3.4v, usually. And yes, I'm pretty sure I'm using the
J.
> > Another thing I noticed is that the solar cell isn't so great.
> > The cap charges to about 2.5 or so when 2 ft away from a 55 watt
> > light. Maybe I've just been spoiled by the 37x33.
>
> That one consists of 8 cells (each the same size as those on the
> 5-cell 24x33). In the same light, it gives you the same current at
> a 60% higher voltage.
Oh, I thought it gave more (although a small amount) because the Solarbotics
site advertises it as such.
> > The thing is I was told that current is "soo much better" than
> > voltage.
>
> Only if the voltage is sufficient in the light conditions you
> design for. Once you have the voltage, increasing the number of
> cells does not make your SE charge faster, but increasing cell size
> does.
>
>
> I haven't seen a 22x33. Maybe you are comparing the 24x33 with the
> 37x33? The cell size of those panels is the same; in the same
> light, they provide the same current, but the 37 with its 8 cells
> does so at a higher voltage than the 24 with 5 cells. Of course, if
> you add more load, the voltage drops and current rises. A panel
> with 60% more total surface area tends to win.
argg....I don't understand the concept of voltage, and "electrical pressure"
means nothing to me. At least I understand current. Good thing I'm taking
that physics course next year, perhaps that'll help me.
BTW, Steve, I must say that I am one of your "biggest fans", by that I mean
that I look forward to your posts and find them very straight forward and
informative. Keep it up!
8) sorry if I seem like a boot licker.
-TurtleTek
"Yu, shall I tell you what knowledge is? When you know a thing,
say that you know it. When you do not know a thing, admit you
do not know it. This is knowledge."
- K'ung-fu Tzu (Confucius)
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