Alt-BEAM Archive
Message #08440
To: beam@sgiblab.sgi.com
From: Bob Shannon bshannon@tiac.net
Date: Sun, 19 Dec 1999 12:48:43 -0500
Subject: [alt-beam] Re: silicon VS SunCeram
I disagree with Adams views below.
Silicon cells are not used in BEAM because the early SE circuits would
lock up
solid with that high a current demand.
The concept that the SunCeram cells are more efficient in lower light
levels is an
interesting assertion, but I think its false.
Silicon cells will deliver far less than their rated power in low light,
but the total
wattage per cell area still seems to be higher than SunCeram cells.
From my experiance
this difference remains in favor of the silicon cells even after a
voltage booster circuit
is used to bring the current/voltage delivery up to the levels expected
from a SunCeram.
Make some measurments, and see for your self. There is a reason NASA
sends silicon
cells out into the dim regions of space, rather than send an amorphous
cell technology.
adam-m wrote:
> Yes Silicon or monocrystalline pv panels (blue) have significant
> amperage over the SunCerams... but there good reasons you don't see
> them in many beam applications...1. They suck like a tornado in
> anything other than bright sunlight. Those wonderful SunCerams
> produce an amazing amount of light in 'less than really bright'
> conditions. To get the numbers you read for the Blue panels, you need
> to be in noon Texas sun.2. Their voltage output is poor, necessitating
> hooking a bunch in series. Now your robots get big and ugly.If you
> want to make big bots that only run outside in direct sunlight, then
> go for the blue PV's.. They will kick ass, and really go fast. BUT
> take them inside and prepare to be underwhelmed.I bought a bunch of
> Monocrystalline cells a while back and after a few tests i was
> completely filled with anticipointment.I like bots that wander around
> on my desk at work under halogen lamps and in bright room lighting.
> For that, SunCerams are the best thing.
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