Subject:
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Re: Solar Power & LEGO
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Newsgroups:
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lugnet.build
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Date:
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Fri, 9 Jul 1999 22:45:29 GMT
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Viewed:
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658 times
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Not a direct question.
In general. Each photo cell will give a certain amount of voltage and current
capability. If a cell is rated at .5 volts, that is generally under very well
lit/bright conditions, which are unusual. It also assumes the panel is pointed
directly at the light source. So your voltage will vary between 0.0v and 0.5
volts depending on conditions.
So how do you make them work for your application in a reliable manner?
It's not easy. Generally you need to wire several of them in series to get a
voltage well above what you need and wire them through a voltage regulator or a
battery charger circuit (with rechargable batteries) to give reliable output.
Not to discourage you, but it's not as easy as you might think. But if you
plan on always running your rcx in the middle of the desert at noon time, with
the panel always pointing at the sun, then it just might work.
On a side note. An interesting design challenge is to build a motor control
circuit that rotates a solar panel to track the path of the sun accross the
sky such that the panel is alway directly exposed to the sun. You could
probably do this with a RCX.
Hope this helps
Ben
In lugnet.build, Alan Carmack writes:
<snip>
> Thanks. I just visited the Edmunds Scientic Page and they said their solar
> panels can be wired in series. The thing I need to know now is how many volts
> and how many amps is appropriate for powering the Rcx. I assume 9 volts. But
> is 12 volts okay? Edmunds has a single panel that is 12v 50 mAmps. They also
> have panels that are anywhere from .5 volts to 3 volts, all with assorted amps
> (current). So my question now is How many amps would I need? Or rather,
> would my Rcx need, for 2-4 motors and 2-3 sensors?
>
> Alan
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Message has 2 Replies:
 | | Re: Solar Power & LEGO
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| Ben Fleskes wrote in message ... (...) Realistically, the load when you try to drive a couple of motors off your RCX is such that solar cells are not a Lego option. 9V at 300mA per motor means you need about 6W coming in. To get that reliably (...) (25 years ago, 11-Jul-99, to lugnet.build)
| | | Re: Solar Power & LEGO
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| (...) This is not far from normal conditions, winter and summer, here in central Texas! :-) (...) Edmund Scientific has an accesory that does just that. Alan (25 years ago, 12-Jul-99, to lugnet.build)
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Message is in Reply To:
| | Re: Solar Power & LEGO
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| (...) Thanks. I just visited the Edmunds Scientic Page and they said their solar panels can be wired in series. The thing I need to know now is how many volts and how many amps is appropriate for powering the Rcx. I assume 9 volts. But is 12 volts (...) (25 years ago, 9-Jul-99, to lugnet.build)
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