Garden Project
Archiver
Posts: 46,084
Hello Stampers
I have a project that I would like to try. The basic stamp would
sleep
most
of the time. About every 24 hours it
would wake up, check soil moisture and if appropriate turn on a
watering
system (soaker hose) for a length of
time. Then its back to sleep.
It seems the power to do this would be small. I have a solar panel
(max
output 12v at 125 ma) that I would like
to integrate into this project. I am considering the possibility of
using
capacitors to store the electricity
from the solar panel.
Could someone help with the calculations needed to determine capacitor
size?
Also anyone know of a source of a valve for the water hose?
Thanks,
Fred
I have a project that I would like to try. The basic stamp would
sleep
most
of the time. About every 24 hours it
would wake up, check soil moisture and if appropriate turn on a
watering
system (soaker hose) for a length of
time. Then its back to sleep.
It seems the power to do this would be small. I have a solar panel
(max
output 12v at 125 ma) that I would like
to integrate into this project. I am considering the possibility of
using
capacitors to store the electricity
from the solar panel.
Could someone help with the calculations needed to determine capacitor
size?
Also anyone know of a source of a valve for the water hose?
Thanks,
Fred
Comments
you might want to go to a boating store and buy a 12v solenoid valve
that they use in the pumping of bilges. The one I found was 42
bucks, surely you can find one cheaper than that but here is the link.
http://www.go2marine.com/frameset.jsp?
servletPath=/g2m/action/GoBPage/id/83009F/hiLiteSku/83009/categoryId/1
1517/
Hope that helps a little bit.
--- In basicstamps@yahoogroups.com, "fpaynefpayne" <fpayne@c...>
wrote:
> Hello Stampers
>
> I have a project that I would like to try. The basic stamp would
> sleep
> most
> of the time. About every 24 hours it
> would wake up, check soil moisture and if appropriate turn on a
> watering
>
> system (soaker hose) for a length of
> time. Then its back to sleep.
>
> It seems the power to do this would be small. I have a solar panel
> (max
>
> output 12v at 125 ma) that I would like
> to integrate into this project. I am considering the possibility of
> using
> capacitors to store the electricity
> from the solar panel.
>
> Could someone help with the calculations needed to determine
capacitor
> size?
>
>
> Also anyone know of a source of a valve for the water hose?
>
> Thanks,
> Fred
used in automatic washing machines. They will probably be 120vac valves,
but you can switch a relay with the stamp and transistor, and control it.
The valves usually have hose bibs molded in so hook up is easy. Be careful
with the AC power!
Jim
http://www.geocities.com/jimforkin2003/
Original Message
From: fpaynefpayne [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=GNIIxXa3FedxB7FS2XEKB5TNgP4T-mhlJYgSvvdMJEWZqJn0JaIL24zV7VGGWRneSA9L7Li-mcKihQ]fpayne@c...[/url
Sent: Wednesday, May 28, 2003 10:20 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Garden Project
Hello Stampers
I have a project that I would like to try. The basic stamp would
sleep
most
of the time. About every 24 hours it
would wake up, check soil moisture and if appropriate turn on a
watering
system (soaker hose) for a length of
time. Then its back to sleep.
It seems the power to do this would be small. I have a solar panel
(max
output 12v at 125 ma) that I would like
to integrate into this project. I am considering the possibility of
using
capacitors to store the electricity
from the solar panel.
Could someone help with the calculations needed to determine capacitor
size?
Also anyone know of a source of a valve for the water hose?
Thanks,
Fred
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low current.
Maybe a boost supply off your 12 volts up to 24 would solve that problem.
Original Message
From: Jim Forkin [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=T3LHsd4-RI93kVWrr-lRTOW6SjjNqJ-SiWNmW3frIik0JCPybT7SNekwr_St7Q3yMzYxKVnfQsA]jjf@p...[/url
Sent: Thursday, May 29, 2003 7:35 AM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Garden Project
Fred, for an inexpensive valve to control water flow, check out the valves
used in automatic washing machines. They will probably be 120vac valves,
but you can switch a relay with the stamp and transistor, and control it.
The valves usually have hose bibs molded in so hook up is easy. Be careful
with the AC power!
Jim
http://www.geocities.com/jimforkin2003/
Original Message
From: fpaynefpayne [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4v-y2mvDziCU9wNx0ILJySv2Tp9p2GiVTWrFbR2iPuEuBAj3aP3-1WwzdurxuU_ANtcYWNLjKIndKKG7Kw]fpayne@c...[/url
Sent: Wednesday, May 28, 2003 10:20 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Garden Project
Hello Stampers
I have a project that I would like to try. The basic stamp would
sleep
most
of the time. About every 24 hours it
would wake up, check soil moisture and if appropriate turn on a
watering
system (soaker hose) for a length of
time. Then its back to sleep.
It seems the power to do this would be small. I have a solar panel
(max
output 12v at 125 ma) that I would like
to integrate into this project. I am considering the possibility of
using
capacitors to store the electricity
from the solar panel.
Could someone help with the calculations needed to determine capacitor
size?
Also anyone know of a source of a valve for the water hose?
Thanks,
Fred
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[noparse][[/noparse]Non-text portions of this message have been removed]
not DC.
-Dustin
--- In basicstamps@yahoogroups.com, Sadler Porter
<porter.sadler@s...> wrote:
> Sprinkler system valves are cheap at Home Depot they run on 24
volts with
> low current.
> Maybe a boost supply off your 12 volts up to 24 would solve that
problem.
>
>
Original Message
> From: Jim Forkin [noparse][[/noparse]mailto:jjf@p...]
> Sent: Thursday, May 29, 2003 7:35 AM
> To: basicstamps@yahoogroups.com
> Subject: RE: [noparse][[/noparse]basicstamps] Garden Project
>
> Fred, for an inexpensive valve to control water flow, check out
the valves
> used in automatic washing machines. They will probably be 120vac
valves,
> but you can switch a relay with the stamp and transistor, and
control it.
> The valves usually have hose bibs molded in so hook up is easy. Be
careful
> with the AC power!
>
> Jim
> http://www.geocities.com/jimforkin2003/
>
>
>
Original Message
> From: fpaynefpayne [noparse][[/noparse]mailto:fpayne@c...]
> Sent: Wednesday, May 28, 2003 10:20 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Garden Project
>
>
> Hello Stampers
>
> I have a project that I would like to try. The basic stamp would
> sleep
> most
> of the time. About every 24 hours it
> would wake up, check soil moisture and if appropriate turn on a
> watering
>
> system (soaker hose) for a length of
> time. Then its back to sleep.
>
> It seems the power to do this would be small. I have a solar panel
> (max
>
> output 12v at 125 ma) that I would like
> to integrate into this project. I am considering the possibility of
> using
> capacitors to store the electricity
> from the solar panel.
>
> Could someone help with the calculations needed to determine
capacitor
> size?
>
>
> Also anyone know of a source of a valve for the water hose?
>
> Thanks,
> Fred
>
>
>
>
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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Subject and
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>
>
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>
>
>
> To UNSUBSCRIBE, just send mail to:
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>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
because it describes a solar/supercapacitor/microcontroller irrigation system.
Also, you might need to use latching valves (I think they are described in the
patent also). These open and close with pulses of power, and thus are more
appropriate for your application because they don't require continuous current.
d...
> Good idea. To clarify, though, sprinkler system values run at 24AC,
> not DC.
>
> -Dustin
>
>
> --- In basicstamps@yahoogroups.com, Sadler Porter
> <porter.sadler@s...> wrote:
> > Sprinkler system valves are cheap at Home Depot they run on 24
> volts with
> > low current.
> > Maybe a boost supply off your 12 volts up to 24 would solve that
> problem.
> >
> >
Original Message
> > Wrom: HDMNNSKVFVWRKJVZCMHVIBGDADRZFS
> > Sent: Thursday, May 29, 2003 7:35 AM
> > To: basicstamps@yahoogroups.com
> > Subject: RE: [noparse][[/noparse]basicstamps] Garden Project
> >
> > Fred, for an inexpensive valve to control water flow, check out
> the valves
> > used in automatic washing machines. They will probably be 120vac
> valves,
> > but you can switch a relay with the stamp and transistor, and
> control it.
> > The valves usually have hose bibs molded in so hook up is easy. Be
> careful
> > with the AC power!
> >
> > Jim
> > http://www.geocities.com/jimforkin2003/
> >
> >
> >
Original Message
> > Wrom: QHYUCDDJBLVLMHAALPTCXLYRWTQTIPWIG
> > Sent: Wednesday, May 28, 2003 10:20 PM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] Garden Project
> >
> >
> > Hello Stampers
> >
> > I have a project that I would like to try. The basic stamp would
> > sleep
> > most
> > of the time. About every 24 hours it
> > would wake up, check soil moisture and if appropriate turn on a
> > watering
> >
> > system (soaker hose) for a length of
> > time. Then its back to sleep.
> >
> > It seems the power to do this would be small. I have a solar panel
> > (max
> >
> > output 12v at 125 ma) that I would like
> > to integrate into this project. I am considering the possibility of
> > using
> > capacitors to store the electricity
> > from the solar panel.
> >
> > Could someone help with the calculations needed to determine
> capacitor
> > size?
> >
> >
> > Also anyone know of a source of a valve for the water hose?
> >
> > Thanks,
> > Fred
> >
> >
> >
> >
> >
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
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> Subject and
> > Body of the message will be ignored.
> >
> >
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> >
> >
> >
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> Subject and
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> >
> >
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> >
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
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>
>
may be able to run them on a lower DC voltage (15-18)
I would say some testing is in order. But much safer than switching 120vc
Original Message
From: dirt939 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=8UFac4FmoLHEyDbrUSaFY6NKeu5Jn_ZF3kTNBW-c3tt0RUIbfsT9pfI5rgnY8Inou4DZl13nxM3wJR_tsQ]stamp@d...[/url
Sent: Thursday, May 29, 2003 12:40 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Garden Project
Good idea. To clarify, though, sprinkler system values run at 24AC,
not DC.
-Dustin
--- In basicstamps@yahoogroups.com, Sadler Porter
<porter.sadler@s...> wrote:
> Sprinkler system valves are cheap at Home Depot they run on 24
volts with
> low current.
> Maybe a boost supply off your 12 volts up to 24 would solve that
problem.
>
>
Original Message
> From: Jim Forkin [noparse][[/noparse]mailto:jjf@p...]
> Sent: Thursday, May 29, 2003 7:35 AM
> To: basicstamps@yahoogroups.com
> Subject: RE: [noparse][[/noparse]basicstamps] Garden Project
>
> Fred, for an inexpensive valve to control water flow, check out
the valves
> used in automatic washing machines. They will probably be 120vac
valves,
> but you can switch a relay with the stamp and transistor, and
control it.
> The valves usually have hose bibs molded in so hook up is easy. Be
careful
> with the AC power!
>
> Jim
> http://www.geocities.com/jimforkin2003/
>
>
>
Original Message
> From: fpaynefpayne [noparse][[/noparse]mailto:fpayne@c...]
> Sent: Wednesday, May 28, 2003 10:20 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Garden Project
>
>
> Hello Stampers
>
> I have a project that I would like to try. The basic stamp would
> sleep
> most
> of the time. About every 24 hours it
> would wake up, check soil moisture and if appropriate turn on a
> watering
>
> system (soaker hose) for a length of
> time. Then its back to sleep.
>
> It seems the power to do this would be small. I have a solar panel
> (max
>
> output 12v at 125 ma) that I would like
> to integrate into this project. I am considering the possibility of
> using
> capacitors to store the electricity
> from the solar panel.
>
> Could someone help with the calculations needed to determine
capacitor
> size?
>
>
> Also anyone know of a source of a valve for the water hose?
>
> Thanks,
> Fred
>
>
>
>
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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Subject and
> Body of the message will be ignored.
>
>
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>
>
>
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>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
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[noparse][[/noparse]Non-text portions of this message have been removed]
these watter sprinkler valves for air cannons needles
to say they will open with two nine volt batterys so
control with a stamp should,nt be a problem
--- Sadler Porter <porter.sadler@s...> wrote:
> Oops. Your right. That would mean, (according to
> other posts I've seen) you
> may be able to run them on a lower DC voltage
> (15-18)
> I would say some testing is in order. But much
> safer than switching 120vc
>
>
Original Message
> From: dirt939 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=K_tuW2N730quYVk7PmaVTl1FZlCCz6fc8SOcZJiuT7cF96pgbDPCv9FDk2qhbA7ifO0rjKmdoaXAu6lvZdbk03c]stamp@d...[/url
> Sent: Thursday, May 29, 2003 12:40 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Garden Project
>
> Good idea. To clarify, though, sprinkler system
> values run at 24AC,
> not DC.
>
> -Dustin
>
>
> --- In basicstamps@yahoogroups.com, Sadler Porter
> <porter.sadler@s...> wrote:
> > Sprinkler system valves are cheap at Home Depot
> they run on 24
> volts with
> > low current.
> > Maybe a boost supply off your 12 volts up to 24
> would solve that
> problem.
> >
> >
Original Message
> > From: Jim Forkin [noparse][[/noparse]mailto:jjf@p...]
> > Sent: Thursday, May 29, 2003 7:35 AM
> > To: basicstamps@yahoogroups.com
> > Subject: RE: [noparse][[/noparse]basicstamps] Garden Project
> >
> > Fred, for an inexpensive valve to control water
> flow, check out
> the valves
> > used in automatic washing machines. They will
> probably be 120vac
> valves,
> > but you can switch a relay with the stamp and
> transistor, and
> control it.
> > The valves usually have hose bibs molded in so
> hook up is easy. Be
> careful
> > with the AC power!
> >
> > Jim
> > http://www.geocities.com/jimforkin2003/
> >
> >
> >
Original Message
> > From: fpaynefpayne [noparse][[/noparse]mailto:fpayne@c...]
> > Sent: Wednesday, May 28, 2003 10:20 PM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] Garden Project
> >
> >
> > Hello Stampers
> >
> > I have a project that I would like to try. The
> basic stamp would
> > sleep
> > most
> > of the time. About every 24 hours it
> > would wake up, check soil moisture and if
> appropriate turn on a
> > watering
> >
> > system (soaker hose) for a length of
> > time. Then its back to sleep.
> >
> > It seems the power to do this would be small. I
> have a solar panel
> > (max
> >
> > output 12v at 125 ma) that I would like
> > to integrate into this project. I am considering
> the possibility of
> > using
> > capacitors to store the electricity
> > from the solar panel.
> >
> > Could someone help with the calculations needed to
> determine
> capacitor
> > size?
> >
> >
> > Also anyone know of a source of a valve for the
> water hose?
> >
> > Thanks,
> > Fred
> >
> >
> >
> >
> >
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed.
> Text in the
> Subject and
> > Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed.
> Text in the
> Subject and
> > Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
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> >
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been
> removed]
>
>
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I got a lot of good ideas on where to get valves etc. Also as someone suggested
the project can easily be done
with power from the house rather than the solar collector.
I was interested in the solar aspect because someone gave me the challenge to do
it with
Capacitors and a solar collector. He also gave me the solar collector (12v at
125 ma max).
No one had any opinions on the capacitor size. Here is what I think. I bet
this will get some responses!
A coulomb is a large quantity of electrons.
An amp is one coulomb per sec moving past a point in a conductor.
Capacitance in farads = charge/volt = Coulomb/volt
One time constant = R*C R(in ohms) C(in farads)
After 5 time constants the capacitor is considered charged.
i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads = 1 sec
It would take 5 seconds to charge a cap through a 1 meg ohm resistor
The charge ( or discharge) curve is nonlinear. The cap will charge or discharge
63% in the first time constant.
Another 63% of what is left during the next time constant.
So if you start out with a cap charged to 12 volts by the solar panel in one
time constant it will discharge to
only 4.4 volts. It (the stamp) better have it’s business done before then.
One possibility:
Lets say the stamp wakes and draws 100 ma for one minute.
R= V/I = 12V/.1 A = 120 ohms
The stamp and other circuitry looks like 120 ohms through which the capacitor is
discharging.
One Time Constant = R*C
C = T/R = 60 sec/ 120 ohms = .5 farads
In my day this size cap was not practical. I have heard 1 farad caps are now
possible.
Anyone know of a source of 1 farad caps at a least 12v or more. Don’t search
just point me in the right
direction.
Thanks
Fred
>Thanks to everyone who answered my questions about the Garden watering
>project.
>I got a lot of good ideas on where to get valves etc. Also as someone
>suggested the project can easily be done
>with power from the house rather than the solar collector.
>I was interested in the solar aspect because someone gave me the challenge
>to do it with
>Capacitors and a solar collector. He also gave me the solar collector
>(12v at 125 ma max).
>
>No one had any opinions on the capacitor size. Here is what I think. I
>bet this will get some responses!
>
>A coulomb is a large quantity of electrons.
>
>An amp is one coulomb per sec moving past a point in a conductor.
>
>Capacitance in farads = charge/volt = Coulomb/volt
>
>One time constant = R*C R(in ohms) C(in farads)
>
>After 5 time constants the capacitor is considered charged.
>
> i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads = 1 sec
> It would take 5 seconds to charge a cap through a 1 meg ohm
> resistor
>
>The charge ( or discharge) curve is nonlinear. The cap will charge or
>discharge 63% in the first time constant.
>Another 63% of what is left during the next time constant.
>
>So if you start out with a cap charged to 12 volts by the solar panel in
>one time constant it will discharge to
>only 4.4 volts. It (the stamp) better have it's business done before then.
>
>One possibility:
>Lets say the stamp wakes and draws 100 ma for one minute.
>
>R= V/I = 12V/.1 A = 120 ohms
>The stamp and other circuitry looks like 120 ohms through which the
>capacitor is discharging.
>
>One Time Constant = R*C
>
>C = T/R = 60 sec/ 120 ohms = .5 farads
>
>In my day this size cap was not practical. I have heard 1 farad caps are
>now possible.
>
>Anyone know of a source of 1 farad caps at a least 12v or more. Don't
>search just point me in the right
>direction.
>
>Thanks
>Fred
Hi Fred -
As far as I've seen, the highest rated Super-Capacitors have a voltage
rating of
4 to 5 volts. Some are even less than that. That will be the limitation.
Bruce
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that sells car audio supplies. They will run you about $80-$120.
Incedently, you made a mistake in your calculations. You assumed
(probably justifiably) that the basicstamp will draw current at a
constant rate and then used this rate to estimate its "resistance."
However, a resistor discharging a capacitor does not draw current at
a constant rate. As the voltage across the capacitor drops, so does
the voltage across the resistor -- using V=iR we can see that the
current through the resistor is falling off linarly. Here's what you
should have done:
The basic stamp will draw 100mA for sixty seconds.
An Ampre is a Coulumb/sec so you need to use 60s * 100mA = 60s *
100mC/s = 6 C of charge.
Afterwards you still need 5 volts on your capacitor. Using the
following formula:
C = q1/V1 = q2/V2
(q2+6C)/12v = q2/5V
q2 = 4.3C
Thus C = q2/V2 = 4.3C/5V = .85F
So you should really get a 1 Farad capacitor. And that assumes that
your basic stamp doesn't draw any current while it's resting.
--- In basicstamps@yahoogroups.com, fred payne <fpayne@c...> wrote:
>
>
>
> Thanks to everyone who answered my questions about the Garden
watering project.
> I got a lot of good ideas on where to get valves etc. Also as
someone suggested the project can easily be done
> with power from the house rather than the solar collector.
> I was interested in the solar aspect because someone gave me the
challenge to do it with
> Capacitors and a solar collector. He also gave me the solar
collector (12v at 125 ma max).
>
> No one had any opinions on the capacitor size. Here is what I
think. I bet this will get some responses!
>
> A coulomb is a large quantity of electrons.
>
> An amp is one coulomb per sec moving past a point in a conductor.
>
> Capacitance in farads = charge/volt = Coulomb/volt
>
> One time constant = R*C R(in ohms) C(in farads)
>
> After 5 time constants the capacitor is considered charged.
>
> i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads =
1 sec
> It would take 5 seconds to charge a cap through a 1 meg
ohm resistor
>
> The charge ( or discharge) curve is nonlinear. The cap will charge
or discharge 63% in the first time constant.
> Another 63% of what is left during the next time constant.
>
> So if you start out with a cap charged to 12 volts by the solar
panel in one time constant it will discharge to
> only 4.4 volts. It (the stamp) better have it's business done
before then.
>
> One possibility:
> Lets say the stamp wakes and draws 100 ma for one minute.
>
> R= V/I = 12V/.1 A = 120 ohms
> The stamp and other circuitry looks like 120 ohms through which the
capacitor is discharging.
>
> One Time Constant = R*C
>
> C = T/R = 60 sec/ 120 ohms = .5 farads
>
> In my day this size cap was not practical. I have heard 1 farad
caps are now possible.
>
> Anyone know of a source of 1 farad caps at a least 12v or more.
Don't search just point me in the right
> direction.
>
> Thanks
> Fred
15V) bank as a backup on a project.
Jonathan
www.madlabs.info
>
> As far as I've seen, the highest rated Super-Capacitors have a voltage
> rating of
> 4 to 5 volts. Some are even less than that. That will be the limitation.
>
> Bruce
>
>
>
>
>
>
> >To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> >from the same email address that you subscribed. Text in the Subject and
> >Body of the message will be ignored.
> >
> >
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>
>
> To UNSUBSCRIBE, just send mail to:
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Body of the message will be ignored.
>
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>
>
>
>
>
or more only 85 cents each. I use these in combination with a solar engine
to power little robots.
Ryan
On Sunday 01 June 2003 02:07 pm, fred payne wrote:
> Anyone know of a source of 1 farad caps at a least 12v or more. Don't
> search just point me in the right direction.
would work fine to run a processor, but anything more would be a real
headache. Besides, most cheap, large value caps will not hold a charge a
long time compared to the supercaps.
Original Message
> www.allelectronics.com under 'super' capacitors. $1.00 each, if you buy
10
> or more only 85 cents each. I use these in combination with a solar
engine
> to power little robots.
> > Anyone know of a source of 1 farad caps at a least 12v or more. Don't
> > search just point me in the right direction.
I have never done this with a cap, but you have to think of the power
consumed by the solenoid. If you leave it energized all the time the water is to
be
on, then the charge will not last very long. If you use a pulse type solenoid
(I think I saw someone suggest this), you have to worry about not having enough
of a charge to shut the water off again. What will happen when the water runs
all day, and through the solar drought that happens every day? Will it just
be a few soggy tomato plants, will you need to get a second mortgage to pay the
water bill, or will people call you looking for Noah?
If you use the solar approach then you may need a backup power supply to
prevent any H2O distress.
Alan Bradford
Plasma Technologies
[noparse][[/noparse]Non-text portions of this message have been removed]
I found the following link a while ago:
http://www.lls.se/~mux/micro/pdf/bs1apps.pdf
This PDF has a ton of BS1 circuits. Including a solar powered BS1 on page 147.
Wow, no that I look at it again, it looks like this PDF is a portion of the
Parallax Basic Stamp Manual 1.2.
Chuck Chargin Jr.
At 02:07 PM 6/1/2003 -0400, you wrote:
>Thanks to everyone who answered my questions about the Garden watering
>project.
>I got a lot of good ideas on where to get valves etc. Also as someone
>suggested the project can easily be done
>with power from the house rather than the solar collector.
>I was interested in the solar aspect because someone gave me the challenge
>to do it with
>Capacitors and a solar collector. He also gave me the solar collector
>(12v at 125 ma max).
>
>No one had any opinions on the capacitor size. Here is what I think. I
>bet this will get some responses!
>
>A coulomb is a large quantity of electrons.
>
>An amp is one coulomb per sec moving past a point in a conductor.
>
>Capacitance in farads = charge/volt = Coulomb/volt
>
>One time constant = R*C R(in ohms) C(in farads)
>
>After 5 time constants the capacitor is considered charged.
>
> i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads = 1 sec
> It would take 5 seconds to charge a cap through a 1 meg ohm
> resistor
>
>The charge ( or discharge) curve is nonlinear. The cap will charge or
>discharge 63% in the first time constant.
>Another 63% of what is left during the next time constant.
>
>So if you start out with a cap charged to 12 volts by the solar panel in
>one time constant it will discharge to
>only 4.4 volts. It (the stamp) better have it's business done before then.
>
>One possibility:
>Lets say the stamp wakes and draws 100 ma for one minute.
>
>R= V/I = 12V/.1 A = 120 ohms
>The stamp and other circuitry looks like 120 ohms through which the
>capacitor is discharging.
>
>One Time Constant = R*C
>
>C = T/R = 60 sec/ 120 ohms = .5 farads
>
>In my day this size cap was not practical. I have heard 1 farad caps are
>now possible.
>
>Anyone know of a source of 1 farad caps at a least 12v or more. Don't
>search just point me in the right
>direction.
>
>Thanks
>Fred
>
>
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Just curious... any particular reason you want to use a capacitor instead of
a battery? I realize you were given a challenge, and I understand the solar
part of it (I have a couple 75W panels here). The capacitor part of it
seems like a round peg in a square hole, though... A battery could store
much more energy and would be less expensive.
Rather than a solenoid, how about a valve operated by a small motor and gear
train. It would only require power during the short time it was opening or
closing. You could mount switches or a position sensor to confirm that the
valve mechanism was truly moving to the fully open and fully closed
positions. The extra energy stored by the battery would be useful to sound
an alarm in the event that the valve did not close properly when commanded
to do so.
Randy
www.glitchbuster.com
Original Message
From: "fred payne" <fpayne@c...>
To: <basicstamps@yahoogroups.com>
Sent: Sunday, June 01, 2003 11:07 AM
Subject: [noparse][[/noparse]basicstamps] Garden Project
>
>
>
> Thanks to everyone who answered my questions about the Garden watering
project.
> I got a lot of good ideas on where to get valves etc. Also as someone
suggested the project can easily be done
> with power from the house rather than the solar collector.
> I was interested in the solar aspect because someone gave me the challenge
to do it with
> Capacitors and a solar collector. He also gave me the solar collector
(12v at 125 ma max).
>
> No one had any opinions on the capacitor size. Here is what I think. I
bet this will get some responses!
>
> A coulomb is a large quantity of electrons.
>
> An amp is one coulomb per sec moving past a point in a conductor.
>
> Capacitance in farads = charge/volt = Coulomb/volt
>
> One time constant = R*C R(in ohms) C(in farads)
>
> After 5 time constants the capacitor is considered charged.
>
> i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads = 1 sec
> It would take 5 seconds to charge a cap through a 1 meg ohm
resistor
>
> The charge ( or discharge) curve is nonlinear. The cap will charge or
discharge 63% in the first time constant.
> Another 63% of what is left during the next time constant.
>
> So if you start out with a cap charged to 12 volts by the solar panel in
one time constant it will discharge to
> only 4.4 volts. It (the stamp) better have it's business done before
then.
>
> One possibility:
> Lets say the stamp wakes and draws 100 ma for one minute.
>
> R= V/I = 12V/.1 A = 120 ohms
> The stamp and other circuitry looks like 120 ohms through which the
capacitor is discharging.
>
> One Time Constant = R*C
>
> C = T/R = 60 sec/ 120 ohms = .5 farads
>
> In my day this size cap was not practical. I have heard 1 farad caps are
now possible.
>
> Anyone know of a source of 1 farad caps at a least 12v or more. Don't
search just point me in the right
> direction.
>
> Thanks
> Fred
>
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
control the current when charging them. Excess current on charge can cause
internal damage and some of the caps must also be limited on discharge. A
short will burn out some of them because the internal resistance is so low.
Jim
http://www.geocities.com/jimforkin2003/
Original Message
From: Rodent [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=nJE9hWJoDLvjMNcafwFBeCBStrm-b6ovBoErfRUHaUTDfX3xOjGEvVKVn-ZyDoEeyFxaNbyN2aYVDaO22TQ]daweasel@s...[/url
Sent: Sunday, June 01, 2003 5:44 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Garden Project
Most solar stuff that runs motors or valves uses storage batteries. Caps
would work fine to run a processor, but anything more would be a real
headache. Besides, most cheap, large value caps will not hold a charge a
long time compared to the supercaps.
Original Message
> www.allelectronics.com under 'super' capacitors. $1.00 each, if you buy
10
> or more only 85 cents each. I use these in combination with a solar
engine
> to power little robots.
> > Anyone know of a source of 1 farad caps at a least 12v or more. Don't
> > search just point me in the right direction.
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
You are right it is more practical to charge a battery or just use electricity
from the house. Do you have any
tips on charging a battery with the solar panel and a source for the battery?
There are some cheap portable drill
batteries at the local hardware store. I was thinking of hacking one of them.
As I think about this Garden Project I think everyone needs a "House stamp"
around to take care of business.
Water the garden, check indoor and outdoor temperature, check for water in the
basement (my sump pump has failed
twice in about 5 years), control x-10 devices, etc, etc.
Thanks for all the help.
Fred
Randy Jones wrote:
> Hi Fred,
>
> Just curious... any particular reason you want to use a capacitor instead of
> a battery? I realize you were given a challenge, and I understand the solar
> part of it (I have a couple 75W panels here). The capacitor part of it
> seems like a round peg in a square hole, though... A battery could store
> much more energy and would be less expensive.
>
> Rather than a solenoid, how about a valve operated by a small motor and gear
> train. It would only require power during the short time it was opening or
> closing. You could mount switches or a position sensor to confirm that the
> valve mechanism was truly moving to the fully open and fully closed
> positions. The extra energy stored by the battery would be useful to sound
> an alarm in the event that the valve did not close properly when commanded
> to do so.
>
> Randy
> www.glitchbuster.com
>
>
Original Message
> From: "fred payne" <fpayne@c...>
> To: <basicstamps@yahoogroups.com>
> Sent: Sunday, June 01, 2003 11:07 AM
> Subject: [noparse][[/noparse]basicstamps] Garden Project
>
> >
> >
> >
> > Thanks to everyone who answered my questions about the Garden watering
> project.
> > I got a lot of good ideas on where to get valves etc. Also as someone
> suggested the project can easily be done
> > with power from the house rather than the solar collector.
> > I was interested in the solar aspect because someone gave me the challenge
> to do it with
> > Capacitors and a solar collector. He also gave me the solar collector
> (12v at 125 ma max).
> >
> > No one had any opinions on the capacitor size. Here is what I think. I
> bet this will get some responses!
> >
> > A coulomb is a large quantity of electrons.
> >
> > An amp is one coulomb per sec moving past a point in a conductor.
> >
> > Capacitance in farads = charge/volt = Coulomb/volt
> >
> > One time constant = R*C R(in ohms) C(in farads)
> >
> > After 5 time constants the capacitor is considered charged.
> >
> > i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads = 1 sec
> > It would take 5 seconds to charge a cap through a 1 meg ohm
> resistor
> >
> > The charge ( or discharge) curve is nonlinear. The cap will charge or
> discharge 63% in the first time constant.
> > Another 63% of what is left during the next time constant.
> >
> > So if you start out with a cap charged to 12 volts by the solar panel in
> one time constant it will discharge to
> > only 4.4 volts. It (the stamp) better have it's business done before
> then.
> >
> > One possibility:
> > Lets say the stamp wakes and draws 100 ma for one minute.
> >
> > R= V/I = 12V/.1 A = 120 ohms
> > The stamp and other circuitry looks like 120 ohms through which the
> capacitor is discharging.
> >
> > One Time Constant = R*C
> >
> > C = T/R = 60 sec/ 120 ohms = .5 farads
> >
> > In my day this size cap was not practical. I have heard 1 farad caps are
> now possible.
> >
> > Anyone know of a source of 1 farad caps at a least 12v or more. Don't
> search just point me in the right
> > direction.
> >
> > Thanks
> > Fred
> >
> >
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >
> >
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
are based on 12 gel cell battery and all ready have
charge controler all you have to do is feed it 12 to
15v a few hunder milliamps to charge it good luck
--- fred payne <fpayne@c...> wrote:
> Randy
> You are right it is more practical to charge a
> battery or just use electricity from the house. Do
> you have any
> tips on charging a battery with the solar panel and
> a source for the battery? There are some cheap
> portable drill
> batteries at the local hardware store. I was
> thinking of hacking one of them.
> As I think about this Garden Project I think
> everyone needs a "House stamp" around to take care
> of business.
> Water the garden, check indoor and outdoor
> temperature, check for water in the basement (my
> sump pump has failed
> twice in about 5 years), control x-10 devices, etc,
> etc.
>
> Thanks for all the help.
> Fred
>
>
> Randy Jones wrote:
>
> > Hi Fred,
> >
> > Just curious... any particular reason you want to
> use a capacitor instead of
> > a battery? I realize you were given a challenge,
> and I understand the solar
> > part of it (I have a couple 75W panels here). The
> capacitor part of it
> > seems like a round peg in a square hole, though...
> A battery could store
> > much more energy and would be less expensive.
> >
> > Rather than a solenoid, how about a valve operated
> by a small motor and gear
> > train. It would only require power during the
> short time it was opening or
> > closing. You could mount switches or a position
> sensor to confirm that the
> > valve mechanism was truly moving to the fully open
> and fully closed
> > positions. The extra energy stored by the battery
> would be useful to sound
> > an alarm in the event that the valve did not close
> properly when commanded
> > to do so.
> >
> > Randy
> > www.glitchbuster.com
> >
> >
Original Message
> > From: "fred payne" <fpayne@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Sunday, June 01, 2003 11:07 AM
> > Subject: [noparse][[/noparse]basicstamps] Garden Project
> >
> > >
> > >
> > >
> > > Thanks to everyone who answered my questions
> about the Garden watering
> > project.
> > > I got a lot of good ideas on where to get valves
> etc. Also as someone
> > suggested the project can easily be done
> > > with power from the house rather than the solar
> collector.
> > > I was interested in the solar aspect because
> someone gave me the challenge
> > to do it with
> > > Capacitors and a solar collector. He also gave
> me the solar collector
> > (12v at 125 ma max).
> > >
> > > No one had any opinions on the capacitor size.
> Here is what I think. I
> > bet this will get some responses!
> > >
> > > A coulomb is a large quantity of electrons.
> > >
> > > An amp is one coulomb per sec moving past a
> point in a conductor.
> > >
> > > Capacitance in farads = charge/volt =
> Coulomb/volt
> > >
> > > One time constant = R*C R(in ohms) C(in
> farads)
> > >
> > > After 5 time constants the capacitor is
> considered charged.
> > >
> > > i.e. 1 meg ohm * 1 micro farad = 1000000 ohms
> * .000001 farads = 1 sec
> > > It would take 5 seconds to charge a
> cap through a 1 meg ohm
> > resistor
> > >
> > > The charge ( or discharge) curve is nonlinear.
> The cap will charge or
> > discharge 63% in the first time constant.
> > > Another 63% of what is left during the next time
> constant.
> > >
> > > So if you start out with a cap charged to 12
> volts by the solar panel in
> > one time constant it will discharge to
> > > only 4.4 volts. It (the stamp) better have it's
> business done before
> > then.
> > >
> > > One possibility:
> > > Lets say the stamp wakes and draws 100 ma for
> one minute.
> > >
> > > R= V/I = 12V/.1 A = 120 ohms
> > > The stamp and other circuitry looks like 120
> ohms through which the
> > capacitor is discharging.
> > >
> > > One Time Constant = R*C
> > >
> > > C = T/R = 60 sec/ 120 ohms = .5 farads
> > >
> > > In my day this size cap was not practical. I
> have heard 1 farad caps are
> > now possible.
> > >
> > > Anyone know of a source of 1 farad caps at a
> least 12v or more. Don't
> > search just point me in the right
> > > direction.
> > >
> > > Thanks
> > > Fred
> > >
> > >
> > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed.
> Text in the Subject and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed.
> Text in the Subject and Body of the message will be
> ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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> Text in the Subject and Body of the message will be
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__________________________________
Do you Yahoo!?
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Well... there are probably contributors on this list who have forgotten more
about battery systems than I know ;-) But I'll take a shot at it...
Before deciding on a battery, I would want to know how much voltage and
current the water valves, etc. would require. For example, would you
perhaps need 12 VDC to operate the water valves? Or possibly 6 VDC? I'll
assume 12 volts, since it might be a good match for your solar panel.
I'm thinking about a small 12 V lead/acid gel battery, which isn't very
expensive (especially compared to monster capacitors). Is your solar panel
possibly one of the units designed to maintain the charge of an automotive
battery? The specs made me think that might be the case. Any idea what the
maximum voltage output of the panel is under maximum sun with no current
output? You might be able to connect it directly to a 12 volt lead acid
battery depending on the panel's max output and the battery.
I'm trying to remember the "rule of thumb" about how much output per day you
could reasonably expect from your solar panel. It depends on the weather,
season, and geographical location, of course. I seem to remember something
about using four hours of output in maximum sunlight as an approximation of
what you'd get from an entire day. I think that was assuming the panel was
in a fixed position (not tracking the sun), but don't remember any
assumptions associated with season or geographic location. What if we
assumed the equivalent of two hours of full output per day. That seems
pretty conservative. I think you said your panel could do 125 mA at 12V, so
that would be...say, 250 mA hour at 12 volts. It would be good for the
battery to have enough capacity to hold several days worth of charge -- just
in case the earth stopped rotating for a while and we were on the dark
side... or something.
How about a battery with 1 A hour (1000 mA hour)? Heck, you could even use
the nicad RC car battery cells for this... If I remember right, the "sub C"
cells were good for 1.7 A hour (1700 mA hour). This goes back about 10
years, and I'm not real confident about it. ,,,Okay, just googled the RC
battery packs and they are showing 3000 mA hr NiMH -- so 1700 mA hr (or
more) nicads sounds about right.
With a battery of nicad cells you would probably need some kind of charging
regulation. If you didn't need to efficiently capture a large percentage of
the solar panel's output, it might be okay to just use a series resistor to
limit the charge to a trickle rate which could continue indefinitely without
battery damage. If you needed to more efficiently capture the panel's
output, you could connect a pass transistor in parallel with the trickle
charge resistance, and turn it on when the battery voltage is below a
certain level (using perhaps a comparator and voltage reference).
An inexpensive microcontroller with A/D could make a nice charge controller.
I attended a Microchip PIC seminar today where they were demoing some of the
new PICs with their "nanoWatt" technology (very low power operation)... They
showed one of the 18-pin parts reading a temperature sensor with the
built-in A/D and running a LCD display showing the reading... from the power
generated by a grapefruit cell. The new 18-pin 16F819 (under $3) has this
very low power technology, and is presently one of the more popular PICs
selling on eBay. It wouldn't be too busy with the charge regulation...
might as well make it read the moisture sensors and control the water valves
too!
Pinning down the energy requirements of the water valves would be a good
first step before putting too much effort into battery selection. Any plans
or thoughts yet in that department?
Randy
www.glitchbuster.com
Original Message
From: "fred payne" <fpayne@c...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, June 02, 2003 10:30 AM
Subject: Re: [noparse][[/noparse]basicstamps] Garden Project
> Randy
> You are right it is more practical to charge a battery or just use
electricity from the house. Do you have any
> tips on charging a battery with the solar panel and a source for the
battery? There are some cheap portable drill
> batteries at the local hardware store. I was thinking of hacking one of
them.
> As I think about this Garden Project I think everyone needs a "House
stamp" around to take care of business.
> Water the garden, check indoor and outdoor temperature, check for water in
the basement (my sump pump has failed
> twice in about 5 years), control x-10 devices, etc, etc.
>
> Thanks for all the help.
> Fred
>
>
> Randy Jones wrote:
>
> > Hi Fred,
> >
> > Just curious... any particular reason you want to use a capacitor
instead of
> > a battery? I realize you were given a challenge, and I understand the
solar
> > part of it (I have a couple 75W panels here). The capacitor part of it
> > seems like a round peg in a square hole, though... A battery could
store
> > much more energy and would be less expensive.
> >
> > Rather than a solenoid, how about a valve operated by a small motor and
gear
> > train. It would only require power during the short time it was opening
or
> > closing. You could mount switches or a position sensor to confirm that
the
> > valve mechanism was truly moving to the fully open and fully closed
> > positions. The extra energy stored by the battery would be useful to
sound
> > an alarm in the event that the valve did not close properly when
commanded
> > to do so.
> >
> > Randy
> > www.glitchbuster.com
> >
> >
Original Message
> > From: "fred payne" <fpayne@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Sunday, June 01, 2003 11:07 AM
> > Subject: [noparse][[/noparse]basicstamps] Garden Project
> >
> > >
> > >
> > >
> > > Thanks to everyone who answered my questions about the Garden watering
> > project.
> > > I got a lot of good ideas on where to get valves etc. Also as someone
> > suggested the project can easily be done
> > > with power from the house rather than the solar collector.
> > > I was interested in the solar aspect because someone gave me the
challenge
> > to do it with
> > > Capacitors and a solar collector. He also gave me the solar collector
> > (12v at 125 ma max).
> > >
> > > No one had any opinions on the capacitor size. Here is what I think.
I
> > bet this will get some responses!
> > >
> > > A coulomb is a large quantity of electrons.
> > >
> > > An amp is one coulomb per sec moving past a point in a conductor.
> > >
> > > Capacitance in farads = charge/volt = Coulomb/volt
> > >
> > > One time constant = R*C R(in ohms) C(in farads)
> > >
> > > After 5 time constants the capacitor is considered charged.
> > >
> > > i.e. 1 meg ohm * 1 micro farad = 1000000 ohms * .000001 farads = 1
sec
> > > It would take 5 seconds to charge a cap through a 1 meg
ohm
> > resistor
> > >
> > > The charge ( or discharge) curve is nonlinear. The cap will charge or
> > discharge 63% in the first time constant.
> > > Another 63% of what is left during the next time constant.
> > >
> > > So if you start out with a cap charged to 12 volts by the solar panel
in
> > one time constant it will discharge to
> > > only 4.4 volts. It (the stamp) better have it's business done before
> > then.
> > >
> > > One possibility:
> > > Lets say the stamp wakes and draws 100 ma for one minute.
> > >
> > > R= V/I = 12V/.1 A = 120 ohms
> > > The stamp and other circuitry looks like 120 ohms through which the
> > capacitor is discharging.
> > >
> > > One Time Constant = R*C
> > >
> > > C = T/R = 60 sec/ 120 ohms = .5 farads
> > >
> > > In my day this size cap was not practical. I have heard 1 farad caps
are
> > now possible.
> > >
> > > Anyone know of a source of 1 farad caps at a least 12v or more. Don't
> > search just point me in the right
> > > direction.
> > >
> > > Thanks
> > > Fred
> > >
> > >
> > >
> > >
> > >
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>
factor in 5 extra days of charge due to cloud cover.
> Pinning down the energy requirements of the water valves would be a
good
> first step before putting too much effort into battery selection.
Any plans
> or thoughts yet in that department?
>