In article ,
Eric F. Richards wrote:
m II wrote:

Anyone hooked up any photovoltaic panels for battery charging? I've been
offered two 75 watt panels and it might be fun to power some small loads
through a battery storage setup.

Major pitfalls? Clouds?

(off to do some research...)
....
I'd tell you how to do it if you weren't such a hateful ****head. In
other words, you're on your own.

So anyone with a concern for truth and justice, (and a bit of a flippant
attitude) is hateful?

Solar cells have a voltage vs. current curve that's roughly square.

|___ Open Circuit voltage
| ====____. maximum power point
V| \ \
| \ \ "Constant" Current
| \ \
| \ \
|---------------
I ^ available current depends on incident light

The no load voltage is determined by quantum physics and is roughly
constant. The current available is determined by the cell area and
the incident sunlight.

In practical terms, if you don't put the cells in a situation where
they're outputting enough current to damage their internal wiring,
you can hook them up and they'll provide a roughly constant current for
charging a battery. You wouldn't want to use too high a voltage array,
as you could damage the battery. And if the sunlight goes away, as it
does every day, leakage back through the cell can discharge the battery.
So the simple "chargers" I've seen where switches to disconnect the
battery when its voltage got too high, or there wasn't enough sunlight.

If you want to be cost effective, you get a fancy charger that
transforms the load on the solar array to the maximum power point
to get the most bang for the buck.

Mark Zenier Washington State resident

(Mark Zenier) wrote:


So anyone with a concern for truth and justice, (and a bit of a flippant
attitude) is hateful?

If his concern was about "truth and justice" AND he'd redirect his
postings to ANY politics group instead of flooding us with them here,
it would be a different story.

In my OPINION (note that I know when to use that word), his worldview
is colored by an unfortunate anti-US bias that a small but vocal
minority in Canada have. Were you here 'round 9/11/01? Remember
psycho-Jim, who was mad on 9/11 for two reasons? 1) not enough
Americans were killed and 2) he couldn't get any music on his radio
that day?

As for his point of view, I might share some of his views. But I
would never, ever consider him an objective observer.


Solar cells have a voltage vs. current curve that's roughly square.

|___ Open Circuit voltage
| ====____. maximum power point
V| \ \
| \ \ "Constant" Current
| \ \
| \ \
|---------------
I ^ available current depends on incident light

The no load voltage is determined by quantum physics and is roughly
constant. The current available is determined by the cell area and
the incident sunlight.

In practical terms, if you don't put the cells in a situation where
they're outputting enough current to damage their internal wiring,
you can hook them up and they'll provide a roughly constant current for
charging a battery. You wouldn't want to use too high a voltage array,
as you could damage the battery.

Bzzzzzt. You were doing fine up to there. Unless you are addressing
alkaline (Ni-Cd) batteries instead of Lead-acid batteries

And if the sunlight goes away, as it
does every day, leakage back through the cell can discharge the battery.

Bzzzzt. Minor problem, not a concern unless you have massively
parallel arrays.

So the simple "chargers" I've seen where switches to disconnect the
battery when its voltage got too high, or there wasn't enough sunlight.

Bzzzt. All chargers are solid-state, PWM based.


If you want to be cost effective, you get a fancy charger that
transforms the load on the solar array to the maximum power point
to get the most bang for the buck.

Back on track again.


Mark Zenier Washington State resident

Obontopic: 14.325 USB hopping, a report of a tornado tearing through
Panama City -- Back Beach Road.



--
Eric F. Richards,
"Don't destroy the Earth! That's where I keep all of my stuff!"
- Squidd on www.fark.com

Eric F. Richards wrote in message . ..
(Mark Zenier) wrote:


So anyone with a concern for truth and justice, (and a bit of a flippant
attitude) is hateful?

If his concern was about "truth and justice" AND he'd redirect his
postings to ANY politics group instead of flooding us with them here,
it would be a different story.

In my OPINION (note that I know when to use that word), his worldview
is colored by an unfortunate anti-US bias that a small but vocal
minority in Canada have. Were you here 'round 9/11/01? Remember
psycho-Jim, who was mad on 9/11 for two reasons? 1) not enough
Americans were killed and 2) he couldn't get any music on his radio
that day?

As for his point of view, I might share some of his views. But I
would never, ever consider him an objective observer.


Solar cells have a voltage vs. current curve that's roughly square.

|___ Open Circuit voltage
| ====____. maximum power point
V| \ \
| \ \ "Constant" Current
| \ \
| \ \
|---------------
I ^ available current depends on incident light

The no load voltage is determined by quantum physics and is roughly
constant. The current available is determined by the cell area and
the incident sunlight.

In practical terms, if you don't put the cells in a situation where
they're outputting enough current to damage their internal wiring,
you can hook them up and they'll provide a roughly constant current for
charging a battery. You wouldn't want to use too high a voltage array,
as you could damage the battery.

Bzzzzzt. You were doing fine up to there. Unless you are addressing
alkaline (Ni-Cd) batteries instead of Lead-acid batteries

And if the sunlight goes away, as it
does every day, leakage back through the cell can discharge the battery.

Bzzzzt. Minor problem, not a concern unless you have massively
parallel arrays.

So the simple "chargers" I've seen where switches to disconnect the
battery when its voltage got too high, or there wasn't enough sunlight.

Bzzzt. All chargers are solid-state, PWM based.


If you want to be cost effective, you get a fancy charger that
transforms the load on the solar array to the maximum power point
to get the most bang for the buck.

Back on track again.


Mark Zenier Washington State resident

Can I put the solar cells in my basement?

Mike Terry.










Obontopic: 14.325 USB hopping, a report of a tornado tearing through
Panama City -- Back Beach Road.

"Mike Terry" wrote in message
om...
Can I put the solar cells in my basement?

Mike Terry.

Sure, right next to your non-existent radios.

MnMikew schrieb:
"Mike Terry" wrote in message
om...

Can I put the solar cells in my basement?

Mike Terry.


Sure, right next to your non-existent radios.

For sure M.T. has more radio(s) than you have brain cells.....




:-)

In article ,
Eric F. Richards wrote:
(Mark Zenier) wrote:


So anyone with a concern for truth and justice, (and a bit of a flippant
attitude) is hateful?

If his concern was about "truth and justice" AND he'd redirect his
postings to ANY politics group instead of flooding us with them here,
it would be a different story.

In my OPINION (note that I know when to use that word), his worldview
is colored by an unfortunate anti-US bias that a small but vocal
minority in Canada have. Were you here 'round 9/11/01? Remember
psycho-Jim, who was mad on 9/11 for two reasons? 1) not enough
Americans were killed and 2) he couldn't get any music on his radio
that day?

As for his point of view, I might share some of his views. But I
would never, ever consider him an objective observer.


Solar cells have a voltage vs. current curve that's roughly square.

|___ Open Circuit voltage
| ====____. maximum power point
V| \ \
| \ \ "Constant" Current
| \ \
| \ \
|---------------
I ^ available current depends on incident light

The no load voltage is determined by quantum physics and is roughly
constant. The current available is determined by the cell area and
the incident sunlight.

In practical terms, if you don't put the cells in a situation where
they're outputting enough current to damage their internal wiring,
you can hook them up and they'll provide a roughly constant current for
charging a battery. You wouldn't want to use too high a voltage array,
as you could damage the battery.

Bzzzzzt. You were doing fine up to there. Unless you are addressing
alkaline (Ni-Cd) batteries instead of Lead-acid batteries

Er, alkaline batteries are primary cells usually, except for those doggy
Rayovac rechargeables. And why would anybody use Nicads or NiMH cells
on a stationary system? Too small, too expensive. For Mike, at
a max of 4.5 amps, a single marine deep discharge lead acid would
probably be good enough.

And if the sunlight goes away, as it
does every day, leakage back through the cell can discharge the battery.

Bzzzzt. Minor problem, not a concern unless you have massively
parallel arrays.

So the simple "chargers" I've seen where switches to disconnect the
battery when its voltage got too high, or there wasn't enough sunlight.

Bzzzt. All chargers are solid-state, PWM based.

Not if you build your own. (Or dig back and look at a few magazine
construction projects).

If you want to be cost effective, you get a fancy charger that
transforms the load on the solar array to the maximum power point
to get the most bang for the buck.

Back on track again.

And if you're just hacking around, you probably won't want to spend
the $$$ for one if it only gets you from 50 watts to 80 watts.

Mark Zenier Washington State resident

(Mark Zenier) wrote:


Bzzzzzt. You were doing fine up to there. Unless you are addressing
alkaline (Ni-Cd) batteries instead of Lead-acid batteries

Er, alkaline batteries are primary cells usually, except for those doggy
Rayovac rechargeables.

Ni-Cds are alkaline, too, and I'm not talking about "D" cells, dummy.
Wet cell Ni-Cds with sodium hydroxide electrolyte and a layer of
mineral oil keeping the electrolyte from being exposed to air are used
in a fair number of systems. They're used in locomotives to start
them. Ni-Iron (Edison) cells are in those boxes at every crossing.

Ni-Cds are dangerous as hell, but handle temperature variation much
better than lead acid.

Bzzzt. All chargers are solid-state, PWM based.

Not if you build your own. (Or dig back and look at a few magazine
construction projects).


All *modern* ones. And a store-bought PWM charger can be had for $30.
And there are designs out there for build your own.

And if you're just hacking around, you probably won't want to spend
the $$$ for one if it only gets you from 50 watts to 80 watts.

If he's using lead-acid and the panel cannot charge faster than C/5,
he can do without a controller altogether. Probably don't want to do
that with a gell cell unless the rate is C/20 or so.

--
Eric F. Richards,
"Nature abhors a vacuum tube." -- J. R. Pierce, Bell Labs, c. 1940

Mark Zenier wrote:

Solar cells have a voltage vs. current curve that's roughly square.

|___ Open Circuit voltage
| ====____. maximum power point
V| \ \
| \ \ "Constant" Current
| \ \
| \ \
|---------------
I ^ available current depends on incident light

The no load voltage is determined by quantum physics and is roughly
constant. The current available is determined by the cell area and
the incident sunlight.

I laid out the panels on the lawn today. It was overcast and I had about
a forty five degree from the panel to the sun. I measured the short
circuit current at **1** amp. That's disgusting. The rated current in
specified light is roughly 4.5 amps per panel. I've paralleled them and
put the bypass diodes in. I also added a blocking diode in each one, as
I want to parallel a small toyish windmill laster on. Open circuit
voltage was a bit over 20 volts.

That 1 amp is troubling. I'll try again at noon tomorrow and pray it
improves.



In practical terms, if you don't put the cells in a situation where
they're outputting enough current to damage their internal wiring,
you can hook them up and they'll provide a roughly constant current for
charging a battery. You wouldn't want to use too high a voltage array,
as you could damage the battery. And if the sunlight goes away, as it
does every day, leakage back through the cell can discharge the battery.
So the simple "chargers" I've seen where switches to disconnect the
battery when its voltage got too high, or there wasn't enough sunlight.

Hopefully the blocking diode is of use.


If you want to be cost effective, you get a fancy charger that
transforms the load on the solar array to the maximum power point
to get the most bang for the buck.

I did a search for that when I saw your post. This one looks
straightforward. I'm wondering if the paralleled setup will work ok, or
if one of these is needed per panel..

http://www.solorb.com/elect/solarcirc/scc2/


This thing is getting interesting. I think I might have found a few 12
volt (six individual cells) fork lift batteries. If they're any good,
I'll be in photovoltaic paradise...



Mark Zenier Washington State resident


Thank you kindly



mike