solar cell vs mili amps

[ken]

does someone know the mili amps vs power vs short circut mili amps and can
explane it to this dummy

--

 

[Helmut Wabnig]

On Sat, 31 May 2014 02:18:02 +0000, ken
<f6ceedb9c75b52f7fcc0a55cf0cfbf5d_981@example.com> wrote:

does someone know the mili amps vs power vs short circut mili amps and can
explane it to this dummy

of course, someone knows.

A solar cell is a current source.
Compare it to a good strong battery.
Although you measure a voltage across its connectors,
the voltage is not corrresponding to the energy.
The voltage is more or less constant.
Example: my solar panel has 36 volts output voltage.

If I let the panel unconnected, there is no power transfer.
When I connect a high ohmic load, a small current will flow
while the cell voltage remains unaffected.
Adding a load with a lower Ohm value will increase the current,
but still the cell voltage remains (almost) the same.
Ading a really low ohmic load will increase the current
and the cell voltage will start to drop a little.

Now add a short circuit, the cell will deliver its maximum current
and the voltage drops down to (almost) zero.

That's how solar cells work.
One has to find the point where the product of cell voltage
times load current is the maximum.
Not the maximum current, not the maximum voltage, but the product.
This is called MPPT, maximum power point tracking.

w.

 

[Maynard A. Philbrook Jr.]

In article <7fd4a$53893bda$43de0cc0$11063@news.flashnewsgroups.com>,
f6ceedb9c75b52f7fcc0a55cf0cfbf5d_981@example.com says...

does someone know the mili amps vs power vs short circut mili amps and can
explane it to this dummy

I've always found it best understood as a current limiting supply..

voltage from each cell has a max output of V, depending on the
temperature of the cell. If memory serves the voltage will drop a
bit when the cells get hot however, that does rob from over all
power.

As load re-creases the voltage will sage slightly until you hit
the point were the cells do not have enough current to maintain
the cell output, then the voltage will start dropping like a
rock to maintain a constant current point. This current point is
subjected to cell size and light source.

I guess if you want to measure power, you would take the readings
of voltage at which point the current turns into a constant as
load increases.

P = I * V.

THat is my experience with panels as for power measurements.

Jamie

 

[Rheilly Phoull]

On 01/06/14 00:25, Maynard A. Philbrook Jr. wrote:

In article <7fd4a$53893bda$43de0cc0$11063@news.flashnewsgroups.com>,
f6ceedb9c75b52f7fcc0a55cf0cfbf5d_981@example.com says...

does someone know the mili amps vs power vs short circut mili amps and can
explane it to this dummy

I've always found it best understood as a current limiting supply..

voltage from each cell has a max output of V, depending on the
temperature of the cell. If memory serves the voltage will drop a
bit when the cells get hot however, that does rob from over all
power.

As load re-creases the voltage will sage slightly until you hit
the point were the cells do not have enough current to maintain
the cell output, then the voltage will start dropping like a
rock to maintain a constant current point. This current point is
subjected to cell size and light source.

I guess if you want to measure power, you would take the readings
of voltage at which point the current turns into a constant as
load increases.

P = I * V.

THat is my experience with panels as for power measurements.

Jamie

What has been said is true, just remember that if you connect a
discharged battery across the cell with no controlling device it will
receive slightly less current than if you maintain the voltage at the
peak current ( the MPTP ).