More Solar for "Us"
Ok, I went off.the deep end? Bought 3 used 37watt uni-solar panels and a blue sky 2000e controller for the hefty price of $400, They were being listed as 75w panels, they are not The tested open...
Forum Discussion
dawn was simply an arbitrary gesitmated time reference
you have to measure the voltage into a fix resistance for testing purposes
because you can't get ANY charging until there is enough current & voltage (above 13v for most controllers before they turn on) but panels start producing power when exposed to light
usable power is when there is "ENOUGH POWER" to create a voltage potential high enough where the batteries can absorb it
its often stated that Photo Voltaic cells are "constant current devices", that means a cell of Xsquared size produces Yamps/mill-amps? output,
its the voltage potential across the cell that goes up as the light intensifies
1amp at 1v will do nothing when connected to a controller or 12v battery
but 1a at 14v will charge the battery, the controller will not even turn on until it has a minimum of 13v from the panel
a panel producing 3amps at 5v will do nothing connected to a solar controller and battery, but should light up a flashlight "bulb" if connected directly, even though it is 16.5v max working voltage, with a 4amp short circuit "zero volts" rating and 23volt open circuit NO amps load rating
cells don't convert "zero light" there has to be enough light energy to over come the resistance of the cell and create the current flow
everything I've read refers to them as "constant current" NOT constant voltage
again we're splitting hairs (which I don't want to debate), I was simply saying with an mppt controller higher & voltage arrangement single or stacked panels, it might create usable charge before lower voltage panels of the same power rating, at Dawn was NOT supposed to be a specified statement saying they would produce power at dawn
at 9:30 friday morning I had less usable power than at 9am thursday morning and at mid-afternoon I less 30% less power than the day before
what was the difference ? available light energy ( light intensity )
whether this is amps thru the cell or volts from the cell ??
what matters is the cumulative effect at the controller
you could try measuring the voltage at the controller input wires at different times of the day ?
ever notice how controllers don't display input voltage only input amps ?
if your right about voltage NOT intensifying, but current intensifying, why are voltaic cells called "constant current devices" ?
i really don't care about the nomenclature, i care about the results
was this in reference to raw individual cells or to completed solar panels
you have to measure the voltage into a fix resistance for testing purposes
because you can't get ANY charging until there is enough current & voltage (above 13v for most controllers before they turn on) but panels start producing power when exposed to light
usable power is when there is "ENOUGH POWER" to create a voltage potential high enough where the batteries can absorb it
its often stated that Photo Voltaic cells are "constant current devices", that means a cell of Xsquared size produces Yamps/mill-amps? output,
its the voltage potential across the cell that goes up as the light intensifies
1amp at 1v will do nothing when connected to a controller or 12v battery
but 1a at 14v will charge the battery, the controller will not even turn on until it has a minimum of 13v from the panel
a panel producing 3amps at 5v will do nothing connected to a solar controller and battery, but should light up a flashlight "bulb" if connected directly, even though it is 16.5v max working voltage, with a 4amp short circuit "zero volts" rating and 23volt open circuit NO amps load rating
cells don't convert "zero light" there has to be enough light energy to over come the resistance of the cell and create the current flow
everything I've read refers to them as "constant current" NOT constant voltage
again we're splitting hairs (which I don't want to debate), I was simply saying with an mppt controller higher & voltage arrangement single or stacked panels, it might create usable charge before lower voltage panels of the same power rating, at Dawn was NOT supposed to be a specified statement saying they would produce power at dawn
at 9:30 friday morning I had less usable power than at 9am thursday morning and at mid-afternoon I less 30% less power than the day before
what was the difference ? available light energy ( light intensity )
whether this is amps thru the cell or volts from the cell ??
what matters is the cumulative effect at the controller
you could try measuring the voltage at the controller input wires at different times of the day ?
ever notice how controllers don't display input voltage only input amps ?
if your right about voltage NOT intensifying, but current intensifying, why are voltaic cells called "constant current devices" ?
i really don't care about the nomenclature, i care about the results
The only pages I have found say that voltage is fairly insensitive to light levels.
was this in reference to raw individual cells or to completed solar panels
