Solar Panel regulator

I think it is no problem. It just adds a tiny temperature rise to the silicon.

Since the panel is completely power limited, it is cheap and reliable.

A current source proportional to light intensity in parallel with a string of silicon diode junctions. Instead of doing this, mathematically, I suggest you simulate it with LTspice, a free circuit simulator. It has built in functions to display voltage, current and power dissipation.

Count the number of cells in series in your panel and use that number of diodes. Set the current source to the panel short circuit current rating.

They are so inefficient that the electric energy is only a small part of the total heating caused by the absorbed light. If you want to eliminate that small additional heating, you could add a power resistor in series with the short that drops just enough voltage to keep the blocking diode from conducting. That will move that extra power to the resistor. A better way might be to have that resistor be the heating element in a water heater, so that you would make some use of the energy.

Its a shunt type regulator.

Solar modules are current sources. Get the data sheet of a module to model it.

Cheers

It is also acceptable to simply open the PV to stop charging.

boB

Many solar regulator designs simply dump the excess current to a load when the power is not needed for charging. Others will open the circuit.

Is the short present without the solar panel connected?

-mpm

John Popelish wrote:

High-efficiency (20% +) concentrator cells (intended for use with a concave mirror and a big heatsink) will run measurably cooler when they are under load. This is of course required by the conservation of energy, but can be a bit surprising when you see it in practice. If you measure the temperature carefully, then this should be observable with more common solar cells too. The manufacturers would almost certainly make sure that each individual module can be run open circuit or short circuit or anywhere in between, but see below for arrays made of several panels.

Regarding the possibility of damage, I would only caution that if there are a lot of cells (and a lot of panels) in series then make sure that you have the right arrangement of power diodes connected backwards across the cells (or modules) according to any requirements of the panel manufacturer. The reason for this is that if you have say 50 volts worth of cells in series, and you short circuit them, and one of the cells is slightly in the shade (or slightly less efficient), then the less efficient cell will be subject to a reverse voltage produced by all of the other cells in the series string. So in this example, one cell could get up to 50 Volts across it the opposite polarity from normal (the p-type semiconductor would be negative and the n-type semiconductor would be positive). If the cell can't handle that much reverse voltage (and usually they can't), then it will start to leak current like a so-called Zener diode, and then it will get more hot and more leaky, and current crowding will take place because the hottest parts of that cell will hog the current, and in the worst case the cell could be damaged. This can be prevented by placing a diode across each cell with the p and n regions of the diode connected the opposite way around to the p and n regions of the solar cell. (For less protection but for lower cost, a diode can be placed in reverse across each group of cells or each module.) The diode should be rated for the max current of the solar cells. In normal operation the diode won't conduct, but if a bird s(h)its on one cell then the diode will prevent damage and will also help to maintain the output power of the array. As John says, you can simulate all of this in some SPICE type thing.

Chris