William_H
Well-Known Member
Solar pamels
These generate about .4volt per cell but they exhibit quite hight internal resistance. That means that if you place a short circuit across the whole panel the power of the panel is dissipated in the resistance of the panel. With no harm to the panel.
This is different from a lead acid battery where the internal resistance is very low such that if you short out the terminals you get a lot of current flowing which is quite dangerous to yourself and the battery.
Shorting out with an amp meter small cells (1.5 volt dry batteries) with an amp meter is a useful test which shows immediately how good the cell is by effectively measuring the internal resistance. Unfortunately it is cruel to the cell in that it will discharge it a bit even in a short time period.
In the case of the solar panel it does no harm and is a much more reliable measure of power capability. ie if you measure volts you can get nearly full voltage 19v in overcast conditions where it will still not provide much power. ie it will drop voltage with a little current drawn. good luck olewill
These generate about .4volt per cell but they exhibit quite hight internal resistance. That means that if you place a short circuit across the whole panel the power of the panel is dissipated in the resistance of the panel. With no harm to the panel.
This is different from a lead acid battery where the internal resistance is very low such that if you short out the terminals you get a lot of current flowing which is quite dangerous to yourself and the battery.
Shorting out with an amp meter small cells (1.5 volt dry batteries) with an amp meter is a useful test which shows immediately how good the cell is by effectively measuring the internal resistance. Unfortunately it is cruel to the cell in that it will discharge it a bit even in a short time period.
In the case of the solar panel it does no harm and is a much more reliable measure of power capability. ie if you measure volts you can get nearly full voltage 19v in overcast conditions where it will still not provide much power. ie it will drop voltage with a little current drawn. good luck olewill