SOALR ENERGY QUESTIN

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The PV panel is almost always designed to have lot a higher voltage, in full sun, than is needed to charge the battery.

The internal impedance of the panel is fairly high. Think of it this way, each photon of light from the sun pushes one electron from here to there. When there is no load on the panel, the electrons just go back where they started inside the panel. When there is a battery connected, some of the electrons flow out one wire through the battery and back through the other. These electrons are taking the long way home and there is a limited number of them so the current is limited.

Once the battery is charged, you need to disconnect the battery from the panel. Often some electronics is provided that does this for you.

How exactly we can know that the battery is charged since the plates are parallely conected to the battery and determine the voltage accross the batery in charge time?

Thanks EC

"MooseFET" ??? ??????: snipped-for-privacy@y38g2000prg.googlegroups.com... > Hi all

The PV panel is almost always designed to have lot a higher voltage, in full sun, than is needed to charge the battery.

The internal impedance of the panel is fairly high. Think of it this way, each photon of light from the sun pushes one electron from here to there. When there is no load on the panel, the electrons just go back where they started inside the panel. When there is a battery connected, some of the electrons flow out one wire through the battery and back through the other. These electrons are taking the long way home and there is a limited number of them so the current is limited.

Once the battery is charged, you need to disconnect the battery from the panel. Often some electronics is provided that does this for you.

Assuming you jsut want a finished product and not to totally design the system, there are modules designed for this duty. Otherwise a (simple) voltage regulator would be a good starting point.

snipped-for-privacy@y38g2000prg.googlegroups.com...

Read the answer you were given, and do a web search on "Impedance".

The battery voltage is determined by the current to the battery and it's state of charge. The PV current, because it is high impedance, is heavily affected by the battery voltage. Depending on the state of charge and the amount of sun shining, a happy medium is found and the batteries charge.

I believe that many PV chargers use switchers to keep the system at an optimal rate of energy extraction/battery charging.