Wiring 12v solar panels into 24v array

[mitiempo]

A solar panel connected directly to the battery will while providing 19v without a load will happily drop the difference in itself to charge a 12v battery. Unfortunately having a starting voltage of 19v means that as the battery reaches full charge the solar panel still has excess volts so can still push its full current in. This means if the solar panel can provide enough amps compared to the battery size it can cook the battery.

The panel doesn't push current into the battery. The battery accepts current based on a given voltage. No regulator - battery charger, alternator, or any other type - controls the amperage only the voltage. At a given voltage - say 14.4 - a battery will only accept what it needs whether the source is a 40 amp alternator or a 100 amp alternator or other source. Now if the voltage is raised to 16 the battery will accept more and that is where the problem is.

 

[William_H]

I imigine that a solar panel, exposed to sunlight, must either deliver electrical power or heat.

If the circuit is broken I think that it will heat up like any other black object in the sunshine. As it gets hotter than its surroundings, it will also lose heat by convection, conduction or radiation. Any electrical power taken from the panel will be offset by a reduction in the heating effect.

You are probably right in terms of conservaion of energy ie the energy can neither be created nor destroyed only converted to different form.
In reality I believe that PV solar panels are just a few percent efficient in terms of radiation arriving to electrical power out. So temperature rise from sun radiation will only be slightly less if electrical energy is taken out. Though to be honest I have never heard of or thought of this concept. olewill

 

[VicS]

You are probably right in terms of conservaion of energy ie the energy can neither be created nor destroyed only converted to different form.
In reality I believe that PV solar panels are just a few percent efficient in terms of radiation arriving to electrical power out. So temperature rise from sun radiation will only be slightly less if electrical energy is taken out. Though to be honest I have never heard of or thought of this concept. olewill

He is right. Sunlight energy falling on the panel will either produce heat or electrical energy. If you take out the electrical energy and stuff it into a battery then there's a bit less energy to turn into heat ... equal to the electrical power taken out.

The concept passed me by at first but dissipated as heat in the panel is were the surplus must go with a PWM regulator as its not dumped into a heat sink like it is with shunt regulators