Solar panel connection voltage...

[mattwithcats]

All,

Installing a 300 Watt grid tie solar panel inverter.

I have two 100 watt, 12 volt, solar panels.

Should I install them in series, yielding 100 watts and 24 volts feeding the inverter,

or in parallel yielding 200 watts and 12 volts feed...

I am thinking 24 volts and 100 watts, total output would be 1.6 amps at 120 volts...

 

[chevrofreak]

Either way it will be 200 watts. You seem to be confusing watts for amps. You will likely get more power from it using them in series. Some grid tie inverters dont do well with low input voltage.

Try it both ways and monitor the actual power produced with a Kill A Watt or something.

 

[mattwithcats]

Figured it out...
Amps is the key, the higher the voltage, the lower the amps...

200 Watts, 12 volts, is 16.6 amps...
200 watts, 24 volts, is 8.3 amps...

Lower amps, higher voltage, has less resistance, and if the wires are undersized, the fewer amps will reduce loss.

Only talking a few milliamps, but i want everything I can get...

 

[Jetronic]

downside is that if 1 panel fails, you'll get nothing...

 

[EdwardC]

Originally Posted By: mattwithcats
Figured it out...
Amps is the key, the higher the voltage, the lower the amps...

200 Watts, 12 volts, is 16.6 amps...
200 watts, 24 volts, is 8.3 amps...

Lower amps, higher voltage, has less resistance, and if the wires are undersized, the fewer amps will reduce loss.

Only talking a few milliamps, but i want everything I can get...


Actually, the resistance is the same, just with increased power loss (i^2 * R).

Assuming the same wire (and resistance), 16.6A will have greater voltage drop than the 8.3A. So, ultimately, like you said, the higher voltage setup is likely the way to go.

 

[JHZR2]

Except that series strings are hampered by the worst performing panels...

I prefer the enphase type system.