solar panels in series?

Is the only advantage to this the lower amps and higher volts?
Or does the number of watts produced increase somehow ? :?

[Gotwind Ben]

The power in watts is the same - no magic here.
The voltage doubles in series, current remains the same.
Ohms law
http://www.gotwind.org/diy/circuit.htm

Shouldn't the amps go down?

Power = Volts * Amps

Example:

2 12V panels each outputting 5A

In Series: (12V + 12V) * 5A = 120W
In parallel: 12V * (5A + 5A) = 120W

In Series:
the output voltage = 24V
the output current = 5A

In parallel
the output voltage = 12V
the output current = 10A

The advantage to series is higher voltage less current = less losses in your wires for any fixed Power.

Example:
Wire Resistance = 1 ohm

for
V = 12V
A = 10A
Loss in wire = 10^2 * 1 = 100W

for
V = 60V
A = 2A
Loss in wire = 2^2 * 1 = 4W

If you are directly charging batteries then it makes sense to match the panel output voltage to the battery voltage.

If you are planning on using a battery fed inverter then it is best to design the system for the inverter, and select the inverter based on your power requirements.

If you are planning on grid tie then it is best to select an inverter with a DC input as close to your mains supply as possible (120V/240V) and select/arrange your panels accordingly.

As ghurd said, no magic.

Fish

Hi Fish,

Nice detailed explanation - its always easier to see how it works with an example.

The difference in wire losses for a higher voltage is much more than I would have expected - I guess nothing worse than capturing all that energy only to go and lose a big chunk of it heating up the wires!

John

[Gotwind Ben]

'Fish' seems to like elongated replies :D
Personally,
I very much appreciate the effort and time he offers for free, along with many others.

Thank you.

ben,

No check? I am hurt :mrgreen:

micro,

Yes, Actually doing the math is a very important part of ANY project.

Fish