need help sizing charge controller

[Sunking]

Solar Queen, Is it possible for my panels to charge the batteries whilst the batteries are being discharged??

The answer is YES and NO. Yes if the panels are producing more current than the load is demanding. No if the load is demanding more current then the panels are producing thus discharging the batteries.

[fopoku2k2]

The answer is YES and NO. Yes if the panels are producing more current than the load is demanding. No if the load is demanding more current then the panels are producing thus discharging the batteries.

Makes sense. I think this forum would be nothing without yourself and Amy@altE a.k.a Solar Queen. Thanks for all your time and effort to educate us newbies . . . . . .

[Living Large]

I can't wait to watch that video.

I feel the same way.

So I have been meaning to ask, is it advantageous wiring your panels in series or parallel. As i said earlier, I have plans of upgrading to a 1.5kw PV system by the end of the year and I was wondering if I would be getting more power from my panels if I wire them in series or parallel. I know there is also some cost involved in this selection. I would be grateful if you could explain both cost and power generation differences to me

Thank you

Using panels in series cuts down the current (since W = Volts * Amps). So you can use smaller wires from the combiner box to the CC. Higher current creates more voltage drop (lost power in heating of wires), which may or may not be an issue depending on how far it is between the two.

On the other side, more panels in series has a practical limit due to the maximum voltage the CC can handle. Many are 150V, some are 600V. The voltage you use is the highest expected - which is at open circuit. Open circuit voltage increases as ambient temperature *decreases*, so you look at the OC voltage at the lowest temperature you expect in your region. Solar panel data sheets have coefficients that are used to derive the OC voltage at a temperature different than standard conditions - many CC manufacturers have a utility available on line (string sizer) than you use. You tell it how many panels you have in series, the array parameters (many you just choose your panel from a drop down list, and it fills them in), and it does the rest.