Different types of panels in array...

  I have an odd mix of panels and am planning on buying a MX60 to charge a 12
volt bank.

 If I wired up my pv panels for 48 volts.

 Could I balance the output from each group of panels so it would match the
out put of the others by paralleling some panels in each set?

 For instance, If I have a string of  3-85 watt panels and 1-70 watt panel.
If I wired a 15 watt panel in parallel with the 65. would that work?
      +85- +85- +85- +70-
                                +15-
 Not the best mix and I know that buying another 85 watt panel would be the
way to fix it but just curious about doing this.
 This is not a real installation, just something I was wondering about. For
the sake of this question lets say the 15 watt panel has a slightly higher
voltage than the 85 watt panels...IF that matters much...

 Thanks joe

 
Merlin-7 KI4ILB wrote:

So they're 12v panels, and you're thinking a series string... Remember,
you don't have to tell an MX-60 what the array voltage is, just what
the battery bank votage is.


I'd bet not. When you mix quality and wattage, the losses get
impressive.


If it were me, I'd run the fifteen into the seventy, and then into the
85s in series. You'd end up with what, a 60v nominal string.
Personally, myself, I'd put the 15 on something else, like a automotive
battery trickle charge or something. It's probably not worth the hassle
of racking it up with the big panels.


Yeah, I don't think you could "make" an 85 out of a 70 and a 15.


Like I said, if you want to use them all, put the entire thing in
series, *starting* with the 15. The reason I'm suggesting that, btw, is
that often those iddy biddy panels have very low amperage ratings and
tiny wires, and it would be best if it was "first", not last.

DJ

 DJ wrote:

========================================
I dont get this. Voltages in series add, and the current is the same in
the whole circuit, so it shouldnt matter if any panel is first or last
in the string....

 
BobG wrote:

Hmm... interesting point... my thinking was that the tiny panel is on
the negative end of the virtual panel, so it isn't outputting the high
current or the high voltage, which was my original thought, but as the
negative lead on this virtual panel, it is taking *in* the electrons
"to be pumped" as it were, and both leads should be rated for the panel
power (virtual as it is), not just the postive.

Yep, I'd be concerned too, about the throughput rating on the little
guy in light of that. Yep, another reason to keep it out of the
array...

DJ

 

If all the panels are in SERIES, AND one of the panels in the string is
only capable of 3 Amps, then 3 amps is the maximum current that can be
produced by the string.  The smallest panel will limit the current in
the string, at it's maximum current.  This is BASIC Electrical Knowledge,
guys......