I'm hoping for some constructive thoughts on diagnosing what seems to be odd results on my first
solar panel
installation.
I finally got my
solar panels mounted and wired in, along with the
solar controller,
monitor, etc., Monday evening. Granted, yesterday was overcast all day and it’s only been low-angle morning sun this morning, but I’m seeing what appears to be an odd result. Note: I'm not focused (at this point) on the total volts/current produced but the amounts relative to one another. Namely, if my understanding is correct, the outputs read as if they’re wired in series, but I’m almost 100% certain they’re correctly wired in parallel (as I intended).
My understanding is:
Multiple
panels wired in series = voltages additive, amps stay the same
Multiple
panels wired in parallel = voltages stay the same, amps additive
In other words, two 170W-rated panels at 12V:
Series – 24V, 14 amps
Parallel – 12V, 28.33 amps
To wire in series, positive terminal of one panel to negative terminal of second panel
To wire in parallel, connect the two positive terminals together and the two negative terminals together
I intended to wire in parallel. For each panel, I connected the 12AWG panel wire from the positive terminal to a 12AWG red wire using an MC4 connector; and the 12AWG panel wire from the negative terminal to a 12AWG black wire using an MC4 connector, then used ring terminals on the opposite ends of each of the red/black wires to connect to a junction box. At the junction box, I connected 10AWG red (positive) and yellow (negative) wires from the junction box to the solar controller.
I’ve attached photos.
The positive and negative terminals on the panels are clearly marked (hard to see from
photo without zooming, but I’ve annotated); they correspond to male and female MC4 connectors, respectively.
It’s hard to see from the
photo, but I just quadruple-checked that the positive wires are connected to my red wires.
The photo of the junction box shows that all the red(+) are connected to one post and all the black/yellow (-) are connected to the second post.
So I believe that this is the correct way to wire in parallel.
But the photo of the results from the
Victron Connect app shows 27.03V, 6.3A – which for two 12V panels, seems like it’s adding voltage, not amps.
Any thoughts to help make sense of this would be greatly appreciated.
Additional details:
- (2) SunPower SPR-E-Flex-170 170W semi-flexible panels
-
Victron SmartSolar
MPPT 100/30 controller
- Victron
MPPT control
- (6) 6v / 225 Ah lead cell
batteries, wired in series/parallel, i.e., 12v / 225 Ah * 3 = 12v / 675 Ah
battery bank