Comparison of wiring solar panels in series or parallel

[Guzziando]

I have a 175W Renogy Solar Panel:
Short Circuit Current (Isc): 10.31A
Optimum Operating Current (Imp): 9.67A
Open Circuit Voltage (Voc): 21.6V
Opitmum Operating Voltage (Vmp): 18.1V
Maximum Series Fuse Rating: 20A

I have added an Eco-worthy 170W solar panel. Unfortunately there was not enough space on my roof for another 175W solar panel.
Short circuit current (Isc): 9.89A
Open Circuit Voltage(Voc): 21.6V
Maximum current (Imp): 9.39A
Open Circuit Voltage:23v
Maximum peak voltage (Vmp):18v

I am using a Victron 100/30 Victron MPPT Controller. Should I wire the panels in series or parallel? What are the advantages/disadvantages of wiring in series or parallel?

 

[RogerIvy]

Your panels are very similar, as such I would wire in series. That way your cable going down through the gland should be fine as the voltage has increased (but not the amps).
But if your cables going down can cope with 20 amps it doesn’t matter if you wire them in parallel. I’d be surprised if they can’t (Unless they’re really thin). Wiring in parallel means if one panel is shaded the other still works.

 

[Jimbohorlicks]

If the panels are monocrystaline then the shading is not so much of am issue.

 

[Guzziando]

Your panels are very similar, as such I would wire in series. That way your cable going down through the gland should be fine as the voltage has increased (but not the amps).
But if your cables going down can cope with 20 amps it doesn’t matter if you wire them in parallel. I’d be surprised if they can’t (Unless they’re really thin). Wiring in parallel means if one panel is shaded the other still works.

It is 4mm from each panel going into 6mm cable from the Y connector into the controller. I have 16mm going from the controller to the battery.

 

[Guzziando]

If the panels are monocrystalline then the shading is not so much of am issue.

Thanks, they are monocrystalline.

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[RogerIvy]

If the panels are monocrystaline then the shading is not so much of am issue.

The bypass diodes will help towards having the whole string not go down. However, both panels performance (ie all panels in the string) will operate at the level of the weakest panel.
So yes, you may still get some reasonable throughput but it will be reduced.
Parallel arrangements are always better in partial shading conditions. I’d love to be corrected but I can’t think of any situations where this is not true.
But let’s face it, a van in the middle of a field will have all panels pumping unless you have something like a satellite dish up.

 

[RogerIvy]

It is 4mm from each panel going into 6mm cable from the Y connector into the controller. I have 16mm going from the controller to the battery.

Sounds like your cables can cope with either configuration. In this case it’s personal preference.