2S3P or 3S2P or something else? - Please help! [Serial & Parallel with plenty of room in the MPPT]

[TaiPan]

In a 24V system, with a Victro MPPT 150V-60A, and 6 195W panels (see specs below), would you recommend having 3 panels in series and 2 parallel OR 2 in series and 3 parallel OR something else?

I read in other posts that I should make sure to multiple the VOC*1.25 (I live in Canada) and make sure is below my MPPT 150V, So even if I use 3S2P the total VOC is 67.23*1.25 = 84V and 19.74A way below the 150V 60A. Also, I learnt that Higher voltage = Less Drop & the possibility to use smaller AWG. So unless I missing something like an unbalanced configuration, or the possibility of shade in some of the panels creating an issue, etc. My guess is this is the best configuration. I never done this before, All the help and advice are more than welcome!! Thank you!!


The Solar Powers Specs:

• Rated power: 195W
• Voc: 22.41V
• Vop: 17.9V
• Short circuit current (Isc): 9.87A
• Working current (Iop): 8.89A
• Output Tolerance: ±3%

My System:
========
SOLAR - 6X Eco-Worthy 195W 12V Monocrystalline
MPPT - Victron Energy SmartSolar MPPT Tr 150-Volt 60 amp Solar Charge Controller
WIND - Eco-Worthy 400W Wind Turbine
PWM - Eco-Worthy 20A (For Wind Turbine)
BATTERIES - 4X FlyPower LifePo4 Battery 12v 240Ah
INVERTER - SunGoldPower 24V 6000W (18000W Peak) Pure Sine Wave Split Phase Power Inverter with Charger 60A
BATTERY-BATTERY - Sterling Power - 12V to 24V 70A Pro Batt Ultra
DC-DC - Victron Energy Orion IP20 24/12-Volt 70 amp DC-DC Converter Non-Isolated, High Power
BATTERY SHUNT - Victron BMV-712 Battery Monitor
BUSBAR With Mega Fuses - Victron Lynx Power-in [LYN020102000]
0/4 AWG and 2 AWG Wires

 

[MichaelK]

Considering your Canadian winter lows would be quite low, I plugged your specifications into Midnight's string calculator. With two parallel strings of three panels in series (3S2P), here's what you get. So, you'd be just fine with a Voc of <80V.

Now, you would NOT want to wire all six panels in series. That would push you over 150Voc.

 

[Rocketman]

I would go 3s2p.
The reasons - higher voltage with 3s (less losses)

With 3p I believe you need to fuse the strings.

 

[Supervstech]

3S is not 67v, it is 84 V... when preventing over voltage, you use the VOC number... times 3 then times 1.25 gives you a max voltage of 84.03 ish...
Still well within the 150V limit.
Heck, putting all 5 in series would work for that matter with less than 141V max

now... if only I would read the entire post, not just the first thing that I see... you knew this already.

 

[TaiPan]

Thank you all for your help!! I am taking from this I should forget about the 2S3P, GO WITH 3S2P AND if by any chance I cannot feet the 6 panels in the roof of my RV, perhaps go with 5S and have an extra panel around... I'll make sure to upload pictures once the spring comes and I am able to set things up!! Thanks again!!

 

[Supervstech]

Keep in mind that most panels are hindered by partial shading if all are in series.

 

[TaiPan]

Keep in mind that most panels are hindered by partial shading if all are in series.

Ohh, that's one of the things that I was concerned about, I am going to use a 2 AWG wire so I am not worried about power loss, in this case, would you still recommend 3S2P over 2S3P? Or Would you recommend 3S2P and inter place them [1A,1B,2A,2B,3A,3B] etc? [I am trying to maximize the performance as much as possible - budget concient]

 

[Forbisher]

Ohh, that's one of the things that I was concerned about, I am going to use a 2 AWG wire so I am not worried about power loss, in this case, would you still recommend 3S2P over 2S3P? Or Would you recommend 3S2P and inter place them [1A,1B,2A,2B,3A,3B] etc? [I am trying to maximize the performance as much as possible - budget concient]

2 AWG from the Panels to SCC is huge and not necessary.

10 AWG is only 1.33% voltage drop.
3S2P
54Vmp
18A
20 feet one way.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

2S3P 10 AWG is 3% voltage drop.

Tilting the angle of your panels would give you the most gain but probably not practical on an RV.

 

[TaiPan]

Thank you All!