Controller Size noct or stc

[gr8pix]

Hello,
The panels have 2 listings and I'm a little confused on which to use in a 2s2p configuration for choosing a charge controller for my RV going to a 24v battery then to a Multiplus II. Are these panels 460W or 343W as the differences are significant? I ran the numbers on Nate's website and came up with this. I originally planed to get 4 JJN 400W panels and I don't have this confusion.

	STC	NOCT
Pmp (W)	460	343
Voc (V)	41.78	39.29
Isc (A)	13.63	11.04
Vmp (V)	34.89	32.46
Imp (A)	13.19	10.57
Max Series Fuse(A)	25	25
Controller	Victron 150/70	Victron 100/50
	4x 460w Solar Panels wired in a 2s2p configuration will result in those 1840 Watts being delivered to the charge controller at 104V when the temperature drops to the low temperature as previously defined. Once the Charge Controller Converts those 104V from the solar array down to the ~29V necessary to charge a 24V battery bank, the charge controller will be putting out 64A to charge the battery bank. Important Numbers: Solar Array Wattage: 1840W Temperature Compensated Array Voltage: 104V Controller Output Amperage: 64A Array Short Circuit Amperage: 27.26A Max Series Fuse Rating: 25A *If the Array Short Circuit Amperage is greater than the Max Series Fuse Rating, each series string must be protected by 2x 25A PV Fuses connected to the positive wires on the ‘panel side’ of the MC4 Combiner. RECOMMENDED CHARGE CONTROLLER​ Note: If there are multiple charge controllers listed below; all are suitable, but the one at the top of the list is the best for this array and the most cost-effective choice. Victron SmartSolar MPPT 150|70 Max Solar Array Voltage: 150V Max Solar Array Amperage Output: 70A Max Solar Wattage 12V Battery Bank: 1000W 24V Battery Bank: 2000W 48V Battery Bank: 3000W	4x 343w Solar Panels wired in a 2s2p configuration will result in those 1372 Watts being delivered to the charge controller at 98V when the temperature drops to the low temperature as previously defined. Once the Charge Controller Converts those 98V from the solar array down to the ~29V necessary to charge a 24V battery bank, the charge controller will be putting out 48A to charge the battery bank. Important Numbers: Solar Array Wattage: 1372W Temperature Compensated Array Voltage: 98V Controller Output Amperage: 48A Array Short Circuit Amperage: 22.08A Max Series Fuse Rating: 25A *If the Array Short Circuit Amperage is greater than the Max Series Fuse Rating, each series string must be protected by 2x 25A PV Fuses connected to the positive wires on the ‘panel side’ of the MC4 Combiner. RECOMMENDED CHARGE CONTROLLER​ Note: If there are multiple charge controllers listed below; all are suitable, but the one at the top of the list is the best for this array and the most cost-effective choice. Victron SmartSolar MPPT 100|50 Max Solar Array Voltage: 100V Max Solar Array Amperage Output: 50A Max Solar Wattage 12V Battery Bank: 700W 24V Battery Bank: 1400W 48V Battery Bank: N/A

 

[MisterSandals]

Running 98Voc into a 100/50 is idiotic.

You NEED the 150, stop overthinking this.

 

[gr8pix]

Running 98Voc into a 100/50 is idiotic.

You NEED the 150, stop overthinking this.

Thank you MisterSandals! That's what I thought, I purchased the 150/70. What about the panel specs, what are they 460W or 343W or somewhere in between? I'm attaching the data sheet for you

 

[MisterSandals]

What about the panel specs, what are they 460W or 343W or somewhere in between?

The specs are for 2 different operating conditions. Neither is wrong.
Which conditions do you have? Is Baja California closer to STC or NOTC?
My guess would be STC in the summer and NOTC in the winter.

 

[gr8pix]

The specs are for 2 different operating conditions. Neither is wrong.
Which conditions do you have? Is Baja California closer to STC or NOTC?
My guess would be STC in the summer and NOTC in the winter.

Thank you again for clarifying, I'll be spending most of my time in the Baja/Southern States!

 

[gr8pix]

I have one more question for you MisterSandals. What if I was to use one charge controller for each panel, this would put the numbers down to

Solar Array Wattage: 460W
Temperature Compensated Array Voltage: 52V
Controller Output Amperage: 16A
Array Short Circuit Amperage: 13.63A
Max Series Fuse Rating: 25A

and I could easily get away with 4 of these for my array Victron SmartSolar MPPT 100|20. Would there be any disadvantage of doing it this way? I'm thinking for shading, or if one panel controller goes south I'd have the other 3.

 

[MisterSandals]

460W / 28V charging = 16.4A
So sized well.

The issue I see is running 4 pairs of wire from roof will be inconvenient. And you would want a bus bar to connect the with the battery. 4 controllers will offer very good redundancy and shade effect mitigation.

I think 2 controllers (150/40 if it exists) would be a happy middle ground.

All will likely work equally well, figure out what matters most to you in terms of cost, space and effort to install and maintain.

 

[gr8pix]

Thank you again MisterSandals for your knowledgeable input, I'll update you with my decision as the prices have dropped significantly on the Victron charge controllers.

 

[gr8pix]

Upon careful thought, I decided to go with the 4 x 100/20 mainly for the redundancy in running a 24v system in remote areas such as the Baja where it's difficult to find basic good quality electronics of any voltage, also for the shading effect benefits. I'm full timing in my RV so this is important. The cost difference is an extra $150 for the bus bar, fuses, cabling & split wire loom and 2 extra DC disconnect breakers (the controller cost is the same). Hopefully I made the right choice given my situation. As for the installation, either way is going to be a PIA to do a nice clean job! ;-)