Verifying Charge Controller sizing and setup

[Ged13]

I am sizing the maximum Amp output to charge LifePO4 batteries. What I am coming up is the following:

4 x Rich Solar 9BB solar panels:
https://richsolar.com/collections/solar-panels/products/200-watt-solar-panel

ATTRIBUTE	VALUE
Maximum Power(Pmax)	200W
Maximum Power Voltage(Vmp	20.4V
Maximum Power Current(Imp)	9.80A
Open Circuit Voltage(Voc)	24.3V
Short Circuit Current(Isc)	10.2A
Maximum System Voltage(Vmax)	1000VDC
Temperature Range	-40°C ~ 90°C
Max Series Fuse Rating	20A

Setup

• 4 Solar Panels in 2S2P configuration that will bring 41V Vmp | 20A Imp because RV is pre-wired with 10 AWG wire ~30 feet long the from panels to charge controller
• Victron SmartSolar Charge Controller 100 | 30 per Victron calculator should be large enough if I made no mistakes there.
• 30A MC4 inline fuse - any difference where to install fuse - closer to solar panels or closer to charge controller?

However when I checked the checked the same on https://www.explorist.life/solar-charge-controller-calculator/ the recommendation for the setup above is much larger charge controller:

• Victron 150|60
• If the Array Short Circuit Amperage is greater than the Max Series Fuse Rating, each series string must be protected by 2x 20A PV Fuses connected to the positive wires on the ‘panel side’ of the MC4 Combiner

Thanks in advance for help with properly choosing setup and components.

Best

 

[sunshine_eggo]

800W / 14.5 = 55.2A

2S2P = 48.6Voc (4S would also be permitted)

Victron 100/50

From:

https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-100-30-&-100-50-EN.pdf

Your 2S2P array meets both the 100Voc limit and the 60A input limilt

Why?
800W of panels will very rarely put out their maximum, so you're not going to miss out on anything.
Victron regularly recommends up to 30% over-paneling for the above reason.
100/50 is at a lower price point than 150/60.

 

[Ged13]

As always great info @sunshine_eggo, thank you very much. Ordered Victron 100/50 charge controller.

To confirm, you also recommend with this statement:

• If the Array Short Circuit Amperage is greater than the Max Series Fuse Rating, each series string must be protected by 2x 20A PV Fuses connected to the positive wires on the ‘panel side’ of the MC4 Combiner

 

[sunshine_eggo]

No. for 2P fuse/breaker is not required.

 

[Pim57]

From Victron documents

100/30 Nominal PV power, 12 V 1a,b) 440 Watt
100/50 Nominal PV power, 12 V 1a,b) 700 Watt
150/60 Nominal PV power, 12 V 1a,b) 860 Watt

1a) If more PV power is connected, the controller will limit input power.

So if you choose the 100/50, you’ll miss ~100 Watt when the array is in full sunshine

 

[sunshine_eggo]

So if you choose the 100/50, you’ll miss ~100 Watt when the array is in full sunshine

Not true. "full sunshine" is vague. You'll miss ~100W when:

1000W/m^2 is hitting the panels
cell temperatures are at 25°C.
perfect clear skies
perfect tilt and orientation, etc.

These things rarely occur at the same time.

I looked at 30 days worth of history on my array from late July 2022 to Aug 2022. Data is logged every 60 seconds.

On average, my array exceeded 90% rated an average of 13 minutes per day. This is a little misleading as most days did not exceed 90% rated.

In most cases, where the array met or exceeded rated was due to cloud edging where max sun hits a cool panel and produces a power spike that exceeds rating and tapers off.

On a minute-by-minute basis, my array only produced:

0.47% of the total energy collected when the array was above 90% of rated.
0.16% of the total energy collected when the array was above 100% of rated.

My array is located at 6500 ft elevation in Arizona with overall good sun and where more light reaches the array due to a thinner atmosphere, i.e., about as good as it gets.

When VRM send me the link to download the last six months of data, I'll repeat the analysis.

 

[Ged13]

@Pim57 panels will be flat fixed in roof. I don’t ever expect them maxed out unless I drive to southern America.

@sunshine_eggo are you saying no to 2 20A in-line fuses OR no need any fuse? If just a single fuse is 30A correctly sized for this setup?

 

[sunshine_eggo]

@Pim57 panels will be flat fixed in roof. I don’t ever expect them maxed out unless I drive to southern America.

Yep. 100/50A is more than enough.

@sunshine_eggo are you saying no to 2 20A in-line fuses OR no need any fuse? If just a single fuse is 30A correctly sized for this setup?

None whatsoever required. You may choose to add either if you wish.

 

[acolunga07]

Yep. 100/50A is more than enough.



None whatsoever required. You may choose to add either if you wish.

I’m in a similar situation using the same calculators. The slight differences are that I’m considering RICH 24V panels (https://thesolartheory.com/products...xfdZ7sYXcqUM1jYcg6dOvf6L3kojMZHoaAnFQEALw_wcB) instead of the 12V (https://richsolar.com/collections/solar-panels/products/200-watt-solar-panel) and I want to add two additional panels (via solar briefcase) at a later date.

I am considering the 24V panels because it seems that this would allow me to do a 4P configuration on RV roof (vs a 2S2P configuration with 12V panels). I am limited by the 10 AWG built in wiring that I don’t want to redo. Because of the AC, I suspect that one of the 4 panels will have a good chance of seeing serious shading (depending on the RV’s orientation wrt to sun). I’m concerned the shading on the single panel will bring down one of the strings on the 2S2P 12V option vs just bring down one panel on the 4P 24V config.

Victron’s calculator says the 100/50 is good (with a little panel over sizing) but the explorist calculator says the 150/60 is what I need. The trickier part to consider is future proofing the addition of 1 or 2 solar briefcases (200W each). But maybe I’m just better off getting another 100/50 when I do that project? It seems like the 100/50 doesn’t have ve.can? Would the ve.direct work such that the cerbo gx would coordinate the two 100/50 MPPTs, Orion TR and the multiplus II (shore power or generator) and charge the battery bank correctly?

 

[sunshine_eggo]

I’m in a similar situation using the same calculators. The slight differences are that I’m considering RICH 24V panels (https://thesolartheory.com/products/richsolar-mega-200-watt-24-volt-solar-panel?currency=USD&variant=44963557572894&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=Cj0KCQjwgLOiBhC7ARIsAIeetVCdsvqrWzERWY6TCZD9cmMxfdZ7sYXcqUM1jYcg6dOvf6L3kojMZHoaAnFQEALw_wcB) instead of the 12V (https://richsolar.com/collections/solar-panels/products/200-watt-solar-panel) and I want to add two additional panels (via solar briefcase) at a later date.

I am considering the 24V panels because it seems that this would allow me to do a 4P configuration on RV roof (vs a 2S2P configuration with 12V panels). I am limited by the 10 AWG built in wiring that I don’t want to redo.

If that's a single pair of 10awg from roof to interior, you're limited to 30A. 24V panels would be necessary for the lower current.

Because of the AC, I suspect that one of the 4 panels will have a good chance of seeing serious shading (depending on the RV’s orientation wrt to sun). I’m concerned the shading on the single panel will bring down one of the strings on the 2S2P 12V option vs just bring down one panel on the 4P 24V config.

The 4P would probably fare a little better.

Victron’s calculator says the 100/50 is good (with a little panel over sizing) but the explorist calculator says the 150/60 is what I need.

No idea who the explorist is, and I don't agree.

800W/14.5V = 55A. A 50A controller is 90% of the needed current. Panels flat on an RV roof are rarely going to produce rated power if ever. Producing 90% or greater? Still very rare.

The trickier part to consider is future proofing the addition of 1 or 2 solar briefcases (200W each). But maybe I’m just better off getting another 100/50 when I do that project?

Either that or just deal with the over-paneling. As long as you don't exceed the MPPT PV input limit, you're good. You may not capture 100% of your PV, but you'll get more for longer. You can always add one if the supplemental array is too limited by the single 100/50.

It seems like the 100/50 doesn’t have ve.can?

No

Would the ve.direct work such that the cerbo gx would coordinate the two 100/50 MPPTs, Orion TR and the multiplus II (shore power or generator) and charge the battery bank correctly?

Too many questions. Let me answer the questions I think you're asking:

GX doesn't do any coordinating between chargers other than respect any programmed limits in DVCC. If you set a 50A charge limit in DVCC, the GX will limit 50A charging from all connected sources it can control. MPPT and MP II for sure, but I don't know about the orion. I would expect it does if it's connected to the GX by VE.Direct.

If you're looking for charger coordination like that with VE.Can connected MPPTs, a VE.Smart network between the MPPTs (Smart solar units or Bluesolar units with the BT dongle) will allow the chargers to coordinate with each other. Pretty sure the Orion is left out of that one.

 

[Pi Curio]

As far as so called 'overpanelling' concerns go, I'm currently building a 600W array for Victron 100/20 @12V system voltage.

The 100/50 recommendation is spot on for your 800W array in my humble opinion.

 

[acolunga07]

If that's a single pair of 10awg from roof to interior, you're limited to 30A. 24V panels would be necessary for the lower current.



The 4P would probably fare a little better.



No idea who the explorist is, and I don't agree.

800W/14.5V = 55A. A 50A controller is 90% of the needed current. Panels flat on an RV roof are rarely going to produce rated power if ever. Producing 90% or greater? Still very rare.



Either that or just deal with the over-paneling. As long as you don't exceed the MPPT PV input limit, you're good. You may not capture 100% of your PV, but you'll get more for longer. You can always add one if the supplemental array is too limited by the single 100/50.



No



Too many questions. Let me answer the questions I think you're asking:

GX doesn't do any coordinating between chargers other than respect any programmed limits in DVCC. If you set a 50A charge limit in DVCC, the GX will limit 50A charging from all connected sources it can control. MPPT and MP II for sure, but I don't know about the orion. I would expect it does if it's connected to the GX by VE.Direct.

If you're looking for charger coordination like that with VE.Can connected MPPTs, a VE.Smart network between the MPPTs (Smart solar units or Bluesolar units with the BT dongle) will allow the chargers to coordinate with each other. Pretty sure the Orion is left out of that one.

Thank you for your very thoughtful reply. For reference, the other calculator I mentioned can be found here:

Solar Charge Controller Calculator

www.explorist.life

The RICH 24V 200W panels were incorrectly priced @ $200 when I first posted. It seems that they have since then corrected price to $250. I should have purchased my 8 panels then! (4 panels for RV roof, 4 panels for two 400W solar briefcases).