Anyone familiar with these SCCs?

[Dzl]

thanks. I’ve seen that link, but it wasn’t described to me like you just did. Very much appreciated.

I don't necessarily recommend that seller over others, they are just a seller I have come to like and be familiar with and trust, and I like that they have a well curated selection. I also like that they put out a ton of content (videos and articles) aimed at DIYers. An added bonus is that they actively participate on the forum.

 

[DerpsyDoodler]

I don't necessarily recommend that seller over others, they are just a seller I have come to like and be familiar with and trust, and I like that they have a well curated selection. I also like that they put out a ton of content (videos and articles) aimed at DIYers. An added bonus is that they actively participate on the forum.

Thanks. Pretty sure I’ve settled on an inverter now. Think I’ll go with the victron Multiplus 3kva. The 5yr warranty won me over.

So, once again back to the original reason for this thread:

found the below linked SCC by powland, which based on what this forum has to say is made by voltronic.
Are these worthwhile units?

I’ve considered 2x 40a charge controllers instead of 1x 80a.
Aside from redundancy, is there any benefit to running 2x 40a controllers vs 1x 80a?

188.25US $ 25% OFF|Mppt 80a Solar Controller 12v 24v 48v Solar Charger Regulator Battery 36v Setting Charger Max 150vdc Controller Regulator - Solar Controllers - AliExpress

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www.aliexpress.com

Also attached is a rough layout of my solar design plan. Solar panel specs included below, in case those are needed to answer any of my questions. Shortly hereafter, I will post the cables I plan on using for connecting and wiring the panels to the SCC. Would like to make sure everything looks good with proper ratings. Pretty sure it is, but I’m not an EE Or electrician. I just want to make sure there isn’t something I am missing.

Electrical Data @ STC	TSM-250 PC/PA05
Peak Power Watts-PMaX(Wp)	250
PTC Rating	227.5
Power Output Tolerance-PMaX(%)	0/+3
Maximum Power Voltage-VMP(V)	30.3
Maximum Power Current-iMPP(a)	8.27
Open Circuit Voltage-VOC(V)	37.6
Short Circuit Current-iSC(a)	8.85
Module Efficiency ηm (%)	15.3
Values at Standard Test Conditions STC (air Mass aM1.5, irradiance 1000W/m², Cell Temperature 25°C). Power measurement tolerance: ±3%

Mechanical Data
Solar cells	Multicrystalline 156 × 156mm (6 inches)
Cell orientation	60 cells (6 × 10)
Module dimensions	1650 × 992 × 35mm (64.95 × 39.05 × 1.37 inches)
Weight	18.6kg (41.0 lb)
Glass	high transparency solar glass 3.2mm (0.13 inches)
Frame	anodized aluminium alloy
J-Box	iP 65 rated
Cables	Photovoltaic Technology cable 4.0mm² (0.006 inches²),
	1000mm (39.4 inches)
Connector	Original MC4

rather than linking anything, I’ll just explain. Much more simple that way.
panel cables are about 40” long as per above specs. None of the numbers below include this length in their measurement.

1. 10awg 3ft (max) run between each series connection
2. 10awg 5ft (max) run between each parallel y branch connection
3. 30a rated y branch connector for each parallel connection (12.8” long)
4. 10awg 10ft (max) run to solar charge controller

I am planning for the longest runs but hoping to shorten where practical. Based on these specs, what kind of efficiency should I expect from the wiring? I would like as little voltage drop as I can reasonably get.

 

[DerpsyDoodler]

Ahh, found this in the beginners’ area.

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

 

[DerpsyDoodler]

Should I make a new thread for these questions?

 

[Dzl]

Ahh, found this in the beginners’ area.

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

That's a good voltage drop calculator, just be aware it uses 1 way distance which is not the norm, but it is a good accurate calculator if you input everything correctly. To get the total voltage drop you'll need to account for PV <---> MPPT and MPPT <---> Battery Bank

You can also use a calculator like this, which will let you compare hypothetical voltage drop for a range of different wire sizes simultaneously.

 

[Dzl]

Thanks. Pretty sure I’ve settled on an inverter now. Think I’ll go with the victron Multiplus 3kva. The 5yr warranty won me over.

So, once again back to the original reason for this thread:

found the below linked SCC by powland, which based on what this forum has to say is made by voltronic.
Are these worthwhile units?

Can't comment on the brand, I know there are a few forum members who have bought from them.

I’ve considered 2x 40a charge controllers instead of 1x 80a.
Aside from redundancy, is there any benefit to running 2x 40a controllers vs 1x 80a?

There are niche use-cases where more small controllers make sense. Beyond redundancy, the theory is that separate controllers let the MPPT algorithm optimize for the specific conditions of the sub array it manages. If different parts of your array face different directions, or are partially shaded at different times, etc, etc, separate MPPT controllers provide full compartmentalization, similar to parallel strings but more completely. Its a technique that is used on sailboats, and its essentially the same concept as microinverters and DC optimizers.

 

[DerpsyDoodler]

Can't comment on the brand, I know there are a few forum members who have bought from them.

There are niche use-cases where more small controllers make sense. Beyond redundancy, the theory is that separate controllers let the MPPT algorithm optimize for the specific conditions of the sub array

I presume the controllers don’t choose which panels to manage and I have to decide based on which panels I physically connect. So, instead of 2s3p, each controller would get its own serial string of 3, for instance. Which would also mean 2 more holes in my roof and another cable shroud (maybe a way around that). Still, I have to wonder if there is that much value in 2 controllers for my small installation, or do I not know what I do not know?

If you were in my shoes staring at this decision, what would you do? What questions would you ask?

Maybe this is all I need to know: Will it measurably increase my solar efficiency, and if so by how much (estimate or informed guess)?

Supposing I could be convinced In a less quantifiable way: is it standard or best practice to compartmentalize?

 

[Dzl]

I presume the controllers don’t choose which panels to manage and I have to decide based on which panels I physically connect.

Exactly. You would essentially have independent PV arrays each with its own controller feeding the battery bank.

So, instead of 2s3p, each controller would get its own serial string of 3, for instance.
Which would also mean 2 more holes in my roof and another cable shroud (maybe a way around that).

Sounds about right.

Still, I have to wonder if there is that much value in 2 controllers for my small installation, or do I not know what I do not know?

There probably isn't. Its the sort of arrangement you would look into if you have a reason to look into it. It won't solve problems that you don't have. So it all depends on your use case (which coincidentally I have forgotten because I've got a toe in too many concurrent convo's)

If you were in my shoes staring at this decision, what would you do? What questions would you ask?

I don't know what sorta shoes you are wearing . I like compartmentalization and redundancy and I mostly am interested in mobile and marine systems so multiple smaller controllers appeals to me. Even if it only made a few % difference on average. Most people outside of the marine world could care less I think.

Maybe this is all I need to know: Will it measurably increase my solar efficiency, and if so by how much (estimate or informed guess)?

Not in the abstract. But in certain contexts yes. If you don't have a reason to, don't overthink it, it probably won't make a difference. If you had an east and west facing array, or a big sail that shaded one side or the other depending on the direction you turn, then its worth considering. If not, don't overthink it, go with the single controller.

Supposing I could be convinced In a less quantifiable way: is it standard or best practice to compartmentalize?

Only if the conditions would benefit from it.

 

[DerpsyDoodler]

Exactly. You would essentially have independent PV arrays each with its own controller feeding the battery bank.


Sounds about right.


There probably isn't. Its the sort of arrangement you would look into if you have a reason to look into it. It won't solve problems that you don't have. So it all depends on your use case (which coincidentally I have forgotten because I've got a toe in too many concurrent convo's)


I don't know what sorta shoes you are wearing . I like compartmentalization and redundancy and I mostly am interested in mobile and marine systems so multiple smaller controllers appeals to me. Even if it only made a few % difference on average. Most people outside of the marine world could care less I think.


Not in the abstract. But in certain contexts yes. If you don't have a reason to, don't overthink it, it probably won't make a difference. If you had an east and west facing array, or a big sail that shaded one side or the other depending on the direction you turn, then its worth considering. If not, don't overthink it, go with the single controller.


Only if the conditions would benefit from it.

After consideration, I think it’s worth it in terms of redundancy, wire efficiency, and because there’s a slight curve to my roof, so pv strings (albeit slightly) will have a tilt in opposite directions. Use case is a charter bus RV conversion. Thanks for your input!

 

[DerpsyDoodler]

As an update for anyone interested and to sort of close out this thread, I ended up going with 2x 40a renogy li rover SCCs ordered from Amazon; and, have changed my solar design plan from 2s3p to 2x separate strings of 3s. Each string will be managed by its own controller. This simplifies solar panel cabling, as well as increases cabling efficiency (less length, fewer connection points, higher voltage, and lower current all mean less voltage drop). It was kind of a no-brainer to do. Thanks @Dzl ! Consequently, this also meant a small drop in cabling/installation costs (even though 2 small SCCs were slightly more expensive than one larger one $25ish). Winwin bonus. Thanks to everyone who contributed here.