Am I making sense here ?

[Scot]

I have four of the pictured panels (2 in series X 2, then paralleled in) feeding the CC shown ....
I've purchased another identical CC, and 2 more identical panels with plans of splitting my panels into 3 in series to one CC and 3 in series to the other CC, does this seem the route to go ? 2-4 panel arrays is my hope for the near future, does that appear as doable to ya'll with the CC's pictured ?I do appreciate any info regarding this ....Thanks

 

[snoobler]

Welcome to the forum.

You do not specify your battery voltage and that appears to matter on that MPPT, which is very odd. Most MPPT have a single limit regardless of battery voltage. Since you're considering 3S, I have to assume you're at 48V and are targeting the 150V max input.

Given that assumption, I see no reason for a second SCC as a single SCC can more than handle 6 panels in a 2S3P config.

If it ever gets below 10°C/50°F in your location, absolutely, positively DO NOT DO 3S.

 

[Scot]

Welcome to the forum.

You do not specify your battery voltage and that appears to matter on that MPPT, which is very odd. Most MPPT have a single limit regardless of battery voltage. Since you're considering 3S, I have to assume you're at 48V and are targeting the 150V max input.

Given that assumption, I see no reason for a second SCC as a single SCC can more than handle 6 panels in a 2S3P config.

If it ever gets below 10°C/50°F in your location, absolutely, positively DO NOT DO 3S.

I have a 1400ah 24v bank ....

 

[Scot]

I have a 1400ah 24v bank .... all six on 1 CC would exceed the CC's max watts of 1700 ....(?)

 

[MisterSandals]

With 46.1Voc x2 for your series, you are very close to the max input voltage which is THE number NOT to be exceeded. The Voc number is rated for 25 deg C. On a clear morning near freezing it would likely exceed the max input voltage and kill your SCC. Unless you are in a climate that does not approach freezing, those panels, even at 2S are not very well suited for that SCC.

Exceeding input watts is usually not a problem as it normally represents the usable watts, which of course changes with battery voltage.

 

[snoobler]

Then you should be limiting your PV input to 100VDC, and you must allow temperature margin. Unless you live in an area that never gets below about 10°C/50°F, you should not even do 2S.

While you exceed the SCC by about 400W w/6 panels, it's rare that you'll ever get the full amount. 6P on a single controller would perform nearly as well as 2X SCC w/3P on each.

Based on the info you've provided, and the lack of response concerning your climate, for the equipment listed, you should have 3P on each SCC. Do not do 2S or 3S.

 

[iamrich]

I have a 1400ah 24v bank ....

Can you make it a 700ah 48v bank?

At 48V I would run all 6 panels off the single charge controller 2S3P and just angle the panels in different directions. One set South East, one set South, one set South West. I would think you would peak on a perfect sunny day at less than 1680w, but your day will start earlier and go later.

But at 24v you are real close to the voltage limit if it gets cold in your area (as mentioned above).

 

[snoobler]

Also, can you link the charger? It looks like the garbage 60A I got on Amazon with only 2 stage charging. Fine if you have LFP. Sucks for FLA/AGM/GEL.

 

[Scot]

Then you should be limiting your PV input to 100VDC, and you must allow temperature margin. Unless you live in an area that never gets below about 10°C/50°F, you should not even do 2S.

While you exceed the SCC by about 400W w/6 panels, it's rare that you'll ever get the full amount. 6P on a single controller would perform nearly as well as 2X SCC w/3P on each.

Based on the info you've provided, and the lack of response concerning your climate, for the equipment listed, you should have 3P on each SCC. Do not do 2S or 3S.

I apologize, I didn't notice a climate response was requested .....south texas
thanks for the info

 

[MisterSandals]

I apologize, I didn't notice a climate response was requested .....south texas
thanks for the info

A year or two ago i would have considered that a "no freeze" zone. What do you consider your temperature range to be?

 

[snoobler]

I apologize, I didn't notice a climate response was requested .....south texas
thanks for the info

I indicated temperatures below 10°C/50°F, and you did not address. South Texas likely sees winter morning lows below 50°F. On that basis, it's confirmed, do not series the panels. 3P on each SCC.

 

[Scot]

I indicated temperatures below 10°C/50°F, and you did not address. South Texas likely sees winter morning lows below 50°F. On that basis, it's confirmed, do not series the panels. 3P on each SCC.

A year or two ago i would have considered that a "no freeze" zone. What do you consider your temperature range to be?

typically, on average, around 40 - 100 degrees ....

 

[snoobler]

You have lead acid or LFP?

Link to specs on SCC?

 

[Hedges]

typically, on average, around 40 - 100 degrees ....

"Typical", "Average" don't count.
"Record Cold" is what matters.

I indicated temperatures below 10°C/50°F, and you did not address. South Texas likely sees winter morning lows below 50°F. On that basis, it's confirmed, do not series the panels. 3P on each SCC.

Can you make it a 700ah 48v bank?

At 48V I would run all 6 panels off the single charge controller 2S3P and just angle the panels in different directions. One set South East, one set South, one set South West. I would think you would peak on a perfect sunny day at less than 1680w, but your day will start earlier and go later.

But at 24v you are real close to the voltage limit if it gets cold in your area (as mentioned above).

If you can do a higher voltage battery (different inverter) that has several benefits.
Higher voltage PV string means lower power loss in wires and cheaper wires.
Battery wires and fuses, and power loss, similarly benefit.
Same charge controller handles more PV power.

Looks like 24V battery doesn't let you do 2s PV, but 48V would.
You can run much larger motor loads with a 48V inverter.

 

[Scot]

"Typical", "Average" don't count.
"Record Cold" is what matters.





If you can do a higher voltage battery (different inverter) that has several benefits.
Higher voltage PV string means lower power loss in wires and cheaper wires.
Battery wires and fuses, and power loss, similarly benefit.
Same charge controller handles more PV power.

Looks like 24V battery doesn't let you do 2s PV, but 48V would.
You can run much larger motor loads with a 48V inverter.

I've been happy with my 24v 1400ah 1320w system for a couple years now, I wired heavy then for this possibility.
I'm just looking into some possible options for the future, this is strictly for hurricane back up etc.
thanks for your time

(it got down to 5 in 1930, but that's just recorded history)

 

[iamrich]

I've been happy with my 24v 1400ah 1320w system for a couple years now, I wired heavy then for this possibility.
I'm just looking into some possible options for the future, this is strictly for hurricane back up etc.
thanks for your time

(it got down to 5 in 1930, but that's just recorded history)

So I would go with: 2S3P and just angle the panels in different directions. One set South East, one set South, one set South West. I would think you would peak on a perfect sunny day at less than 1680w, but your day will start earlier and go later. You would only need to add more panels. You are risking going over voltage which is bad, but if you have been getting away with it for two years (including our recent snowmeggedon) I think you are not risking anything more by going this way.

 

[snoobler]

So I would go with: 2S3P and just angle the panels in different directions. One set South East, one set South, one set South West. I would think you would peak on a perfect sunny day at less than 1680w, but your day will start earlier and go later. You would only need to add more panels. You are risking going over voltage which is bad, but if you have been getting away with it for two years (including our recent snowmeggedon) I think you are not risking anything more by going this way.

It doesn't have to be at freezing. It has to be below 25°C. The question is how much.

I would not go 2S unless I calculated the temp-adjusted Voc.

I've been happy with my 24v 1400ah 1320w system for a couple years now, I wired heavy then for this possibility.
I'm just looking into some possible options for the future, this is strictly for hurricane back up etc.
thanks for your time

(it got down to 5 in 1930, but that's just recorded history)

Again, are these 1400Ah lead-acid? If so, you're likely doing harm. Charging at too low of a current encourages sulfation. A 1400Ah battery needs to be charged around 140A. 140A * 24V = 3360W. You're well short of that. However, if these are only used for hurricane backup, and mostly sitting in float, the existing solar is likely fine, it's just limiting to what you can use on a daily basis.

 

[iamrich]

It doesn't have to be at freezing. It has to be below 25°C. The question is how much.

I would not go 2S unless I calculated the temp-adjusted Voc.

I understand, but he mentioned the current setup has been running for years in 2S2P, so either he is really lucky, or the controller is under rated. South Texas stays pretty warm, but I know they got cold temps this year when Texas was frozen. I don't think adding another two panels in 2S configuration is going to change the risk he is already taking?

The safe bet would be as you mentioned. Get a second controller and run both 3P.

 

[snoobler]

I wouldn't hesitate to put 6P on the one controller, but he said he already bought it.

 

[Scot]

I understand, but he mentioned the current setup has been running for years in 2S2P, so either he is really lucky, or the controller is under rated. South Texas stays pretty warm, but I know they got cold temps this year when Texas was frozen. I don't think adding another two panels in 2S configuration is going to change the risk he is already taking?

The safe bet would be as you mentioned. Get a second controller and run b