2 SCC and 2 arrays fed into batteries

[pda1]

My system is over-paneled (so I've been told). The array is 2.5kW with only one scc- Victron 150/60 which reduces the power to a maximum of about 1.5 kW. So, I'm not using all the available power.

The new design will have 2 arrays next to each other- 2S-3P and 2S-2P

2S-3P- 1.5 kW
2S-2P- 1 kW

Total- 2.5 kW

Charge controllers
Victron 150/60 for the 2S-3P- 1.5 kW array
Victron 150/35 for the 2S-2P- 1 kW array

Batteries
2 BB- 12v-100ah in series- 24v-100ah

The question I have is, will the new design using 2 arrays and 2 separate SCC indeed pump 2.5kW (I understand there will be losses) OR....will the amperage the batteries can safely be charged at cut and limit me back down to the 1.5kW (plus or minus...of course)?

 

[Mattb4]

My system is over-paneled (so I've been told). The array is 2.5kW with only one scc- Victron 150/60 which reduces the power to a maximum of about 1.5 kW. So, I'm not using all the available power.

The new design will have 2 arrays next to each other- 2S-3P and 2S-2P

2S-3P- 1.5 kW
2S-2P- 1 kW

Total- 2.5 kW

Charge controllers
Victron 150/60 for the 2S-3P- 1.5 kW array
Victron 150/35 for the 2S-2P- 1 kW array

Batteries
2 BB- 12v-100ah in series- 24v-100ah

The question I have is, will the new design using 2 arrays and 2 separate SCC indeed pump 2.5kW (I understand there will be losses) OR....will the amperage the batteries can safely be charged at cut and limit me back down to the 1.5kW (plus or minus...of course)?

Lets do the math:
60a X 27vDC=1620w
35a X 27vDC=945w
Added together they equal 2565w So yes you could reach that amount (though likely 80% of it).

Would this be too much for your battery to charge it at 95 amps? It would seem so. Consult your battery specification for max charge and best charge amperage. The only charge limit is one you set if the Victron SCC has that ability to set less than their full charge rate.

 

[pda1]

Lets do the math:
60a X 27vDC=1620w
35a X 27vDC=945w
Added together they equal 2565w So yes you could reach that amount (though likely 80% of it).

Would this be too much for your battery to charge it at 95 amps? It would seem so. Consult your battery specification for max charge and best charge amperage. The only charge limit is one you set if the Victron SCC has that ability to set less than their full charge rate.

Battleborn says charge the batteries at 50A maximum. My concern is, ok, so the panels are trying to pump 2.5kw (on a good day) into the SCC's but the batteries can only be charged at 50A so I'm stuck again at only being able to get about 1.5kW because the 2 SCC's only will allow 50A.

Another possibility is the Multiplus connected to the system will indeed use the surplus power generated by the panels in excess of what the battery charge limit is set to. I hope I'm right

 

[Mattb4]

Battleborn says charge the batteries at 50A maximum. My concern is, ok, so the panels are trying to pump 2.5kw (on a good day) into the SCC's but the batteries can only be charged at 50A so I'm stuck again at only being able to get about 1.5kW because the 2 SCC's only will allow 50A.

Another possibility is the Multiplus connected to the system will indeed use the surplus power generated by the panels in excess of what the battery charge limit is set to. I hope I'm right

Your SCC do not restrict charging based on the batteries limit. So if your limit is 50a than you would exceed it. However if additional loading was always being applied than what the battery sees would be whatever is left over. Example your multiplus has load drawing 60a worth (60 X 25vDC =1500w) The panels are producing 2500w the load is 1500w the rest can go to the battery or 1000w. 1000w/25vDC=40 amps

I should mention the multiplus only has load if you have something running. It does have a small idle load but that is rather minor. I also should mention that Loads drive supply and not the other way. Panels do not push power, Loads draw it.

 

[SparkyJJO]

This is where an AIO shines because you can tell it a max battery charging current and it'll adjust its MPPT output accordingly. Example: 90A available from solar MPPT output, 50A max charging, and you have 25A load, so the AIO draws 75A from solar to charge the battery.

Separate devices, unless there's some sort of communication between them, can't do this. So you limit your charging current to not go over the battery max, but then if you have a bunch of loads and excess solar, then what?

This is something I'm pondering for eventually if we get the homestead and I hook up my Radian not in AC-coupled mode anymore, what SCC do I use, how do I maximize solar while maximizing my charging rate with a separate MPPT...

 

[pda1]

To be clear, for my batteries, Battleborn says to set the scc charging current to 50A maximum.

 

[sunsurfer]

There was a 4P 4S (16 total) battle born setup in Hawaii that had a melt down. 2 batteries got out of balance in series and the BMS FAILED to disconnect. They where at 18v at the time of melt down, still connected.

I would get a battery balancer just incase the battle borns have a problem with the BMS.

 

[pda1]

Your SCC do not restrict charging based on the batteries limit. So if your limit is 50a than you would exceed it. However if additional loading was always being applied than what the battery sees would be whatever is left over. Example your multiplus has load drawing 60a worth (60 X 25vDC =1500w) The panels are producing 2500w the load is 1500w the rest can go to the battery or 1000w. 1000w/25vDC=40 amps

I should mention the multiplus only has load if you have something running. It does have a small idle load but that is rather minor. I also should mention that Loads drive supply and not the other way. Panels do not push power, Loads draw it.

99% of the time loads are over a minimum of 300w

 

[pda1]

There was a 4P 4S (16 total) battle born setup in Hawaii that had a melt down. 2 batteries got out of balance in series and the BMS FAILED to disconnect. They where at 18v at the time of melt down, still connected.

I would get a battery balancer just incase the battle borns have a problem with the BMS.

Installed a victron balancer last year.

 

[Mattb4]

99% of the time loads are over a minimum of 300w

Thus not enough. Your options if you go the two SCC's (and Arrays) is to either add more battery or limit charging.

 

[Brucey]

To be clear, for my batteries, Battleborn says to set the scc charging current to 50A maximum.

You are going to be battery limited, not SCC limited.

When you series the two 12 100 Ah batteries, the current limit for the pair will still be 50A, but at 24V. So it doesn't matter how many more controllers you add.

 

[pda1]

You are going to be battery limited, not SCC limited.

When you series the two 12 100 Ah batteries, the current limit for the pair will still be 50A, but at 24V. So it doesn't matter how many more controllers you add.

Nuts. So, I'll have to add another 2 batteries.

This is more expensive than a boat.

 

[pda1]

I think I'm asking the wrong questions.

I was just monitoring the actual charging current to the batteries. It's bright and sunny. The charging current measured with a clamp on meter read 25A or so. BUT....from the SCC the current measured 45A. My guess is the excess current is feeding the loads from the Multiplus. (I have DVCC set to 50A).

Previously, my SCC was set to 60A which increased the overall system output.

My guess is that the SCC is never sending 50A to the batteries as the Multiplus/AC loads consume a lot of that.

....I hope.

 

[pda1]

Thus not enough. Your options if you go the two SCC's (and Arrays) is to either add more battery or limit charging.

Limit charging sounds less expensive. Does that mean to set each SCC to 50A....or....set each SCC to 25A?

 

[Brucey]

I think I'm asking the wrong questions.

I was just monitoring the actual charging current to the batteries. It's bright and sunny. The charging current measured with a clamp on meter read 25A or so. BUT....from the SCC the current measured 45A. My guess is the excess current is feeding the loads from the Multiplus. (I have DVCC set to 50A).

Previously, my SCC was set to 60A which increased the overall system output.

My guess is that the SCC is never sending 50A to the batteries as the Multiplus/AC loads consume a lot of that.

....I hope.

I didn't realize you had a Cerbo and DVCC available. Yes, it will allow for additional loads to be fed, while allowing a max of 50A charging to the batteries. In that case your additional controller may help, as you have more than 50A of total load (loads plus charging)

 

[Brucey]

You should be able to see what's happening by connecting to VRM/Victron Connect, it will show you where the power is going.

 

[pda1]

You should be able to see what's happening by connecting to VRM/Victron Connect, it will show you where the power is going.

VRM is very helpful.

Take a look at these screenshots which were taken a few seconds apart from each other (no shading on the panels).

Notice in the first picture that the current is limited to 50A. That's fine.

The second picture shows that the current (Battery summary) is 13.90A.

The second picture means to me the panels are not over-driving the batteries (even though current was set to 50A) and that the entire system is being provided with 50A but that the second picture shows that only 13.9A are being used to charge the batteries. The difference between the 50A and 13.9A is being used to power the loads connected to the Multiplus.

Is that correct?

 

[Brucey]

Show the dashboard page, easier to visualize

 

[pda1]

Ok....

 

[Brucey]

Ok....




View attachment 227999

Yup so 1621W solar input, 797W to load and the balance of 641W to batteries as it's less than 50A going there. The difference would be your system losses (SCC conversion, inverter idle load etc).

 

[pda1]

Phew.....thanks