Two Victron SCC . Run together or seperate.?

[JRH]

If wanting to add more panels to a working system was the goal, and you had 2 Vic 100/ 50 SCC‘s ,would it be better to create two new banks and run them separate and joined with the main SCC OR parallel them as a single higher voltage unit to be joined with the main SCC presently in place ( Vic 150/100). Is that even possible .??? . Can you have 3 different inverters ( all Victron ) all synced to work together ? Would the acceptable voltage / amperage be the sum of the two new Units for that array .. 200v/100a total or limited to the 100/50 each.
I want to place this aux array at different angles than the main system. it will be wired 4s4p at about 87v VOC at STC. But in cold temps here( 10 to 15 below zero F) that would put me sorta close to the limits of 100 v With these units.
I have to plan what gear to get in advance and I’m not sure at all what would be best depending on how I can configure them.
I can’t add anymore panels to the main SCC , that I do know.
I am open as to the best ( any ) way to add them to my present system and still have plenty of voltage headroom left even when it’s very cold…
thank you ,
Jim..

 

[rmaddy]

Add panels to each SCC such that the panel array doesn't exceed the specs for that SCC. Each one will be independent of the others. In other words the panel array on the 150/100 must honor the 150V limit of that SCC. The panel array on a 100/50 must honor the 100V limit of that SCC. Same for the 2nd 100/50.

You would wire each SCC to your bus bars just like your other components. You only need one battery bank.

As long as you setup all of your Victron gear to use the same VE.Smart networking network then all of the devices will communicate and work together. Also be sure to setup all of the SCCs with the same battery charge settings (other than max charge current).

Your total charge current will be the sum of all of the charge controllers. If you have a 150/100 and two 100/50 then you could have up to 200A of charge current. Can your battery bank handle that much charge current? That's your biggest limit. If your battery bank can't handle 200A then set the max charge current of each controller so the total doesn't exceed the max for the battery bank.

 

[JRH]

Add panels to each SCC such that the panel array doesn't exceed the specs for that SCC. Each one will be independent of the others. In other words the panel array on the 150/100 must honor the 150V limit of that SCC. The panel array on a 100/50 must honor the 100V limit of that SCC. Same for the 2nd 100/50.

You would wire each SCC to your bus bars just like your other components. You only need one battery bank.

As long as you setup all of your Victron gear to use the same VE.Smart networking network then all of the devices will communicate and work together. Also be sure to setup all of the SCCs with the same battery charge settings (other than max charge current).

Your total charge current will be the sum of all of the charge controllers. If you have a 150/100 and two 100/50 then you could have up to 200A of charge current. Can your battery bank handle that much charge current? That's your biggest limit. If your battery bank can't handle 200A then set the max charge current of each controller so the total doesn't exceed the max for the battery bank.

Ok .. that’s close to what I was thinking.. cool , I found them in a box from when I started buying stuff a year ago ….forgot I had them .. I was considering buying another 150/100 this spring to have more panels . NO I will use these two .
the main system I’m building consist of 6 normal BB ( for now ) with 2 more coming about Xmas .. wired 24 volt .4s4p to pos and neg batt buss
that wold be 300 ah total now or 400 after the next 2 get here…
unfortunatly I have to save up for these things…
it’s my understanding the batts would be ok , but correct me if I’m wrong ..with 6 or 8 batts I believe I’m ok..
im trying to get the time it takes for a full recharge low as I can with extra panels so that during the day I can quick fill the bank as in mountain winters we have alot of snow , short days and some times a while between sunshine.
this is all for my rv. I have propane for heat so that helps a lot..
I am not sure the 100 v ones will be as happy with the 85+ volts voc at STC that I have now on the 150 unit if it gets really cold.. close. It no headroom.
would that concern you.?

 

[rmaddy]

Post a link to the actual specs of the panels. With the exact voltages and temperature coefficient we can calculate the exact temperature your panel array would reach 100V (or any other voltage).

 

[JRH]

Post a link to the actual specs of the panels. With the exact voltages and temperature coefficient we can calculate the exact temperature your panel array would reach 100V (or any other voltage).

This is as best a photo I have At this moment . this is why I was going to wait till I found out how I could join the SCC before I got new ones.. maybe it would be best to use fewer but larger watt panels . Not sure. But this is what I have now.. I’m open to use the same or use different panels , if that would be better..

 

[rmaddy]

Those panels in 4S have a Voc of 86.4V. With the stated temperature coefficient Voc that would reach 100.0V at about -8ºF. If you get to -10º or -15ºF then you could fry the SCC. At -15ºF the Voc would be 101V. Your call if you want to gamble on frying a $324 SCC. It is close.

If the Voc was 21.3V instead of 21.6V you'd be a hair under 100V at -15ºF. Or if the temperature coefficient was -0.3%/ºC instead of -0.33%/ºC you be a hair under 100V at -15ºC. So close.

 

[JRH]

Those panels in 4S have a Voc of 86.4V. With the stated temperature coefficient Voc that would reach 100.0V at about -8ºF. If you get to -10º or -15ºF then you could fry the SCC. At -15ºF the Voc would be 101V. Your call if you want to gamble on frying a $324 SCC. It is close.

If the Voc was 21.3V instead of 21.6V you'd be a hair under 100V at -15ºF. Or if the temperature coefficient was -0.3%/ºC instead of -0.33%/ºC you be a hair under 100V at -15ºC. So close.

No , i agree it’s too close …. if you factor temp and add to that 4500 ft elevation , snow , very bright sun after a cold front passes and very clean air too , I may not be safe at even at 0 degrees F , and it’s around 0 degrees many times during winter…it would be a risk..

Since your saying i have to consider each charger as a single unit as far as the voltage goes …how would running 3s4p work on the two smaller units (about 65 v + ) at STC ? Would that be compatible with the main 150 unit running at 86V + when all are joined at the buss Barr .? Can you combine different voltages like that ?
It would give a lot more headroom on voltage .
The amperage would be ok there too ,I believe ..
would that work ?
?? ….?.

 

[JRH]

rmaddy, sorry I stated that question wrong.. this can get confusing if one dwells on it too long. I missed a step when thinking it through..
by the time the two different voltages reached the buss barr from the different chargers wouldnt their voltages have been brought down by each solar charger to the voltage needed to charge the one battery bank ( 27- 28 ish V ) , Right ? Wouldn’t you be able to fine tune them in the Victron software to work together..
Is that a workable scenario?
jim …

 

[rmaddy]

rmaddy, sorry I stated that question wrong.. this can get confusing if one dwells on it too long. I missed a step when thinking it through..
by the time the two different voltages reached the buss barr from the different chargers wouldnt their voltages have been brought down by each solar charger to the voltage needed to charge the one battery bank ( 27- 28 ish V ) , Right ? Wouldn’t you be able to fine tune them in the Victron software to work together..
Is that a workable scenario?
jim …

Now you get it. The input to each SCC is irrelevant as far as your system is concerned. It's the SCC output that matters. That's why I specifically stated that you want to setup all of the SCCs with the same charge settings (other than max charge current). This way they all provide the same charge voltage to the battery. And with all of them setup to use the same VE.Smart network, they will all work together. Even VictronConnect will show you some combined charge details.

 

[JRH]

Now you get it. The input to each SCC is irrelevant as far as your system is concerned. It's the SCC output that matters. That's why I specifically stated that you want to setup all of the SCCs with the same charge settings (other than max charge current). This way they all provide the same charge voltage to the battery. And with all of them setup to use the same VE.Smart network, they will all work together. Even VictronConnect will show you some combined charge details.

Cool ..
thank you… that’s a clear way of putting it..