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Adding another charge controller to my Growatt 12kw inverter with 1000 ah's of prismatic lifepo4 cells

hotrod

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Hi I've got a question about adding a Growatt Charge Controller | SC48120-MPV 7000w to my existing 48v setup to help charge my battery bank. I've got a Growatt 12kw inverter with 9kw of solar panels connected to 1000+ ah's of prismatic lifepo4 cells. The 12kw Growatt inverter is maxing out at 120amps and a little over 6.6 kw's of solar . When I try to charge my EV and run my shop lights and my pool it takes everything the solar panels can provide (6.6kw) (120amps) and also starts pulling power from my batteries to keep up with the load and its not able to put any charge back into my battery bank when I'm pulling a load thru it like that. So I have purchased a separate Growatt 7kw charge controller and I have 6 more kw's of solar panels to connect to the new charge controller. I want to put the new charge controller up with the new solar panels and connect the output from the charge controller to my + and - bus bars that my existing 1000 + ah battery bank is connected to so it can help charge my battery bank back up when I'm pulling large loads like that. Will this work ok to help charge my battery bank. Or will this cause some sort of back feed to my existing 12kw Growatt inverter. Has anyone of you used a 12kw growatt inverter and a 7 kw charge controller together on the same battery bank.
 
It will work just fine. I'm running the 8kw Growatt and the same SC48120 controller and everything plays fine together.
Thank you, I was hoping it would but I was worried 1 might try to push dc voltage back on the other one instead of everything going into the battery.
 
I was always under the impression that the 12kw Growatt inverter could use 6kw's of solar panels to charge the batteries at 120 amps max and if you had another 6kw's of panels they could carry the large loads without taking away from the charge controller of the inverter. But mine definitely does not work that way. I have been told by Growatt and the company I purchased the Growatt inverter from that each pv input was 2 separate mppt charge controllers and each 1 could handle 7000 watts of solar panels and up to 250 dc volts each string. But I'm not able to get but about 6500 watts combined out of mine.
 

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I was always under the impression that the 12kw Growatt inverter could use 6kw's of solar panels to charge the batteries at 120 amps max and if you had another 6kw's of panels they could carry the large loads without taking away from the charge controller of the inverter. But mine definitely does not work that way. I have been told by Growatt and the company I purchased the Growatt inverter from that each pv input was 2 separate mppt charge controllers and each 1 could handle 7000 watts of solar panels and up to 250 dc volts each string. But I'm not able to get but about 6500 watts combined out of mine.
That looks like clipping, in the graph.
You are at maximum amperage input.
 
Yes it is defiantly clipping for about 2 hours and that was back in January
Yeah, you can't get any more production, unless you can increase voltage.
And that's only possible, if you aren't already maxed out there, too.
 
I have two controllers charging up the same bank. Both are set to a voltage appropriate for the bank (57.6v max) and no problems thus far.
 
What panels do you have, and how are they attattached to the growatt? Which model growatt?
The Growatt inverter model is SPF 12000T DMV-MPV Max input voltage is 250 vdc Max charge current 120A 2 strings . The solar panels are Hyundai 260 watt panels Voc 37.9 Vmpp 31.1 Isc 8.9 Impp 8.4 I have them configured into 3s 6p on each pv string going to a midnight solar combiner box then going into each string into the inverter. 113.7 vdc 53.4 amps for each pv string. Do you think I could get any better results if they were configured differently.
 
. I have been told by Growatt and the company I purchased the Growatt inverter from that each pv input was 2 separate mppt charge controllers and each 1 could handle 7000 watts of solar panels and up to 250 dc volts each string. But I'm not able to get but about 6500 watts combined out of mine.
According to the datasheet, the GW has 2 mppts, but a combined 7,000 watt max. Not each. At 6,500 watts, you are probably maxing out on amps.

Try 5s3p into both mppt. Still won't get more than 7,000 watts.
 
According to the datasheet, the GW has 2 mppts, but a combined 7,000 watt max. Not each. At 6,500 watts, you are probably maxing out on amps.

Try 5s3p into both mppt. Still won't get more than 7,000 watts.
I don't think it will change anything by changing it . I was hoping and thinking that this inverter would charge at 7000 watts (120A) and then run loads off of the other 5000 watts 12000 watts total. But I guess that's not the way it works.
 
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