Growatt Parallel or No?

Solargrow

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If I'm using two of the Growatt spf3000tl lvm inverters (3000watt 48v w/ 4500watt max pv input), what is the benefit of connecting them parallel as opposed to keeping them two separate units? I have four 48v 100a batteries that I can split to 9600 watts each or I can connect all the batteries for 19200 watts.
Is the main benefit of going parallel that I only have to worry about the one 6000watt ceiling as opposed to having two different 3000 watt limits to worry about? Is it about how I plan on consuming the power?
I appreciate your input and your experience.
Thanks.
 

T-486 Ashepoo

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You can either stack them in 120v to get 6000 watts or use both as single 120v to get 240v. If all of your loads are 120v, then stacking gets you 6000 available watts. Either way, it's probably better to run them as one system since they communicate with each other, draw from a common battery bank and have lower standby power consumption. I only have 1 as backup power for power outage.

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Rednecktek

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You can either stack them in 120v to get 6000 watts or use both as single 120v to get 240v.
That's the main benefit. Some higher power devices like well pumps and aircon units need 240v split-phase power to run, and there's no good way to do that with a single 120v power leg.

As I understand it from some of Will's and Dave Poz's earlier teardowns, the larger units (5Kw units at the time) were just 2 of the smaller units paralleled and connected together in the same big box which is why they had 2 SCC's and 2 AC outputs and such.
 

timselectric

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If they are feeding power to the same loads, they should be paralleled. If they are feeding separate loads, you can go either way.
 

GSG

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Is there a limit to the loads they can feed? For on-grid, you just tap the inverter's AC OUT to the main distribution panel and it serves as supplemental power. For off-grid, I read that it can only be tapped to load lower than the AC OUT? Is that right?
 

timselectric

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Is there a limit to the loads they can feed?
Yes
The output rating is the limit.

For on-grid, you just tap the inverter's AC OUT to the main distribution panel and it serves as supplemental power.
No, this is an off grid inverter.
Never connect the inverters output to the grid.
(This could be the beginning of an insurance claim)

For off-grid, I read that it can only be tapped to load lower than the AC OUT? Is that right?
Yes, 3kw per unit.
 

Zwy

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If I'm using two of the Growatt spf3000tl lvm inverters (3000watt 48v w/ 4500watt max pv input), what is the benefit of connecting them parallel as opposed to keeping them two separate units?

You can run 240V split phase devices in parallel. If you keep them seperate, then you only have 2 120V outputs, and this will also require a dedicated 120V panel for each unit with each supplying seperate circuits as there can't be a shared neutral.

I see no reason to keep each unit separate, it would take twice the wiring, twice the subpanels and even battery wiring would be times 2. It's best to run in parallel with a 240V split phase capability into a single split phase panel.

I have four 48v 100a batteries that I can split to 9600 watts each or I can connect all the batteries for 19200 watts.
Is the main benefit of going parallel that I only have to worry about the one 6000watt ceiling as opposed to having two different 3000 watt limits to worry about? Is it about how I plan on consuming the power?

It would not make any difference as far as the 3000W limit. You would only be able to have 3000W output from each unit, not 6000W total on one line. In either split phase or each unit seperate, the 120V output of 3000W is all you get. For split phase, you get 3000W per 120V phase, seperate units per each 120V unit is 3000W.

I appreciate your input and your experience.
Thanks.
 

timselectric

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Paralleled in split-phase, gives you the option of running 120v and 240v loads.
Paralleled in single phase, gives you a higher surge capacity on 120v loads.
 

GSG

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Yes
The output rating is the limit.


No, this is an off grid inverter.
Never connect the inverters output to the grid.
(This could be the beginning of an insurance claim)


Yes, 3kw per unit.
Thanks, Timelectric.

Would you know if hybrid inverters have that same limitation?
 

Zwy

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Paralleled in split-phase, gives you the option of running 120v and 240v loads.
Paralleled in single phase, gives you a higher surge capacity on 120v loads.
Ian had mentioned something about needing the parallel cable between both inverters but I thought it only applied to split phase. I checked the manual and yes, parallel operation for 120V single phase is shown but will require the parallel cable.

But I have to wonder why one would want 6000W on 120V with 2 units? That's 50A. Granted surge but the cost of wire would not make sense if one could utilize 240V split phase.
 

timselectric

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Thanks, Timelectric.

Would you know if hybrid inverters have that same limitation?
This is a hybrid inverter.
It does everything, except export back to the grid. (Known as a "grid tied " inverter)
"Hybrid inverter" , covers a lot of different types.
 

timselectric

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Ian had mentioned something about needing the parallel cable between both inverters but I thought it only applied to split phase. I checked the manual and yes, parallel operation for 120V single phase is shown but will require the parallel cable.

But I have to wonder why one would want 6000W on 120V with 2 units? That's 50A. Granted surge but the cost of wire would not make sense if one could utilize 240V split phase.
I'm right there with you, on this.
 
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