Question about GroWatt all-in-ones

oktmighty

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Jan 6, 2022
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TL;DR: What is the practical difference between the different 5000W GroWatt all-in-ones? Can they schedule power?

I purchased some land, and am going to be building a house on it. While waiting on permits/rights/loans I have started building a barn. I picked up 20 x 203W panels for about $40 each a while back I plan to install on the roof of the barn with a GroWatt 5000W and batteries inside. For now it will be pure off-grid, but I want to run conduit between the house and barn, feed grid power to the GroWatt and attach some of the lower load/important stuff in a different panel in the house (Lights, refrigerator, furnace, etc...).
First question: there are 3 or 4 options in that power range from GroWatt, and it is hard to tell what the difference is between the units (probably because of translation issues). Are they just newer models? Is one of the models generally more reliable/has a better featureset?
Second question: Can these units do power scheduling? My power company offers off-peak rate discounts, and if I could schedule the unit to be more aggressive with staying on solar/batteries during peak hours that would generate more returns for me.
Thank you!
 

sunshine_eggo

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Generally speaking, it's just features. You would need to get more specific with models.

120/240VAC split phase output
230VAC EU output
Different MPPT voltage/current.
Stackable or not.

To my knowledge, I have never seen power scheduling options in any of the Growatt manuals; however, all can set SBU priority - solar, battery, utility. In that case, utility would only take over when solar is insufficient and if the battery voltage drops to whatever limit you set it to.

Lastly, Growatt AC chargers are atypical. They do NOT do bulk/absorp/float. They are like a float valve. AC charger ON at X V, AC charger off at Y V. Example:

Specify a X=46V cut-off and a Y=57.6V termination (typical absorption voltage).

If the unit is 46.1 - 57.5V, the AC charger will not function.
Once voltage drops below 46V, the AC charger will come on. It will stay on until the moment the battery voltage hits 57.6V, and then it will turn off.
 

TomC4306

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That AC charging anomaly was one of the items that led me to go MPP solar. With respect to scheduling, see this link scroll to the bottom and look at power management.
 

sunshine_eggo

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That AC charging anomaly was one of the items that led me to go MPP solar. With respect to scheduling, see this link scroll to the bottom and look at power management.

And to confirm, Solar Assistant is an add-on piece of hardware/software?
 

TomC4306

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And to confirm, Solar Assistant is an add-on piece of hardware/software?
Correct. A pre-configured raspberry pi connected USB to the inverters.
No affiliation but I love it.
Provides rich data.
I have an experimented with power management yet but understand it to be changing output mode from SBU to SUB on a schedule also dependent on SOC.
 

oktmighty

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Jan 6, 2022
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I decided on GroWatt because it seems to be very good value for what you pay, and I like the idea of being able to stick another unit in if I need more power availability. I have splitphase, but I was planning on using the solaredge autotransformer to provide a neutral for that. I am not looking to spend over $2000 on this. I have an EPEver 60A unit I have been using for a while, and I recently picked up stuff to make a 48V 70AH LiFePo4 battery. I was looking to get an inverter, and the GroWatt was not much more than an equivalent inverter. Is there another direction I should be considering? I liked the idea of a more unified system. I will look at MPP too.
 

oktmighty

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Jan 6, 2022
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Just looking over their system, that does look nice! It looks like the yellow lid is the current model? It is more than the growatt, but it has an autotransformer included so the cost is about the same...
 
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