Grid Down House Inverter Setup Inquiry

[JMS922]

Hello All,

I was wondering if I could get some opinions on my hypothetical setup and see if my logic makes sense for how I would like to setup my equipment:

Currently Owned Equipment:

1. 16S 48v Ganfeng 280AH Cells (14.34kWH)
2. 200A JK 2A Active Balancer BMS
3. Victron Smart Shunt 500amp (cannibalizing from a DIY solar generator box I built last year)
4. x1 Victron MPPT 100/30 (cannibalizing from a DIY solar generator box I built last year)
5. x2 Hardibacker over drywall w/ 16" studs

Hypothetical Equipment:

1. x2 48V 3kVA 120/240v Victron Multiplus II UL1741 (technically, 4800 watts?), Most likely current connected because of the 10yr warranty - right?
2. x8 Mono Panels between 250-300~watts ea for around 2kWH all together, DIY ground mounted
3. x2 Victron MPPT 100/30 (Owned: 1 of 2)
4. Victron Power-In (w/ CNN fuses for the VDC rating)
5. Victron Venus OS+VRM (running on Virtual Machine (VM) on desktop Linux PC until Raspberry Pi come back down from the stratosphere lol..)
6. Subpanel 100A (8 space 16 Circuit)
   1. x1 50amp double pole via 6/3 connect over to an existing subpanel (I got the 6/3 wire for cheaper than 8/3 so why not lol)
      1. currently setup for a 50amp grid double pole breaker and a 30 amp generator double pole breaker
         1. 50amp grid breaker will be off when inverters are running
   2. x1 40amp double pole breaker
      1. fed via the Victron inverters to give 240v
   3. x1 30amp double pole breaker
      1. fed by generator, 30amp generator breaker moved from current subpanel to this new subpanel
   4. x1 15amp single pole connected to a quad outlet box right below
   5. x1 open space for future needs
7. 2/0 Cables via battery to Victron Power-In, CNN fused to 200A - (should I do a Class T or is CNN fuse ok?)
8. 6 AWG Cables via Victron Power-In to Inverter, no fuse but breaker to 100A each inverter

Use Case Scenarios:

• The current subpanel has isolated my entire basement which contains the following equipment breakers: 240v 15amp well pump, 120v 20amp freeze, 120v 20amp effluent pump, 120v 15amp sump pump, 120v 15amp outlets.
• I am considering victron over EG4, MPP Solar, etc as my forum research and youtube reviews seem to lead to EG4, MPP, Growatt, and all the other Chinese inverters just being nothing but a problem if I value system efficiency and ease of use without update etc issues. Open to opinions on other than victron but everything I have found seems to suggest that an EG4 6500 in parallel is the next best alternative to victron on the current market without going Sol-Ark etc.
  1. With the above information and due to the 240v well pump, I assume I must buy x2 of the Victron inverters in order to service the well pump... I thought about somehow just doing x1 48v/3kva Victron inverter to service my 120v loads and somehow setting up the existing subpanel to service the well pump as the only 240v load - any recommendations in order to be the most equipment efficient on this scenario?
  2. Should I just buy x2 Victron 48v/3kva and call it good? I am concerned that buying into Victron 48v with only 3kva, which from my research maxs out at 2400w (4800w in parallel) is limiting? Re-selling Victron should they come out with something new for the US market shouldnt be terribly difficult but I just want to make sure I am being equipment efficient as possible.
  3. Open to your opinions/hypothetical setup recommendations
     1. I am somewhat budget conscious (i.e. quattros are a no go), space limited... I only have about 4-5feet of horizontal space to work with and about 8ft of vertical space to work with ( the size of 4x8 plywood from home depot lol)

Unknowns:

• I have seen setups with a AC-IN and AC-OUT subpanels - is this necessary for a setup like this? If I wanted to do a "Solar>Battery>Grid" setup, I assume an AC-IN subpanel and AC-OUT subpanel would make sense... unless I just directly connect the AC-IN from grid direct to the victrons but the wiring will likely be messy without a subpanel and conduit to keep it clean.
• Maybe I should just buy a 48v 3K-4K watt inverter and just 12 gauge extension to my basement needs and not overthink this and go nuts on wiring into my panel? lol
  • Maybe I should just sell my gas generator and buy a tri-fuel Nat Gas powered one and hire a plumber to tap into my gas valve and run it during grid down? lol

Thank you all for reading my wall of text and appreciate your feedback.

 

[rodrick]

If it’s only for grid down buy the generator

 

[JMS922]

@rodrick sorry I should of been more specific, with the inverter and battery etc.. I plan to take my basement off grid by flipping the grid breaker on my subpanel or wiring the grid to the victron inverter to use the powerassist function when there is no solar or batt is low.

 

[rodrick]

Having 3 pumps and a freezer on this system is a large surge potential by the way did I say large I mean large

you need to find out what the starting amperage of each of these are by using a clamp type amp meter that will log peak amps so you know what your potential load could be, add them all together plus some head room for other possible loads running that would be the minimum I would go with

LF type inverters are best suited for motor type surges that is what I would go with

there has been a lot of issues lately with the eg4 6500 check out the posts on them, a lot of flickering lights ect

 

[JMS922]

Having 3 pumps and a freezer on this system is a large surge potential by the way did I say large I mean large

you need to find out what the starting amperage of each of these are by using a clamp type amp meter that will log peak amps so you know what your potential load could be, add them all together plus some head room for other possible loads running that would be the minimum I would go with

LF type inverters are best suited for motor type surges that is what I would go with

there has been a lot of issues lately with the eg4 6500 check out the posts on them, a lot of flickering lights ect

So you recommend the Victron then? I measured the well pump LRA at 28amps*240v=6,720 watts (largest surge potential on the subpanel)... with the Victron Multiplus II combined surge capability being 11,000 (5,500 per Line) when run in parallel... I should be good to go from that perspective?

 

[rodrick]

Victron is a good choice for that application

you also have the option to move one of the loads back to grid if you start having issues