Dumb question: Do more panels and Sunny Boys offer more amps in offgrid SMA installation

[SilverbackMP]

Based on 4x SI and AC coupled SBs.

I tried to search the forum, but didn't get a definitive result.

I am pretty sure the answer to the question is yes based on that slightly older post of the guy building out a big SMA powered crypto miner system and also the post a couple of months ago where we discussed adding amps from a generator.

The recent discussion of mini splits - both direct solar and 48v variants prompted me to post this.

I would like various outbuildings to have AC and heat. But some of this is for climate controlled storage...which wouldn't need 24/7 operation.

I'm thinking that if extra SBs and panels allow for more amp capacity while the sun is shining, I stick to mostly conventional mini splits along with local (to the minisplit) panels and a Sunny Boy tied into my entire local grid. And the mini splits set to mostly operate while there is enough capacity being produced from the adacent panels to it. This could be accomplished with a KISS time/calendar based setting or one could bang their head against the wall and use something like home assistant to actually monitor the power being produced and turn on/off the minitsplits.

This setup would facilitate extra solar collection during the winter for the batteries in the power shed.

A few outbuildings that would benefit from 24/7 cooling/heat could use the 48 volt mini splits and local batteries, panels, and charge controller(s).

These outbuildings will be heavily insulated...foam and/or rockwool.

This would allow for max availability of amps available for power tools (i.e. dust collector and planer operating at the same time) in both the day and evening. I have just under 100 amps available from the Sunny Islands and batteries after the sun goes down. I am trying to maximize what I can use those 100 amps for. So shutting down mini splits in areas that aren't being used by actual people would be part of that plan.

And might prolong the time I have before I install a second system or third system and/or a SMA multi-cluster box to gain more amps . I am running oversized 3-phase wire for my "mains" but using just two legs right now while I have 240v split. Any 240v split phase runs are also oversized by at least a gauge over the NEC requirement (in other words, my wiring has extra amp carrying capacity if I need it).

Thoughts?

 

[SilverbackMP]

I might have found my answer from Hedges is an older post.

Referencing 4 Sunny Islands 2s2p:

“If off-grid, maximum 48kW of Sunny Boy could be controlled.”

So that would be 200 amps at 240v not accounting for any resistance or power factor.

Sound right? Can anyone confirm that is available when the sun is shining at peak? 150-200 amps available during the day would be more than enough for my needs for a while (for my shop, my mom’s house, various smaller outbuildings).

Will likely install a second/third system when I build a house or if I put in a second workspace if I expand my local employee pool. I am leaning that way rather than a SMA multicluster box for redundancy and lightning considerations. $15k (price of multicluster box) can buy a lot of used continuous duty industrial/military generators to place one for every 4x SI installation.

Down side is, can’t easily share power between various sections of infrastructure but I think the redundancy and KISS is more valuable.

 

[Hedges]

According to SMA, SI can control SB with 2x wattage of SI.
Note that SI can surge 2x for 3 seconds to start motors, and that should be long enough to frequency shift down and bring SB online. So 4x SI should be able to go from zero to 44kW, and SB should pick up some/all of that.

However, load of > 1x SI wattage suddenly shut off (load dump) after SB was carrying it, I don't think SI could suck down the extra power while frequency shifting up.

So I'm not sure where the 2x limit came from.

Also, SB can be over-paneled and with multiple orientations could produce flat power during the day.

If you want 2nd/3rd system, maybe you would like Multi-cluster, which is 3-phase and off-grid only. Up to 12x SI combining their output.

SI can control relays for 2 levels of SoC to shed loads. Also if it enters derating.
What we would really like is to smoothly enable or ramp loads in response to frequency shift, below the frequency where SB starts to curtail production. Thought there was a product once, but can't find it. Have to roll our own, I guess.

 

[SilverbackMP]

According to SMA, SI can control SB with 2x wattage of SI.
Note that SI can surge 2x for 3 seconds to start motors, and that should be long enough to frequency shift down and bring SB online. So 4x SI should be able to go from zero to 44kW, and SB should pick up some/all of that.

However, load of > 1x SI wattage suddenly shut off (load dump) after SB was carrying it, I don't think SI could suck down the extra power while frequency shifting up.

So I'm not sure where the 2x limit came from.

Also, SB can be over-paneled and with multiple orientations could produce flat power during the day.

If you want 2nd/3rd system, maybe you would like Multi-cluster, which is 3-phase and off-grid only. Up to 12x SI combining their output.

SI can control relays for 2 levels of SoC to shed loads. Also if it enters derating.
What we would really like is to smoothly enable or ramp loads in response to frequency shift, below the frequency where SB starts to curtail production. Thought there was a product once, but can't find it. Have to roll our own, I guess.

I think I had edited and added to my post above while you were reading and responding to the original.

My fear with centralizing it is lighting or a severe storm taking out my power shed. There’s no Ameren UE to call.

My shed is also too small at 12x12 with a garage door (which could have a false wall placed behind it).

Ideally it would all be in an “Under Ground Facility” but that’s not likely to happen…at least for a long while.

 

[SilverbackMP]

There are images floating around on the net of a multicluster box installation in Guam. Fairly certain it’s a military site. Quite impressive.

 

[Hedges]

I think I had edited and added to my post above while you were reading and responding to the original.

My fear with centralizing it is lighting or a severe storm taking out my power shed. There’s no Ameren UE to call.

Consider letting one SI system be the "grid" and enable it to feed others. They could charge their batteries from it, and they could export SB PV power to it.

Ideally it would all be in an “Under Ground Facility” but that’s not likely to happen…at least for a long while.

The Under Ground Facilities I'm familiar with (by reputation only) required rebuilding after each use ? ?