Adding to existing 15K

[Armorer266]

Okay so this might be a long one. Let me first say say thanks to all who have posted on this site it's been a help when I needed to figure stuff out. I need some advice and have read about bits and pieces but nothing quite like what I feel are my options here or whatever you think I should do of these all are bad.

I have an existing Solark 15K with 12 KW worth of panels. The panels are on a custom engineered steel solar structure / shade structure about 150' feet from the house by the pool. Pool is between the house and the structure, not shown below. I installed a heat pump for the pool a few months ago. I had the company that I had do the structure and solar run the electric for heat pump then, none of this is trenched its in emt along the perimeter of the property as there is a cinderblock wall run to about where the structure is. After that is just a fence that encloses the rest of the property. I with the company also installed at the time of installation batteries that I made out of Catl batteries from Battery Hookup and connected them to my 15K. The solar and batteries have been installed and operating for a little more than a year now. Happy with all of it. All solar stuff, electric, and structure was permitted and I am connected to the grid. I am in Arizona.

Well it's time for the next phase of the projects and due to awesome prices on panels and the heat pump sucking and additional 45kw daily when it runs... I need more panels and already bought 8KW worth as that is all the will fit on the shop roof that will soon be built. I also need to install natural gas and water around the perimter and a workshop outbuilding. The company I am having do the trenching can put the gas and water 36" down and I can run whatever electric above that as long a I allow 18 inches of separation per the code here... there will be various natural gas ports, hose bibs and outlets added along the permiter of the property. Still working out those details and permits.

I now find myself needing some advice. Below is the drawing. Wrote some notes on it.




So I have four options what would you do and why?
1. Enphase Micros into gen port of 15K from the outbuilding. Can I add a disconnect and not deal with the enphase keep alive and monitoring panel and go straight into the gen port of the 15k? My understanding is the 15K will send the keep alive signal to the micros. Separate electric run to main panel to subpanel in the outbuilding and separate wire run for micros to solark.

2. Go DC with a grid tie string inverter and add the rsd to the panels and grid tie it to the 15K gen port. Same deal with the electric as above except the DC to the inverter.
Both of the above scenarios I believe will shut down everything if the current RSD activated.

3. Go DC and get another Hybrid... probably want to stay with Solark not opposed to EG4. Use the gen port on the new hybrid to load shed to the gen port of the existing 15K. Do some of the crazy stuff below in option 4 but really no grid connection on the line side of the new hybrid.

4. GO DC and get another hybrid and hook up the line side of the new hybrid to the existing 15K gen port, use the load side to add a sub panel and power the outbuilding with it as well as move my house A/C electric to this subpanel, add batteries here too. I would use the old A/C electric that's from the house to keep the batteries and myself out of trouble chargeverter connected from the now new batteries topped up.

I realize option 3 and 4 are a little crazy, but I want about another 30 to 45kw of batteries and my garage where the existing batteries currently are is space limited might not be so much when the outbuilding is built. RSD probably won't work on the new panels without some extra effort with these options. All the above are going to require direct burial electric with various combos and neutrals and grounds. I have most of that worked out. Again I'll have an electrician do most of this stuff. (to code you tell me 3 and 4 probably not)?

Also I am going to add a generator probably trifuel to a chargeverter to power the 15K batteries if I loose grid so gen port on the 15K will always be free. I consume base load 30KW a day 3 to 6 months and if the A/C and heat Pump pool heater run it's anywhere from 80 to 140 KW a day the other 6 to 9 months.

I am not net metered, only get a fraction of the export as a credit so I could care less about exporting excess to the grid this is more about covering my new extra loads. Basically this outbuilding and the pool heater I'll probably consume more than I make anyways for most of the year. Lastly, most of this is going to be done by electricians or plumbers... permits mostly- maybe, not at most of those stages yet.

Let me know your thoughts sorry for the long one and potentially crazy ideas. Thanks.

 

[TechRider]

Why not just add another 15k in parallel and be done with it? Then you can use all your battery and solar together. Plus it will double what you could output at any given time. I built a system similar to yours and am already considering phase 2 which I will do exactly that. (Add another 15k in parallel.) You can add RSD at your outbuilding locally with something like the Tigo RSD.

 

[zanydroid]

Can you go back and for each of the scenarios list the pros & const (capabilities, things that don't work)? I don't see an analysis from that angle from OP.

Quick feedback.

RSD is probably pretty easy and can be dealt with after the main issues. Don't get distracted and focus on the real bottlenecks, is my advice.

Stacking a 15K is the simplest answer and requires the least engineering/thinking through scenarios. BUT. you want advice from forum members that build systems on properties of your size, mine is 1/30th the size of your property. There could be considerations like whether you want two separate systems.

AC coupling cannot double your power capability except with very specific combinations of hardware, none of which you have mentioned (Specifically IQ8 with Enphase grid forming battery). Basically the amount of power you can count on, is the size of your grid forming inverter. And this inverter/charger + battery has to be sized large enough to absorb the output from the AC coupled solar. And you can only ever charge as quickly as the existing AC/battery charging capacity of your 15K (i think that is 12kW from gen port). 15K Datasheet says 275A to the battery = ~13.5kW

IOW, if you align the new panels to produce at the same time of day as your existing 15K panels, you most likely will be forced to export a good chunk of it to your power supplier, because you are bottlenecked on charging capacity.

Now, your pool heatpump operates continuously, so potentially you can directly send this extra power to the pool heatpump, bypassing the charger.

So in terms of bottleneck/critical path thinking. Looking at your battery charging graphs will be very interesting. If you are using 275A for most of the day, then AC coupling a lot more solar panels in will leave the panels stranded.

Generator assist of cheaper inverters vs stacking another 15K implies you're capable and willing to deal with the extra complexity. Do you feel the DIY battery experience, other DIY experience, translates to this? I'm feeling not really, and there is a new learning curve, but I guess can be convinced.