Is it possible to divert excess PV power to an inverter that isn't being used by an EG4 Hybrid heat pump?

[Xyrinexe]

What's up!? I currently have a 9.5kw PV system with a Solar Edge Inverter. I'm interested in installing a whole home ductless system to replace my inefficient and aging rooftop packaged unit. I have a lot of sun where I live, and I like the idea of powering an AC system completely from PV. But what if my PV is capable of producing more power than what my heat pump is using, or what if I'm not using the heat pumps at all? Is all that excess PV power being wasted and just doing nothing? That seems a little silly if that is the case, that's a lot of lost potential that could be used for charging batteries or exporting back out to the grid!

I understand that your PV systems aren't going to produce more power if the current has no where to go. So the question is, is it possible to divert the full potential of your PV system to an inverter for other uses? For example, if my PV is capable of producing 1KW, and my EG4 is only using 300watts, can that extra 700watts be dumped into an inverter?

My inverter has a lot of room to add more PV, it would be really cool if I could add that additional PV capacity into my overall PV system. Thanks a lot!

 

[timselectric]

But what if my PV is capable of producing more power than what my heat pump is using, or what if I'm not using the heat pumps at all? Is all that excess PV power being wasted and just doing nothing?

Yes
This is the downside of a dedicated PV array for only one piece of equipment.

 

[400bird]

Seems like this PV array dedicated to a heat pump trend is going about it backwards and like you pointed out, leaves a lot of idle time and lost production.
It does have a place (off grid or not solar friendly power co, etc) but you're already on some agreement with the power co, so I think you've got better options.

You've already got a grid tied system in the Solar Edge set up. Why not just expand that or add another, smaller grid tie system to offset the heat pump?

Going grid tied (if you have net metering) you would just need enough PV to offset the total energy used.
If you go with a dedicated array to power the heat pump, the array needs to be much larger to be able to power the peak consumption, then the PV just sits idle/under utilized the rest of the time when it's not running at peak output.

 

[Xyrinexe]

My understanding of electrical theory is a little lacking, but hear me out. Current from a PV array needs a place to go, and if there isn't a path or enough capacity at the load, "limitations of an MPPT" then the PV simply will only produce enough for what the load demands. What if one were to place a DC bus bar between the PV and the heat pump, one branch terminating at the PV input of the heat pump inverter, and the other terminating to the home's inverter / MPPT. Theoretically, if the heat pump is pulling 300watts, and the PV is capable of producing 1000watts, then the additional 700watts would be pulled by the next path of resistance, the home inverter / MPPT.

To my understanding this would work, but I'm probably completely wrong. If this isn't how it works, then what am I missing?

 

[Plum Crazy Rob]

The Solar heat pump has an MPPT as well, so sounds like you're hooking them in parallel and their algorithms will mutually run in circles.

My inverter has a lot of room to add more PV, it would be really cool if I could add that additional PV capacity into my overall PV system. Thanks a lot!

What did I miss. Why aren't you just using the current (pun intended, lol) arrangement to power non solar mini splits with more PV? As you say you must REALLY just want a Solar heat pump

 

[Hedges]

What's up!? I currently have a 9.5kw PV system with a Solar Edge Inverter. I'm interested in installing a whole home ductless system to replace my inefficient and aging rooftop packaged unit.

Solar Edge, as in grid-tied? No battery, never operates with grid down?
Do you feed back into the grid? Net metering, or something less than 1:1 credit?
Or, is it zero export?

If you are grid tied, consider an AC grid powered A/C or heatpump.
If it has a variable speed compressor, you might be able to vary thermostat setting to vary its power draw. But only useful if you don't have 1:1 net metering.

If you had an off-grid system, you might similarly power the heatpump from AC or battery DC. Enable when there is surplus production, or ideally vary it's speed to keep battery at float voltage.

That's just one of several possible "dump loads" to use surplus PV generation.

 

[Xyrinexe]

Solar Edge, as in grid-tied? No battery, never operates with grid down?
Do you feed back into the grid? Net metering, or something less than 1:1 credit?
Or, is it zero export?

If you are grid tied, consider an AC grid powered A/C or heatpump.
If it has a variable speed compressor, you might be able to vary thermostat setting to vary its power draw. But only useful if you don't have 1:1 net metering.

If you had an off-grid system, you might similarly power the heatpump from AC or battery DC. Enable when there is surplus production, or ideally vary it's speed to keep battery at float voltage.

That's just one of several possible "dump loads" to use surplus PV generation.

I am grid tied, I'm not sure if I'm at 1:1 credit, but its pretty close. Even with my massive, one stage, falling apart packaged heat pump that draws over 5.5kw, my power bill is still almost zero. Even if I don't get more PV, upgrading to a modern AC heat pump, preferably ductless, will still grant me a ton more credits from my power company. I do want to get batteries eventually, but I do have a Cybertruck on the way, more PV wouldn't hurt for that. I guess I just like the idea of having a AC/DC hybrid heat pump, I think its cool even though it isn't necessary and doesn't make much sense. But if I cannot utilize the full production of the PV, I cannot justify it.

 

[Hedges]

Solar Edge has it's own proprietary optimizer/RSD. Possibly they work with other string inverters?
I think you can replace it with StorEdge and add a proprietary battery.

Does your Solar Edge support "Rule-21" frequency-watts?
If so, could AC couple with a battery inverter such as Sunny Island or another.

If your heat pump work on AC and is more efficient, that should be fine while on grid. It will draw power you banked with net metering. In making a decision, it would be good if you knew how long your net metering plan will remain.

Off grid, I suggest getting a power-factor corrected unit. Someone here noted a window unit that is 0.98 PF.
(poor power factor draws a waveform that is more stressing for inverters, causes higher losses, in the case of my equipment upsets GT PV so they don't connect.)

My system works nicely off-grid, including a conventional A/C, but the VFD pool pump causes problems.

 

[Checkthisout]

Panels are cheap.

The idea is you install the mini-split then throw up some panels close by and never think about it again.

In your case, don't get a mini split with mppt.

Just get a regular one and wire it into your house electrical and feed it from your existing pv system

 

[zanydroid]

Solar Edge has it's own proprietary optimizer/RSD. Possibly they work with other string inverters?

They work in theory, if you can find a unicorn accessory from SolarEdge.

SE has not implemented RSD compatibility with third party inverters.