zanydroid
Solar Wizard
My brain was actually broken too.
I thought SUB was battery less but if you run out of sun it cuts back to utility. Not blended
Utility company visited me for exporting from my solar Off-grid growatt LVM-ES SPF 3000TL
- Thread starter vallesj
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I thought SUB was battery less but if you run out of sun it cuts back to utility. Not blended
Subdood
Photon Wrangler
But like I said I was in SUB for like 8 months but no knock on the door..
Does the fact that I'm feeding a separate sub panel from the inverter's output make back feeding unlikely if not impossible?
Depends on the loads you have in the sub panel and the loads you have in your main panel. You may not be able to trigger enough backfeed blip to overcome your existing loads in your main, so nothing goes past your main panel.
that makes sense, in that case, I could never backfeed.
zanydroid
Solar Wizard
Why does the location of the loads matter, vs the total load in the house?
Is the idea that the loads being offset are really small, which bounds the amount of over export?
Anyway this ends up being pretty similar to the zero export debate so the SUB and zero export folks can collaborate
It also might be easier to just buy a cheap battery and go SBU. No permits anyway
Funny thing I noticed is in sub mode mine dumps spike into the battery for a second or so when stuff cuts off.
Never expected that.
I'm running is sub mode most of the time because I don't have enough battery capacity yet.
Well that and I'm worried a huge tree is about to take out the power lines before the tree guy and the power company work out cutting the tree down
Mine does percentages not complete cut over. It just gets what the pv doesn't provide. It may be kw's or it may be just a few watts.
Subdood
Photon Wrangler
Loads in the sub panel are all 120V loads. Largest loads are washer, microwave, toaster oven, hair dryer, and a frig and freezer. Not all on at the same time of course.
All the 240V loads (heater, A/C, stove, dryer, hot water tank) are in the main house panel, along with the dishwasher and smoke alarm, both 120V.
timselectric
If I can do it, you can do it.
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It's great for batteryless and a small battery capacity.
I ran this way at first.
But it's not what I want for a permanent system.
timselectric
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No difference.
You just got lucky or they weren't watching yet.
Edit: if you have enough loads between the inverter and grid, that's enough buffer on its own.
Last edited:
timselectric
If I can do it, you can do it.
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Yes, it's the same situation.
timselectric
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That's preferable.
Butt not possible if the battery is full.
zanydroid
Solar Wizard
A 3kW inverter only needs one server rack battery to buffer the load. Or maybe even just half of one.
Seems pretty straightforward.
timselectric
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If the battery capacity cannot make it through the night.
(At first my capacity only lasted a few hours)
SUB mode is better. And you just save the battery for emergency use.
Subdood
Photon Wrangler
Ok? Excuse my denseness, but how? It pushes a brief reverse current pulse back through the inverter AC input onto the grid?
I could just leave the AC input breaker off, plus it's been in SBU mode for two months now, so it's not an issue anyways.
timselectric
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I edited my post.
If you have loads between the inverter and grid. They provide a buffer against export.
Crevelingk
New Member
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Could you use the same process to turn on grid when the battery is low instead of turning on a chargeverter? If the grid turns on only when the battery is low, then any back surge should go to the battery instead of the grid? And then you shouldn’t need to configure a minimum grid usage either?
kolek
Inventor of the Electron
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Have you Tim, or anyone else here tested how much load was necessary to buffer how much export?
In my own testing, I found 100W reduced a 340W export to 30W, and 200W reduced a 340W export to zero.
But that was changes to the Zero export setting in my inverter, not actually putting a load between the inverter and grid.
timselectric
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It depends on the size of the loads that shut off abruptly.
300w was plenty for me, most of the time.
But it would be different for everyone.
wheisenburg
Independent Solar Consultant
Off-Grid vs Grid-Tied
Off-Grid:
You are Off-Grid if you are not connected to the grid or at least you are not running your inverter in parallel with the Grid. When you lose power and disconnect from the grid, then and only then can you turn your inverter on and start supplying power to the home. You can use the grid as a source of power for your charger when connected to the grid and still fall under this definition. A true "Off-Grid" inverter should lack a "Grid Following Mode" that lets the inverter operate in parallel with the gird. An inverter that allows that is by definition a Hybrid inverter. It is designed to allow both Grid-Tied and Off-Grid operation.
Grid-Tied:
If you are using your inverter while it is connected to the Grid, then you are interacting with the grid and by definition you are Grid-Tied. As others have said, you may set your software configuration to "Zero Export", but that does not disconnect your inverter from the grid. If you have a Hybrid inverter that can be configured to turn off all the features that allow it to follow the grid and interact with it, then you could at least simulate being Off-Grid. Your inverter would need to turn on only in the case where the in coming power was turned off. In that case the inverter would disconnect from the grid and start supplying power to your home. If you set your system up for load shifting or grid support, those types of features will interact with the grid.
If you have Load Support turned on, you have not configured the system to be Off-Grid. Your inverter will be producing power while the grid is connected. I am not sure about the Grow Watt, but most Hybrid inverters will allow you to configure them for an Off-Grid mode
Off-Grid:
You are Off-Grid if you are not connected to the grid or at least you are not running your inverter in parallel with the Grid. When you lose power and disconnect from the grid, then and only then can you turn your inverter on and start supplying power to the home. You can use the grid as a source of power for your charger when connected to the grid and still fall under this definition. A true "Off-Grid" inverter should lack a "Grid Following Mode" that lets the inverter operate in parallel with the gird. An inverter that allows that is by definition a Hybrid inverter. It is designed to allow both Grid-Tied and Off-Grid operation.
Grid-Tied:
If you are using your inverter while it is connected to the Grid, then you are interacting with the grid and by definition you are Grid-Tied. As others have said, you may set your software configuration to "Zero Export", but that does not disconnect your inverter from the grid. If you have a Hybrid inverter that can be configured to turn off all the features that allow it to follow the grid and interact with it, then you could at least simulate being Off-Grid. Your inverter would need to turn on only in the case where the in coming power was turned off. In that case the inverter would disconnect from the grid and start supplying power to your home. If you set your system up for load shifting or grid support, those types of features will interact with the grid.
If you have Load Support turned on, you have not configured the system to be Off-Grid. Your inverter will be producing power while the grid is connected. I am not sure about the Grow Watt, but most Hybrid inverters will allow you to configure them for an Off-Grid mode
dougbert
Solar Addict
that is great to have such a low load!
now for my house, which has grid breaker off during the summer, the lowest I have seen at nite is 290w
there are computers and homelab on, frig/freezer, LED nite lights, security, etc
during the day with major apps off, the house coasts at 900w draw. when the battery is full and the water heater diversion load starts (3000w 240v coils) 3.9kw to 4.2kw draw occurs, mostly from direct solar conversion
load management is a fundamental skill to continuing improvement
Zwy
Emperor Of Solar
Inverter is off on Voltronic unless it is a hybrid.
It doesn't happen all the time but my refrigerators and freezers occasionally align up and shutdown after reaching their set points. At that point the house draw is just a few minor items. It would be zero (not counting the AIO's idle to operate but the loads from the house) other than the items that use power when in an off condition.
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