Industry standard for Hybrid Inverters Self Supply and TOU modes

[scrambler]

Hi
Can people with a hybrid inverter and a battery system share the details of how the Self supply and or TOU modes work on their configuration?

In my mind below is what I thought made the most sense for a system connected to a utility that allows solar production grid export.
Apparently some systems operate a different way, so I am trying to find out what is the industry standard on that subject.

- Solar production will never be limited, full solar production enabled and any surplus exported to the grid.
- The battery will recharge on solar using whatever solar power is available after fulfilling the house loads
- The battery will discharge when there is not enough solar power available, to minimize or avoid any grid Import
* In Self Supply that would be true all day
* In TOU mode that would only happen in user defined time frames corresponding to peak/part peak rate.

Also let me know what system model you are using

Thank you

[Ampster]

Hi
Can people with a hybrid inverter and a battery system share the details of how the Self supply and or TOU modes work on their configuration?

In my mind below is what I thought made the most sense for a system connected to a utility that allows solar production grid export.
Apparently some systems operate a different way, so I am trying to find out what is the industry standard on that subject.

- Solar production will never be limited, full solar production enabled and any surplus exported to the grid.
- The battery will recharge on solar using whatever solar power is available after fulfilling the house loads
- The battery will discharge when there is not enough solar power available, to minimize or avoid any grid Import
* In Self Supply that would be true all day
* In TOU mode that would only happen in user defined time frames corresponding to peak/part peak rate.

Also let me know what system model you are using...............

I have an Outback Skybox. It has four operation modes. I don't know if there is an industry standard. I think it is about features and marketing splash.
Net metering with Back Up - supports loads and sell to grid. This is the only mode that uses TOU periods to determine when to prioritize battery over the grid.
Self Consumption - Minimize grid use.
Non Export - Support loads without export.
Maximum Independence - Grid use is last resort

Though not a mode, AC coupling is a feature because it allows leveraging an existing GT system that otherwise would not work in a grid down situation. Grid zero is also a descriptive term that describes how at least two of the above modes operates.

Hope that helps. I did not respond to your specifics because my notes were organized around the modes in my Skybox. After you reflect on my answer I would be happy to discuss further. I don't know how many members here actually use hybrid inverters.

[scrambler]

Thanks Ampster, here are additional questions on your modes if you know the answers

Net metering with Back Up (TOU).
- I understand from what you said that it allows full solar production and export surplus to the grid
- Does it charge using solar only, meaning it regulates charging as not to import from grid while charging?
- Does it discharge at a fixed rate, dumping excess battery discharge into the grid, or does it modulates battery discharge to only fulfill house loads but not discharge into the grid?

Self Consumption - Minimize grid use
Same questions as above

Maximum Independence - Grid use is last resort
What is the difference between that and Self Consumption?

[Ampster]

Thanks Ampster, here are additional questions on your modes if you know the answers
.....................

Those are good questions. I am going to have to answer your questions in detail tomorrow. That will give me time to go through a complete cycle to better answer your questions. I just fired up my new pack and am seeing behaviors inconsistent with my other pack. It may be a result of changing voltage settings with a different chemistry. I don't want to give you an answer that is based on old data.

[Ampster]

Thanks Ampster, here are additional questions on your modes if you know the answers

Net metering with Back Up (TOU).
- I understand from what you said that it allows full solar production and export surplus to the grid
- Does it charge using solar only, meaning it regulates charging as not to import from grid while charging?
- Does it discharge at a fixed rate, dumping excess battery discharge into the grid, or does it modulates battery discharge to only fulfill house loads but not discharge into the grid?

Depending on where the pack is. it typically will charge from solar. With my old pack it did charge from the grid but its SOC tracking wasn't very good with that pack.
I can control the maximum discharge in Amps. Today with my new battery pack it seems to be discharging the battery into the grid. I have never seen that before on the old pack. I don't have permission to do that so I am going to change modes soon after I log some results. Since it was in float mode it did curtail solar to the limit of the float setting. I might think about cranking that up.

61

Self Consumption - Minimize grid use
Same questions as above

This is also described as a grid zero mode and it charges from solar unless I hit minimum SOC.
In this mode it does export.excess generation. I haven't used this mode but it differs from Backup in that it does not use time of use and since its main priority is not backup it does not keep the battery at a higher level of SOC.

Maximum Independence - Grid use is last resort
What is the difference between that and Self Consumption?

There is no excess sold to grid and only on last resort will it charge from the grid. This morning my pack was at 30% DOD which was my minimum setting and therefore it was using the grid. My coulomb counter is still calibrating so that was not a reliable estimate of DOD.It did allow me to see that my minimum SOC parameter was working. My guess from kWhrs consumed was that it was more like 50%. It is going to take a couple of cycles to reset the SOC calculation. In the meantime it began charging from solar and SOC is now reading 61%. I have three more hours of solar so I hope it gets to 100% to reset SOC

There are a lot of subtle settings that can influence this and I am just getting my feet wet with the Maximum Independence mode. So far so good. I hope that helps inform folks how one hybrid inverter can be programmed.
I did start out yesterday with a pack that was above my rebulk voltage so it did not bulk charge but it did float charge which was just enough to keep the battery constant at 53 volts (the refloat setting) but not enough to take it to the top to reset the coulomb counter.

[scrambler]

Thanks Ampster.

Overall, can you confirm that both for TOU and Self Supply, the system (either by default or through an option) does not limit Solar production, lets full solar production happen and exports the unused portion to the grid?
The mode being used mainly to manage how the battery is used (charge and discharge), without affecting solar production.

Can you clarify what the "float" mode is in your remark "Since it was in float mode it did curtail solar to the limit of the float setting. I might think about cranking that up." Is that a setting that fixes an upper limit to the amount exporte, or something else?

[Ampster]

Thanks Ampster.

Overall, can you confirm that both for TOU and Self Supply, the system (either by default or through an option) does not limit Solar production, lets full solar production happen and exports the unused portion to the grid?
The mode being used mainly to manage how the battery is used (charge and discharge), without affecting solar production.

Yes solar is not curtailed because in either mode the excess is sold to the grid. One exception to that is that the system does have the option to control how much solar is exported, That is useful in my case because my NEM agreement allows me to add 1 kW of solar generation without triggering a new NEM agreement. I have about 2kW of solar connected to the Skybox but it is west facing with some shade.

Can you clarify what te "float" mode is in your remark "Since it was in float mode it did curtail solar to the limit of the float setting. I might think about cranking that up." Is that a setting that fixes an upper limit to the amount exporte, or something else?

There is a setting for Float time and voltage. I did not have the shunt connected yesterday so I could not see what kind of Amps were being put out but looking at my solar production it was being curtailed. By cranking that up I meant taking the battery to a higher SOC since I had the solar capacity. The time was set to two hours and I am going to make that 4 or 5 hours but I am going to increment that and voltage slowly because I don't want them sitting at a high state of charge for a long time. As soon as the sun retreats the batteries start discharging,
Keep asking questions, This is a work in progress that is evolving I a few weeks I am going to be adding the second 14 kWh of batteries.

[scrambler]

Thanks that confirms the essentials

[Ampster]

It would be nice to get some information on SolArk and a few others. I would be disappointed if I were the only one on this forum that actually has deployed a hybrid inverter or chooses to comment.