Hybrid inverter main panel wiring for grid export and TOU settings?

[tacomaguy20]

I'm working on designing my system and I was considering purchasing the new Growatt Hybrid SPH 10000TL-HU-US system or I might go with EG4 18K and I've been watching some videos and reading about connecting inverters to the grid. However, I was unclear on how to hook up a panel like mine to one of these inverters. My panel is connected directly to the meter so I don't know if it's even possible to hook up a disconnect between the meter and the main panel breaker. I do not have a separate subpanel (critical load panel) either and so I'm assuming that I'd either need to install one or hook up connection directly to my main panel. I believe I can hook up a breaker and connect the inverter directly into the panel and the extra power generation will backfeed the grid but is it possible to control time of use hours if connected this way? I would like to run on solar generation/batteries during certain hours of the day and charge batteries when not on peak hours and then backfeed once the batteries are full. Suggestions on how to hook this up would be appreciated.

 

[1201]

View attachment 219286View attachment 219287

I'm working on designing my system and I was considering purchasing the new Growatt Hybrid SPH 10000TL-HU-US system or I might go with EG4 18K and I've been watching some videos and reading about connecting inverters to the grid. However, I was unclear on how to hook up a panel like mine to one of these inverters. My panel is connected directly to the meter so I don't know if it's even possible to hook up a disconnect between the meter and the main panel breaker. I do not have a separate subpanel (critical load panel) either and so I'm assuming that I'd either need to install one or hook up connection directly to my main panel. I believe I can hook up a breaker and connect the inverter directly into the panel and the extra power generation will backfeed the grid but is it possible to control time of use hours if connected this way? I would like to run on solar generation/batteries during certain hours of the day and charge batteries when not on peak hours and then backfeed once the batteries are full. Suggestions on how to hook this up would be appreciated.

Yeah you connect the grid side of your inverter into your main panel. You won't have backup capability though. An electrician should be able to set up a backup sub panel for you(you would connect load side of inverter to backup panel )

With the growatt (and I'm sure the eg4) you can have it use pv and batteries during certain hours (time of use). If the battery is full it will backfeed any excess

Can you give an example of how you would want this set up as far as charging/discharging hours?

 

[BentleyJ]

Whole home back up is possible. All that is required is to remove the wires between the meter output lugs and the main breaker. Then run new wires to the Inverter Input breaker. (if the inverter is placed next to the utility meter, it may be possible to get the installation approved without a separate disconnect since the breaker is right there.)

Then the output of the inverter is rewired to feed directly to the breaker panel main. This is the easiest, least expensive way.

A better method would be to do the installation with a maintenance bypass in case the inverter fails or needs service.

Time of Use can be programmed with the user set up menus.

 

[jpwhit]

Whole home back up is possible. All that is required is to remove the wires between the meter output lugs and the main breaker. Then run new wires to the Inverter Input breaker. (if the inverter is placed next to the utility meter, it may be possible to get the installation approved without a separate disconnect since the breaker is right there.)

Then the output of the inverter is rewired to feed directly to the breaker panel main. This is the easiest, least expensive way.

A better method would be to do the installation with a maintenance bypass in case the inverter fails or needs service.

Time of Use can be programmed with the user set up menus.

That style of panel typically doesn't have wires from the meter to the main breaker. There are typically bus bars between the meter socket and the main breaker. The main breaker connects to bus bars on both sides.

 

[BentleyJ]

That style of panel typically doesn't have wires from the meter to the main breaker. There are typically bus bars between the meter socket and the main breaker. The main breaker connects to bus bars on both sides.

That is certainly a possibility. Then its a matter of either being able to remove the bus bars and substitute for lugs and wire if that can be done without loosing the UL rating or changing out the main panel entirely.

 

[jpwhit]

My panel is connected directly to the meter so I don't know if it's even possible to hook up a disconnect between the meter and the main panel breaker.

Typically for that type of panel it's not possible to install a disconnect between the meter and the main panel breaker. But to be sure, open the right side and remove the cover and look closely at the main breaker. Are there wires coming from the meter side to the main breaker, or are there metal bus bars.

I had the same issue at my lake house. I installed another panel right next to the combined panel and moved about 75% of my circuits to the new panel. That panel is setup as a critical load backup panel. It's fed by the backup power output of my GoodWe inverter. I was very careful about the placement of that new panel relative to the wires coming into the original panel such that I had enough wire length to pull all those circuits out of the original panel and they could still reach the breakers once fed into the new backup panel. You can look at my build thread if you want to see a picture of the panels.

You other option is to have the combined panel completely replaced with a new meter box and new panel(s). Just for grins before I did my solar install at the lake house, I had Tesla do a quote. When they did the quote, they said they couldn't do the job on my house without replacing the combined panel with a new separate meter box and new panels. They added $10k to the quote just for that. But the Tesla guy told me that was ridiculous and to find a local electrician to do it and then contact them back for a new quote.

 

[jpwhit]

Then its a matter of either being able to remove the bus bars and substitute for lugs and wire if that can be done without loosing the UL rating or changing out the main panel entirely.

That's right, you can't change that in a panel. Doing so voids the UL certification.

 

[tacomaguy20]

Yeah you connect the grid side of your inverter into your main panel. You won't have backup capability though. An electrician should be able to set up a backup sub panel for you(you would connect load side of inverter to backup panel )

With the growatt (and I'm sure the eg4) you can have it use pv and batteries during certain hours (time of use). If the battery is full it will backfeed any excess

Can you give an example of how you would want this set up as far as charging/discharging hours?

Well during the summer, 2pm to 8pm weekdays are peak hours, everything else is off peak. I'd like to charge batteries off peak and run the batteries between 2pm and 8pm. Backfeeding the grid has the same price anytime of day so whatever hours are good after the batteries are charged. During the winter 5am to 9am and 5pm to 9pm weekdays are peak hours.

 

[1201]

Well during the summer, 2pm to 8pm weekdays are peak hours, everything else is off peak. I'd like to charge batteries off peak and run the batteries between 2pm and 8pm. Backfeeding the grid has the same price anytime of day so whatever hours are good after the batteries are charged. During the winter 5am to 9am and 5pm to 9pm weekdays are peak hours.

Questions- will you have pv? Or solely checking from grid?

What price do you get for feeding the grid?

Are you looking to feed grid from battery or only from excess pv(if you'll have pv)?

 

[tacomaguy20]

Typically for that type of panel it's not possible to install a disconnect between the meter and the main panel breaker. But to be sure, open the right side and remove the cover and look closely at the main breaker. Are there wires coming from the meter side to the main breaker, or are there metal bus bars.

Here are the pictures of inside, it's wires. So would it be possible to put a disconnect in?

 

[tacomaguy20]

Questions- will you have pv? Or solely checking from grid?

What price do you get for feeding the grid?

Are you looking to feed grid from battery or only from excess pv(if you'll have pv)?

Yeah I think PV would make the most sense in the long run. If I can get a system going for cheap enough and DIY it myself, then that would be ideal. To be honest the price for feeding the grid is like 2.81 cents (might not be worth it really). I pay between 5.36 and 7.98 cents per kwh but I'm on a demand plan so that has a multiplier effect during peak hours. Mostly I'm looking to eliminate that as well as have emergency power if needed. I'm also told by my utility company that any system I hook up has to be grid tied (not sure how true that is exactly) but I'd like to have the option regardless. I'm mostly just looking for any excess PV to feed the grid. Eliminating peak hour usage & back up power are the top priorities.

 

[1201]

Yeah I think PV would make the most sense in the long run. If I can get a system going for cheap enough and DIY it myself, then that would be ideal. To be honest the price for feeding the grid is like 2.81 cents (might not be worth it really). I pay between 5.36 and 7.98 cents per kwh but I'm on a demand plan so that has a multiplier effect during peak hours. Mostly I'm looking to eliminate that as well as have emergency power if needed. I'm also told by my utility company that any system I hook up has to be grid tied (not sure how true that is exactly) but I'd like to have the option regardless. I'm mostly just looking for any excess PV to feed the grid. Eliminating peak hour usage & back up power are the top priorities.

Dang your power is so cheap that it almost doesn't seem worth it to do battery but no pv.

However, you said you want backup and battery interest are great for backup.

As far as what you're looking to do, you'll setup a time of use plan for the peak hours and the inverter will support the grid/backup up to it's max capability. It will discharge from battery first during this time.

Then when power is cheap you can set it to charge from battery.

Keep in mind though depending on your demand you could still be drawing from the grid. So if you have a 10kw growatt and have 18kw of load, 8kw would still be coming from the grid, so size accordingly

 

[tacomaguy20]

Whole home back up is possible. All that is required is to remove the wires between the meter output lugs and the main breaker. Then run new wires to the Inverter Input breaker. (if the inverter is placed next to the utility meter, it may be possible to get the installation approved without a separate disconnect since the breaker is right there.)

Then the output of the inverter is rewired to feed directly to the breaker panel main. This is the easiest, least expensive way.

A better method would be to do the installation with a maintenance bypass in case the inverter fails or needs service.

Time of Use can be programmed with the user set up menus.

How does that maintenance bypass look? Is that a manual transfer switch between the inverter power and grid power?

Also, how would this work during a power outage? Does the inverter separate the backfeeding of the grid internally (and stop it during a power outage) but continue supplying the output to the panel directly from the batteries at the same time? I'm used to seeing off grid hookups so it's never been that clear to me.

 

[tacomaguy20]

Dang your power is so cheap that it almost doesn't seem worth it to do battery but no pv.

However, you said you want backup and battery interest are great for backup.

As far as what you're looking to do, you'll setup a time of use plan for the peak hours and the inverter will support the grid/backup up to it's max capability. It will discharge from battery first during this time.

Then when power is cheap you can set it to charge from battery.

Keep in mind though depending on your demand you could still be drawing from the grid. So if you have a 10kw growatt and have 18kw of load, 8kw would still be coming from the grid, so size accordingly

Yeah the power is cheap mostly because of the demand multiplier plan I'm on (which can get really high really fast). It's between 10 and 36 cents per kw on the other plans. I've been able to drop my usage down to between 3 to 4kw as the highest consumption per hour for most days so I don't see myself maxing out 10kw unless I'm running multiple major appliances at the same time but I do like that I can have that pull from the grid if needed.

 

[1201]

Yeah the power is cheap mostly because of the demand multiplier plan I'm on (which can get really high really fast). It's between 10 and 36 cents per kw on the other plans. I've been able to drop my usage down to between 3 to 4kw as the highest consumption per hour for most days so I don't see myself maxing out 10kw unless I'm running multiple major appliances at the same time but I do like that I can have that pull from the grid if needed.

Wow, 4kw peak demand is good. I see peaks of 10-14kw a few times a month.

 

[tacomaguy20]

Wow, 4kw peak demand is good. I see peaks of 10-14kw a few times a month.

I have had peaks that high when running everything at the same time but I'm a single guy and recently installed a mini split and window AC unit so I don't have to use my main house AC very often (if ever) so that cut out a lot of my usage. My house AC pulls about 5 to 6kw by itself. Other than that it's mostly just the home theater, oven and dryer which use most of my power which I'm not usually running all at the same time.

 

[tacomaguy20]

Additional question, since the inverter would be next to my panel outside (I'm in Arizona) and it gets pretty hot, behind the wall the inverter and electrical panel are on is my garage. It's not cooled or anything and is actually vented to outside in two spots. What is the consensus on putting batteries in a hot garage? It's about 100 degrees in there today for example. I could put them in the house but it's about 20 feet from the corner of the house where the electrical panel is to my inside bedroom closet. Or I could try sealing the garage to try to keep it a little cooler in there.

 

[1201]

Additional question, since the inverter would be next to my panel outside (I'm in Arizona) and it gets pretty hot, behind the wall the inverter and electrical panel are on is my garage. It's not cooled or anything and is actually vented to outside in two spots. What is the consensus on putting batteries in a hot garage? It's about 100 degrees in there today for example. I could put them in the house but it's about 20 feet from the corner of the house where the electrical panel is to my inside bedroom closet. Or I could try sealing the garage to try to keep it a little cooler in there.

Wouldn't put them in the house. What direction does that wall face? How about putting the inverter inside and installing an inexpensive mini split for the garage?

 

[tacomaguy20]

The wall faces west. Right now it's getting a decent amount of sun as you can see in the pictures but sometimes it's blocked by the neighbors house. I thought about installing the inverter inside the garage on the opposite side of the electrical panel (close nearby) It wouldn't be hard but wasn't sure if it would be approved if wasn't right next to the electrical panel outside. I'd have to check with my utility company/city. A mini split in the garage would be doable. I'm assuming it's better for batteries to be at a cooler temperature so they last longer.

So to clarify with my setup, I could, for example, disconnect the wires from the output lugs of the electrical meter, run them to a manual transfer switch with the other input coming from my inverter (inside the garage) and the output going back to the panel? Then I could have the grid power running through the inverter but if I ever needed to do maintenance (as suggested above) I could then switch the back to grid power? Does that work or did I misunderstand?

 

[1201]

The wall faces west. Right now it's getting a decent amount of sun as you can see in the pictures but sometimes it's blocked by the neighbors house. I thought about installing the inverter inside the garage on the opposite side of the electrical panel (close nearby) It wouldn't be hard but wasn't sure if it would be approved if wasn't right next to the electrical panel outside. I'd have to check with my utility company/city. A mini split in the garage would be doable. I'm assuming it's better for batteries to be at a cooler temperature so they last longer.

So to clarify with my setup, I could, for example, disconnect the wires from the output lugs of the electrical meter, run them to a manual transfer switch with the other input coming from my inverter (inside the garage) and the output going back to the panel? Then I could have the grid power running through the inverter but if I ever needed to do maintenance (as suggested above) I could then switch the back to grid power? Does that work or did I misunderstand?

Jmo but I wouldn't put an inverter on a West facing wall in Arizona. I would do everything I could to have it inside and air condition the garage. It'll make the components last a lot longer.