What to look for in new battery install?

[h2ofun]

My process is slowly moving along. But, if I get batteries, wanting to start a list of what to look out for, meaning, what things did folks miss that came back to bite them?

I know I am doing all I can to make sure the drawings and permits are accurate. Have already updated my power panels.
Would put outside so no issues with ballords or code for inside house.

Would have 2 inverters and 2 gateways, with solar split to be balanced for each GW. Would have both inverters with EV charging in them, why not.

Where does these CT's get installed with a double GW system to report correctly? Two zigbees?

 

[Ampster]

Are you doing this yourself or are you talking about two Powerwalls?
If you are doing it yourself the biggest thing is the new 2020 NEC and how soon that get implemented by your local building officials. It makes bollards seem trivial.

 

[miimura]

He is talking about two parallel systems serving more than 200A. Not many people here have experience with setups like that.

 

[h2ofun]

He is talking about two parallel systems serving more than 200A. Not many people here have experience with setups like that.

I am paying a company to install. No way would I consider a challenge like this. Currently I have 47 solar panels (14.5K) to one Solaredge 11.4K inverter. Drives into a 70 amp breaker generator panel. I have a 400 amp service, with 2 breakers. I had to replace one 200 amp breaker with a 125 so I could meet code driving through the generation panel to my garage 200 amp panel. This goes my garage lights, but is also powers my 3 mini split compressors, 10 heads, with a 100 amp line. After the generation panel it connects into my ATS for my generator then to the garage sub panel. The other 200 amp breaker connects to the other ATS and goes to the house 200 amp panel. I have attached a crude drawing I did for my existing setup.

What I am hoping to get approved and installed is a 5 battery setup with 2 gateways and 2 inverters. This should allow me to put the 200amp breaker back in since the GW will now control the solar and grid. The 47 panels, 3 strings would be split into two sets, either 2 or 4 strings, whatever the installer wants to do. So, the idea is the replaced 200 amp breaker goes to the GW for garage. This GW has half the solar connected to its generation panel. This GW has 2 PW's connected. It then is connected to one ATS which the generator is connected and connects to my garage 200 amp panel, which has my heat pumps as described above. The second 200 amp breaker goes into the second GW. It gets the other half of the solar panels. The output goes to the other ATS and this drives my house 200 amp subpanel.

The split panels drive into solaredge 11.4 K inverters, with the EV option in both. One new, one upgrade to existing. (I learned about this option in this group)

I will not be having an essential and non essential wiriing/panels. Everything just drives 100% of stuff, and iit is up to me to manage usage of loads if I get a power outage.

All 5 PW's will be installed outside, under my land bridge so will never get wet, or direct sun. They still will get cold or hot just not wet.
I want to have them single spaced on my stucco wall rather than stacking, to save room for walking by them. I hope to install in a way that if I could find 2 more PW's, I still have room on the wall for 2 more. I am asking the installers to embed as much of the wiring in my walls, as today I have 100% of the wiring for everything in the walls. I just cut out sheet rock, and replaced after we were done.

So, this is currently what I am thinking of doing. What am I missing?

 

[miimura]

What you're asking for is complicated because you want not only two Gateways, but a single generator to back up both as well. You will have to talk to installers that have experience with large installations like this. Some installers in CA specialize on jobs like this and on new construction integration and keep busy doing just that. Not many of those customers hang around on forums like this one. Good luck with your project.

 

[h2ofun]

What you're asking for is complicated because you want not only two Gateways, but a single generator to back up both as well. You will have to talk to installers that have experience with large installations like this. Some installers in CA specialize on jobs like this and on new construction integration and keep busy doing just that. Not many of those customers hang around on forums like this one. Good luck with your project.

Just trying to get thoughts.

The generator is easy. The single unit splits between both ATS's switches. They only trigger if there is not power. Today that is the grid power goes out. If I have GW's, it would be the GW's open up if there is no power. Now an interesting question is what happens if one gateway opens? Will have to look into this, but I guess this could imply the generator comes on and runs one of the sub panels while the other is still being run by PW's?

Just sent off this question to the engineer, since just wanting to make sure no surprises since my setup is so complicated.

 

[ltphoto]

Any updates on your project? Asking since I am looking at a similar system. Currently considering 44 330W panels with tow SolarEdge inverters. Have two 200A panels and want to backup both. Probably just 4 PW's for me.

 

[h2ofun]

Any updates on your project? Asking since I am looking at a similar system. Currently considering 44 330W panels with tow SolarEdge inverters. Have two 200A panels and want to backup both. Probably just 4 PW's for me.

Some plans were put into county and rejected because they wanted on blade disconnect per battery. Holidays slowed things down. I have been requesting to be involved in the plan reviews since I found issues with the first ones, and continue to find issues. Makes sense since I have a very complicated install. We all got together on a phone conference yesterday and my generator has continued to be not dealt with correctly, meaning, the solar and batteries must be in a generation panel before my 2 generator automatic transfer switches or things could be burned up.

Since you already have two SE inverters things will be easier for you since my 47 panels are in one inverter.

So, you just need to decide how flexible you want to make your setup.

But, the first big issue to deal with is where do you put the batteries? Meaning, since Tesla does not have a 400 amp TEG, you may have to make trade offs. Also are you going to do whole house backup, or split to critical vs non critical. This decisions drives one in one direction. It also can mean, as for me, that the amount of batteries are not what they seem.

In my case, I am doing whole house. But, I have critical loads in both subpanels. So, lets say I get 5 batteries. Where do I put them.
My garage panel contains all my mini split heat pump stuff. So for all practical purposes, I am backing up two homes. Since it seems I use more suds on the heat pumps subpanel, I would put the odd extra there. But one needs to make sure one have enough suds to overcome the startup loads.

Another decision is how do you connect your inverters and batteries. There is space and parts for the TEG to connect up to 6 batteries. Since I want the ability to maybe expand things in the future, we are going to use seperate 200 amp panels for generation panels, rather than connecting into the TEG and limit what could be done in the future. No one else would ever do this, but I always like to be ready for future changes if needed.

Hoping to get back updated drawings soon so I can make another look.

So, most folks never get into the details I am getting into. Most do not have to worry that a generator works also. But doing my best to make sure I have no issues once things start being installed. I am out measuring now to make sure I can fit the batteries all side by side.
Not sure where all the disconnects are going. Going to be a ugly install of boxes.

 

[ltphoto]

Thanks for the extra details. Spent a couple of hours this morning with the project manager working on design. Looks like in our case we are going to rearrange loads to an always backed up panel, and a manually backed up panel. I'll have things like the shop 240V circuits, second water heater, second range, resistance heating and elevator in the manual panel. In an outage I will have to throw a manually operated switch to bring the secondary items online for backup. That manages the maximum peak load at the outage, and theoretically means I can get by with three Powerwalls instead of four. The extra items I will not generally need, so 99% of the time the system will behave like a whole house backup since we won't be using the other items anyway. Simpler system to design, and one less gateway reduces cost. I'll see how much in a few days when I have a new design and cost.

 

[h2ofun]

Thanks for the extra details. Spent a couple of hours this morning with the project manager working on design. Looks like in our case we are going to rearrange loads to an always backed up panel, and a manually backed up panel. I'll have things like the shop 240V circuits, second water heater, second range, resistance heating and elevator in the manual panel. In an outage I will have to throw a manually operated switch to bring the secondary items online for backup. That manages the maximum peak load at the outage, and theoretically means I can get by with three Powerwalls instead of four. The extra items I will not generally need, so 99% of the time the system will behave like a whole house backup since we won't be using the other items anyway. Simpler system to design, and one less gateway reduces cost. I'll see how much in a few days when I have a new design and cost.

If one is starting from new, as I believe you are, then doing what you are doing is a great option. In my case, I cannot rewire anything, so I choose to just allow me to decide what to use and not use. IMO, no matter how many PW's, my behavior will be guess what, we are out of power, for unknown length of time, so I would use my house with that attitude, not that I have PW's and can keep my life style the same. Assuming one has the money, IMO, getting stuff now makes sense since it is one permit. Things do not get cheaper. And the rules are changing SO fast with this stuff that one may not be able to do things in the future like one did in the past. I know I am trying to take this approach. Like one change maybe you can only have so much power at one location.

I got my plans finished with the installers yesterday. Hoping they get back to the county today. They just needed to get the engineering stamp. If I can get approved, maybe I can get batteries in a few weeks. And having tons of knife disconnect blades.

 

[Vines]

I got my plans finished with the installers yesterday. Hoping they get back to the county today. They just needed to get the engineering stamp. If I can get approved, maybe I can get batteries in a few weeks. And having tons of knife disconnect blades.

More AC Disconnects clearly means more safety! /S

 

[h2ofun]

More AC Disconnects clearly means more safety! /S

Yea, but boy will I be in the running for the ugliest wall of panels.

 

[ltphoto]

If one is starting from new, as I believe you are, then doing what you are doing is a great option. In my case, I cannot rewire anything, so I choose to just allow me to decide what to use and not use. IMO, no matter how many PW's, my behavior will be guess what, we are out of power, for unknown length of time, so I would use my house with that attitude, not that I have PW's and can keep my life style the same. Assuming one has the money, IMO, getting stuff now makes sense since it is one permit. Things do not get cheaper. And the rules are changing SO fast with this stuff that one may not be able to do things in the future like one did in the past. I know I am trying to take this approach. Like one change maybe you can only have so much power at one location.

I got my plans finished with the installers yesterday. Hoping they get back to the county today. They just needed to get the engineering stamp. If I can get approved, maybe I can get batteries in a few weeks. And having tons of knife disconnect blades.

We are not starting from new. Just lucky that our systems are set up in a way that makes it easy to reconfigure. Panels are set adjacent with about 3" between them. There is a pass through at both the top and bottom and nothing routed through yet, so plenty of room to pull wiring as the circuit breakers are reconfigured. It will cost a lot less than having two gateways, and simplify system management.

 

[h2ofun]

We are not starting from new. Just lucky that our systems are set up in a way that makes it easy to reconfigure. Panels are set adjacent with about 3" between them. There is a pass through at both the top and bottom and nothing routed through yet, so plenty of room to pull wiring as the circuit breakers are reconfigured. It will cost a lot less than having two gateways, and simplify system management.

Great you are able to do it the right way. Looks like I am stuck with basically 2 complete systems for my house, since it is wired basically as 2 homes. Oh well, nothing in my house is easy.