Home owner installable AC coupled system help.

[aceinc]

I have an existing SolaEdge 10 KW grid tie system, 2 5 KW HD Wave inverters. without throwing out the existing inverters, I would like to integrate batteries.

It is my understanding I can do this with an AC coupled system. I believe I could implement something like a Tesla Powerwall or 4, but I would prefer LiFePo4 batteries, which take up more room, but are more durable, les dangerous & less problematic environmentally.

I also believe I can install a system myself, if it is not too complex. Where can I go to get competent help in designing what I need and identifying the parts?

 

[fafrd]

I have an existing SolaEdge 10 KW grid tie system, 2 5 KW HD Wave inverters. without throwing out the existing inverters, I would like to integrate batteries.

It is my understanding I can do this with an AC coupled system. I believe I could implement something like a Tesla Powerwall or 4, but I would prefer LiFePo4 batteries, which take up more room, but are more durable, les dangerous & less problematic environmentally.

I also believe I can install a system myself, if it is not too complex. Where can I go to get competent help in designing what I need and identifying the parts?

By ‘install myself’ do you mean with a permit and inspected by your AHJ or not? What state are you based in?

 

[Ampster]

I learned everything I needed to self install a system from Forums like this. Most likely you would need skills to add a circuit to a breaker panel and possibly even add a sub panel.

 

[fafrd]

I learned everything I needed to self install a system from Forums like this. Most likely you would need skills to add a circuit to a breaker panel and possibly even add a sub panel.

Did you manage to install your own ESS and was it permitted and inspected by your AHJ?

After installing my own permitted and inspected grid-tied solar system in 2016, I started down that same path in 2019 to install an ESS when they announced the SGIP battery incentives, but the pathway for owner-installation of ESS systems was blocked… (owner had to also be a licensed electrician),

 

[Ampster]

Did you manage to install your own ESS and was it permitted and inspected by your AHJ?

My GT system is permitted and inspected by my AHJ. My hybrid inverter and battery storage was not permitted. The wiring is per code but the batteries are DIY and not UL listed.

but the pathway for owner-installation of ESS systems was blocked… (owner had to also be a licensed electrician),

Professional installation was not an issue with my County Building department because my GT system was installed on an Owner Builder permit. My issue, as mentioned above, was that the batteries were not UL listed and therefore not in compliance with NEC 2020.

 

[aceinc]

My existing system was installed by others. However, I did not feel confident penetrating my roof.

I have been mucking about in electrical panels since I was ~13, and haven't killed myself yet.

I would not object to paying someone to install a system for me, however, I haven't found anyone in my area (S Florida) who I feel confident knows what they are talking about in regards to batteries. It was tough enough finding someone who could install the PV system.

Where I need the most help if I install it myself is designing the system and selecting the components.

 

[Ampster]

Where I need the most help if I install it myself is designing the system and selecting the components

Most of the critical design questions revolve around how much capacity you want to have.
The two capacity issues are inverter capacity in kWs and battery storage capacity in kWhs. Those are the critical questions any designer is going to ask you before they design a system. If you don't give some thought to those questions you can pay someone to guess for you but the chances are you will not get a system that will satisfy your needs.

 

[fafrd]

My GT system is permitted and inspected by my AHJ. My hybrid inverter and battery storage was not permitted. The wiring is per code but the batteries are DIY and not UL listed.

Professional installation was not an issue with my County Building department because my GT system was installed on an Owner Builder permit. My issue, as mentioned above, was that the batteries were not UL listed and therefore not in compliance with NEC 2020.

Are you saying your AHJ would let you install your ESS yourself as long as the batteries used were UL-listed?

Perhaps the restriction I ran into were only to qualify for the SGIP credit (from the utility)…

 

[aceinc]

Most of the critical design questions revolve around how much capacity you want to have.
The two capacity issues are inverter capacity in kWs and battery storage capacity in kWhs. Those are the critical questions any designer is going to ask you before they design a system. If you don't give some thought to those questions you can pay someone to guess for you but the chances are you will not get a system that will satisfy your needs.

I have given much thought to these questions. If possible, how I would like to proceed is;

Maximize the KWs while minimizing initial KWHs. For example I would like to be able to provide power to my whole house for a short period of time, perhaps ~100 A @ 220 V (22KW). I would then like the ability to add additional capacity over time, eventually having 50-100 KWHs of capacity.

 

[hayhayday]

If you don't need and simply want peak shifting adding a resu or solaredge battery and swapping the inverter is very simple and only requires running 2 wires to the battery and a ethernet cable for communication. I initially swapped my solaredge inverter for a solaredge energy hub inverter(600 ebay new in box, sold used inverter 300), lg resu 10h $2500 off craigslist, eventually added the $1300 solaredge backup gateway for partial backup. Worked fine for about a year until battery bms bricked during a firmware update itself and lg wont help me since it wasnt installed by authorised installer. Likely would have had a better outcome with Solaredge branded batteries as they seem ok with diy but at $9k per 10kwh not cost effective. Currently in progress of remove resu and swap the backup interface for sol-ark 15k to ac couple to eg4 rack for about $18k for 30kwh and might be permittable as they both are ul listed but not 9540. When the optimisers eventually die and force me on the roof I might remove solaredge inverter and dc couple.

 

[zond2]

I am interested in doing something similar. I am located in NorCal and am planning on having a commercial PV array installed and at the same time install a battery bank made of LiFePo batteries instead of a comnercialTesla powerwall/ LG or others. Need to get out from under PGE's thumb.

 

[Hedges]

Maximize the KWs while minimizing initial KWHs. For example I would like to be able to provide power to my whole house for a short period of time, perhaps ~100 A @ 220 V (22KW). I would then like the ability to add additional capacity over time, eventually having 50-100 KWHs of capacity.

4x Sunny Island would be 23kW, also a lot of $$.
Some less expensive brands available. But you need to consider surge current; motor loads? Or resistance heaters?
Mine has 20kWh gross, 14kWh usable AGM.

I am interested in doing something similar. I am located in NorCal and am planning on having a commercial PV array installed and at the same time install a battery bank made of LiFePo batteries instead of a comnercialTesla powerwall/ LG or others. Need to get out from under PGE's thumb.

Hey Zond2,

I'm somewhere in your general area.
I didn't use a kit for my first computer, I wire wrapped a Z80. With an entire 1k byte of RAM! (It had less functionality than your ZX80, no video driver.) Later I helped design microprocessors at the level of schematic, SPICE, IC layout.

Consider designing and installing more of the PV system yourself.

PG&E is still a reliable and affordable source of power, beats using a generator. Consider signing up to have a net metered system under NEM 2.0, think the paperwork deadline is prior to April 14th 2023.

 

[zond2]

4x Sunny Island would be 23kW, also a lot of $$.
Some less expensive brands available. But you need to consider surge current; motor loads? Or resistance heaters?
Mine has 20kWh gross, 14kWh usable AGM.



Hey Zond2,

I'm somewhere in your general area.
I didn't use a kit for my first computer, I wire wrapped a Z80. With an entire 1k byte of RAM! (It had less functionality than your ZX80, no video driver.) Later I helped design microprocessors at the level of schematic, SPICE, IC layout.

Consider designing and installing more of the PV system yourself.

PG&E is still a reliable and affordable source of power, beats using a generator. Consider signing up to have a net metered system under NEM 2.0, think the paperwork deadline is prior to April 14th 2023.

Yeah I'm in Lake County, installed a whole home switch after the last big fire and run 12kW generator when the power goes down. Won't have enough liquid cash until after the deadline to pay for the install and get I want to go with an installer for the warrantee and freedom from the hassle to get it permitted. Lookin at a beefier than standard storage system since i'll be on NEM 3.0

 

[Hedges]

Deadline is just for filing a piece of paper. Maybe a few pieces of paper.
I've read as long as 3 years to do the install. A form I just reviewed regarding service upgrade said that would be closed after 1 year.
You should be able to get on NEM 2.0, which gives the value of storing power until winter, and storing power between cycles of A/C or water pump.

Be sure to look at SanTan solar and similar liquidators, prices could at times be far better than you imagine.

You should be able to get permits and signoff yourself. Warranties may be worth at least the paper they're printed on. Some require certified installer, an some (e.g. Enphase) have on-line training so you can be certified. I just buy good quality panels and SMA inverters. SMA has even replaced Sunny Islands for consumers who bought DC Solar trailers. If you buy panels for 50% or 25% of retail because they're slightly used (tested and shown good), no warranty except 1 year from SanTan is perfectly fine.

 

[Ampster]

I agree with @Hedges, it would be worth some effort to get a GT system permitted and the PTO application submitted before April 14th just to get in under NEM 2.0. Later you can add batteries, a hybrid inverter and more solar panels connected to the hybrid. I am of the belief that the second phase does not reguire a change in your NEM agreement, expecially if you do not export the solar from that phase. I am a little closer to you. I am seven miles south of Santa Rosa.