Adding second ESS

[agarg]

Folks:

In Sonoma county, due to Wildland Urban Interface (WUI), AHLJ have taken a very conservative stance on more than one Li-ion battery in close proximity (except Tesla). In my case, the SMA Storage needs a high DC voltage BYD or LG Chem RESU and both are (a) expensive), and (b) is not convenient after 6 ft of separation. I will have to take that some 25 ft away.

My load profile (minus the heat-pump) is about average 10 kwh during the non pv production time right now. While it improves as the day become longer, this will get worse in winters. During the grid available period, I have no problems. However, if PG&E does planned shut down (as it often does) or they do unplanned shut down (as they also often do!!), we may run into a problem as our ESS does not take us across to the solar production hours (and we produce enough, if we can store).

Even though, it sounds like an edge case, I would be delighted, if I could find enough electricity to take up to next day until PV start to produce (as a backup).

I am wondering, if I can charge a battery kept far away and then use a grid micro-inverter to produce electricity during the night, it might solve the problem.

I made this schematic and wonder if you guys would look at it and red flag what you see as concern area.

Much appreciate.

 

[400bird]

Folks:

In Sonoma county, due to Wildland Urban Interface (WUI), AHLJ have taken a very conservative stance on more than one Li-ion battery in close proximity (except Tesla). In my case, the SMA Storage needs a high DC voltage BYD or LG Chem RESU and both are (a) expensive), and (b) is not convenient after 6 ft of separation. I will have to take that some 25 ft away.

Wow, that's quite the distance. Would you put the inverter out there? Schneider and other inverter manufacturers recommend a max DC run to the battery, 10 feet for Schneider.

My load profile (minus the heat-pump) is about average 10 kwh during the non pv production time right now.

Your energy usage after the sun is down is 10kWh average? That says to me a constant 10kWh load, that's quite a lot.

While it improves as the day become longer, this will get worse in winters. During the grid available period, I have no problems. However, if PG&E does planned shut down (as it often does) or they do unplanned shut down (as they also often do!!), we may run into a problem as our ESS does not take us across to the solar production hours (and we produce enough, if we can store).

Even though, it sounds like an edge case, I would be delighted, if I could find enough electricity to take up to next day until PV start to produce (as a backup).

I am wondering, if I can charge a battery kept far away and then use a grid micro-inverter to produce electricity during the night, it might solve the problem.

The schematic looks like you have two different brand inverters in parallel powering through loads. That's not going to fly.

Seems easier to run some heavy cables to a second battery bank, paralleled to the first. Under heavy load you would see some voltage drop over the 50' of battery cable, but at lower load the distant battery should help replenish the close battery and cover the load. Not ideal, but it's the best idea I've got.

I made this schematic and wonder if you guys would look at it and red flag what you see as concern area.

Much appreciate.

 

[Hedges]

Sunny Island (48V) specs allow far greater than 10'

Sunny Boy Storage is high voltage battery inverter, should tolerate distances almost as great as PV array to inverter, except it does have to supply surge. Peak 9kW surge, so not a lot of current at 400V, just over 20A.

AHJ may not like two batteries keeping each other warm, but at least one of the SBS supported brands uses a (series) stack of batteries. More on top of each other is just a different model, more kWh and more volts.

Oh, you already have 10kWh, think that is the big one.

If you don't mind the price, another high voltage battery on SBS ought to work, regardless of distance. Maybe even 12 awg 200' run, but probably 10 awg for 30A is better.

You could probably use a Rule-21 compatible battery inverter AC coupled to SBS, best if its charge and discharge behavior responds to frequency-watts. (That's how I would like to use SBS downstream of SI).

 

[zanydroid]

is not convenient after 6 ft of separation.

IIRC California code allows this to be overridden if the manufacturer deems it OK. Sounds like the issue is either (1) your existing battery does not have this manufacturer blessing (2) your AHJ has amended the code (3) I hallucinated this clause, or it’s in code not yet adopted.

This is actually in a code section I've seen before and will dig up one of these days to bookmark more properly.

 

[zanydroid]

One thing to watch out for is, as you cobble together more battery components, you need to see if it kicks you into a new category of storage interconnect agreement with PG&E.

The rules are quite complicated.

IE there is a regulation angle on top of finding batteries and inverters with the functional and performance characteristics you are looking for.

EDIT: I guess worst case, you can probably get anything UL listed you want installed, with the caveat that you might get downgraded to a storage agreement with worse terms.

 

[zanydroid]

Even though, it sounds like an edge case, I would be delighted, if I could find enough electricity to take up to next day until PV start to produce (as a backup).

Another option here is to load shed for 2-3 years until better options come along like V2H. I’m actually evaluating today’s available V2L, it’s very close.

I think load shedding can work in summer PSPS for most homes with 10kWh battery. Short night, low night time cooling load in California climate.

If you have electric heat and need to make it in the winter, it won’t work (but you probably also can’t harvest enough solar to charge the battery).

 

[Hedges]

One thing to watch out for is, as you cobble together more battery components, you need to see if it kicks you into a new category of storage interconnect agreement with PG&E.

The rules are quite complicated.

Do those rules apply only if you backfeed grid from battery?
Or do they apply to every UPS type system? Every inverter/charger with a large (e.g forklift) battery?

Maybe the functions could be split.

 

[agarg]

Wow, that's quite the distance. Would you put the inverter out there? Schneider and other inverter manufacturers recommend a max DC run to the battery, 10 feet for Schneider.

Easiest would be a Sunnyboy compatible battery (high voltage 500 Vdc / 25 amps) and voltage drop on a 25 ft run with a #10 thhn will be minimal. However this would set me back $10-12K.

Your energy usage after the sun is down is 10kWh average?

Our energy usage between 8:30 am and 6:30 pm is only 6kwh. We take our dinner at 730P and cook our lunch before 8:30am. There is also furnace running for heating during the early morning. Microwave, toaster, and two refrigerators are energy hogs.

two different brand inverters in parallel powering through loads.

Nope! The connection to the load center is only a battery charger.

You could probably use a Rule-21 compatible battery inverter AC coupled to SBS, best if its charge and discharge behavior responds to frequency-watts. (That's how I would like to use SBS downstream of SI).

What if I replace the AIO with a Chargeverter for the 48V battery and a grid tied micro inverter. Micro's does not care if its connected to PV or the battery. I wonder if I will have to connect a current limiting device between the battery and micro inverter. The Sunnyboy will frequency shift if it does not need power from the micro inverter.

AHJ may not like two batteries keeping each other warm, but at least one of the SBS supported brands uses a (series) stack of batteries. More on top of each other is just a different model, more kWh and more volts.

Not sure how is that. Its connected during day time when PV are active for charging. And connect to PV combinerbox during night when PV panels are dead.

You could probably use a Rule-21 compatible battery inverter AC coupled to SBS, best if its charge and discharge behavior responds to frequency-watts. (That's how I would like to use SBS downstream of SI).

A micro-inverter will do that.

IIRC California code allows this to be overridden if the manufacturer deems it OK. Sounds like the issue is either (1) your existing battery does not have this manufacturer blessing (2) your AHJ has amended the code (3) I hallucinated this clause, or it’s in code not yet adopted.

The fire marshal says that even with UL9540 no one (other than Tesla) has submitted a large scale test data to support that fire will not spread from one to other in case of a thermal runaway.

Another option here is to load shed for 2-3 years until better options come along like V2H

Yes, Ford already plays nice in V2G area, it appears!

I think load shedding can work in summer PSPS for most homes with 10kWh battery.

Yes, PSPS is in summer. However this winter, we have seen serious outages from PG&E.

If you have electric heat and need to make it in the winter, it won’t work (but you probably also can’t harvest enough solar to charge the battery).

I suspect, we will put our gas fired fire place to use!!

Every inverter/charger with a large (e.g forklift) battery?

40 years ago, I worked at a place to make these with lead acid. I did weld and then melt a big crow bar back then (Circa 1978)!!

 

[zanydroid]

Do those rules apply only if you backfeed grid from battery?
Or do they apply to every UPS type system? Every inverter/charger with a large (e.g forklift) battery?

I didn’t look into which types were covered.

Couple of options I remember around protecting “NEM integrity”, ie make sure you are not cheating.

• basically zero export
• get a production meter so they can cap your export to
• cap NEM credits based on modeled output for that month
• configure inverter to use a lab certified charging/export algorithm (EG charge only from DC coupled solar)

Yes, Ford already plays nice in V2G area, it appears!

I don’t think there are any V2Grid available to end users, those are still mostly for trials. They have a V2H thing that seems to use proprietary CCS extension. Along with a quite pricy hybrid inverter setup. So it’s a big cost for the shoreside hardware and for the truck, which I can’t easily park at my house and takes a lot of energy to drive.

Hyundai/Kia’s flagship EV platform can send 1800W at 120v, which is decent, and would last full blast with their battery size. That would pair nicely with a hybrid inverter+fixed storage battery running in generator assist mode.

Yes, PSPS is in summer. However this winter, we have seen serious outages from PG&E.

Ah right, same down here. Which is why I have been planning ahead to next winter.

For winter I think you have to either import energy with an EV from somewhere else or use a generator. Probably a stationary gas generator is the most convenient.

 

[Ampster]

Down the road from you I recently found out I am now in a fire risk zone which might qualify me for SGIP funds to get a UL approved system installed with a huge subsidy. I have not looked into what the WUI is and how that might affect it.

 

[agarg]

I have not looked into what the WUI

Hi neighbor, you too are in Wildfire and the Wildland Urban Interface. And, yes, you may qualify for SGIP funds ($850/kwh for the battery). More about WUI is here: FEMA website

 

[629658]

Hi neighbor, you too are in Wildfire and the Wildland Urban Interface. And, yes, you may qualify for SGIP funds ($850/kwh for the battery). More about WUI is here: FEMA website

$850 per kWh will pay for everything new inverter, panels, and storage. Add in the FTC and you will make some money. I just got $300/kWh rebate on my ESS and it paid for my batteries and inverter with the FTC.

 

[agarg]

$850 per kWh will pay for everything new inverter, panels, and storage.

I think the state wants to pay for everything. I am not sure but here is the brochure:

https://www.cpuc.ca.gov/-/media/cpuc-website/files/uploadedfiles/cpucwebsite/content/news_room/newsupdates/2020/sgip-residential-web-120420.pdf

 

[629658]

I think the state wants to pay for everything. I am not sure but here is the brochure:

https://www.cpuc.ca.gov/-/media/cpuc-website/files/uploadedfiles/cpucwebsite/content/news_room/newsupdates/2020/sgip-residential-web-120420.pdf

Well then I’d design out a system that will do what you wish. Get rid of your old stuff.

 

[Hedges]

This page says,

"
December 2020 Update - Customers who rely on electric well pumps as their eligibility pathway into the equity resiliency budget must now:

• Have an annual household income no greater than 80 percent of Area Median Income (AMI);

"

Participating in Self-Generation Incentive Program (SGIP)

www.cpuc.ca.gov

Link "Verified Equipment Lists", 3x batteries for 27kW usable AC storage

BYD

Battery-Box H10.0

3

SMA

SBS 6.0-US-10

1

27.210

SGIP | Resources

www.selfgenca.com

One 10kW battery sets you back $6500 (before rebate). Attractive for those who get larger rebate.
I have not found the terms of what qualifies. If in fact < 10kW, not < 10kWh,

BYD Battery-Box H10.0 - Complete 10.24kWh system

BYD Battery Box H10.0 - Complete 10.24kWh system | Battery-Box H10.0 from BYD for retail price $6,498.90. Get more discount today in our store.

portablepowerusa.com

1x battery, 30kW storage (for some reason, doesn't show 3x battery)

BYD

HVL 32.0

1

SMA

SBS 6.0-US-10

1

30.880

LG RESU-H is on "Legacy" tab, apparently no longer allowed.

 

[agarg]

Have an annual household income no greater than 80 percent of Area Median Income (AMI);

I knew this / suspected this.

 

[Hedges]

HVL 32.0 kW battery has 50A output, 75A peak (3 seconds)
Since SBS has a max current per input, I suspect multiple inputs are paralleled when connecting this battery.
Ought to be able to derate battery and use up to three for three inputs.

BYD Premium HVL Battery System 32 kWh

BYD Premium HVL Battery System The Battery-Box Premium HVL has high-powered emergency-backup and off-grid functionality. It has the highest efficiency due to a real high-voltage series connection. The patented modular plug design eliminates the need for internal wiring, allowing for maximum...

generationecostore.com

Price about 2x server rack LiFePO4 batteries.
Not much more than what AGM cost me ($5000 for 20kWh gross, 14kWh usable)

10 year warranty. Don't know what cycle and calendar life are expected. Presume at least 3650 deep cycles.

 

[agarg]

In contrast to AGM or SLA, LFP is desirable. And, now CA would not even approve an SLA on permits.
For simplicity, BYD appears to be proven/tested and not that much more than other options.

Will think about this.

 

[Hedges]

And, now CA would not even approve an SLA on permits.

But FAA approves them, won't allow any lithium chemistry as cargo.

What's next, is California going to ban lead acid starting batteries in cars?

 

[rodrick]

But FAA approves them, won't allow any lithium chemistry as cargo.

What's next, is California going to ban lead acid starting batteries in cars?

Won’t have to they are going to ban the whole car no gas or diesel allowed soon