My New Net Zero Home Battery Surprised Me

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00:00 - Intro
00:50 - What Did I Get?
01:40 - Why This Battery ... or Any Battery?
05:05 - What Did it Cost?
08:07 - What About The Pros & Cons?
11:31 - What Would I Have Done Differently?

[TJPavey]

We need a standard for interfacing all of this together. So many of these systems are propriety and you are in a walled garden.

[davidkendall]

We installed two Tesla PW2's in 2018 for $15k to complement our existing 2012 installed 13.2 kW Solar PV system with microinverters and have been operating as a microgrid for ~8 months of the year in Edmonds, WA, while suppling our energy needs to our all electric home, charging two Tesla's and exporting ~50 percent of our excess energy back to grid via Net Metering. Last year we produced 474 percent (Solar production: 12, 197 kW versus Net electric use: 2628 kW). We also have electric heat pump and heat pump water heater, and have done lots of other things to increase our energy efficiency. Our home was certified as being a Net Zero Energy building in 2016 by the International Living Future Institue. Our setup as been exceptionally satisfying for us, and we have weathered many power outages successfully with our system.

[greenshadow]

All of these battery puns have left me completely drained.

[tjones]

"One throat to choke" is what we called it when we chose a single vendor solution... Time will tell and we all know you WILL tell how it works out in time! Thanks.

[MonkeyJedi]

Love that impact barrier in front of your wall batteries. Very smart, as well as clean-looking.

[mrfusioneng]

We also have a net zero home in south florida. Where typically near 50% of our electrical usage goes to air conditioning. Of course we have a well insulated home, with all energy star appliances and such. We regularly get hurricanes and sometimes lose electric for a couple weeks after. So we designed our system around that need. Some pointers about real electrical consumption. First off you can ignore needing to run tv’s, internet, computers, etc during an outage, because none of that stuff will work anyway, ( because it’s cut off at the source, which we have no control over). Next on the list is washer and dryer, you won’t need those either because there is no water, ( and even if there is, it won’t be drinkable or usable, ( all the pumping stations run off the grid, no grid no water)).
Next is lights, it’s much easier to use portable rechargable lights in rooms where you plan to occupy at night. However a few lights and ceiling fans should be included in the mix.
Next up is electric oven, forget about it, get a convection microwave, or a toaster oven/ air fryer, ( much more energy efficient, and runs on 120 ac typically.
Forget about electric vehicle charging, you won’t need it, all the roads are destroyed, and there are no stores or gas stations open anyway. We do have a 4 wheel drive jeep, which can ford deep water and can get thru some pretty rough stuff, but again there is nowhere to go.
We have an in ground pool, where the filter and heating system runs typically 8-10 hrs/day. In an emergency we can get by with higher chlorine contend, and run the filter for a couple hours every 2-3 days, ( basically turn some other stuff off during the time the pool pump is on, so we can use our solar and battery bank, on a sunny day, to keep the pool alive. It’s call time sharing, you only run certain things at the cost of others to not deplete your battery bank.
If you think you are going to live normal life, using all the energy you want, you are in for a rude awakening, ( unless you have of course unlimited funds and want to spend $150k on your system, ( we paid around $25k for our whole system complete).
Down here our number one priority is air conditioning and dehumidification, as the inside of the house gets over 100f and 90% humidity with no ac. And forget about nighttime cooling with the windows open, ( we don’t do that here). The lows at night are typically in the mid 80’s and the humidity actually goes up at night typically, ( sometimes over 90%). And there is typically no wind in florida anyway, ( especially in cities, where we live). We do live right near the gulf, and that helps moderate temps some, but that’s a double edge sword, ( coastal flooding).
Instead of trying to use the central ac system during a a grid outage, ( which uses tremendous amounts of energy, ( 50% of our usage when the grid is up and running). We elected to design and build a water based TES, ( thermal energy storage system). When we have an outage we only use the TES system, and a whole house dehumidifier system. Both of which run off of a secondary solar system we have on a shed in our back yard, ( none of which is connected to the house wiring in the house, ( completely self sufficient). Every car in America has a similar system installed, ( using circulating water, running thru a radiator to transfer heat). During the day, ( when the sun is shining), we circulate the water, ( stored in two large insulated tanks in our garage, ( 100 gallons each, ( home depot, $140 bucks ea)). A small circulating water pump, ( normally used on boiler systems, ($60 bucks)). A radiator for the air to pass thru, ( mounted in a duct box, in the center of our attic, between the air return, and main plenum, with a small inline circulating fan mounted in the duct to circulate the air thru the house).
What occurs is hot air rises into the return ducts, runs thru the radiator, ( heat exchanger), get cooled down, then the cool air just fall out of all the register in the ceiling in the house, ( remember cold air falls). Though the system is very small, it keeps the house below 80f and the humidity below 60%, ( via the whole house dehumidifier). Without needing to run the central hvac system at all, ( during the power outage).
During the day electric chillers, ( running on sun power) cool the house, and cools the water in the tanks. Once the sun goes down, the chillers go off, and the reserved energy in the water itself keeps the house cool thru the night, ( continuously circulating, taking the warm in from the returns, then expelling the cool air out all the registers in each room. The only power used at night is the water pump, and the solid state inline circulating fan. So we can operate the whole works off of around 400ah of lithium phosphate batteries, then the next day the cycle begins again. For really rainy days we do have a small honda generator, that we can charge the bank up in a couple hours if needed. We found even on partially cloudy days, our solar generates enough to keep everything going, ( without needing the generator).
When the grid is up and everything is healthy, we still use the TES system, because it cuts the run time hours on the main hvac system in half, so instead of the main hvac system working 10hrs a day on stage 2, it only needs to run on stage 1, half the runtime, and using much less power, than without the TES system. The result being instead of the ac electrical cost being $5-$6 dollars a day, our main hvac system costs about a buck or two, ( electrical usage). The TES system is always totally free because it’s powered by it’s own solar array and battery bank, ( thru a pair of Growatt all in one inverters, ( not tied to our big grid tied solar system at all).
I just don’t understand why people are spending so much trying to do simple tasks. We generate more energy than we use typically.

😂

[SteveMichaels]

Lots to think about when I do something like this in a year or two. Thank you Matt I feel informed about what I going to be getting into.

[johannan]

I am pretty excited for sodium ion batteries. They are getting more and more close to the energy density of LFP. But even if they stay below it, you don't need high energy density for home storage.

[ninefox]

I see news articles talking about how cell costs have gone below $100/kWh but then home batteries are selling for over 10x that cost...

[pathfinderGM]

What I want to see is a center lot in a residential neighborhood turned into a dedicated energy storage center. Something that can turn the a few blocks of residential into a bit of a micro grid. That way the whole neighborhood can get solar and focus in electric for heat and cooking and provide emergency power as an option. I'm thinking like having 2 breakers in people's homes here. A normal 100amp service and then a optional 20/40amp emergency service that people can pay for for direct access to the battery system at all times. Think people with special medical needs kind of thing. The battery center's main goal would be a local place to be a energy buffer to overall lower the cost of electricity for the entire neighborhood. Reducing strain on the main grid acting like an expansion tank. And if it acts as a distributer for electricity then it can become its own net metering system for the local grid even if the state doesn't have one.

[Triflixfilms]

If parts are not readily available for consumers to repair or if working on it yourself voids the warranty that is an immediate no-go. Enphase website pricing is not transparent requiring you to hand over personal data to get a rough estimate.

This is the same reason I refuse to purchase a Mitsubishi mini split. I'd suggest people keep looking for a product that isn't anticonsumer. I really hope that Right to Repair outlaws these business models.

[esumiwa]

I bought the Tesla Battery system. I will be paying off a loan for 6 more years. Was it worth it? I live in Hurricane prone area and a city entergy relationship that is toxic. Blackouts happen weekly because of archaic wiring. Then there are the weeks after a hurricane with no grid power. Having the batteries for four years now: WORTH EVERY PENNY. Was it over priced 4 years ago. Yes. Is elon musk a raging idiot: yes. Regrets: none.

[brucecampbell]

We have been very happy with the Enphase system (with a 10P battery) that we installed in our 63 year-old, 1400sf home going on 2-years ago. We also installed 6kW of PV at that time. We pushed forward with our installation schedule to ensure that we qualified for the California NEM-2 (Net Metering Agreement) and qualified for the CA State rebates as well as the Federal tax credits. NEM allows us to bank kWh stored on a one to one basis with a tru-up once a year. There are several additional benefits of NEM-2 over had to put the cart before the horse and design /install the new HVAC system based on modeled improvements rather than measured loads ( backwards from the best practice). We are finishing up the energy efficiency upgrade / electrification conversion this coming month and it appears my modeling/calcs were close enough to get us very close to net zero. We went from an old 3-ton forced air furnace /package-unit AC to a 1-ton inverter driven air-to-air heat pump with a mid-static head ducted indoor unit. The foundation of this kind of upgrade is improving the air-tightness and insulation of the envelop. We also have east-west orientation of the of the roof long dimension, 2-foot eaves all around and good late afternoon west facing shade.

[jbattermann]

We've had five 5Ps & the Span Remote Meter with that severe 'drift' issue & it took months of discussion, convincing, replacement, diagnostic and internal escalation at Span.. and several weeks back they finally confirmed that their SoC algorithm has wrong assumptions about the 5P's (dis)charge curve and behavior. They said it would be addressed with a firmware update but that one has yet to materialize. I can provide the support ticket no for reference if anyone wants to increase focus on / priority of fixing the issue at Span given the defacto defunc load-shedding capability with these wildly incorrect state-of-charge assumptions. I've stopped recalibrating quasi every 2-3 days for now & the end result is that Span thought i.e. yesterday that we were at 35% even though we had been at a 100% for hours at that time of day. Either way, it's a proper bug in their FW for 5Ps, not just mere compounding CTs measurement inaccuracies.

[jemezname]

20 Kwh isn't remotely enough for an off grid system, particularly if you have an ev to charge. I currently have 60 kWh of batteries with an sol-ark18 kW inverter and a combination of Big Battery which I don't recommend and eg4 batteries. I really need to double this system before getting a cybertruck. You drive your vehicle mostly during the day. You need to be able to charge it at night while you sleep. You can only do that if you have a really large battery at home. But you also need a large battery to get through winter storms without having to run a generator. Of course my situation is quite different to most people. The local coop does not allow solar so I refused to hook up to them. I am truly off grid on a small ranch. I heat and cool with a heat pump and cook on an induction cooktop. I haven't had to use a generator in over two years. I have a separate system at a small farm with an eg4 18K inverter and 30 kWh of eg4 batteries. Again I need more batteries on this system for nighttime operation of hydroponic systems. I currently have to shut them down at night which isn't ideal. The solar energy world is improving but the cost of batteries is still too high. It needs to drop by at least 50%.

[trevorksanders]

I wonder if the newer batteries that you showed on wheels would be considered stored vs installed for the purposes of requiring the sprinkler system when over a certain capacity. I wouldn't be surprised if there is some legal loophole to slip through like that.

[davelindgren]

I have 33KW of the older Enphase batteries.
I wanted to get more this year. I went to get quotes on the newer Enphase batteries and they told me that I could not mix the older batteries and the new batteries.
Let's just say I was not happy at all.
There are a lot of advantages of the Enphase batteries if you have Enphase inverters but someone has completely dropped the ball by not designing them to work together in the same home.
I went with Franklin batteries which was not what I wanted to do.
My point is, you better purchase all the Enphase batteries you think you are going to need for the next 20 years because you don't know if the newer batteries will be compatible with what you have. And BTW, you won't be able to purchase the older model anymore when the new ones come out.
Now I am worried about replacement parts for my version.
For those of you wondering how I'm doing that. I have 2 200 AMP panels. I have 2 separate solar systems connected to each one of the 200 AMP service panels and 1 battery system connected to each of the 200 AMP panels.

[dlg]

I'm a big fan of the EcoFlow modular system because it's so easy to expand as your need and/or budget grows.

[seanmcguire]

You mentioned that your Tesla has a 60 KWH battery. I would love to see more options for using electric vehicles for home backup power. We have solar with a string inverter already and just wish it were easier to tie an electric car into the system rather than buying a home battery. It seems like a no-brainer to me.

[testthewest]

I really wait for sodium base ultra-cheap batteries!
In a home, i have space, weight is no problem, but money is. Also, they could be saver as well, if I understand correctly.