Is it just me?

[WorldwideDave]

Gas heated pool.
Nice..

I’ve just completed a DIY solar pool heater set up and it’s working fantastic. I will start a new thread and post pictures and such shortly. Just to wet your whistle… I have two solar panels, low voltage, disconnects, fuse on the PV side, a solar charge controller with a fuse between it and the battery, 200 amp hour lithium iron phosphate battery, a custom enclosure, a digital meter and shunt to read what the solar panels are doing before reaching the solar charge controller, another digital meter and shunt to read the battery usage, a fused DC load which is a 12 V pump, all with oversized wires, and a main battery disconnect. I have not used my gas pool heater at all this year, and the pool is at 80° right now. My gas bill and electric bill combined to run the gas pool heater in Los Angeles cost around $500 a month. I also got a Betta solar pool skimmer. So right now I run the pools 240 V 15 amp 2 hp pump for an hour every three days to vacuum up any debris that falls deep from the surface. Otherwise, I would estimate my costs for maintaining the pool to be about $60 a month. The system that I built to heat the pool and the cost of the solar powered skimmer cost probably $1300. So by the end of the summer, the system will have paid for itself and we can probably keep the pool on and heated well into October. Possibly year-round if I wanted to. Once I figure out the actual usage of the small DC 12 V pump I have, I will probably build a DIY battery with Bluetooth battery management system . The DC motor I have at 12 V uses anywhere between 2 A and five amp surge. If I run the heater from 8 AM to 7 PM every day for 11 hours, and if I want to have a reserve for three cloudy days, I need to find out what size battery I would need for the three days, and build a custom battery based on that. But maybe my 200 amp power battery is the right size already.

Thanks for listening.

 

[Hedges]

You must have missed the thread where with state rebates in CA, it is actually cheaper to buy a heat pump water heater than resistance.

If true, "Advantage, HPWH"

When doing a comparison, one should not cherry pick data in an attempt to prove a point. A 6 year warranty resistance water heater is not even close to 10 year resistance water heater in price. When you cherry pick, it makes your side of the debate much weaker.

I wasn't cherry-picking. Tried to select "Resistance" and "HPWH" of comparable performance at Lowes.

However, 2 points:

1) The longer the warranty period, the more likely it is there for a reason. To allay legitimate fears of the consumer that it will break sooner. Doesn't mean it will last longer, almost certainly won't.

2) This anecdote wasn't for a resistance water heater, rather for gas. A Kenmore water heater came used with my house when I bought it. It sprang a leak recently, had to replace. That was 21 years after I bought the house, not sure how much older the water heater was.

I had used stainless steel braid hoses, to replace a mixed copper/steel plumbing connection done by previous owner. Turns out, (at least some) stainless braid hoses have carbon steel crimp connections, and those rusted through due to environment. That dripped water down outside of tank, probably was the cause of failure. Otherwise, glass-lined tank could have lasted longer.

Compare that lifespan to several refrigerators I've got. Some I was happy lasted 25 or more years. Others died sooner due to refrigerant loss (or I serviced them, recharging to keep using.)

HPWH is a refrigerator, much more to wear out, fail, leak than an electric water heater.

If you really want to save money, use a gas water heater. In my area, costs 1/8 as much to operate as resistance. 1/4 or 1/3 as much as HPWH?

At any higher electric price, I agree HPWH has quick payback.
Assuming $0.10/kWh (turnkey PV) is reasonable, and that gives 3.5 year payback.
Using $0.025/kWh for DIY PV is valuing our time at zero. Fair to value our time same as turnkey.

Similarly, I do use CFL and LED.
But to the extent I have surplus kWh, I'm happy to burn them off with cheaper RELIABLE equipment.

And I don't pay retail. I can pick up a used gas or electric water heater for ~ $100. Can't do that for HPWH.

Rob Peter to Pay Paul:

I refer to HPWH taking the heat from your house in the winter to heat water. That isn't providing any savings at all, just consumes more power in your furnace.

In summer, could be a benefit.

Ducted air could help. Except not to heat water when air outside is freezing.

KISS.

 

[Nobodybusiness]

I’ve just completed a DIY solar pool heater set up and it’s working fantastic. I will start a new thread and post pictures and such shortly. Just to wet your whistle… I have two solar panels, low voltage, disconnects, fuse on the PV side, a solar charge controller with a fuse between it and the battery, 200 amp hour lithium iron phosphate battery, a custom enclosure, a digital meter and shunt to read what the solar panels are doing before reaching the solar charge controller, another digital meter and shunt to read the battery usage, a fused DC load which is a 12 V pump, all with oversized wires, and a main battery disconnect. I have not used my gas pool heater at all this year, and the pool is at 80° right now. My gas bill and electric bill combined to run the gas pool heater in Los Angeles cost around $500 a month. I also got a Betta solar pool skimmer. So right now I run the pools 240 V 15 amp 2 hp pump for an hour every three days to vacuum up any debris that falls deep from the surface. Otherwise, I would estimate my costs for maintaining the pool to be about $60 a month. The system that I built to heat the pool and the cost of the solar powered skimmer cost probably $1300. So by the end of the summer, the system will have paid for itself and we can probably keep the pool on and heated well into October. Possibly year-round if I wanted to. Once I figure out the actual usage of the small DC 12 V pump I have, I will probably build a DIY battery with Bluetooth battery management system . The DC motor I have at 12 V uses anywhere between 2 A and five amp surge. If I run the heater from 8 AM to 7 PM every day for 11 hours, and if I want to have a reserve for three cloudy days, I need to find out what size battery I would need for the three days, and build a custom battery based on that. But maybe my 200 amp power battery is the right size already.

Thanks for listening.

I was just saying it was nice to have a gas heated pool.

That’s your business what is cost to run it.

 

[Hedges]

I've got a 25,000 gallon, 20 x 50' swimming pool. Plus spa.
The pool is bigger than my house.

One summer, I turned on the gas water heater and let it warm up the pool.
Couple days later, my wife called. PG&E had come by, apparently looking for the gas leak.

It also seems my gas meter was jammed, not registering anything. And it was small for the flow. PG&E replaced it with one 4x the size.

I decided heating pool with gas was going to be too expensive.

But water heater + range only costs $8/month. No need for instant water heater, HPWH, or anything else. Would never pay for itself, unless free (including installation costs) after rebate. And even then, likely shorter life would have me trying to replace it after manufacture and sale of gas water heaters are banned.

They can have my gas storage-type water heater when they pry it out of my cold, dead fingers.

 

[Hedges]

Also I can’t afford to do everything at once. I can spend maybe 1000 per month max on gear. My hope is to get some roi right away vs having gear sit for months at a time while products get cheaper and better and more powerful.

There could be an order that gives the most bang for the buck upfront.

For some plans, GT PV is highest payback, if net-metering terms are good.

For others (typically commercial, but also consumer with PV) there are "demand charges", a fee based on highest power draw. Shifting when loads are turned on, or priority switch that turns off a big load like electric water heater when another like well pump kicks on, should be economical; just controls. Battery inverter for peak shaving is another approach.

Knowing what complete system you want in the end, you can try to select and inverter that supports it (e.g. batteries + PV) and wire boxes together in a way that avoids duplication of effort.

 

[Zwy]

If true, "Advantage, HPWH"



I wasn't cherry-picking. Tried to select "Resistance" and "HPWH" of comparable performance at Lowes.

I wouldn't buy an AO Smith water heater, last propane AO Smith Powervent I purchase failed in less than 5 years. Strike one on Lowe's. Home Depot and Menards sell Rheem/Richmond. Better products IMO.

In order to be a fair comparison, then the same warranty period should be used. 6 compared to 10 is only 60% of warranty. The closest Lowe's can get in a resistance electric is 9 years. 50 gallon is $749 so once rebates and tax credits are calculated for the HPWH, it is cheaper to purchase a HPWH.

However, 2 points:

1) The longer the warranty period, the more likely it is there for a reason. To allay legitimate fears of the consumer that it will break sooner. Doesn't mean it will last longer, almost certainly won't.

I bought an electric water heater for a rental with a lifetime warranty on the tank.

Will it last longer than a 6 year?

2) This anecdote wasn't for a resistance water heater, rather for gas. A Kenmore water heater came used with my house when I bought it. It sprang a leak recently, had to replace. That was 21 years after I bought the house, not sure how much older the water heater was.

You should replace it with HPWH.

I still have a propane in series with the HPWH. Doubles the storage (like a bigger battery) and in case my battery is depleted, I can still have hot water, just a slightly lower temp.

I had used stainless steel braid hoses, to replace a mixed copper/steel plumbing connection done by previous owner. Turns out, (at least some) stainless braid hoses have carbon steel crimp connections, and those rusted through due to environment. That dripped water down outside of tank, probably was the cause of failure. Otherwise, glass-lined tank could have lasted longer.

Compare that lifespan to several refrigerators I've got. Some I was happy lasted 25 or more years. Others died sooner due to refrigerant loss (or I serviced them, recharging to keep using.)

The biggest issue with many refrigerators now is not the compressor and refrigerant leak failures but the controls fail and service parts are not available. Going to circuit boards was not a positive for longevity.

HPWH is a refrigerator, much more to wear out, fail, leak than an electric water heater.

How will it leak water sooner? Explain this in detail because it is stretch of imagination.

Same tank, same construction. One uses an element, the other a heat pump. The HPWH will somehow leak water sooner?

Yes, it can develop a refrigerant leak. Hermetically sealed systems as a rule don't leak for many years. Technology in sealing has greatly improved since the 1920's.

An element can fail, I guess that isn't a failure with your line of thinking? I've replaced enough elements over the years.

If you really want to save money, use a gas water heater. In my area, costs 1/8 as much to operate as resistance. 1/4 or 1/3 as much as HPWH?

As I'm using PV power, gas/propane can't compete. It costs me nothing to heat my water after the purchase of the HPWH. It is free hot water. Compared to propane, I did some calculations using the 300 gallons of propane to provide hot water to the average household per year, which is pretty close to what I have experienced. At $1.45 per gallon, that comes to $435 per year. Since installing the HPWH in March of this year, we used 358.9 Kwh. Basically 4 months at 90 Kwh per month. I always use the figure of $0.20/Kwh as it is simple even though here cost currently is slightly lower than $0.20/Kwh but is changing with rate increases. 1080 Kwh per year comes to $216/year.

Propane isn't cheaper or I'd run it more and just use the HPWH as a dump load. I realized this after the first month, the HPWH was about 1/2 the cost to operate if purchasing electricity off the grid.

At any higher electric price, I agree HPWH has quick payback.
Assuming $0.10/kWh (turnkey PV) is reasonable, and that gives 3.5 year payback.
Using $0.025/kWh for DIY PV is valuing our time at zero. Fair to value our time same as turnkey.

I just showed it is cheaper to run HPWH compared to propane by 1/2. My payback is less than 2 years after tax credits/rebates.

Similarly, I do use CFL and LED.
But to the extent I have surplus kWh, I'm happy to burn them off with cheaper RELIABLE equipment.

How reliable is something that parts can be sourced for? I had a perfectly functioning refrigerator as far as the refrigerant side but the circuit board failed and it ended up being replaced. We ran it for 2 years during covid shutdowns simply due to availability of replacements. The board had the temp stuck at 41°F.

And I don't pay retail. I can pick up a used gas or electric water heater for ~ $100. Can't do that for HPWH.

I was reading some comments on a website the other day and the person commenting stated his father told him to put his money in quality assets and it will pay out long term.

I've purchased and used water heaters that were second hand. Every single one didn't last over 3 years. Penny wise and pound foolish is no way to go thru life.

I'm at the age where I realize I only have a certain amount of time left in this world and I'd rather spend it productively than changing out water heaters.

Rob Peter to Pay Paul:

I refer to HPWH taking the heat from your house in the winter to heat water. That isn't providing any savings at all, just consumes more power in your furnace.

Hybrid can be run with the element in winter, non issue simply because the choice is there. The element used in winter will take the same Kwh as a resistance water heater.

My water heater is in the basement, I have inverters and batteries there plus a freezer and the furnace. I'm not too concerned about the heat energy the HPWH is using from the basement.

In summer, could be a benefit.

In Iowa, at least over 10 months it has a benefit. If I heat my house with wood during the coldest 2 months of the year, do I care if the HPWH was to take some of the heat and put it in the tank?

I have the choice to use the resistance element in the hybrid for a dump load on days with excess PV during those 2 months. The rest of the year, we have been heating the house with heat pumps and resistance heating and not burning propane.

I have multiple days of hot water stored due to having 2 hot water heaters in series. I can "weather" thru those cloudy days.

Ducted air could help. Except not to heat water when air outside is freezing.

KISS.

I have a real nice simple and efficient system. It just works.

Get with the times, the days of the resistance only water heaters are numbered, too inefficient. Gas is doomed too, just watch for some taxes to be put in place to force you to move to a different source.

 

[WorldwideDave]

You both seem like very smart people. Can you both just agree to disagree and start a new thread or something please.

 

[Lawrence_SoCal]

Add a story?
Re-shape roof and add an attic that serves as living space?

The downside to that is potential property tax impact... great if money available, and space desired... otherwise
maybe if needing to redo the roof anyway, changing the roof line to give you an optimal solar slant (and some 'attic' storage space??) which may involved a lot less engineering/permits/costs than for a occupiable space ?? just a thought

 

[Zwy]

You both seem like very smart people. Can you both just agree to disagree and start a new thread or something please.

I know its a little sidetracked but one needs to realize the various impacts certain appliances have on the overall system plan. You asked for input, sometimes you get more than what you really wanted.

One thing I noticed is you went to tankless on demand water heaters, those really don't save you any money, they do supply as much hot water as you need. It still takes X number of btu's/Kw to heat the water from X degrees to X degrees. Where those btu's/Kw come from is important, hot water is a huge energy user.

Just be aware that sometimes the side tracks lead to something you might gain some knowledge from.

Accept my apologies if you feel the information wasn't useful.

 

[OffGridForGood]

So Returning to the topic for Worldwide Dave - ie his planning for solar
last I recell, we had the following info so far:
historical info shows 24kWh per day avg.
Southern Cal location Someone said Manhattan Beach CA - ie 33.89 N x -118.42 W
plugging in that location to PV Watts and using 1kW solar array due south set to 34 degree tilt we get: 109 to 156 kWh/month
with Dec the lowest at 109 and August the highest at 156, and most months 130-140kWh/month per 1kW array size.

using the 130kWh per month as a close average - this is 4.3kWh per day per 1kW of PV panels.
for the 24kWh per day target then we would need 24/4.3 = 5.6kW array size for the average month.
but looking at December for the worst month at 109kWh for the month = this is 3.5kWh per day per 1kW of PV
for the 24kWh per day target during December we now need 24/3.5 = 6.9 kW array size instead of 5.6kW for the average month.

Not sure if we picked out the peak instantaneous power required, I recall some discussion about a pool pump and a few other loads, likely we need a bit more information to pick an inverter size. And since this is Cali, it needs to be on the California inverter list - likely in the resources section (?)

With the whole NEM3 thing, I think we were going - no grid feed, since it doesn't pay, and adds complications.
If this is roof mounted, you need a RSD system and AFDD. If ground mount, then you don't need those.

Summary:
PV about 7kW size seems appropriate, future loads may mean going a bit bigger.
Peak load and RSD/AFDD requirements will help us to select an inverter
Batteries? a few for overnight or a larger system for days of clouds in December?

Is an EV in the picture for the future? - ie a big load we didn't discuss would certainly change the planning for a larger system either right away, or to be ready for expansion.

 

[WorldwideDave]

Well I just got my first quote from someone I met at a solar expo. Here is there recommendation:

14 panels at 425 watts.

6000 watts (6kW) from PV

4.5 hours per day of production.

27000 watts produced a day (27kW)

Usage is 25,000 watts (25kW) or less a day.

We would be over paneled.

Battery: recommending 13,500 watts (13.5kW) Powerwall Plus, which is inverter.

They offer two options paying full for 35k USD or making payments at 190/mo.

Don’t have quote in hand yet. I spent 2 hours on calls and texts and emails to arrive at this with my bills as evidence.

Yes, I see electric car in future. Have NEV/LSV now on 120v charger once a week or so.

 

[WorldwideDave]

And no, I would never pay 35k for a system.

 

[Lawrence_SoCal]

24kW per day
744 kW per month
9,000 kW a year

19 months ago, my SoCal coastal usage had moved up from a typical monthly 400kWh/mo to closer to 600 with additional of PHEV
However, after 25+ years with any Air Conditioning, the plan was to install solar and immediately install a heat pump central HVAC (for upstairs system/zone... skipped replacing gas heater downstairs as that space RARELY gets hot enough to need A/C, especially with a slightly oversized upstairs unit and warm air rising... 1.5 yrs later, happy with choice).
As I was able to get onto NEM2 (3 hadn't been formalized at time I signed contract), I skipped getting battery system for now. And I knew that within 20 year NEM2 tariff agreement, that at least 1 of our ICE vehicles (if not all) would likely get replaced by EV. So I intentionally sized my system for expected future loads (knowing small limit to expand but stay on NEM2)... Solar companies asked to confirm why I wanted 2X number of panels they proposed, but there was no issue getting system permitted/approved by local PoCo?? I went with 19x425W panels which was listed on my contract as a 8.08kW (solar energy) system but Net Metering Permission to Operate lists 7.392 kW electricity generation system (Max output VA/panel after micro-inverter being 384 [not 425 marketing number]). I am currently a net generator every month (even winter) (which SDG&E can NOT accurately bill, as acknowledged by their own CSRs, but other issue). On NEM2, the NBC are annoying but WAY cheaper than getting a battery system. Your calculation on NEM3 will be different

I mention the above context to mentally consider
- What my system (intentionally) skipped was the hybrid inverter (and associated grid-tied) electrical work I'll need when I get around to adding a battery. At this point, grid-down isn't a worry in my area (really rare, and UPS for all computers and network gear, so it takes an extended outage for any of us to care). But that is a NEM2 specific consideration
- the small investments over time (vs full system purchase and install, benefit over time) approach most likely means sticking with grid-tied to start (and simply reducing kW usage with PV...)... ie, what I have.. .much less involved wiring in/around main load center associated with a grid-forming inverter
- But as you are talking NEM3 and family indifferent to TOU rates, your bigger ROI will come from battery (10kWh won't be enough, but would probably cover peak rate usage (4-9p) and something like 14.3kWh coving much of the night??.. presuming not running A/C all night... depends on how close to the coast you are)
I can download from PoCo my usage in 15-min increments for years. From that you can determine peak and average usage for 4p->9(or10)am if you wanted to avoid a large portion of grid consumption. As others have said, getting a battery to cover 80+ percent of your typical usage isn't that hard or expensive.. It can get real costly to cover that last percentage (short sunlight winter days, storms, etc)
- the issue with NEM3 is there will be a significant limit on system sizing (PV # / output) without getting re-tariffed (sorta non-issue if nothing after NEM3, but at some point adding panels will move you into next tariff plan. For similar reason, I over-paneled to start, but that does take the up-front investment. Your issue will be if you don't have a battery to capture excess, your benefit will be limited.
- the risk you have is buying, say, half the panels now and hoping the rules don't change by the time you are ready to add more PV panels
- Now there are battery systems that work only when grid-is up. The batteries themselves aren't 'cheaper' but you do avoid grid-forming hybrid inverter expense. And you can re-wire later.... though to minimize cost, I'd wire once as though there was a hybrid inverter (with enough spare cable loop length) such that you don't have to do significant re-wiring later... but I could see arguing either way
- The costly and beneficial product purchase/install will be the grid-forming hybrid inverter, and then the question becomes sizing
- You can get your max kW draw now (most likely from PoCo). And then consider any likely planned additional near-term peak kW loads to support with a hybrid inverter (as in 5-10 yr timeframe). I've seen reference by some knowledgeable industry folks to not expect hybrid inverters to last as long as say an oven or your roof. So, wiring up front to include an inverter bypass seems prudent (those 3 generations will get quite testy if power is down for days (or much longer) due to inverter failure at some point)

The Emporia Vue has been mentioned already, and would be a great place to start, to collect more detailed (and some circuit specific) usage metrics

One other thought on decision process.... how are you (and the family) on handling grid-down situation?
For some, that is important. For others, largely a non-issue. Adding a grid-forming inverter adds a material amount to the system cost. DIY type solutions cost one thing (see comments about end-user frustrations, firmware faults, etc), and more mature (reliable) solutions costs even more. You can skip (or postpone) that cost, even with a battery, recognizing that if the grid goes down in the middle of the day, and you don't have grid-forming inverter, then power out at house (even if you have plenty of battery juice and/or PV)
if your grid fairly reliable, and grid-down situations not a excess drama creating situation (no powered medical devices, etc), then doing grid-tied solar and battery now (my recommendation to wiring assuming future hybrid inverter install to make that much less involved when the time comes)
With limited budget, the question of how many PV panels to get when, and battery gets tricky.
And be aware of how non-certified setups might impact homeowners insurance (not saying don't do go that route, just be eyes open about it).
Your challenge is that there is a certain up-front cost for systems capable of your expanded system capacity (ie battery system that could cover whole house or critical loads [assuming plan to re-wire to enable such] while starting small) vs expense of replacing (expensive) components as you outgrow early installations .. and issues with permitting etc for a grid-tied system

 

[Lawrence_SoCal]

Summary:
PV about 7kW size seems appropriate, future loads may mean going a bit bigger.

14 x 425w panels definitely seems a bit small to me (or at least no room for future appliance electrification/EV)

 

[WorldwideDave]

Thank you everyone. No medical devices. Have battery apc ups on all tech outlets. Dont fear grid going down.

A bit confused on grid tie vs hybrid.

I was thinking diy battery if an inverter can be time of use.

The NEM and getting credits from PoCo aren’t a priority. Being off grid is. The thought of PoCo knowing what I’m generating or storing and charging me more or less is ridiculous.

If battery size is too small then tell me what to build. Or buy…I’m leaning that way.

Could start by getting that all in one inverter, use it to charge batteries when off peak then when awake at 7 am switch all loads to battery and again at 9 pm charge when cheap.

Will this work or is it recommended?

 

[JRH]

I second OffGridInTheCity's, and 45North's idea of a small system to learn on. It does help. Gives you an idea of real output in your desired location, vs. panel specs vs. theory. If you have the patience, a small system will tell you a lot. You get to learn how panels string together, amperage of wire needed for a real project, all that fun stuff.

I went from a harbor freight type $150 setup, to a 400, turned 800 watt cabin build, to my home system that is quite large vs. those.

You can also go straight to the big leagues, as long as you are smarter that I am that is

I'm not taking a side on this one. But I will say I am weird enough to still rock halogen bulbs, and some good quality CFL's. Much of the led lighting I find to be depressing, and too blue. I figure since I make my own watts, I make my own rules

I guess I just don't do everything I'm told...

I should say: I have tried some LED flood lights for the can lights, but couldn't find a good one that doesn't flicker. I think there are good regular LED bulbs now, but I see the low "refresh rate" ones like I see taillights that ghost in the cheaper LED taillights.

GO old school compact fluorescents ….warm natural light…pleasing to the eyes …..bought a ton of em in 2006.. still runnin good..

 

[Hedges]

The NEM and getting credits from PoCo aren’t a priority. Being off grid is. The thought of PoCo knowing what I’m generating or storing and charging me more or less is ridiculous.

If battery size is too small then tell me what to build. Or buy…I’m leaning that way.

If you have a battery, being able to dump it into the grid daily in September for an average of $3.50/W under NEM 3.0 could be useful. For each kWh you give them, you can get back about 10 kWh during other times/months.

Helps pay for the battery. And doesn't use up much of its cycle life.

 

[JRH]

Just be aware that sometimes the side tracks lead to something you might gain some knowledge from.

Totally , absolutely true… it’s the way people talk …and there’s a reason…it works..

 

[JRH]

GO old school compact fluorescents ….warm natural light…pleasing to the eyes …..bought a ton of em in 2006.. still runnin good..

Bankers light…been running 10 yrs plus… 15 watts …

 

[Zwy]

Well I just got my first quote from someone I met at a solar expo. Here is there recommendation:

My average usage daily is similar to yours.

14 panels at 425 watts.

I have 16 530W panels.

6000 watts (6kW) from PV

I have 8.4Kw of PV. During heat of the day in summer on hot days, max output is about 80% of rated.

4.5 hours per day of production.

27000 watts produced a day (27kW)

Usage is 25,000 watts (25kW) or less a day.

We would be over paneled.

You will be under paneled during late fall/winter. Many days you may not cover full usage due to reduced sunlight hours and weather. Even though I am in IA and you are CA, winter is a very tough time period. I am adding another 4Kw of array to the house, this should make us completely off grid in the house. That last 10% is costly.

I will have the ability to shift generation from house to shop and vice versa. Shop usage is higher in summer, house usage is higher in winter.

Battery: recommending 13,500 watts (13.5kW) Powerwall Plus, which is inverter.

We have 58Kwh of battery and as soon as I run the battery cables it will be 72Kwh.

They offer two options paying full for 35k USD or making payments at 190/mo.

I spent $40K on house system. Array with MT Solar mount custom built about $15K. Some of this was due to covid price pressures. MT Solar mount was $6500, a pair of poles $1800, panels $4000, cement about $1000, wire and essentials the rest. I could cut corners and went cheaper but I wanted seasonal tilting panels and location of array cost more to run wire. Covid didn't help, I could have purchased poles for about half before then.


Shop array being built is $2000 for 31 370W panels of which 20 are being installed so 7.4Kw on that array, so $1300. MT Solar mount was purchased used for $4000 and I'm using 1/2 of it so another $2000. Cement is higher, $1300. Not as much wire but we still figure $1000 for wire and essentials. $5600 total. Used components do not qualify for residential 30% tax credit but I can depreciate the shop system out, new or used as it is for commercial use.

House system battery is 72Kwh and cost is $13K with the addition of one more 280Ah battery. Batrium BMS added to the cost. Shop system will be 72Kwh. Cells are much cheaper, about $8K for cells and enclosures. Wire, JK BMS's and other items about $1500. So $9500 for 78Kwh.

Inverters on house system, a pair of 6.5Kw, cost about $3K back then. Other items about $2K, did add in transfer switch and did some upgrades in the process. Shop system inverters, a pair of 10Kw output, are almost twice the capacity and cost $2300.

Costs are heading down as more competition and advances in tech are helping plus supply chain issues from covid are gone. However tariffs will increase costs in the future.

Don’t have quote in hand yet. I spent 2 hours on calls and texts and emails to arrive at this with my bills as evidence.

Yes, I see electric car in future. Have NEV/LSV now on 120v charger once a week or so.

Plan ahead for this.

 

[OffGridForGood]

Well I just got my first quote... Here is the recommendation:

14 panels at 425 watts.

27000 watts produced a day (27kW)

Usage is 25,000 watts (25kW) or less a day.

Battery: recommending 13,500 watts (13.5kW) Powerwall Plus, which is inverter.

Yes, I see electric car in future. Have NEV/LSV now on 120v charger once a week or so.

Using your current loads we see a 6-7kW PV array would be suitable, if you know you have future loads in mind (ie the EV) then it only makes sense to at least plan for a larger PV array now, since it will be needed eventually. Depending on how much you drive, the extra PV needed can vary a lot. Our own EV is a commuter daily-driver and that eats up about 9kWh per day on average, five days a week. More like 13kWh/d during winter.
Say you need 15kWh/d for the EV - this is 15/3.5= 4.3kW of PV (winter) or 15/4.3= 3.5kW of PV (summer) in addition to the 6kW of PV for the current loading. ie 50% more panels required. something to consider and plan for.

The NEM and getting credits from PoCo aren’t a priority. Being off grid is. The thought of PoCo knowing what I’m generating or storing and charging me more or less is ridiculous.

If battery size is too small then tell me what to build. Or buy…I’m leaning that way.

Battery size - at 24kWh per day, and you just want to get through the night - maybe 20kWh will get you through generally,
at 24kWh per day and you want three days of autonomy - now you need 72kWh ESS.
Batteries are by far the most expensive part of the system, so you want to carefully consider what you need. Batteries are also the easiest place to expand on a system, as long as you have the space for the racks, ie adding on to the ESS over time is one approach.

Could start by getting that all in one inverter, use it to charge batteries when off peak then when awake at 7 am switch all loads to battery and again at 9 pm charge when cheap.

I don't know if we have seen what the max load is for your plan - do you need 12kW instantaneous output or would 8kW be sufficient?
It is likely you should plan for adding an inverter when you add an EV (ie parallel inverters), and at that time plan to add 4kW of PV to supply the EV load.
Also - do you plan on roof mount, or ground mount? (affects the whole RSD/AFDD requirements) would help us to narrow the options that will be suitable.

 

[WorldwideDave]

Roof probably best. Ground would be difficult. Trying small array of 2-4 panels now on smaller off grid setup to learn.