BartHenry
Solar Enthusiast
Grid tied in my area pays zero...plus they require a 1 million dollar insurance policy incase one of there guys gets fried.
My build thread
- Thread starter timselectric
- Start date
sunshine_eggo
Happy Breffast!
Yes. By making it MUCH worse. W/O batteries and doing all of my own work using used SanTan panels... I'd have a 12 year ROI breakeven with panels alone.
Only true if using lead acid as you must balance charge current and capacity.
dougbert
Solar Addict
it is the features I need not the money it costs that matters most to me
I am at 60kwh with my teslas, I want 100 kwh. at this time my current battery will go 2 days, I prefer 5 days of backup time
I am at 60kwh with my teslas, I want 100 kwh. at this time my current battery will go 2 days, I prefer 5 days of backup time
Why stop at 5 days?
Plum Crazy Rob
Solar Enthusiast
Haven't you stated your charge / discharge percentage goals are more restrictive than most?? Smart, as that's the way Toyota did it from the get go to preserve its hybrids' batteries. Obviously requires a larger gross kwh to provide a working capacity number.
Edit: I thought you said that. Maybe not. Seems others are saying go full 0-100% for LFP..
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Zwy
Emperor Of Solar
Find uses for it. We have doubled our electric usage per day since installing solar except for when we normally would have had high loads. Right now I'm heating my house with excess solar power using a heat pump.
You might think that until the utility changes net metering agreements. Already happening here as Mid American has put up large wind all over the state plus large solar. They don't need the little guy generating anymore to meet renewable standards, they can generate their own. So they will lobby the statehouse to enact regulation of the little guy plus only pay a few cents for your grid input, then charge a much higher rate for what you input from grid. Net metering is dying and it will be a painful death for those who installed a system with net metering. They stand to profit immensely by lobbying the state to dump net metering.
I don't care what the utility pays for power. I'm not selling to them. I do care about what they charge for power. https://diysolarforum.com/threads/utility-rate-increases.70643/ I will be getting an extra 20% return per Kwh my system produces. For those on net metering, the rules are already changing, no payout at true up, any excess over bank you give away. It will change again, some piece of legislation will get slipped into some bill and the rules will change once again.
The purpose of batteries is not only to have power 24/7/365 but to also hedge against any changes in the rules which will not benefit the little guy. The rules will not be changed to favor the little guy.
One also gets the tax credit for batteries, you might not get that after 2030. If you install grid tie, then decide you want solar power when grid is down, you will be changing your system and adding batteries. Why not build it with batteries from the start?
Zwy
Emperor Of Solar
I go about 5 days now, but found I might need 6. https://diysolarforum.com/threads/5th-day-of-no-sun.71590/
Fair but now add another 130kwh of storage and the associated cost-is there a benefit there?
Yes, they are changing but the sell back price for most is avoided cost. Most people here can probably add solar for .02 to .03 per kWh. If the choice is between selling excess back or just letting it go to waste, it makes sense to get some money for it. Any money is better than no money.
My utility pays .06 per kWh. 10 years from now it may be .01
Doesn't mean I can't enjoy many years of getting something for my excess production. If their buy price goes to zero I can just switch to a regular plan and stop selling . No?
Agree but it will take a while
For example I have 43kwh of batteries and enough solar to offset about 80% of my annual use.
Adding battery won't help me because I don't have enough production. Adding more pv without battery would mean some pv would go to waste. If I connect to the grid I can add pv above 100% offset and not need to add a ton of battery to capture all the production because frankly no one can afford enough battery to capture all their excess production if they have 100% offset. IMHO. And even if you could afford the 300kwh of battery it makes more financial sense to just grid tie, at least for now
timselectric
If I can do it, you can do it.
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Possibly
If you size the storage capacity for 3 or more days of bad weather. It should also lower the charge/discharge rates well below 0.20 C. Which will decrease the stress put on the cells. My current figures indicate that I will be somewhere around a 0.07 C rate on discharge. Charging rate is of course dependent on season.
dougbert
Solar Addict
space = small house, small lot
another issue with "Net metering" is yet another data stream for gov/grid to monitor you and your solar system. No thanks
Zwy
Emperor Of Solar
Yes, if charging of an EV during night is desired.
If consistently hitting 100% SOC, would be smart to add more battery capacity is another. Use that power on days when needed.
Just buy batteries and use it.
Batteries allow full retail price per Kwh to be recovered. About $0.20/Kwh here. Certainly more than $0.06/Kwh.
Once you get to 100% you can find more uses for the excess.
I run 8.4Kw of array, 58Kwh of battery. I run off grid, since installing my system I've run about 3 days with grid turned on, but not used all those days. I think with another battery I could go 100% off grid. I'm a firm believer in having a large battery bank with a smaller array.
I manage loads and have dump loads. I heated my house entirely off PV power for most of this week. Even heating the house to 78F yesterday I still had excess I wasn't capturing. I could actually have used that today, partly cloudy and yield isn't great. More battery and I would have it to use today.
See the reason for more battery capacity?
wattmatters
Solar Wizard
Simple fact is the variance from place to place with:
- local and other regulations
- applicable tariffs
- system set up costs, whatever that may be (PV, storage, inverters, charge controllers, approvals, labour, metering etc)
- each property's unique production capacity (location, space for solar PV, orientation, seasonal variability, climate)
- each property's unique energy consumption (total and consumption patterns over a day, and seasonally)
just means the optimal scenario in each case can be quite different.
Layer on top what premium we each subjectively assign to other intangibles (such as level of energy independence, enjoyment in learning, designing and/or building, the hobby factor, a reduced reliance on fossil energy etc) and everyone will have a different "optimal" outcome.
The variance with these combination of factors across the USA seems to be quite large. The variance is much less across Australia.
I'm sure timselectric is optimising to suit their household's unique set of parameters.
- local and other regulations
- applicable tariffs
- system set up costs, whatever that may be (PV, storage, inverters, charge controllers, approvals, labour, metering etc)
- each property's unique production capacity (location, space for solar PV, orientation, seasonal variability, climate)
- each property's unique energy consumption (total and consumption patterns over a day, and seasonally)
just means the optimal scenario in each case can be quite different.
Layer on top what premium we each subjectively assign to other intangibles (such as level of energy independence, enjoyment in learning, designing and/or building, the hobby factor, a reduced reliance on fossil energy etc) and everyone will have a different "optimal" outcome.
The variance with these combination of factors across the USA seems to be quite large. The variance is much less across Australia.
I'm sure timselectric is optimising to suit their household's unique set of parameters.
I don't.
How much excess do you have? Let's say you had 5000kwh excess per year. You could sell that back to the grid for something, or buy more battery to store it? How much would the grid pay you net for 5mwh of export? Vs how much would a battery cost to capture that same 5mwh.
It's a simple math equation and I bet for most people it makes more financial sense to export excess to the grid, than it does to store it
sunshine_eggo
Happy Breffast!
Based on my personal situation, the sell back to the utility is so cheap, it's not worth the added costs/complexity associated with the contract with the utility.
My AHJ simply requires a NEC 2017 compliant PV installation WITHOUT a permit. Once the utility gets involved, everything has to be pre-approved, and they have "authorized installer" or "authorized personnel" attached to every step of the process making DIY quite cumbersome. Additionally, most of my potential savings are gobbled up by peak use based fees that are not associated with the quantity of energy used, but the single highest power 30 minute period of use.
I would rather have PV go to waste rather than deal with the hassle associated with selling it back.
timselectric
If I can do it, you can do it.
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You also have to factor in all of the additional costs. Just to be able to export. More expensive equipment, permitting, and agreements.
Which is all wasted money, when the utility decides to say it's over.
Lt.Dan
Solar Wizard
I mean the batteries definitely help me in my scenario. I dump all my PV during peak hours only. It makes me want to double my battery capacity. Doesn't mean it will work for everyone, but this was my bill last month:
Lt.Dan
Solar Wizard
I would bet its because SoCal Edison wants you to feel like you're saving money during Super Off Peak, but you're not lol.
OffGridForGood
Catch, make or grow everything you can.
I likeTim's goal of 200kWh ESS, and I am convinced he has worked through the options and costs for his location and situation to arrive at this target.
I also subscribe to @sunshine_eggo 's comments on the (deliberate) PITA it is to set up feed-in to the local utility, and all the rules and various barriers errected to prevent said feed-in. While they can change the game anytime it suits them, but I can't. Add my own personallity is more of a 'take care of yourself and you don't need big brother' state of mind.
So for my set up my goal is 100-114kWh ESS plus 2 EV's with another 175kWh of available storage potential - ie summer time place to put the extra solar.
The math for me is not what the utility would pay for my excess (if I were to take all the steps to have this feed-in permitted), the math is what is the value of a kWh in the EV compared to buying gasoline.
Right now, 17.4kWh of solar will offset 8L of gasoline: in other words, a kWh (to me) is worth 71-cents CAD (55 cents USD) and that is tough to beat.
In winter, a 7.4cent/kWh off-peak utility kWh is well worth the 71cents saved compared to gasoline purchases.
I also subscribe to @sunshine_eggo 's comments on the (deliberate) PITA it is to set up feed-in to the local utility, and all the rules and various barriers errected to prevent said feed-in. While they can change the game anytime it suits them, but I can't. Add my own personallity is more of a 'take care of yourself and you don't need big brother' state of mind.
So for my set up my goal is 100-114kWh ESS plus 2 EV's with another 175kWh of available storage potential - ie summer time place to put the extra solar.
The math for me is not what the utility would pay for my excess (if I were to take all the steps to have this feed-in permitted), the math is what is the value of a kWh in the EV compared to buying gasoline.
Right now, 17.4kWh of solar will offset 8L of gasoline: in other words, a kWh (to me) is worth 71-cents CAD (55 cents USD) and that is tough to beat.
In winter, a 7.4cent/kWh off-peak utility kWh is well worth the 71cents saved compared to gasoline purchases.
timselectric
If I can do it, you can do it.
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I'm the oldest of 5 siblings.
I am the only big brother needed around here.
I am the only big brother needed around here.
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