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batteries vs generator

Discussion in 'Tesla Energy' started by h2ofun, Oct 30, 2020.

  1. jboy210

    jboy210 Supporting Member

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    Are you sure you can run it for an unlimited time? In another thread, someone pointed out that residential nat gas systems are sized for heating and cooking needs, not for whole house generator needs which are higher. They figured if 2 of the people in the Cul-de-sac got natural gas generators there would not be much leftover for the rest of the homes.
     
  2. getakey

    getakey Member

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    But you get 2 years of savings and piece of mind as backup
     
  3. jboy210

    jboy210 Supporting Member

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    Agreed. Also, just because there is a new design does not mean it you need to upgrade until there is a need to make a change. You have a 10 year performance warranty.
     
  4. h2ofun

    h2ofun Active Member

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    Help me, how are batteries giving real savings vs cost. As my charts show, my solar generation vs usage is such that I will never
    have an electric bill. So, why would folks not just increase the size of their solar panels for " savings"?

    And then when you get into backup. For most, who have short stuff, what do you really need? Does one really need to be able to run the entire house? During the day it is light outside. Most of the dark I am sleeping. So many much cheaper solutions for short outages.
     
  5. getakey

    getakey Member

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    Increasing panels does not provide backup. I explained before that PWs provide savings as well as backup. I bought for backup and the savings is icing. Generators have no "icing"
     
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  6. h2ofun

    h2ofun Active Member

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    As I said, for cost savings, I need not batteries since my solar cover all plus more so I have a zero bill. Seems IMO to be cheaper to get more solar for savings.

    Now for backup, what really needs to be backup? Refrig, for 100 bucks of food? lights? light during the day. Etc. So, what is a total must, and I mean must, to backup to live, for a few hours, or days, which I assume is more folks?

    For what most think of backup, you can buy a 500 buck generator and run an extension cord. This is what I see most do. not spend ten of thousands for lights? Again, what is life or death backup?
     
  7. getakey

    getakey Member

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    Last year, the PSPS was several days in the middle of summer. I'm fine spending more money to be comfortable in my home with AC during 100 degree days and having refrigs backed up. And, not having to put gas into a $500 generator every few hours.
    The icing is that the PWs do offer a payback.
     
  8. sorka

    sorka Well-Known Member

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    #48 sorka, Oct 31, 2020
    Last edited: Oct 31, 2020
    Yea, but their solar was WAY more expensive until they did their massive drop to $2/watt installed before the tax credit. I ordered on July 25th when the they still had the $2500 PW bundling discount but right after the dropped the solar price. So something isn't adding up.

    Your price for solar after subtracting 4 PWs + GW2 + $2000 install - $2500 discount is just about $2 / watt long before they dropped the price.
     
  9. sorka

    sorka Well-Known Member

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    And in two years, the next newer cheaper better design will be just two years away :rolleyes:
     
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  10. CrazyRabbit

    CrazyRabbit Member

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    now when the grid goes down, virus or war, i will be home safe with everything i need to protect my self. and you will be roaming the streets, possibly killing people over a can of beans. all fresh food will spoil in the supply chain.
     
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  11. jboy210

    jboy210 Supporting Member

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    #51 jboy210, Oct 31, 2020
    Last edited: Oct 31, 2020
    I think for a lot of people increasing array size is not an option. There is only so much good producing roof space on homes. Read through the threads. It is not unusual to see people limited to 5-8 kW total.

    And without Powerwalls (or more specifically the Tesla Energy Gateway and Powerwalls) a grid-tied solar system with 10, 40, or even 100 kW of solar panels produces 0kW if the grid is down. Because, if the grid is not up, the solar power must be turned off to prevent producing electricity that can get fed back into the grid and shock utility workers trying to get the grid repaired.

    Now, you have a nice generator and a large propane tank. But where most people live, in cities, there are limits on natural gas line supply volumes which limits the number of generators. And there are restrictions on the propane tank size (5-10 gal max).

    FWIW, there are threads here that talk about installing a Tesla Energy Gateway or equivalent that can isolate the home from the grid and start a generator in the event of an outage. I am not sure if this will work without a Powerwall installed.
     
  12. h2ofun

    h2ofun Active Member

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    My automatic transfer switches isolate the generator from the grid and my solar.

    From the design I have seen, the gateways with isolate the grid from the batteries. So at this point, how I am wired, the generator can never see the batteries.

    I am just trying to really understand what folks are doing. When I have talked to some directly about their batteries, they had NO idea what was really happening!!

    So again, I just think it is a two step process, and I just do not see things really thought about, from the responses I am getting. First is the grid is on. Now, if one can only put up a small solar setup, I really do not see how batteries help for the cost. Just am not seeing how one really save money compared to lets say put that money in the bank. 20 year ROI, well, how many investments would folks make with very long ROI's?

    And then we get to the power goes out. How often? I saw one person who just put a few deep cycle batteries together with a big inverter and that is what he used to keep his refrig going. He bought rechargeable lights for the night. Others spent 500 bucks on a 10K generator and use propane tanks, or gas to power with multi fuel options.

    I try to spend money wisely. Guess this is why I was able to retire at 52. Just like to get the best bang for the buck. Now, I LOVE technology, but, .......
     
  13. getakey

    getakey Member

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    How many times do I have to explain that my ROI is ~6 years?
     
  14. TMThree

    TMThree Active Member

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    There is no savings unless you have TOU. Most people don't have TOU.
     
  15. TMThree

    TMThree Active Member

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    yeah, all homes in the neighborhood are custom homes. Our water heaters, stoves, fire places, home heaters, are all linked to it. My neighbor has a house generator linked to it.
     
  16. TMThree

    TMThree Active Member

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    Not really. Model S till now have the same basic battery with some chemistry changes. The new battery is tabless and designed for lower cost higher output. That's why Cybertruck with 500mi range is only 70k.
     
  17. h2ofun

    h2ofun Active Member

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    Well, please explain again, since I missed it.

    Now, ROI is only about grid is on, not about backup for a power outage. I am really trying to see what I am missing and every solar sales person who I talk with that says batteries have no decent ROI.

    So, lets start with basically, even with TOU, I see no real savings adding a battery.

    I have 43 panels, and no battery. My PGE with TOU and no worry when use electricity will end up being a negative use. So, zero cost.
    So, how will adding batteries save me money when I have no cost?

    Now, lets take what I assume is your situation. I assume you have small solar array which does not cover all electricity cost. So turn off your batteries, now much are you spending for electricity? Again, no batteries.

    Now, add your batteries and turn off you solar. How much will you spend on electricity to use your batteries which charge them. Now if you tell me you have TOU and time shift, again, show me how much you spend since with no solar, you are always having to charge from the grid.

    After these two numbers, again, show me how you get a 6 year ROI JUST JUST for adding the batteries. I may be wrong, but my guess is you are adding your solar, which I can see may have a 6 year ROI, but so far, do not see how the batteries, own there own, can give you a faster real ROI. Again, we are just talking grid usage since outages have no ROI.
     
  18. emoore33

    emoore33 Member

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    I'm guessing some or a lot of people will get batteries since they don't want to burn natural gas. I'll never buy another gas powered device again so my only choice would be batteries. But I only lose power about once a year for an hour at most so I don't have a battery backup.
     
  19. Dukeybootie

    Dukeybootie Member

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    When I lived in NJ I suffered through Sandy and Irene, each causing power outages > 10 days. Swore I would never deal with that again. I researched a Generac standby natural gas generator but found out the city gas line infrastructure would not support more than 2-3 houses on the street having such generators turn on or run simultaneously in an outage. Ended up buying a high end portable Honda inverter generator and having a transfer switch installed, and even then it was not powerful enough to run the entire home. Also had to maintain the generator (fuel stabilizer, oil change, running it for 15 minutes every month). Did I mention buying multiple gas tanks to refill the generator with? And a long thick cable to connect to the generator while keeping it far enough away from the house so the carbon monoxide didn't circulate indoors? Or the 3-4 hr lines for gasoline for days in the aftermath of those hurricanes? It was not exactly an ideal arrangement.

    For sure, I would not recommend Powerwalls to anyone who was primarily concerned with ROI. But for me, it was not a matter of ROI, but the following:
    -seamless instant backup power
    -indefinite off grid capability when combined with my solar panels
    -near zero maintenance and no garage clutter
    -daily load shifting and arbitrage capability (especially as TOU rates in my area become mandatory and solar payback rates become less favorable)

    I don't plan on moving from my current home for a long time. I had the budget for 2 Powerwalls. I got them with 30% federal tax credit and a hefty SGIP rebate and they have been working perfectly. Absolutely zero regrets, and zero concern with ROI. Just my 2 cents.
     
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  20. h2ofun

    h2ofun Active Member

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    Yep, if one is not concerned about ROI, great.

    How large is your solar? I know folks who during the winter have not been able to recharge their single PW. So to assume one can always recharge their PW(s) is not 100% true. I know for me, in the summer I get like 80kwh per day, now in Nov it is like 25 and heading lower.

    I am not at all trying to suggest what is right or wrong. BUT, to have folks say it has a decent ROI, well, still waiting for a real non emotional analysis. THanks for you objective thoughts. I would like batteries for a lot of the reasons you say, even though with my 22kw generator connected to my 500 gallon propane tank, I am set basically forever. But if I can get the batteries for free, well, why not.
     

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