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Gravity as home battery backup TWICE now..

Jasondeno

Jasondeno

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Gravity GT Model S Plaid
Hello!

Just wanted to share how pleased we have been to have our Gravity AC outlets on the ready. In the last two weeks, we’ve had bad weather come thru Chicagoland. Knocked out our power both times for almost a day each.

The power outlets in the Gravity truly can handle significant and independent load. As we ran our fridge, Internet, ice maker, and sump pump on the rear jack. Ran the freezer in the garage as well as dewalt/ryobi chargers in the garage on the middle jack. This last time, we even plugged on the television and a lamp.

We burned less than 1% of our battery per hour and had plenty more capacity from the car if needed.


View attachment IMG_1461.jpeg
 
Jasondeno said:
Hello!

Just wanted to share how pleased we have been to have our Gravity AC outlets on the ready. In the last two weeks, we’ve had bad weather come thru Chicagoland. Knocked out our power both times for almost a day each.

The power outlets in the Gravity truly can handle significant and independent load. As we ran our fridge, Internet, ice maker, and sump pump on the rear jack. Ran the freezer in the garage as well as dewalt/ryobi chargers in the garage on the middle jack. This last time, we even plugged on the television and a lamp.

We burned less than 1% of our battery per hour and had plenty more capacity from the car if needed.


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@marqie
 
That is one of the many reasons why I got a Gravity. The plan is to use it during the fall/winter power outages that we get at least once a year. Glad to hear it loses such a small % of the battery
 
Nice. I'm in the process of planning a solar install, and I'm not doing a home battery because it doesn't make financial sense. Once V2H is a real thing this will be really compelling; I already have a 123 kWh battery sitting in my driveway! Why should I pay a whole lot more for smaller stationary batteries that don't do much all day? (We do not have TOU metering where I am.)
 
Oh IDK about stationary batteries on a solar system not doing much! The power produced whilst the sun is high in the sky and blaring gets captured and stored in those batteries and then later drawn on in the afternoon/evening when the solar is no longer producing much if anything. This cuts a LOT off what you would otherwise draw from the grid and that truly reduces your monthly bill each month right now. Without them, a bunch of power your system could produce that can't be used immediately is just wasted and not captured at all so later must be drawn through your meter from the grid. If you pencil out the monthly electric bill savings it easily pays for the batteries over time if you plan to stay in your home enough years (unless your 3pm-midnight peak rates are a hell of a lot lower than what we pay in Calif!!)

If Gravity is your solar system storage battery then if you go drive anywhere your excess daytime solar production has nowhere to be stored and in the afternoon/evening your home must then draw from the grid. If your car is home most solar systems will not fully replenish Gravity's big battery and you're limited trying to power things by three plugs that will shut off if you try powering anything that has a strart up surge like a shop vacuum or various tools because of the sensitive e-breakers

Although its a nice concept, you might grow old waiting for V2H features to be a reality
 
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jered said:
Nice. I'm in the process of planning a solar install, and I'm not doing a home battery because it doesn't make financial sense. Once V2H is a real thing this will be really compelling; I already have a 123 kWh battery sitting in my driveway! Why should I pay a whole lot more for smaller stationary batteries that don't do much all day? (We do not have TOU metering where I am.)
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I’d recommend researching solar energy sell vs grid buy rates. Are they equal? If you are in an area covered by NEM3 or similar, home batteries are a must, IMHO. Utility companies have been lobbying hard to make a profit off of your solar cells. See the discussion in another thread.

I view V2H as emergency backup, only, to augment the home batteries during extended outages and low sunlight conditions (winter and storms). Also, for V2H, make sure your solar system is ready for it. Enphase and Sygenergy are one of the few companies with a fully integrated system that I know of. Key capabilities to consider:
  • Load balancing so that you don’t have to upgrade your main panel for EV charging.
  • Dedicated EV smart circuit so that EV charging is halted if the grid goes down or home battery SOC reaches a threshold.
  • Be able to charge the EV off of excess solar only, without drawing from the grid or home battery.
  • V2H capable with the appropriate EV charging station.
I wish I had done more research before selecting my solar system. I went with Franklin batteries, which require the FranklinWH controller. I also need the Enphase app for solar cell monitoring (I have Enphase micro inverters). Now I’m looking at patching in the Emporia or Wallbox L2 charger that will adjust EV charging rate to use access solar only. There is no V2H capability for Franklin. I must use V2L and plug in to the generator port. It will work, I think, but it’s a Frankenstein system, at best.

If anyone is using FranklinWH and has a good configuration, I’d love to hear about it!
 
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hwy17er said:
interesting...I have Enphase
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The IQ bidirectional EV charger may be of interest, available soon. One stat that may be of interest is the minimum solar energy required to charge. I’ve read Emporia is 6A but Enphase is 8A (with some saying IQ EV2 is also 6A).
 
hwy17er said:
Oh IDK about stationary batteries on a solar system not doing much! The power produced whilst the sun is high in the sky and blaring gets captured and stored in those batteries and then later drawn on in the afternoon/evening when the solar is no longer producing much if anything. This cuts a LOT off what you would otherwise draw from the grid and that truly reduces your monthly bill each month right now. Without them, a bunch of power your system could produce that can't be used immediately is just wasted and not captured at all so later must be drawn through your meter from the grid. If you pencil out the monthly electric bill savings it easily pays for the batteries over time if you plan to stay in your home enough years (unless your 3pm-midnight peak rates are a hell of a lot lower than what we pay in Calif!!)

If Gravity is your solar system storage battery then if you go drive anywhere your excess daytime solar production has nowhere to be stored and in the afternoon/evening your home must then draw from the grid. If your car is home most solar systems will not fully replenish Gravity's big battery and you're limited trying to power things by three plugs that will shut off if you try powering anything that has a strart up surge like a shop vacuum or various tools because of the sensitive e-breakers

Although its a nice concept, you might grow old waiting for V2H features to be a reality
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I’m on NEM2, so you’re right. NEM3, which is the current scheme, sucks, and the energy you sell back during the day nets you basically nothing.
 
hwy17er said:
Oh IDK about stationary batteries on a solar system not doing much! The power produced whilst the sun is high in the sky and blaring gets captured and stored in those batteries and then later drawn on in the afternoon/evening when the solar is no longer producing much if anything. This cuts a LOT off what you would otherwise draw from the grid and that truly reduces your monthly bill each month right now. Without them, a bunch of power your system could produce that can't be used immediately is just wasted and not captured at all so later must be drawn through your meter from the grid. If you pencil out the monthly electric bill savings it easily pays for the batteries over time if you plan to stay in your home enough years (unless your 3pm-midnight peak rates are a hell of a lot lower than what we pay in Calif!!)
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As i mentioned, we do not have time-of-use billing in Massachusetts (same rate all day) and we have full net metering (same cost in as out). There is zero benefit today to home battery storage beyond reliability during an outage.
 
Saksak said:
I’d recommend researching solar energy sell vs grid buy rates. Are they equal?
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Yes, buy vs sell are the same price, 24 hours a day. Production AND distribution fees; the meter just "runs backwards".

A suitable battery system would double or triple my costs to no benefit. My average daily use is around 138 kWh; the largest system practical for my roof only covers around 17-20% of usage.

I suspect V2H will become mature around the same time as we do introduce TOU metering. I've been researching this for years and was hoping to get nice-looking BIPV ("solar shingles") but after a decade of waiting it's now clear to me that that technology being "real" (e.g. cost effective and reliable) is at least another decade away. In the meantime, my electrical costs keep going up...
 
While waiting for V2H, it sure would be nice if Air owners could get a 'power strip' adapter which could be plugged into the charging port, tapped into the main battery, and used to power several critical appliances during a power outage. Given that no third party has made this available, my guess is that some modifications to the car itself are required. Does anyone know what (internally and/or externally) is holding up this very reasonable alternative as we wait for true V2H?
 
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Buffalo Bob said:
While waiting for V2H, it sure would be nice if Air owners could get a 'power strip' adapter which could be plugged into the charging port, tapped into the main battery, and used to power several critical appliances during a power outage....
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I'd just wait for V2H. To do what you are asking, you'd need a high power connection to the car's battery - exactly like the J1772 or NACS connector the car already has.
I think we'll see practical V2H from Enphase and/or Sigenergy within a year, and this is with me having waited 4+ years already.
 
I am looking at V2H in general but it is complicated by my existing configuration, so I’ve been thinking about trying to do a manual transfer switch that runs on the EV battery if I have no solar and no batteries anymore and prevent using my propane generator unless an absolutely last resort
 
jered said:
Yes, buy vs sell are the same price, 24 hours a day. Production AND distribution fees; the meter just "runs backwards"....
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Essentially using the grid as an infinite battery. Nice to have it while your utility will allow it.

jered said:
...I've been researching this for years and was hoping to get nice-looking BIPV ("solar shingles") but after a decade of waiting it's now clear to me that that technology being "real" (e.g. cost effective and reliable) is at least another decade away....
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Several homes in our area have Tesla solar shingles. One thing I didn't expect - the solar shingles are quite thin in appearance, and really reveal imperfections (waviness/swaybacked appearance) of the roof framing in the older homes, detracting from their appearance.
 
flarbear said:
And, on cue, Tesla appears to have just discontinued the solar roof shingles

https://electrek.co/2026/08/20/tesla-discontinues-solar-roof-panels-only/
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Wow.... barely made it 9 years since the sales announcement. They kept at this long enough that I don't think this was a financial fake-out just to bail out his brother, but I do wonder why they were never able to make it work. Too much cabling?

On one hand, I wish I had done solar sooner instead of holding out for shingles. On the other hand, the panels I'm getting now are ~50% more efficient than the ones a decade ago. I got a final engineering design and signed off to go to permitting (which will be interesting, since I have a historic property), and they were able to get it up to 29 panels. Still only covers less than half my consumption, but has an estimated 5.9 yr payback so I'll take it.
 
I had looked at the Tesla solar shingles but when it would’ve been with 2 powerwall+ over 100k, I think I know why it wasn’t working all that well. But I know part of the reason was at least in 2023 where the sheer number of pieces. I believe it was v3 or v3.5 that cut the number of SKUs to like 35-40% of what it had been.
 
DeaneG said:
I'd just wait for V2H. To do what you are asking, you'd need a high power connection to the car's battery - exactly like the J1772 or NACS connector the car already has.
I think we'll see practical V2H from Enphase and/or Sigenergy within a year, and this is with me having waited 4+ years already.
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azgagi.webp

🤣🤣🤣
 
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