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Tesla solar panels experience (1 Viewer)

foos

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That's not bad at all.
Nope, and that is about as bad as it gets. I have seen lower but that was a really nasty day where I had to leave lights on all day to see around the house. Todays generation just hit zero and I made 13.8kWh of power. This month is at 978kWh produced 688.6kWh used for 142% offset. Lifetime of the system so far is 6.7MWh produced and 5.7MWh used for an offset of 117%.

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Last bill was -24.47 but I have average billing and that is calculated off the last 12 months and I did not have solar 6 of the last 12 months so the calculation is off. I have not complained since my plan is not supposed to give back any negative but average billing has it getting credited so it looks like having that on sidesteps the no credit for production over use.

Reliant's Simple Solar Sell Back is surprisingly simple. $0.13/kWh charge for use, $0.13/kWh for solar feed back up to canceling out all grid use, and that is it. That is the full bill, no other fees or anything. Average bill before solar was ~$180/mo and depending on how the next few months go I should have an average negative.

There is someone else in Katy that just got solar and posted on reddit, they got a slightly larger array than me and all south facing. Their production is insane. Looks like they have less than 10% more solar panels than me but they look to be making ~30% more power.


I have a 11.24kW system and made 63.3kWh on the same day.
 

RR-MAN

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What kind of warranty Tesla offers on the batteries?

My sister just bought a Tesla model Y and I think she has a 10/y warranty on the car battery. For almost $70k I don’t think that’s enough. 😂😂😂
 

foos

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What kind of warranty Tesla offers on the batteries?

My sister just bought a Tesla model Y and I think she has a 10/y warranty on the car battery. For almost $70k I don’t think that’s enough. 😂😂😂
Warranty is 70% rated capacity for 10 years. I am currently at 103.19% rated capacity. They warranty for unlimited cycles so their data shows that a battery should have over 70% at 10 years with daily cycling of it. Otherwise, you know, they would not warranty for that. lol

Lithium cells degrade if they are held at 100%, get too hot, or get too cold. 100% is not set in stone and can be a bit of a range. If you look at the voltage of lithium cells at different charge levels, it is rather flat and falls off like a rock near 0% and spikes near 100%. A lot of companies used to, and some still do, charge to the absolute limit so they can advertise a larger battery. That is why laptop and cellphone batteries seem to die overnight. They are charged to the limit and overheated causing them to break down fast.
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Basically, I would not be overly concerned about battery life on cars or powerwall type devices from any company that has experience. These are not devices you are expected to replace every 1-2 years so they are not going to push the batteries to the limit sacrificing longevity for a slightly larger number for marketing.
 

foos

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If there are any days you want numbers, just let me know.

People found via the installer interface that there is a binary blob accessible via the api that gives internal health data. This looks to be raw data directly from the bms.
./vitals.py|grep nom_full_pack_energy
"POD_nom_full_pack_energy": 13897.0,
"POD_nom_full_pack_energy": 13939.0,
"POD_nom_full_pack_energy": 13942.0,

It looks like this is the ideal charge level, not the max you can fit in battery health be damned level. They sell the batteries at 13.5kWh capacity and mine have 13.8/9kWh usable. I know when they first came out people were happy since they are advertising at usable, not at theoretical max that would destroy the batteries quickly.

There is also interesting info like if the heating system is on and the temp of the battery packs.

./vitals.py|grep 'Temp\|Heat'
"POD_ActiveHeating": false,
"POD_ActiveHeating": false,
"POD_ActiveHeating": false,
"THC_AmbientTemp": 28.400000000000006,
"THC_AmbientTemp": 28.400000000000006,
"THC_AmbientTemp": 27.30000000000001,

The temps are not actually that accurate, I think it is an artifact of the data format and conversion. This is also based off a modified standard and they could be appending something to the end to get more data on a smaller data packet.
 

foos

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Interesting bit of data for anyone thinking about solar. 6 degrees F hotter today and 300W less peak production. Heat reduces efficiency of panels by I think it was up to 10%. Spikes in usage are air conditioner, kicked on right after taking the screen shot so it started same time today. lol
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BigRick

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Interesting bit of data for anyone thinking about solar. 6 degrees F hotter today and 300W less peak production. Heat reduces efficiency of panels by I think it was up to 10%. Spikes in usage are air conditioner, kicked on right after taking the screen shot so it started same time today. lol
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Wow so so 90-100* it should produce a little less...... anyone see the new tesla building on hwy6/290 that used to be gander mountain? Wonder what that's gonna be. Hmmm
 

foos

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Yeah, in the summer when it is hot the peak should be a little lower but it is the space under the curve that matters and the days being longer should make it generate a lot more overall.

So, winter solstice was Dec 21 and it was a clear day for 44.6kWh produced. Yesterday was clear and I produced 72.1Kwh and we are half way to the summer solstice. The 12th was clear, cold, and windy and I produced 76.6kWh.
 

BigRick

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Yeah, in the summer when it is hot the peak should be a little lower but it is the space under the curve that matters and the days being longer should make it generate a lot more overall.

So, winter solstice was Dec 21 and it was a clear day for 44.6kWh produced. Yesterday was clear and I produced 72.1Kwh and we are half way to the summer solstice. The 12th was clear, cold, and windy and I produced 76.6kWh.
Makes sense.
 

BigRick

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Came in handy yesterday.
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Geez that can kill a lot of electronics in the house. Probably not on your system cause it catches it so fast. My DVR is not working since last outage Tuesday. Generators create dirty electricity.. not stable enough for sensitive electronics.
 

BigRick

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Came in handy yesterday.
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Also reveals my theory. Sitting at home with all the tanks running I can hear the power surging. Never was it like this up until around the pandemic. Shows that consumption is heavy and the grid is weak.
 

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