Just found this on hackaday, enjoy!
Anyone in for a group buy on some 18650s? :bigsmile:
Yeah, someone posted that a couple days ago. Pretty cool!
I wonder if it’s full of 18650’s 
i read somewhere they are 18650s, over a thousand i believe ? Lots of run time there bolting that to a EDC light. :bigsmile:
The original Tesla pack has around 8000 cells in it. I think that some of the newer ones have quite a few more.
Now my question
I wonder if a buck circuit…bring that 400vdc down to say 100~vdc, then run it thru a true sine wave inverter…hmmmm
I always wanted to build a straight 110VAC rectified to 110~DC straight into a bank of 10+ lead acid batteries, then build a 1 for 1 true sine wave inverter…due to 12vdc to 110VAC at 70-90% efficiency, it’s no wonder these 1500watt jobbies pull upwards of 100+ amps of 12VDC thru them…at 100VDC the current draw would be much much less…but the battery bank would suck
If you rectify 110VAC line you get more than 110VDC out. 110VAC is the RMS value. Peak voltages are 1.414 times that. Oh, and it’s 117VAC, not 110 VAC nominal voltage.
Right…but straight out of say a 7Kw AC generator that doesn’t always make good AC frequency and gobbles gas, charging the battery bank 2.3vdcx60cells (6 cells in each 12vdc batteries x 10 batteries the voltages match up fairly closely), then shutting down generator would save a ton of fuel (kind of based upon the old diesel submarine technology/ideology)…as long as you weren’t drawing crazy huge amounts of AC all the time.
Was just a spitball pipe dream of mine is all
If I thought of it…guarantee you some dude with a large bankroll has already mulled the idea around and found it NOT cost effective, otherwise…we would have off grid one-for-one true sine wave systems up and running all over the place
Our local power company has a plan called “free nights” where all your electricity after 10:00 is free. I seriously considered building a very large battery system based upon my peak summer usage (we use a LOT of juice here for air conditioning). Charge the batteries at night for free. When not using the full capacity sell the excess back to the power company. Without even doing that it could pay for itself in about three years…
This one has 7,104.
8064 cells. Wow. Telsas are amazing!
I counted 504 per module, 16 modules laid out in the last pics. Remember the front bay has 2 modules stacked.
12noon is after 10p no?
That's a great program. Most power companies should have something like this to take advantage of all the excess base load, with the exception being those that already have their own energy storage of sufficient capacity.
all those liions together are scary!
I would have tried to leave the whole thing together and design some controllers to use the pack as he got it, though it is fascinating to see inside. I wonder if Tesla contacted him asking him to sign a waiver of responsibility or something.
Why didn’t you build your pack pyro?
Too much work. Not enough time. I was going to use some A123 20 Ah pouch cells. Availability was a bit spotty. They were apparently recycles from the Fisker Fiasco.
Also no guarantee of how long that free electricity program would last. Another idea was to freeze or heat the pool at night and use that to cool/heat the house during the day.
That reminds me there is an outdoor supply store around here that was going to freeze ice off peak and use it to cool the store during the day, i’m not sure if there ever implemented it
I think the battery count changes with different models, configurations, and over time. I think they’ve all been between 5000 and 10000 18650s and many of the Model S use NCR18650A.
https://electrek.co/2017/03/22/tesla-battery-cell-breakdown/
Holy thread revival batman! Good stuff link above. Someone tore apart and tested some old Tesla/Panasonic 18650 cells and compared them to Panasonic’s regular NCR 18650 cells. Very interesting chart. It doesn’t say what year the cells were produced. It’s likely that the internal chemistry between cells made in 2014 are different than cells in 2015 etc etc as knowledge develops. So due to that it’s hard to say exactly what is what. But we do know the short version.
The short version (in case the link disappears): the regular Panasonic NCR 18650 (the flashaholics gold standard) 70% capacity after 500 cycles. Tesla’s Panasonic cells 85% after 3000 cycles!