The 1.21GW Powerwall

Chris Davis

Member
Joined
Aug 11, 2017
Messages
30
Hello everyone,

I have been doing a lot of reading, watching, and learning over the last month, and I am starting down my paths.

Here are the goals I am trying to reach...

By the end of my life I want to be able to store 1.21 GW, so a can go Back to the Future!

To get there I am going to need to break it up into a few milestones.
  • Be able to charge my Chevy Volt at 120V@12a (1.4kw) with a total output of ~12kwh
  • Be able to charge my Chevy Volt at 240v @14a (3.3kw) with a total output of ~ 12kwh
  • Be able to charge my car, and run my server farm 120v @ 5a
  • Be able to recharge my PowerWall via solar
  • Be able to run my house off battery for 1 month ~2,000kwh
I plan on trying to stay with SMA Sunny Islands for my inverters and charge controlers as I want to make sure, that my inverters are able to hand spikes that comes from the AC unit, Electric Dryer, and Furnace.

So far I amthe very beginning stages, Here is what I have so far,
  • ~500 cells from HP, and Dell Laptop packs, (Most of them still in there plastic shells)
  • SMA 40 Amp Charge Controller
  • 4 18650 Chargers so I can work with 16 Batteries at a time.
  • Battery Spot Welder
  • Cables, XT-90 Connectors, 1a glass fuses (on there way from china)
  • Batrium Battery BMS -14s with 375a shunt
  • Raspberry pi3 (for Graphana, and other things)
  • 2x Arduinos (I was going to build my own bms, then I found Batrium, so I will do something with them)
  • A local supplier that will sell me used but still working laptop packs for $3 each. So far most of the batteries have testing ~2,200ma -2,000ma
Questions:
  • Do you think I should start my own Youtube channel for documenting my project, as there are already so many good people out there like Peter, and Average Joe and so on...
 
Chris Davis said:
Hello everyone,

I have been doing a lot of reading, watching, and learning over the last month, and I am starting down my paths.

Here are the goals I am trying to reach...

By the end of my life I want to be able to store 1.21 GW, so a can go Back to the Future!

To get there I am going to need to break it up into a few milestones.
  • Be able to charge my Chevy Volt at 120V@12a with a total output of ~12kwh
  • Be able to charge my Chevy Volt at 240v @30a with a total output of ~ 12kwh
  • Be able to charge my car, and run my server farm 120v @ 5a
  • Be able to recharge my PowerWall via solar
  • Be able to run my house off battery for 1 month ~2,000kwh
I plan on trying to stay with SMA Sunny Islands for my inverters and charge controlers as I want to make sure, that my inverters are able to hand spikes that comes from the AC unit, Electric Dryer, and Furnace.

So far I amthe very beginning stages, Here is what I have so far,
  • ~500 cells from HP, and Dell Laptop packs, (Most of them still in there plastic shells)
  • SMA 40 Amp Charge Controller
  • 4 18650 Chargers so I can work with 16 Batteries at a time.
  • Battery Spot Welder
  • Cables, XT-90 Connectors, 1a glass fuses (on there way from china)
  • Batrium Battery BMS -14s with 375a shunt
  • Raspberry pi3 (for Graphana, and other things)
  • 2x Arduinos (I was going to build my own bms, then I found Batrium, so I will do something with them)
  • A local supplier that will sell me used but still working laptop packs for $3 each. So far most of the batteries have testing ~2,200ma -2,000ma
Questions:
  • Do you think I should start my own Youtube channel for documenting my project, as there are already so many good people out there like Peter, and Average Joe and so on...
Definitely start your own channel and get monies from it.
 
Soldering tends to be recommended rather than spot welding due to the ease of it.
 
Does it matter whether we think you should start your own YT channel or not? :) Go ahead if you like!

Have you realized that you need more than 163 million cells at 2000mAh to store 1.21gWh using todays technology? I wish you a very long and healthy life, lots of space and hopefully one or two major breakthroughs in cell technology :D
 
zag2me said:
Soldering tends to be recommended rather than spot welding due to the ease of it.

Yea, I have done a lot of soldering in my rc car days.... so I thought it would be good to pick up a new skill. I like the way it looks when the fuses are spot welded, so I will give it a shot. If it doesn't work out, then I learned something new.


DarkRaven said:
Does it matter whether we think you should start your own YT channel or not? :) Go ahead if you like!

Have you realized that you need more than 163 million cells at 2000mAh to store 1.21gWh using todays technology? I wish you a very long and healthy life, lots of space and hopefully one or two major breakthroughs in cell technology :D

Yea, I know it is a big number, but why not go big. When I retire, I want to be a solar farmer, on 100 acres so I will need somewhere for all that power to go... maybe I will become the first commercial 18650 power plant :)Dream Big!
 
maybe I will become the first commercial 18650 power plant Smile Dream Big!

Awesome! As long as you don't live in Florida :p And certain other states, too.

But that'd be awesome if you could end up bein a power source for a few neighbors. Even if you were just a backup source for them.
 
Stop reading and do it.. you need 10k views to monitise so start today!
 
I wouldn't mind having another youtube channel about 18650 to follow. When I'm done tinkering myself I love watching other people tinker with batteries!
 
Chris. THAT WOULD BE MASSIVE :D

I would love that kind of battery bank :D
 
I'm watching Julian Ilett's videos on the Hall Effect sensor ACS712. I was surprised that there was so much noise in that sensor. I know it's a fairly cheap sensor, but still. He did find a way to correct it, reduce the noise at the loss of loosing sampling times, but even at a 1000 times per millisecond, that's pretty good Tongue (i think that's what he figured, I might be off by a fraction)

But what I was really wondering, has anyone used Hall Effect sensors to measure their amps being used? The pros of using an HE sensor is that it's truly bi-directional. So you can use 1 sensor to determine charge into the batteries, and discharge from the batteries. I'm not sure how easy this would be able to be done with a shunt.

I'm assuming that you could read the voltage difference on either side (as normal) (assuming left-right arrangement, batteries left & load right) and when the voltage is higher on the left, amps are discharging, and if the voltage is higher on the right, amps are charging. Is this correct thinking?

If that is so, then I would gather that a shunt would be far superior over an HE sensor as the HE sensors have a very limited amperage threshold; whereas the shunt, could be made at home and use a known resistance to get the calculations (far cheaper)

Which is more accurate, shunt or an HE sensor? Again, I would assume that a shunt would be because it is less likely to be subject to external interference (ie. a magnetic object gets close to an unshielded HE sensor can through it's readings off easily, as Julian showed in his first video).
 
A shunt works just fine to do biderctional. As long as you ADC does +-V then its fine. Thats how everyone using shunts does it.

Your other questions i cant answer. but i preffer callibrated shunt.
 
Yea, sort of.... cell 100 tested, .... and it has 471 mAh [emoji32] .... oh well maybe 200 will be better.
image_ukxfev.jpg
 
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