What is the general idea of a Powerwall?
Its a good question and Im going to answer it based on what I think it is about :)
The short answer is that what I got is a "proper" powerwall. Unfortunately my design is more of a "power-shelf" :)
The powerwall is comes from Tesla Powerwall. A battery bank from beginning hangs on the wall. Enough talk about him! What is Powerwall for me.
For me the powerwall idea is when you take heaps of batteries and get them together and then power part or the whole house of yours.
Some people go big and some go small. Most people though use 18650 cells either from laptops, ebikes or medical packs. Thats currently the most common if we skip Lead acid batteries.
The most common setups today are either 12V (3s/4s), 24V (7s) or as I use, 48V (14s).
The 3s-14s is how many of those Lithium 18650 cells you have in series. Above is also cells with a nominal Voltage of 3.6-3.7V.
Unfortunately many people still believe that all cells on Ebay and others are genuine cells. This is not true and above is a good example of a cell that is FAKE. There are not cells above 4Ah....
Its important when scouting for cells for your powerwall that you go for proper cells! Even though you go for 2nd hand cells they are generally 2-4x better than the fake ones :)
Stay tune for articles about how to find the cells and sort out fake ones to also testing them!
Testing is also important. I test all my cells that are 2nd hand and above you can see my testing-station! Stay tuned for that.
So when you got enough cells its just a matter of building them together into packs. I have choosen 80 cells per pack in paralell and its common out there.
I then add upp 14 in series to create a 48V battery bank
On top of this I add Batrium BMS for balancing and protection.
When all thats done its time to hook it up to my powerwall electronics!
With all that said you will have your powerwall up and running!
If you are interested in finding out more about above build and approaches dont forget to
follow me!
Youtube can be found here: https://www.youtube.com/channel/UCI6ASwT150rendNc5ytYYrQ