Fellow Brisbane battery enthusiast

[1.21 Gigawatts]

Hey forum,
I found this place from HBPowerwall's youtube channel. Retail powerwall solutions are so over priced and building my own battery sound like a really cool project, so here i am. I've already started collecting 18650s (only have about 200ish). I think i need about 1,000 for a 10kw battery, so long way to go...

I designed and 3D printed the 20 slot changer for my18650's (pictured bellow) as charging 4 at a time would have taken forever. The charging chips are TP4056's if anyone interested. Each chip charges up to 1000mA, & ramps down as battery gets full. Very cheap way to build a charger.

 

[OffGridInTheCity]

Welcome to the forum! For a 10kwh battery, at 2200mah / cell you would need on the order of 1,330 cells. I use this link all the time - https://milliamps-watts.appspot.com/ - for ball-park calculations like this. Here's what I did for this post:

Typed in 10,000Wh (10kwh) and used 48v (nominal for a 14s lithium ion battery) and get 208,333mah. Divide 208333/<avg-cell-mah>. Let's say you're cells test out at 2200mah / cell then its 208333 / 2200 = 94.6 cells per pack of 14s battery. Multiply 95 * 14s = 1,330 cells.

If you do 3000mah cells then its 208333 / 3000 = 69.4 * 14 = 980 cells. If you play with 52v instead of 48v you get a few less cells. And so on. You don't need the web site as its basic algebra but I'm lazy and the web site helps get me off the dime

 

[hbpowerwall]

Welcome! Neat charger even if I don't agree with its location.

 

[1.21 Gigawatts]

I use this link all the time

Thanks, handy tool.
I was just doing 3A x 3.6V = 10.8W per battery
10,000W /10.8 W = 926 batteries
rounded up to 1,000 because most probably aren't going to be 3A.
2.5A is probably a better number to use.
1,330 'good' cells.... feels like such a huge number to aquire

Welcome! Neat charger even if I don't agree with its location.

haha yes not the best spot, just popped it in front of the telly to take a pic with the channel in the background. Thanks for the welcome. Awesome channel btw.

 

[OffGridInTheCity]

>1,330 'good' cells.... feels like such a huge number to aquire
If you're patient (or spend big $) it will come so don't give up. For me its been really rewarding to build a powerwall for a fraction of the cost of buying one and just the whole idea of capturing/producing/consuming power on my own.