Question for DIY battery builders

[Alkaline]

nice the active balancers will keep the cells balanced.

 

[GuyG]

Thanks for all the responses. Good points.

I was trying to compare apples to apples, and the over-the-counter apples were all in the range of 100ah, so that’s what I was thinking of. Think I made some basic mistakes in my math, because after going back to my scratchpad, I can’t figure out how I got a materials cost in excess of $2,000 for a 100ah rack of batteries; would prolly be closer to the $1,500-$1,800 range.

But yeah, there’s a big economy of scale by building a battery out of 280 or 304 cells: cheaper cost per ah of cells, only one bms, only one set of cables, etc.

So I’ll be looking at the options for building a couple of 14kwh batteries for the system I’m working up.

Thanks again for all the responses. Good stuff.

 

[timselectric]

Which JK BMS do you use? The 200A?

Yup
B2A20S20P

18650batterystore has them, now.
I'll be getting them there, for now on.

 

[Solarisium]

Building a battery pack sounds much more fun than a grid tie solar!
Do you have wiring diagram, or something that can get me started?

What size of battery pack can I build with 100 18650s and a single 455W panel? I’d like to build a small system just for the fun part and may be to charge some garage tools!


Thanks

 

[JJJJ]

This might be helpful:

Cell Configurations for 12V 24V and 48V LiFePo4 Batteries

This short deck shows 1P and 2P cell configurations for 12V, 24V & 48V LiFePO4 batteries. To get the deck, click on the orange button at the top of this page. Note: Reviews, Comments and corrections are welcome Document Revision History...

diysolarforum.com

 

[upnorthandpersonal]

Cost is one thing. Control is the other: I know how my system works, I can swap out a BMS if needed, if a cell breaks, I can swap it out.
Never mind that those rack batteries aren't available here (and generally weren't available at all when I built my first set of batteries). I also needed an insulated enclosure and heating, which means if I had rack batteries I'd still have to build something around it.

Also, as others implied or stated, it's fun

 

[timselectric]

Building a battery pack sounds much more fun than a grid tie solar!
Do you have wiring diagram, or something that can get me started?

What size of battery pack can I build with 100 18650s and a single 455W panel? I’d like to build a small system just for the fun part and may be to charge some garage tools!


Thanks

Building batteries with 18650 cells is a lot of work.
Most people use prismatic cells, now. Since the cost has dropped dramatically.