going to try to build a BIG battery and I need some help please .

[dankleinman]

hello all

new guy here and I am wanting to build a powerwall . I have a chance to get a bunch of batteries for a very good price .
these batteries are made by allcell and are lithium ion made from 18650 packs . I am wanting to try to figure out how big of a pack to make . there are 13 blocks of 18650 batteries in each one . If i am reading this right each block is 150ah so if I put the whole pack in parallel how many ah would that be 2100ah seems right if i am doing the math right . so if i do that with 13 of these packs and use each big battery as a 3.7 volt cell I can just run 1 smart bms correct ? If I am thinking this out right this will be one big ass battery. its going to weigh about 1400 pounds. I only have 20 340watt Q.plusl-g4.2 panels to charge this with so i think it will take a while to build and get it balanced but it should run things for a while . I will be charging it usuing the eg43000ehv-48 I realize this will be a very large battery and I am a novice at this but I will be very carefull and I am thinking about building a small building to house this far away from my house . of course I will have to have heat and air in it but thats not a problem . thanks for any info and if theres anyone near wilmington ohio thats way more informed about this stuff that wants to help a new guy out please by all means message me

thanks

dan kleinman

 

[sunshine_eggo]

Confirm you plan to:

Buy 13 batteries.
Break each battery down and parallel the 13 "cells" as a single cell.
Take those 13 parallel cells and then put them in series forming a 13P13S battery.

How much do you expect to spend on the batteries?
How confident are you that they will deliver 100% rated capacity?
How confident are you that hey will all deliver exactly the same capacity?

 

[dankleinman]

sunshine

13p13s is what I was trying to say in my long-winded post. if I do that, can just use 1 jk bms to monitor it ?
if these cells are as nice as the first ones I got they were almost brand new . the ones I got the first time said they had only had 10 cycles thru them.

I am supposed to be picking up 30 of them tomorrow and a buddy of mine is getting 30 also I'm going to be keeping most of mine but I believe he is going to be selling most of his .

as far as the same capacity I will have to charge and discharge them to figure out the closest ones . that's why i said it would take a while to build it.

 

[sunshine_eggo]

sunshine

13p13s is what I was trying to say in my long-winded post. if I do that, can just use 1 jk bms to monitor it ?

Yes, but you'll be limited to whatever current the

Personally, I'd by a 14th for 13P14S as 14S is a better match for 48V systems.

Each series "cell" should be the same capacity, thus the sum of all 13P "cells" should yield the same capacity within a 13 or 14S string.

 

[DukuClan]

hello all

new guy here and I am wanting to build a powerwall . I have a chance to get a bunch of batteries for a very good price .
these batteries are made by allcell and are lithium ion made from 18650 packs . I am wanting to try to figure out how big of a pack to make . there are 13 blocks of 18650 batteries in each one . If i am reading this right each block is 150ah so if I put the whole pack in parallel how many ah would that be 2100ah seems right if i am doing the math right . so if i do that with 13 of these packs and use each big battery as a 3.7 volt cell I can just run 1 smart bms correct ? If I am thinking this out right this will be one big ass battery. its going to weigh about 1400 pounds. I only have 20 340watt Q.plusl-g4.2 panels to charge this with so i think it will take a while to build and get it balanced but it should run things for a while . I will be charging it usuing the eg43000ehv-48 I realize this will be a very large battery and I am a novice at this but I will be very carefull and I am thinking about building a small building to house this far away from my house . of course I will have to have heat and air in it but thats not a problem . thanks for any info and if theres anyone near wilmington ohio thats way more informed about this stuff that wants to help a new guy out please by all means message me

thanks

dan kleinman

Hello Dan...
Pls do you mind telling me how much this battery cost and where to buy them. Good luck on project. Thanks in advance.

 

[byteharmony]

I'm in process with this same task right now on a few projects.


I propose you size your batteries based on reasonable bms limits and charging speed needs.

Then if you have more cells after that build another battery and parallel them as will directs

@Will Prowse has done a great video on parallel batteries and bus bars.

Working on becoming an expert here. Hoping this post will trigger some of.those with 18650 experiance. I will echo switching from 13s to 14s sounds right... I'm in a hot tub so I don't have my spread sheets on me right now.


My question would be more along the line of how many in parallel gets dangerous from the perspective of a single bad cell being fed by the others in parallel causing a BIG fire?