Want to build
First off, number each cell and carfully take note of all resting voltage drift that occured with time, for each cells (make an excell file... To keep a logbook of all cells health parameters).
Then figure out the exact manufacture date of each cell from the numbered labelling of the cells... This will help you match the cells for age (calendar aging does affect performance of cells, even if they stay on the shelve without being used for 10 years).
Now determine capacity of each cell and take note in your excel logbook.
Now determine DCIR either using an Imax B6 or by using the load method (requires a set of high power (aka 50 to 150W) resistor of differnet values (aka 0.5, 1.0, 2.0 and 5.0 Ohms), a voltmeter, an ammeter and a camera to take pictures of A and V values simultaneously)... You need the DCIR of each cells. Note in you cell logbook. In my experience, VTC4 of DrBass that are 2-4 yers old should have a healthy 21-23 mOhm DCIR. Warning some of these Makita Pack was lower standard VT4 cells that have DCIR in the 26-28mOhm range...
So that s the start if you want to make things right...
Now charge all your cells to the exact same voltage with + or - 0.01V difference at most. I recommend a voltage of 3.55V, so if you accidently short your pack during assembly you'll have less chance of a big fire (or explosion) than if you do so at 4.20V.
All cell being the same voltage, you can now start.
Lets say you make a 10S5P pack... For sake of example.
You need each 5P pack to be the same capacity (ex:10.5Ah each). If one of the 5P pack is lower capacity (ex: 10.1 Ah), then the whole pack will only be 10.1 Ah max (the weakest link).
Make each 5P pack the same DCIR (ex: 4.6 mOhm... Wich is 5 parralleled 23 mOhm cells). If one pack is higher DCIR, it will heat up, voltage sag, trigger early BMS LVC, and go out of balance... That weak link will make balancing by BMS a lot harder and the BMS will have to balance for longer times... Making charging time much longer... Avoid pack wich have extreme DCIR resistance. Ex avoid puting a 5P group with DCIR of 23, 23, 23, 23 and 23 mOhm in series with a 5P groups that has DCIR of 18, 22, 23, 24 and 28 mOhm, even is the overall average DCIR seem similar. Rather, try to even thing out as much as you can. 18, 23, 23, 23, 24 and 22, 23, 23, 23, 28 pairing would probably be less extreme, but also keep all 10 5P groups the same overall DCIR.
Make each 5P group the same age. Example each pack is on average 2.5 year old. With some cells 3.0 and others 2.2 , 2.8, 2.6 and 2.0 year old... For example). Dont make one 5P group 1.8 year old and the next 5P group 4.5 year old... Or the older 5P group will die way before the others . "Calendar aging of lithium cells is no joke. It's one of the most important factor to consider. Cycle number is too, but DrBass cell all have low count cycles because Dr Bass dont sell cells with higher than 100 cycles...
Once all 5P pack are constructed, each having around 10.5Ah capacity, 4.6 mOhm DCIR, and average same 2.5 year old... Assemble each 5P groups into a 10S5P battery pack.
Can t really explain into more details than that...
PS: in my experience most cells I got from Dr Bass werr almost exactly the same DCIR... All VTC4 i got tested 22+/- 2 mOhm and all VT4 tested 27+/-1 mOhm. Out of 290 cells, only 4 i got were sigbificantly off of these values, so i didnt use these 4 cells. Other than that, as long as your carfull to not mistaken VTC4 cells with VT4 cells, you can almost assume all the VTC4 you got are 22 mOhms. Thus don t worry too much about DCIR mismatch, especially with the VTC4.
Matador