The best way to initially test and prepare a 13s16p

Hello all, I have a moderately n00bish set of questions. Hopefully it is nothing too annoying.

I plan to get 9 of these:

• JohnsonControls
  
  
• Number of cells - 24
  
• Construction - 12s x 2
  
• Length - 14.5"
  
• Width - 9"
  
• Height - 6.5"
  
• Weight - 40 lbs
  
• Output terminal - Custom
  
• Amp Hour - 30Ah
  
• Total Voltage. - 44.4vdc
  
• Chemistry - NMC
  
• Capacity - 2.5kWh
  
• Output. - 10C
  
• Density - 138Wh/kg

Click to expand...

I plan to break them up into a 13s16p configuration.

My first conundrum is: what would be my first steps after breaking them up?

My thought (which is most likely wrong) would be to measure each of their voltages, and as long as they were not too far off from each other, I would then connect them all in parallel to "even them out." Assuming that went ok, and I did not blow anything up, I would then drain them to 50% (arbitrary number due to my current ignorance of Lion batteries). After that, assuming I once again did not blow anything up, I would break them up into the 13s16p configuration.

After that I would probably use a batrium for the BMS (which I still need to research more, but that is for another post).

So... am I completely wrong, partially correct, or sorta right?

Thanks for any info in advance.

Why not build 14s directly?

I would just break them appart and put them together again in correct setup. if needed balance them all to same voltage. no need to drain them just because...

If you want to know the actuall capacity you need to test each module. Ie each parallel module that is assembled today. no real use splitting them into smaller pieces.

Hello and welcome.
If you have not already done so, please read the FAQ.
Also find your cell(s) in the Cell Database to find out what they were supposed to be by design

Your view of what needs to be done is pretty close. You would test them without paralleling them. This is usually the sequence of events:
* full charge
* full discharge (this is to get the capacity of the cells)
* full re-charge
* rest period
* check for self-dischargers and discard
* build packs of desired design (this is either system voltage packs, or all parallel packs)
* hook up other equipment
* if using bms, let it start balancing and monitor everything closely

If you don't have any Lithium based chargers, you need those first. You can't use a standard battery charger as it either goes to 1.5V or is only for NiMH/NICad
And finally, please at least skim through others builds to get an idea of what has been done, and especially the mistakes others have made so you can avoid them or tips/tricks so you can process faster and more efficiently.

Now, our questions:
Why 13s?
What equipment do you have already?
How many cells have you done so far, how many total do you have, and what is your end goal of cells/capacity/runtime?

For the Number of cells in Series always comes up and I really wish we required people to read the entire FAQ thread as it answers 90% of the question here. What Equipment are you going to be hooking up to this battery. That's #1 before guessing at a battery setup. then go from there

I have no equipment yet, I am in the "about to buy" stage.

I thought 13s as I thought that would get me 48.1v, as they list the current setup of 12s yields 44.4v. This is going to be for a 48v solar system, so I thought getting them as close to 48v as possible was ideal.

I was thinking the 13s16p would give me 48.1v and roughly 24kwh

And I appreciate the tips, I will definitely check out the other builds and the cell database.

That is nominal voltage. Not top/bottom voltage.

13s is usually overall too low with a range of 41.6 - 53.3 (3.2 - 4.1 per cell range)
14s can get a little high if you go to full voltage of 4.2/cell, but 4.1 is fine with a range of 44.8 - 57.4V (3.2 - 4.1 per cell range)

Korishan said:

That is nominal voltage. Not top/bottom voltage.

13s is usually overall too low with a range of 41.6 - 53.3 (3.2 - 4.1 per cell range)
14s can get a little high if you go to full voltage of 4.2/cell, but 4.1 is fine with a range of 44.8 - 57.4V (3.2 - 4.1 per cell range)

Click to expand...

Ah hah! Thanks for clearing that up. I checked my planned inverter's specs (Radian 8048a) and it can handle a battery voltage range of 40-64vdc, so it seems even 4.2v would be within range

So it appears I would be going for a 14s15p setup now.