Erm, I don't think you have the definition of C rating correct. The C rating is the capacity multiplier to get the discharge rate. In your example, a 10C battery of 3Ah capacity has a safe discharge rate of 10*3 = 30A, not 3.3A. I = C * Ah, or C = I / Ah, not I * Ah as you have specified.
when calculating the required cells in series for a given voltage, you should take the required volt / nominal voltage of the cell (not its max) and then always round up.
Great video, thanks Adam! Not sure if the explanation for C rating is correct. I think that C * Ah = max discharge current. E.g .a 3Ah 10C battery can discharge at 30A, not 3.3A. Also, could you please give an affiliate link for the BMS you used? Thanks!
Excellent information on Li Ion Battery in short period of time. You can make few more videos on Li Ion battery bigger size/rating capacity & thermal management system.
Hey, great video. Can you tell us about the mechanical packaging of battery pack and different materials used for specific function and the factors to be considered??
Really good quality, clear information on how to make a battery pack. Keep these videos coming, hopefully the mysterious google ad beast will give you some well earned attention :)
Great tutorial! I'm trying to mod my scooter to be airplane-carriable, so I'll be 3D printing a quick-relases battery sled, to which I can easily add or remove indivudual cells. It currently has a cilindrical 5.4AH 36V 10S2P 18650 pack, and due to size constraints, I'm figuring a 5AH 10S1P 36V 21700 pack would do the trick. Any thoughs or suggestions for this endeavor?
Hmm, you'll need to build a self contained module to place all the cells in that breaks the battery output to a nice XT60 series connector or similar. You'll want the mechanical enclosure to be fairly robust. As long as you leave enough slack on the wires to plug and unplug it, you should be ok.
@@AdamBender Thank you, I'll be aiming for something 3D printed that uses keyston clips to hold the batteries in place, and the XT60 connector is a very good Idea. By the way, have you had any experience with 21700 or on-parallel battery packs (10S1P)? I see that the max discharge rate of a single cell should be enough for the peak 350W draw of the 250W motor at 36V, but I've never actually tested a 21700 before.
What is the base copper foil thickness and characteristics, are only ED copper foils used, can RA copper foils be also used, just curious whether RA copper foils are also used in making the anode current collectors : Thanks
Is there a way to half the battery pack and place them side by side and still have a 12s4p battery? This application would be to long for an electric skateboard. So basically instead of this. ---------- I want this ===
Your lack of cell fuses is worth consideration. If a cell in a parallel group develops an internal short circuit then the other 3 cells in the group will dump into it - or in other words that parallel group as a whole will be shorted out, which is probably a bad thing. The BMS can not protect against that.
Cell fuses are certainly important for the reasons you mentioned. Unfortunately, they can be a bit difficult to install by conventional means, and the soldering risks damaging the cells. Do you know of another good way to DIY attach cell level fuses without too much heat? Thanks for watching!
@@AdamBender Spot welding a single strand of suitable gauge wire that fuses at around the max discharge current of the cells for the parallel connections for each cell to the nickel strip connecting pairs of groups in series is doable. Or if you can find it then a considerably narrower and thinner nickel strip for the parallel connections than for the series connections. Certainly more difficult to build and perhaps less mechanically robust. An argument could be made it's not worth it for less than some number of parallel cells, and for modern cells the potential for internal shorts is low, but where exactly to draw the line I don't know. The thought of 3 fully charged 10C cells through a failed short cell gives me the willies, but also hard to test without actually having a failed-short cell to test with.
@@JamesSleeman spot welding a small wire on could be tricky, but if successful, that would definitely add in a nice safety layer to isolate a bad cell. Would be interesting to try, maybe I'll see if I can get my hands on some thin wire and give it a go. Agreed on that much current dumping into a single cell from the parallel stack. Could definitely result in some thermal runaway which could propagate to surrounding cells. I wonder how much fault current an average 18650 can take before it ignites. Sounds like a test best done outside
goddamn this video is SOOOO FRUSTRATING. what if you're building your own? can you explain anything besides how to build your stupid own 10s4p double layer?
