That's not how the BMS works.GiantYukon said:
If you hit it's current limit long enough for it to react, it just shuts off the output completely. That is the only thing it *can* do.
A BMS cannot limit current the way a controller or charger does, which is to lower the voltage on the load until the load's resistance/etc holds the current output at the current limit of the controller or charger. A BMS simply doesn't have the necessary electronics.
To do that, it would instead have to be a DC-DC converter, but it is not. It is just a simple switch, which turns on or off based on whatever limits it has (current or voltage).
Not necessarily; if it was the battery actually limiting the current, it would shut off, and the bike would stop.
The battery voltage sag does limit the *power*, but only because the battery is being pushed harder than it can really handle (most generic ebike batteries have "ratings" that are significantly higher than what they can really handle without stressing the components).
Using better cells (which is more expensive) would help even more. Note that just because a company *says* it uses a particular cell, even if their pictures show them, doesn't mean that's what they actually have in their packs. You'd have to disassemble the pack you get to see what's actually in it, and how well (or poorly) it is constructed.
Also, using enough cells so none of htem are under any kind of stress, like keeping them at 0.5C to maybe 1C, would make for much less voltage sag, and much longer lifespan for the pack.
Couldn't say anything about hte pack itself; never heard of the company so don't know if their stuff is any good or not.
What the pack's "ratings" say might be suitable for your usage, but I don't know how well the pack can support that (you'll find I'm typically doubtful of most pack builders/sellers, based on what I've seen around here on ES in pack repair threads, etc).
Note that it says 90A continuous, which for a <20A pack is nearly 5C. That's usually pushing 18650 cells fairly hard.
Even if using it at only 60A, that's still >3C.
If the cells are 3200mAh, then with 84 cells on a 14s pack, that's 6 cells parallel, times 3200 is exactly 19.2Ah. Since the BMS should have an LVC high enough to prevent completely discharging the cells to dead, you wouldn't actually get that capacity out of the pack. Don't know how much you would get, you'd have to look at the cell's spec sheet from the cell manufacturer to see what their discharge curve indicates for the current draw you will use the pack at; this will help you determine what you might actually be able to get out of it, as well as how much voltage sag you will get from *new* cells at that rate. (as it ages, taht will get worse and worse, so you want one with virtually no sag to start with).
