Links to stuff you're going to (or want to know about) use in a project, etc., are fine anywhere. (LInks to stuff you're selling, if you ever do, only go in the for sale subforums).
Some further questions and thoughts:
How fast do you have to charge?
That linked LiPow charger is only going to *draw 100w from it's USB-C supply* and will have less than that available to send to the battery (probably 80-90% of that, depends on it's conversion efficiency and exactly how it works inside, and how close the source voltage is to your pack voltage; the greater the difference the worse the efficiency, usually).
However, that is only at 68F (20C); they don't show the derating chart above that temperature but unless it's always really cold where you are, the charger will not be at that temperature, and won't be able to charge at that rate. Their spec is also only for their specific 3D printed case with fan, presumably designed to ensure proper airflow over the right parts inside it. If your dock is designed to do the same job for the bare board it would then do the same rating...but unless you chill the air going into it, it's likely that it won't be that cold most of the time.
So you might want to count on only say, 50w of charging power. That'd be
Even if you assume it's the low end of the max, for 80w total charging power: 80w / 16.8v = 4.8A max current (which you won't get all the time, only when the pack is far enough discharged to get that much current). For 12.4Ah, assuming totally empty, it'd take at least 12.4 / 4.8 = 2.6hours, but it will really take a lot longer because current tapers off as the cells fill up (and if it has to finish balancing before release, if balancing takes longer because of cell problems...could take hours).
They don't specify balancing current, but many of these things (and most cheap BMS) only do around 50mA of balancing. If this is like that, then if you had a really bad cell group that was say, 3Ah different from the others, then 3000mAh / 50mA = 60 hours to correct the difference assuming ideal conditions. For chargers or BMS that only balance near full charge, you have to add the time to reach that charge level first.
The linked BMS looks typical of most of them; the design of almost all of them is about the same, and they have assorted undesirable failure modes you can't really do much about...but the worst problem with using any of the common ones is that they don't ask the device if it's ok to turn off--they just shut off power whenever a problem is detected, so if your device is aerial, it will just crash and stay there with no power, no way to signal you, etc.
There are ways around that by modifying the BMS, taking off the discharge FETs and wiring across the D-S pads where they had been. and using their gate signal to tell the device that there's a battery problem, and let the device decide when to turn off--like go into parking mode, land, and signal you it's in trouble. Since it's not using high current at that point, it owuldn't need to shutdown completely and could keep pinging you with status and location.
If you're using RC LiPo then the typical BMS (including this one) goes too low for LVC, and higher HVC than you might want to use.
I don't have any specific BMS recommendations, though.
If you're still designing the electronics, you could just get the chips used on these BMS, put it on your control PCB with everything else, and have it monitor the LVC, and signal your controls as noted above so the device chooses how to proceed or not. Some of the chips are externally programmable for LVC, HVC, etc., and you can set them to whatever values you want, instead of being stuck with the values in there already. This is a page I don't know the age of the data on, but shows you a few
Then your dock could do all the balancing during charge, or you could keep the already-planned active balancer, etc. Personally I'd keep that all in the dock if you can add the pack protection functions to the device itself. Makes it lighter, with less stuff to go wrong and damage the pack.
Are you using RC LiPo packs? Or some other kind of cells?
The former are rarely good quality and even rarer using matched cells (never, in my little experience with them, and based on posts by others over the years, but I'm sure there are exceptions). Used hard, they tend to age fast, compounding the problems of unmatched cells, requiring more balancing more frequently.
There are better cells out there, especially EV-grade stuff out of used EV modules, that are well-matched to each other, and dont' require any balancing until they have aged significantly (I have some ancient (for battery technology) EIG C020 NMC that was used when I got it, and is now well over a decade old, used every day on my SB Cruiser heavy-cargo trike, and still hasn't reached the point of requiring balancing, with only one cell (on an earlier bike) having failed...I'm sure newer EV-battery technology is even better). At least some of these cells are a high enough C-rate for your needs; my 20Ah cells are 5C continuous 10C burst for 10sec (IIRC), so if they were still available they'd do the job if you didn't need 120A for very long.
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