In order to solve the charging issue FullspeedRC (yes the same ones that launched the Leader series of micro quads) have released a simple board that allows the batteries to be balance charge using the existing USB port. It can be bought for around $10 at the following retailers:
Please note this is not a beginner install but if you can solder a FPV cam and vtx to a flight controller you can probably do this. I've put in a LOT of photos and steps in below to make it as straightforward as possible since Fullspeed's manual is accurate but overly short. As usual click any image below to embiggen.
Tools I recommend for this job:
I did a thing. After reviewing the new FullSpeed TinyLeader 2s-3s brushless whoop (review here) I learnt to fly around the heavier weight which has come about because of it's larger motors and better FPV system. I still think that 1103 motors like on the TinyLeader and Beta75x are better suited to a lightweight 2" propeller like my ultralight build here rather than the 40mm props (1.6") as we see so commonly on the brushless whoops now. I decided to put my money where my mouth is so to speak and prove it rather than just hypothesing.