10s3p Scooter battery packs for Ebike question

Just got four 36v 10s3p scooter battery packs for my DIY battery build from fleabay quite cheap. Pack is 7.7ah 36v with LG cells. Tested each pack and was 40v. Was going to make myself a DIY 52v 14s pack but might be hard if since these battery are spot welded so might be easier just to upgrade my controller to 72v.

Question to all is there appears to be a BMS for each pack of 10s3p since it the pack is whole and the connector to charge the battery is still there. Can I combine them to make a 72v 15.4Ah battery pack instead? two in series and two of them parallel. Do i need another BMS and if so what kind? I do not mind charging each 36v battery pack separately as I have four 40v Meanwell 1Ah chargers from my reefing LED days. Can I just connect each battery pack with fast connectors to connect them to make myself a 72v system and then disconnect the 4 packs when I need to charge or when I am done riding?

Nice packs! I have the hoverboard style packs, but these look even better. Where did you buy them and how much were they?

To answer your question, you can do a 2 series 2 parallel connection with plugs of your choice, and just disconnect the packs and charge separately. You just have to be careful that when connecting batteries in parallel each pack has an equal voltage, otherwise a large amount of current will flow from the high voltage battery to the lower voltage one. I would personally charge the 2 parallel packs together, that way they will never get out of balance or cause problems.