Milwaukee M12 and M18 Battery Protection

Hi, I was wondering if anyone knew of a small battery protection circuit for Milwaukee M12 and M18 batteries, m12 uses 3x 18650 and m18 uses 5x 18650 or the 21x size batteries.

I have some ebay battery to 2 wire output connectors but not sure if they have built in protection for low voltage cut-off, overcurrent, etc. Would like to use the batteries to run 12v projects, so they’d probably both need to have 12v power supply built in too for the circuit but I really want low voltage cutoff and whatever else needed to protect them. Doesn’t need charging circuit, although if anyone has a cool circuit for that for solar I’d love to see it too but mainly interested in just having a portable 12v battery system.

Thanks.