12 Volt Lithium Battery Individual Cell Regulator
This looks interesting. I wonder if they can be paralleled for larger batteries. The price is certainly reasonable.https://www.ebay.com/itm/Lithium-Battery-Charger-Protection-Board-BMS-Li-ion-Charging-Module-3S-10A-12V-/142341287021?_trksid=p2349526....