Been digging around to find a solid reference for the pinout of the M12 packs. From what I can find online, it's C1- to negative, C3+ as the positive, the T line go to a thermistor to monitor the temperature of the pack, and C1+ and C2+ are the balance pins for each cell group.
Given the number of cells in the pack, it makes sense that these balance pins would be along each group of cells. It seems like there's some debate about whether the charger or the pack itself performs the balancing function, though. I haven't scoped the thermistor on any Milwaukee M12 packs yet to find the value of the thermistor that they use. Does the tool check the thermistor on the pack itself? Also, are the balance pins always live, or only if there's a pack docked to the tool? Has anyone rebuilt any of these packs? If so, did they have to take any special steps to reattach the balance leads? There doesnt seem to be much documentation on how these M12 packs work outside of the tool's documentation, so figured it was worth a thread.
Given the number of cells in the pack, it makes sense that these balance pins would be along each group of cells. It seems like there's some debate about whether the charger or the pack itself performs the balancing function, though. I haven't scoped the thermistor on any Milwaukee M12 packs yet to find the value of the thermistor that they use. Does the tool check the thermistor on the pack itself? Also, are the balance pins always live, or only if there's a pack docked to the tool? Has anyone rebuilt any of these packs? If so, did they have to take any special steps to reattach the balance leads? There doesnt seem to be much documentation on how these M12 packs work outside of the tool's documentation, so figured it was worth a thread.