Four contacts of tool battery

Why do drill batteries have 4 terminals?

With four terminals on a drill battery, likely, some of them are there for battery balancing purposes. Those terminals marked for individual cells (e.g., C1, C2, etc.) are connected to different cells to ensure that they can charge and discharge at the same pace. As a result, those battery cells are balanced and will last much longer.

What does B+ mean on a power tools battery?

See "Notes on 18V/20V Lithium Ion Battery Packs" section in the "Power Tools Battery Conversion Guide" page. B+ stands for battery positive terminal. TH is the thermistor; a temperature-sensitive resistance that enables the tool to cut off the power to save the battery from overheating. (See "Comments & Discussion".) ID.

Can a battery be used in a power drill?

By joining these cells together, the battery’s overall capacity increases, making them suitable for use in a power drill. However, not all of the cells in your drill battery will charge or discharge at similar rates. So, to ensure that the cells can keep up with each other, these batteries tend to be designed with battery balancing in mind.

How many terminals does a drill battery have?

The Thermistor terminal: marked with a T, TH, NTC, or something similar. The Battery ID terminal: marked as ID, D, or something similar. Here’s another thing to understand about your drill battery’s four terminals. Sometimes, one terminal can serve more than one purpose. It’s perfectly normal to see a terminal with two markings instead of one.