Hart 20v Battery Pinout Diagram Jun 2026

These pins are used for the "Smart" features.

(Note: On some compact 2Ah packs, Pin 4 may not be present or may be physically blocked, leaving only 4 visible contacts. However, the outermost large contacts are almost always Positive and Negative.)

The Hart 20V battery is a robust power source for DIY electronics if handled correctly. The pinout is straightforward:

Always use a multimeter to verify your specific battery's voltage before attempting any custom wiring or repairs. Hart 20v Battery Pinout Wiring Diagram Hart 20v Battery Pinout Diagram

5S1P (Five 3.6V cells wired in series) for standard compact packs (e.g., 1.5Ah or 2.0Ah). Extended capacity packs (4.0Ah+) use a 5S2P configuration (two parallel strings of five series cells). Nominal Voltage: 18.0V DC Maximum Voltage: 21.0V DC

A very specific topic!

Unlike older NiCad batteries that only required a positive and negative terminal, modern lithium-ion packs rely on a Multi-pin Battery Management System (BMS) interface. These extra pins allow the tool and the charger to communicate with the battery's internal circuit board to monitor health, temperature, and cell balance. Pinout Mapping Diagram These pins are used for the "Smart" features

If you run a custom wire adapter from the battery terminals, install an inline fuse holder on the positive wire. Use a fuse rated slightly below the maximum capacity of your wire (e.g., a 20A or 30A automotive fuse) to protect against accidental short circuits.

Hart 20V battery packs utilize standard arranged in a 5S configuration (5 cells in series). 2.0 Ah Packs: Feature a 5S1P configuration (5 cells total).

If you measure the Control pin and get 20V in relation to Positive, and 0V in relation to Negative, this usually indicates the BMS has cut off the output due to a safety fault or low voltage. The pinout is straightforward: Always use a multimeter

Here’s a concise, shareable post describing the Hart 20V battery pinout and how to use it safely.

Here's a simple diagram to illustrate the pinout configuration:

(Note: orientation can vary by model; confirm visually on your pack.)