About this replacement
Therabody Theragun G5 Pro / G4 Pro — 11.1V Li-ion Replacement Battery (TB-RA4-01)
This is an 11.1V 2600mAh lithium-ion battery that replaces part number TB-RA4-01 in the Theragun G5 Pro and Theragun G4 Pro percussive massage devices. It fits the swappable battery slot on both models and runs the same BMS handshake as the original cell pack. Capacity is 2600mAh (28.86Wh) — matching the factory spec.
- G5 Pro and G4 Pro compatibility: Both models use the same 11.1V battery rail, identical connector pinout, and the same BMS communication protocol. One replacement part covers both devices without any adapter or modification.
- Bench tested on actual hardware: We cycled this battery in a G5 Pro unit under motor load across all five speed settings. The BMS held voltage within spec at peak draw and tripped the protection circuit correctly at the low-cell threshold — no false cutoffs under normal use.
- Port hygiene after percussive use: The G5 Pro is frequently used during or after exercise. Sweat contact on the battery terminals can cause resistance buildup that the BMS reads as a connection fault. Wipe the battery contacts and device bay with a dry cloth before reinserting — do not use alcohol directly on the gold contact pads.
Motor power dropping before the battery indicator hits low on the G5 Pro
The G5 Pro motor draws sharp current spikes at higher speed settings, especially on setting 4 and 5. An aged or partially degraded cell pack can't sustain the voltage under that load — so the motor slows or stutters while the indicator still shows two or three bars. This is voltage sag under load, not a gauge error. A new cell pack with full internal resistance spec restores stable voltage delivery across all five speeds.
G5 Pro shows solid charge light but won't power on after sitting unused
If a Theragun battery sits dormant for several weeks, the cells can drop below the BMS re-engagement threshold — typically around 2.5V per cell for an 11.1V (3S) pack. The charger light may illuminate because the dock detects a connection, not because charging is actively occurring. Plug the battery into the charging dock and leave it undisturbed for 20–30 minutes without pressing the power button — the BMS needs time to trickle-charge the cells back above the 9V pack-level floor before it will allow a full charge cycle or power-on.