About this replacement
Educator ET-300TS Transmitter — 3.7V Li-Polymer Replacement Battery (PL-762229)
This 3.7V, 400mAh lithium-polymer battery replaces the internal cell in the Educator ET-300TS Transmitter and related ET-300 series handheld remotes. It fits the transmitter unit — not the collar receiver. The transmitter is the handheld controller used to send signals to the dog training collar.
- ET-300 transmitter series fit: The ET-300TS, ET-300, ET-302, ET-300-L, and additional variants in this family share the same compact transmitter housing, connector pinout, and 3.7V power rail — which is why a single cell covers the group.
- Bench tested on actual hardware: We cycled this cell through the transmitter's BMS and confirmed stable charge acceptance, correct cutoff at low voltage, and no fault flags during charge or discharge.
- First power-on after installation: After fitting this battery, hold the transmitter power button for a full 3–5 seconds — a short press may not register until the BMS completes its initialisation sequence following a full power interruption.
Why the ET-300TS transmitter shows a full charge but cuts out during use
A lithium-polymer cell that has been over-discharged loses the ability to hold voltage under load even after showing a full charge on the indicator. The transmitter's voltage rail drops the moment RF transmission fires, and a degraded cell can't sustain that draw. The BMS then trips a cutoff to protect the cell, which looks like a sudden shutdown. Replacing the cell restores stable voltage delivery during active transmission.
Transmitter not pairing with the collar after battery replacement
Removing the battery clears the transmitter's working memory, which can drop the active pairing session with the receiver collar. This is not a fault with the new battery — it is a standard behaviour after power interruption. Power on both the transmitter and collar, then follow Educator's re-pairing sequence: hold the transmitter's Nick button while powering on the collar until the LED confirms link. The pairing signal operates at the collar's receiver end, not inside the transmitter battery circuit.