Tri-Tronics Pro 500XL Replacement Battery 3.6V 700mAh Ni-MH

Tri-Tronics Pro 500XL / G2 Pro — 3.6V Ni-MH Replacement Battery (1107000)

This 3.6V, 700mAh Ni-MH battery replaces the rechargeable cell inside the Tri-Tronics Pro 500XL, Pro 500XLS, and G2 Pro receiver collar units. It slots into the collar housing and powers the stimulation and vibration circuitry that the collar relies on during training sessions. Voltage and physical dimensions match OEM spec — 45.10 x 31.00 x 10.70mm.

• Pro 500XL, Pro 500XLS, and G2 Pro compatibility: These three collar models share the same battery bay geometry and the same 3.6V supply rail for the stimulation driver circuit. The connector orientation and cell footprint are identical across the series, so one battery covers all three.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Pro 500XL collar. The protection circuit responded correctly to charge termination and did not trip on the brief current spike the stimulation output draws at activation.
• Collar reassembly tip: The receiver collar housing on the Pro 500XL uses a threaded contact cap that must seat fully — a partially tightened cap creates an intermittent connection that mimics a dead battery. Torque the cap until it stops, then verify with a short activation before putting the collar on the dog.

Why the Pro 500XL collar stops responding mid-session after a battery swap

Ni-MH cells require a proper initial charge before they deliver rated capacity. A cell shipped in a partially discharged state may power the collar long enough to pass a quick bench check, then drop below the operating threshold once the stimulation circuit fires repeatedly. The collar's control electronics need a stable 3.6V supply — once cell voltage sags under load, the receiver stops acknowledging transmitter signals. Charge the replacement fully on the Tri-Tronics charger before first field use.

Collar reads as charged but delivers weak or no stimulation output

This usually points to a cell that has developed high internal resistance from deep discharge or age — it accepts charge current and shows a nominal resting voltage, but collapses under the brief high-current pulse the stimulation output requires. A healthy cell should hold above 3.4V under load during an activation. If the collar passes a no-load voltage check but fails on stimulation, the cell is the likely cause. Swap the battery and retest with the collar set to the lowest stimulation level first.