About this replacement
Tri-Tronics 1038100-D Series — 3.6V Ni-MH Replacement Battery (CM-TR103)
This is a 3.6V, 300mAh Ni-MH battery for the Tri-Tronics 1038100-D dog training collar and related models. It powers the electronic stimulation and vibration circuits inside the collar receiver unit. Fits the 1038100, 1038100-D, 1038100-G, 1038100E, and more than 20 additional variants in this collar family.
- 1038100 collar family fit: These collar variants share the same receiver housing, connector pin-out, and 3.6V NiMH cell format. The BMS in the transmitter reads charge state from this chemistry — swapping to a different voltage or chemistry will cause incorrect charge termination.
- Bench tested on actual hardware: We ran charge and discharge cycles on the collar receiver. The BMS reached full termination cleanly at 3.6V with no false cutoff. Stimulation and vibration circuits triggered correctly at all output levels throughout the test.
- First charge after installation: Tri-Tronics collar receivers require a full charge cycle before the transmitter pairing re-establishes stable communication. Place the collar on the charger until the indicator shows complete before attempting to pair or test stimulation output.
Why the 1038100 collar stops responding mid-session
The 1038100 receiver cuts off stimulation output when cell voltage drops below the BMS protection threshold under load. A degraded NiMH cell can read sufficient voltage at rest but sag hard when the stimulation circuit fires. This creates an intermittent fault that looks like a range or pairing issue but is actually a voltage sag event. Testing the collar under load — not just at rest — is the only reliable way to confirm the battery is the cause.
Collar receiver showing full charge but depleting within one session
NiMH cells in small collar packs are vulnerable to shallow-cycle degradation. If the battery was repeatedly topped off from 50–80% without full discharge, capacity fade sets in faster than normal aging alone would cause. The charger reads a full state because the voltage curve looks normal, but actual usable capacity is much lower. Replace the cell and run two full charge-discharge cycles to confirm the new cell is performing at rated 300mAh.