About this replacement
Trimble TDC100 / Mapper 50 — 3.7V Li-ion Replacement Battery (106661-10)
This 3.7V, 3000mAh Li-ion battery replaces OEM part numbers 106661-10, 106661-20, and 106661-40 in the Trimble TDC100 data collector, Mapper 50, and mmsp20. These are rugged handheld units used for field surveying, construction layout, and geospatial data collection. The cell and BMS circuitry match the original charge profile so the host instrument registers state-of-charge correctly.
- TDC100, Mapper 50, and mmsp20 compatibility: All three models share the same battery bay geometry, connector pinout, and 3.7V power rail. The BMS communication protocol is identical across the group, so one cell design covers all three without modification.
- Bench tested on actual hardware: We ran this pack through charge-discharge cycles on the TDC100 platform and confirmed the BMS handshake initialised correctly at power-on. Cell voltage held within spec under the sustained GPS and data-logging load the instrument produces in normal field use.
- Pre-deployment calibration on the TDC100: After installing a fresh pack, run a full calibration cycle through the instrument's system menu before heading to site. The TDC100 maps battery state during calibration, and skipping this step causes the low-battery warning to fire early on the first field session even when the pack is at full charge.
TDC100 shutting down mid-session when GPS locks or GNSS antenna initialises
When the TDC100 acquires a GNSS lock or powers a connected antenna module, current draw spikes sharply for a short window. An aged or partially discharged OEM pack can drop below the BMS cutoff threshold during that spike, triggering an immediate shutdown even though the charge indicator showed adequate capacity seconds earlier. This is not a firmware fault — it is the BMS protecting the cell from an undervoltage event. A fresh pack with a full charge holds the voltage rail through that initialisation surge without tripping the cutoff.
Pack not recognised after the unit sat unused in a carry case for months
Li-ion cells self-discharge over storage, and the TDC100's BMS enters a protective sleep state when cell voltage drops below approximately 3.0V. In that state the instrument either shows a battery error or fails to power on at all, which looks like a dead pack but is a recoverable condition. Place the battery on a compatible charger and leave it for at least 30 minutes — many chargers apply a low-current trickle below 3.0V to recover the cell before stepping up to normal charge current. Once voltage climbs above 3.2V the BMS wakes, the instrument recognises the pack, and normal charging resumes.