M-Tronic SDT-2000/U Replacement Battery 8.4V 1200mAh Ni-MH
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M-Tronic SDT-2000/U Replacement Battery 8.4V 1200mAh Ni-MH - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
Battery Care Tips
🔹 Getting Started
Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.
🔹 Keep It Healthy
Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.
Delivery and Shipping
Delivery and Shipping
🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.
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Disclaimer
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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.
M-Tronic SDT-2000/U Replacement Battery 8.4V 1200mAh Ni-MH - is backordered and will ship as soon as it is back in stock.
Voltage
8.4V
Amp
1200mAh
M-Tronic SDT-2000/U — 8.4V Ni-MH Replacement Battery (91507401)
This is a 8.4V, 1200mAh Ni-MH replacement battery for the M-Tronic SDT-2000/U surveying instrument. It replaces OEM part number 91507401. It fits the SDT-2000/U directly and restores field operation when the original pack has degraded past usable capacity.
- SDT-2000/U platform fit: The SDT-2000/U uses a fixed 8.4V Ni-MH pack with a specific connector and cell arrangement. This replacement matches that voltage rail and cell count so the instrument's internal power circuit operates within its specified input range.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on the bench and monitored the BMS response at probe initialisation. The pack held voltage through the current spike at sensor power-up without triggering a protective cutoff.
- Calibration cycle before first field use: After fitting this pack, run a full calibration cycle through the SDT-2000/U instrument menu before deploying it to a job. The instrument maps battery state during that sequence — skipping it causes premature low-battery warnings in the first measurement session even when the pack has substantial charge remaining.
BMS lockout after the SDT-2000/U sat unused in its carry case for months
Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A pack stored for several months can drop below the BMS recovery threshold, putting the protection circuit into a locked state that the charger alone cannot wake. The SDT-2000/U charger checks for a minimum voltage at the battery terminals before enabling the charge current — if the pack is below approximately 5.5V it reads the circuit as a fault, not a flat battery. To recover it, apply a slow trickle charge externally at 100mA until terminal voltage climbs above 6V, then return it to the instrument charger to complete a full charge cycle.
Readings drifting or logging session resetting mid-measurement
Sustained sensor load during a logging session draws more current than standby operation, and an aged or partially charged Ni-MH pack experiences a steeper voltage sag under that continuous draw. When the pack voltage dips below the instrument's operating threshold — even briefly — the SDT-2000/U can reset its active session to protect data integrity. This is not a firmware fault; it is a voltage dropout at the supply rail. Start a logging session with a fully charged pack, and confirm terminal voltage reads at or above 8.0V before beginning a long measurement run.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: M-Tronic
- Manufacturer: CS
- Series: Standard
- Color: Black
- Product Type: Ni-MH
- Battery Type: Ni-MH
- Warranty: 12 Months
- Bulk Orders: sales@batteryweb.com
Frequently Asked Questions
My SDT-2000/U powers on but shuts off the moment I start a USB data transfer to the PC — is this a port issue or the battery?
The USB transfer adds a combined draw from the instrument's processor and the USB interface on top of the active sensor load — Ni-MH packs with degraded capacity cannot sustain that combined current without voltage sagging below the cutoff threshold. It is not a port fault. Replace the pack and confirm it carries a full charge before transferring data. Terminal voltage should sit at or above 8.0V at the start of the transfer.
The SDT-2000/U won't charge after sitting in storage for several months — the charger light just blinks and stops.
The Ni-MH cells have self-discharged below the minimum voltage the SDT-2000/U charger requires before it will pass charge current. The blinking light is the charger detecting a below-threshold voltage and refusing to start — it reads as a fault condition, not a discharged battery. Apply an external trickle charge at 100mA directly to the pack until terminal voltage climbs above 6V, then place it back in the instrument charger to complete a normal charge cycle.
The battery percentage on the SDT-2000/U display jumps around after I fitted a new pack — it shows 80% then drops to 30% within minutes.
The SDT-2000/U's voltage-threshold indicator was calibrated against the discharge curve of the old, degraded pack. A new Ni-MH cell has a flatter discharge curve and holds voltage higher for longer, so the instrument's indicator misreads state-of-charge until it learns the new cell's behaviour. Run two full charge and discharge cycles through the instrument — avoid pulling the pack mid-cycle — and the percentage display will stabilise against the new pack's actual discharge profile.
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