{"product_id":"m-tronic-sdt-2000u-replacement-battery-84v-1200mah-ni-mh","title":"M-Tronic SDT-2000\/U Replacement Battery 8.4V 1200mAh Ni-MH","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eM-Tronic SDT-2000\/U — 8.4V Ni-MH Replacement Battery (91507401)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 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.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSDT-2000\/U platform fit:\u003c\/strong\u003e\n    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.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    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.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eCalibration cycle before first field use:\u003c\/strong\u003e\n    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.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBMS lockout after the SDT-2000\/U sat unused in its carry case for months\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eNi-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.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eReadings drifting or logging session resetting mid-measurement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSustained 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.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360460570714,"sku":"BWCS-MTU200SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360460603482,"sku":"BWCS-MTU200SL-2","price":46.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360460636250,"sku":"BWCS-MTU200SL-3","price":51.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MTU200SL-1.webp?v=1778615900","url":"https:\/\/batteryweb.com\/products\/m-tronic-sdt-2000u-replacement-battery-84v-1200mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}