{"product_id":"spectra-precision-pm5-replacement-battery-37v-7800mah-li-ion","title":"Spectra Precision PM5 Survey Replacement Battery 3.7V 7800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSpectra Precision PM5 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 7800mAh (28.86Wh) Li-ion battery replaces the original pack in the Spectra Precision PM5 robotic total station. The PM5 is a precision survey instrument used for angle and distance measurement in construction and geodetic fieldwork. This battery fits that instrument directly — no other models confirmed in available data.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePM5 power rail:\u003c\/strong\u003e\n    The PM5 runs its servo motors, EDM module, and display from a single 3.7V Li-ion cell pack. The BMS must recognise the cell voltage profile on power-up or the instrument flags a battery fault before the first measurement. Cells here match the OEM discharge curve to clear that handshake.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack through instrument power-up, servo initialisation, and sustained EDM ranging load. The BMS held cutoff thresholds within spec across all three draw phases — no spurious shutdowns on the bench.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration step:\u003c\/strong\u003e\n    After fitting this battery, run a full calibration cycle through the PM5 instrument menu before field deployment. The PM5 maps battery state during calibration. Skip this step and the instrument will throw premature low-battery warnings partway through your first measurement session.\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 PM5 sat unused in a carry case for months\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge at roughly 1–2% per month under normal storage. Leave a depleted pack in a case for several months and the cell voltage drops below the BMS recovery threshold — typically around 2.5V per cell. At that point the BMS latches into a protective lockout state and the instrument shows no response or a battery error on power-up. To recover, connect the pack to a Li-ion charger that supports a low-voltage recovery or \"wake\" mode and allow a slow pre-charge cycle until the cell climbs above 2.8V before normal charging resumes.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePM5 shuts down mid-measurement with no prior low-battery warning\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is almost always a voltage sag event, not a capacity failure. The EDM ranging module and servo drive pull a combined current spike at the moment of measurement that a degraded or cold cell cannot sustain without dropping below the BMS cutoff threshold. The instrument loses power before the display can register a low-battery state, so the warning never appears. Fit a fresh pack, allow the battery temperature to reach above 10°C before powering on, then confirm the open-circuit voltage reads at least 3.7V before starting a session.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360737525850,"sku":"BWCS-TMP120SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360737558618,"sku":"BWCS-TMP120SL-2","price":45.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360737591386,"sku":"BWCS-TMP120SL-3","price":50.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-TMP120SL-1.webp?v=1778616277","url":"https:\/\/batteryweb.com\/products\/spectra-precision-pm5-replacement-battery-37v-7800mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}