{"product_id":"survey-equipment-replacement-battery-74v-3400mah-li-ion","title":"Survey 29518 Replacement Battery 7.4V 3400mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSurvey Equipment — 7.4V Li-ion Replacement Battery (29518 \/ EI-D-LI1)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V, 3400mAh Li-ion pack replaces OEM part numbers 29518, 38403, 46607, 52030, C8872A, and EI-D-LI1 in Survey portable field instruments. It delivers 25.16Wh of capacity through the same connector and BMS handshake as the original pack. Voltage and cell count match the original specification exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMulti-OEM cross-reference compatibility:\u003c\/strong\u003e\n    The six OEM part numbers listed above span different production runs of the same instrument platform — same voltage rail, same connector pinout, same BMS communication protocol. Swapping between these part numbers does not change the electrical interface.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack through probe initialisation sequences and sustained sensor logging loads. The BMS held voltage above the instrument's cutoff threshold without tripping, and the protection circuit responded correctly to a simulated overcurrent event at probe power-up.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration cycle:\u003c\/strong\u003e\n    After fitting this pack, run a full calibration cycle through the instrument menu before field deployment. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings on the first measurement session, even with a fully charged pack.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBMS cutoff when the probe module initialises\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWhen a probe or sensor module first powers up, it draws a short inrush current that spikes well above the steady-state measurement load. An aged or deeply discharged pack can't sustain voltage through that spike, and the BMS interprets the drop as a fault condition and cuts output. This pack's protection circuit is rated to handle the initialisation surge without triggering a false overcurrent trip. If the instrument still shuts off at probe connect, charge the pack to full (8.40V at the terminals) before testing again.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eInstrument fails to recognise pack after months in a carry case\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge slowly during storage — after several months, the pack can drop below the BMS recovery voltage threshold and enter a low-power sleep state. The instrument then sees no communication from the pack and either refuses to power on or shows a battery error. Place the pack on the charger for at least 30 minutes before inserting it into the instrument; most chargers will push a trickle current that wakes the BMS before handing off to CC\/CV charging. If the charger shows no activity after 10 minutes, check terminal voltage — recovery is unlikely below 6.0V.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360746537050,"sku":"BWCS-LI1HL-1","price":36.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360746569818,"sku":"BWCS-LI1HL-2","price":42.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360746602586,"sku":"BWCS-LI1HL-3","price":46.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LI1HL-1.webp?v=1778616259","url":"https:\/\/batteryweb.com\/products\/survey-equipment-replacement-battery-74v-3400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}