{"product_id":"topcon-stonex-unistrong-replacement-battery-74v-2600mah-li-ion","title":"Topcon STONEX Unistrong BP-5S Replacement Battery 7.4V 2600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTopcon STONEX Unistrong — 7.4V Li-ion Replacement Battery (BP-5S)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V 2600mAh Li-ion battery replaces the BP-5S pack in the STONEX Unistrong GNSS receiver. It fits the same footprint at 70.70 × 39.40 × 21.70mm and matches the original voltage rail the instrument expects. Use it in the field wherever the original pack no longer holds a usable charge.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSTONEX Unistrong GNSS compatibility:\u003c\/strong\u003e\n    The Unistrong platform runs satellite acquisition, IMU logging, and radio link on a shared 7.4V bus. Any replacement pack must match that voltage rail exactly and present the correct BMS handshake — a mismatched pack causes the instrument to refuse to power on.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack through cold-start acquisition and sustained RTK logging. The BMS held voltage above the instrument's cutoff threshold under combined GNSS and radio draw without tripping protection.\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 sequence through the instrument's system menu before field deployment. The Unistrong maps battery state during that cycle — skip it and the low-battery warning triggers early on the first session, even with a full pack.\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 Unistrong sat unused in a carry case for months\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge slowly in storage. If the pack drops below roughly 2.5V per cell, the BMS enters a deep-sleep lockout to prevent cell damage. The Unistrong will show no response when you press power — no splash screen, no charging indicator. Connect the pack to the original Topcon charger and leave it for at least 30 minutes before attempting to power on. Once the charger pulls the cell voltage above the recovery threshold, the BMS resets and normal charging resumes.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUnistrong shuts down mid-session during USB data transfer to PC\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eUSB data transfer adds a sustained draw on top of the active GNSS and radio load. On a partially depleted pack, this combined current pulls voltage below the BMS cutoff threshold and the instrument shuts off without warning. This is not a pack fault — it is a voltage-sag event under stacked load. Start any data transfer session with a freshly charged pack, and check that the USB cable is not simultaneously charging a connected device, which adds reverse load to the bus.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360515555418,"sku":"BWCS-TOX110SL-1","price":67.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360515588186,"sku":"BWCS-TOX110SL-2","price":79.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360515620954,"sku":"BWCS-TOX110SL-3","price":88.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-TOX110SL-1.webp?v=1778615963","url":"https:\/\/batteryweb.com\/products\/topcon-stonex-unistrong-replacement-battery-74v-2600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}