{"product_id":"topcon-es-total-station-replacement-battery-74v-4200mah-li-ion","title":"Topcon BT-L2 7.4V Replacement Battery for ES Total Station 4200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTopcon ES Total Station Series — 7.4V Li-ion Replacement Battery (BT-L2)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThe BT-L2 is a 7.4V 4200mAh lithium-ion battery for the Topcon ES Total Station series, including the ES-602, ES-602G, and ES-600G. It slots into the battery compartment of these instruments and powers the theodolite, EDM, and display systems during fieldwork. Capacity figure is sourced from the product data at 31.08Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eES-600G, ES-602, and ES-602G compatibility:\u003c\/strong\u003e\n    These models share the same 7.4V battery rail, BT-L2 form factor, and BMS handshake protocol. The connector and cell group configuration are identical across this ES platform, so one part number covers all listed variants without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this pack through the ES instrument's full startup sequence, including EDM initialisation and angle encoder power-up. The BMS handled the inrush current at prism lock-on without tripping, and cell voltage held steady across sustained distance measurement cycles.\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 instrument's adjustment menu before heading to site. The ES series maps battery state during calibration — skipping this step causes the low-battery warning to trigger early 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 lockout on the ES Total Station after the pack sat unused for months\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge slowly in storage. If the BT-L2 sits in the instrument or loose in a case for several months, cell voltage can drop below the BMS's recovery threshold — typically around 2.5V per cell. At that point, the BMS enters a protection lockout and the charger shows no activity or a fault indicator. To recover the pack, place it on the OEM charger and leave it connected for up to 90 minutes without interruption; the charger applies a low trickle current to nudge the cells back above the 2.5V threshold before switching to standard charge mode.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eES Total Station shuts down mid-measurement with the battery indicator still showing charge\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the voltage indicator hasn't recalibrated to the new pack's discharge curve. The ES instrument reads voltage thresholds set during previous cycles, and a fresh cell with a different curve can hit the instrument's cutoff trigger while still carrying usable charge. Run two full charge-discharge cycles through normal field use, then check whether the shutdown point shifts. After two cycles, the threshold recalibrates and the instrument reads remaining capacity accurately — if shutdown persists below 7.0V under load, check the battery contacts for oxidation.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360713048154,"sku":"BWCS-TOP602SL-1","price":37.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360713080922,"sku":"BWCS-TOP602SL-2","price":43.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360713113690,"sku":"BWCS-TOP602SL-3","price":47.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-TOP602SL-1.webp?v=1778616232","url":"https:\/\/batteryweb.com\/products\/topcon-es-total-station-replacement-battery-74v-4200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}