{"product_id":"deviser-at400-replacement-battery-111v-5200mah-li-ion","title":"Deviser AT400 Replacement Battery HYLB-1378 11.1V 5200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDeviser AT400 \/ E7000A — 11.1V Li-ion Replacement Battery (HYLB-1378)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is an 11.1V, 5200mAh Li-ion battery for the Deviser AT400 digital theodolite and E7000A surveying instrument. It powers the electronic display, angle measurement electronics, and onboard data functions. Capacity is sourced from product specification — 57.72Wh total usable energy.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAT400 and E7000A platform fit:\u003c\/strong\u003e\n    Both instruments share the same battery bay geometry, voltage rail, and BMS handshake protocol. The 11.1V three-cell configuration matches the power rails for the display driver and angle sensor circuits on both models.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack through full charge and discharge on the AT400 platform. The BMS handled the initialisation current spike at instrument power-up without tripping, and cell balance held within 20mV across all three cells after five cycles.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst field deployment step:\u003c\/strong\u003e\n    After installing the battery, run a full calibration cycle through the instrument menu before leaving for site. The AT400 maps battery state during calibration — skipping this causes premature low-battery warnings during 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 after the AT400 sat unused in a carry case for months\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge at roughly 2–3% per month. After a long storage period, cell voltage can drop below the BMS recovery threshold — typically 2.5V per cell on this pack. When that happens, the BMS enters a protective lockout state and the instrument will not power on or accept a charge. To recover the pack, connect it to a charger that supports a low-current pre-charge or conditioning mode, which trickle-charges the cells back above the 2.5V per cell threshold before the BMS re-enables normal charge current. If the charger shows no activity after 30 minutes, the cells may have dropped below the point of BMS recovery.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eAT400 display drops to zero percent and shuts down mid-session with no warning\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the voltage-threshold indicator in the instrument has not recalibrated to the new cell's discharge curve. The instrument was previously reading an aged battery with a steep voltage drop near end of charge — the new cells hold voltage flatter for longer, then drop sharply, which the uncalibrated indicator reads as sudden depletion. The fix is to run two full charge-discharge cycles through the instrument's normal operation before trusting the percentage display. After two cycles, the instrument's threshold logic resets to match the new pack's curve and low-battery warnings return to accurate timing.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360634568794,"sku":"BWCS-DRT400SL-1","price":204.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360634601562,"sku":"BWCS-DRT400SL-2","price":242.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360634634330,"sku":"BWCS-DRT400SL-3","price":271.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DRT400SL-1.webp?v=1778616113","url":"https:\/\/batteryweb.com\/products\/deviser-at400-replacement-battery-111v-5200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}