{"product_id":"att-sl219a-replacement-battery-385v-4000mah-li-polymer","title":"AT\u0026T SL219A Cordless Phone Compatible Battery BL-A67CT 3.85V 4000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAT\u0026amp;T SL219A \/ Verge — 3.85V Li-Polymer Replacement Battery (BL-A67CT)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.85V, 4000mAh Li-Polymer cell built to the BL-A67CT specification. It fits the AT\u0026amp;T SL219A and Verge cordless handsets. The cell is 89.10 × 66.50 × 4.30mm and connects directly to the handset's onboard charge circuit.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSL219A and Verge compatibility:\u003c\/strong\u003e\n    Both handsets share the same battery bay geometry and charge IC voltage rail at 3.85V nominal. The BL-A67CT connector and BMS profile match both without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the SL219A charge circuit and confirmed the BMS accepted the charge IC handshake, held full charge termination at 4.35V, and discharged cleanly to the low-voltage cutoff without premature BMS trip.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    After fitting this cell, run one complete discharge to auto-shutoff and a full uninterrupted charge before normal use. The handset's fuel gauge IC was calibrated to the old cell's discharge curve — one full cycle resets the coulomb counter against the new cell.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the SL219A reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe SL219A uses a coulomb-counter fuel gauge that tracks charge in and out of the cell over time. When the original cell is removed, those accumulated reference values no longer match the new cell's actual capacity. The gauge reports percentage against a stale baseline, so readings drift high or low until the IC relearns the curve. One full discharge-to-shutoff followed by a full charge corrects the baseline and stabilises the percentage display.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eHandset dead after sitting in storage — won't power on at all\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eLi-Polymer cells that sit discharged for several weeks can drop below 2.5V per cell, which triggers the BMS protection circuit into lockout. The handset shows nothing when placed on the base — no charge indicator, no response. Place the handset on the base station cradle and leave it undisturbed for 20–30 minutes before pressing power. The charge IC applies a trickle pre-charge current that slowly brings the cell above the BMS re-enable threshold, typically around 2.8V, at which point the BMS releases and normal charging resumes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391774982234,"sku":"BWCS-ATS219SL-1","price":40.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391775015002,"sku":"BWCS-ATS219SL-2","price":47.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391775047770,"sku":"BWCS-ATS219SL-3","price":52.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ATS219SL-1.webp?v=1779141870","url":"https:\/\/batteryweb.com\/products\/att-sl219a-replacement-battery-385v-4000mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}