{"product_id":"welch-allyn-wa49020-ef-replacement-battery-36v-3000mah-ni-mh","title":"Welch-Allyn WA49020-EF 3.6V Replacement Battery 3000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eWelch-Allyn WA49020-EF Series — 3.6V Ni-MH Replacement Battery (72250)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.6V, 3000mAh Ni-MH replacement for the Welch-Allyn battery part number 72250. It fits the WA49020-EF, WA49020-EF-M, WA49020, WA49020-M, and related models in the WA49020 family. The cell matches the original voltage, capacity, and form factor for this portable diagnostic examination device.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWA49020 family compatibility:\u003c\/strong\u003e\n    These models share the same 3.6V single-cell Ni-MH architecture, connector pinout, and BMS handshake protocol. Swapping across WA49020 variants is consistent because the charge IC targets the same termination voltage and temperature curve across the series.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the WA49020 charge circuit and confirmed the BMS accepted the new cell without flagging a fault code. The charge IC reached delta-V termination correctly on the first full charge cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation self-test cycle:\u003c\/strong\u003e\n    After fitting this battery, allow the device to complete its full power-on self-test without interruption. The WA49020 runs BMS verification at startup — cutting power mid-sequence leaves a false battery fault flag that persists until the next full reboot.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eDevice not completing boot sequence on new battery\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe WA49020 runs a BMS learn cycle during its first few power-on sequences after a cell swap. If the device stalls mid-boot, the charge IC has not yet established a baseline for the new cell's internal resistance. This is not a faulty battery — it is the device calibrating against unfamiliar cell characteristics. Run one full charge-discharge cycle before placing the unit back in clinical rotation to let the BMS complete its calibration pass.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCharge indicator not reaching 100% on the first charge attempt\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn the first charge, the WA49020 charge IC applies a conservative termination threshold when it encounters a new Ni-MH cell. The delta-V detection window is tighter than on a conditioned cell, so the indicator may stop early — typically around 85–90% on the display. The actual cell state of charge is higher than the indicator shows. Complete a second full charge cycle and the IC recalibrates its termination point to the cell's actual peak voltage.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43381511749722,"sku":"BWCS-AMS155MD-1","price":37.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43381511782490,"sku":"BWCS-AMS155MD-2","price":43.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43381511815258,"sku":"BWCS-AMS155MD-3","price":47.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AMS155MD-1.webp?v=1778901324","url":"https:\/\/batteryweb.com\/products\/welch-allyn-wa49020-ef-replacement-battery-36v-3000mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}