{"product_id":"sony-nw-wm1a-replacement-battery-37v-1900mah-li-polymer","title":"Sony NW-WM1A Replacement Battery 3.7V 1900mAh Li-Polymer","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSony NW-WM1A \/ NW-WM1Z — 3.7V Li-Polymer Replacement Battery (1-853-588-15)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1900mAh (7.03Wh) Li-Polymer replacement battery for the Sony NW-WM1A and NW-WM1Z Walkman digital audio players. It fits the internal battery bay directly and matches the OEM part numbers 1-853-588-15 and LIS1626HNPC. Swap this in when the original cell no longer holds a usable charge across a listening session.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNW-WM1A and NW-WM1Z compatibility:\u003c\/strong\u003e\n    Both the WM1A and WM1Z use the same 3.7V cell format, connector pinout, and BMS handshake. The WM1Z is the flagship copper-body variant; internally, the battery bay and charging circuit are identical, so the same replacement cell works in both.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge on a WM1A unit. The BMS accepted the cell without fault flags, and the charge circuit stepped through its expected CC\/CV phases correctly. No protection-mode lockouts occurred at end-of-discharge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap charge sequence for the WM1A:\u003c\/strong\u003e\n    After installing a fresh cell, connect the WM1A to its charger before powering on. If the old battery was deeply discharged, the device may sit in trickle-charge mode for up to 30 minutes before it accepts normal current. Do not force a boot during that window — the BMS needs to confirm minimum cell voltage before handing off control to the main board.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBattery percentage jumping after cell swap on the WM1A\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe WM1A uses a voltage-threshold fuel gauge, not a coulomb counter. When a new cell goes in, the device has no charge history to work from, so it estimates state-of-charge from open-circuit voltage alone. This causes the displayed percentage to jump — sometimes from 40% to 90% within a few minutes of use. Run two or three full charge-to-discharge cycles and the gauge will stabilise. After the third cycle, readings should track within roughly 5–10% of actual capacity.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePlayback cutting out before the battery indicator reaches empty\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe WM1A's audio output stage draws a spike of current during high-gain, high-volume playback — particularly through balanced output. Near the bottom of the discharge curve, cell voltage sags under that load and can drop below the BMS cutoff threshold momentarily, triggering a shutdown even though the indicator still shows residual charge. This is a voltage-sag issue, not a capacity issue. If playback cuts at high volume but resumes after a short rest, reduce output gain or switch from balanced to single-ended output to lower the current draw. If it persists, check that the replacement cell voltage reads at least 3.5V under no-load before charging.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43381326020698,"sku":"BWCS-SNW100SL-1","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43381326053466,"sku":"BWCS-SNW100SL-2","price":35.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43381326086234,"sku":"BWCS-SNW100SL-3","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-SNW100SL-1.webp?v=1778900030","url":"https:\/\/batteryweb.com\/products\/sony-nw-wm1a-replacement-battery-37v-1900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}