{"product_id":"philips-sjb-2121-replacement-battery-24v-700mah-ni-mh","title":"Philips SJB-2121 Cordless Phone Replacement Battery 2.4V 700mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003ePhilips SJB-2121 Series — 2.4V Ni-MH Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 2.4V, 700mAh Ni-MH rechargeable battery for the Philips SJB-2121 cordless phone handset. It fits the SJB-2121, SJB-2121\/17, SJB-2121\/37, and SJB2121 variants. Install it when the original pack no longer holds a charge and the handset cuts out before calls finish.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSJB-2121 handset compatibility:\u003c\/strong\u003e\n    All SJB-2121 variants share the same 2.4V two-cell NiMH pack format and connector pinout. The base station charges via contact pads, so physical dimensions matter — this pack matches the original at 43.55 x 20.42 x 10.60mm.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack on a SJB-2121 handset through charge and discharge under RF transmit load. The NiMH cells accepted charge without heat spikes, and the base station showed a normal charge indicator on the first seating.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst charge after installation:\u003c\/strong\u003e\n    Place the handset in the base immediately after fitting and leave it for a full 16 hours before use. NiMH cordless phone packs ship partially discharged and need one slow full charge to initialise rated capacity — a short first charge means the pack will underperform for weeks.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the SJB-2121 base station shows a charging error on a new NiMH pack\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe SJB-2121 base uses a delta-V detection circuit to confirm the battery is accepting charge. A new NiMH pack that shipped at low voltage can sit below the threshold this circuit expects to see. The base interprets that low starting voltage as a fault rather than a depleted cell. If the indicator flashes or stays red, remove the handset, wait 10 seconds, and re-seat it firmly — the base will retry the charge cycle from scratch.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eTalk time shorter than the original battery after fitting a new pack\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eNiMH cells need three to five full charge-discharge cycles before they reach rated capacity — this is normal chemistry behaviour, not a defective pack. After the first 16-hour charge, use the handset until it needs charging, then return it to the base for another full charge. Repeat this three times. By cycle four, the cells will be delivering close to the rated 700mAh and talk time will stabilise.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43340047122522,"sku":"BWCS-UT3101CL-1","price":20.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43340047155290,"sku":"BWCS-UT3101CL-2","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43340047188058,"sku":"BWCS-UT3101CL-3","price":25.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-UT3101CL-1.webp?v=1778367047","url":"https:\/\/batteryweb.com\/products\/philips-sjb-2121-replacement-battery-24v-700mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}