{"product_id":"hagenuk-e20-replacement-battery-37v-600mah-li-ion","title":"Hagenuk E20 Replacement Battery PHBA-309 3.7V 600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHagenuk E20 — 3.7V Li-ion Replacement Battery (PHBA-309)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 600mAh Li-ion replacement battery for the Hagenuk E20 mobile phone. It replaces OEM part PHBA-309 when the original cell no longer holds a charge or has degraded to the point of causing shutdowns. Voltage and capacity match the original spec exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHagenuk E20 fitment:\u003c\/strong\u003e\n    The E20 uses a compact 41.54 x 41.54 x 4.47mm cell with a low 600mAh draw profile suited to the phone's basic modem and display stack. The connector and BMS communication protocol are matched to the original charge IC on the E20 board.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the E20's charge IC and confirmed BMS handshake, charge termination at 4.2V, and stable voltage delivery under combined screen and modem load. No false full-charge cutoff was observed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first installation, disable fast charging if your charger supports it, then run one full discharge down to automatic shutoff before charging completely to 100%. This gives the fuel gauge IC a clean reference curve against the new cell before it starts tracking capacity under normal use.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the Hagenuk E20 after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff problem, not a capacity problem. The E20's fuel gauge IC was calibrated to the discharge curve of the original cell. When the phone's modem or display pulls current at the 20–30% mark, the new cell's voltage can drop below the system cutoff threshold before the percentage display reaches zero. The fuel gauge doesn't know this yet — it's still reading against the old curve. One full discharge-to-shutdown followed by a full charge to 100% resets the coulomb counter and maps it to the new cell's actual curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eE20 showing erratic percentage jumps after replacement battery installed\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003ePercentage jumping — say, from 54% down to 31% in minutes, or spiking back up when the load drops — is the fuel gauge IC actively recalibrating against an unfamiliar cell. It hasn't completed enough discharge cycles to build an accurate model of the new cell's voltage-to-capacity relationship. This is normal in the first one to three cycles after a cell swap. Run two full discharge-to-shutoff and charge-to-100% cycles and the reported percentage will stabilise.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405076332634,"sku":"BWCS-HFE200SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405076365402,"sku":"BWCS-HFE200SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405076398170,"sku":"BWCS-HFE200SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HFE200SL-1.webp?v=1779369919","url":"https:\/\/batteryweb.com\/products\/hagenuk-e20-replacement-battery-37v-600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}