{"product_id":"sony-ericsson-788-replacement-battery-48v-750mah-ni-mh","title":"Sony Ericsson 788 Replacement Battery 4.8V 750mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSony Ericsson 788 \/ T18 Series — 4.8V Ni-MH Replacement Battery (BKB1931022R2A)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 4.8V, 750mAh Ni-MH replacement battery for the Sony Ericsson 788 and related handsets. It matches the original BKB1931022R2A and BKB1931030R1A part numbers. Compatible fits include the 788, 768, T18, and T10 series.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e788, 768, T18, T10 platform fit:\u003c\/strong\u003e\n    These models share a common 4.8V battery bay, connector pinout, and charge management circuit. The BMS handshake uses the same termination threshold across the range, so one cell fits the full group 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 charge and discharge on a T18 and 788 unit. The charge IC accepted the cell on first insertion, delta-V cutoff triggered correctly at full charge, and the protection circuit interrupted current cleanly at the low-voltage floor.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After fitting this cell, disable any fast-charge or rapid-charge mode if available, then run one full discharge-to-charge cycle before normal use. This gives the fuel gauge IC time to map the new cell's discharge curve before reporting capacity to the OS.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the 788 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC on these Sony Ericsson handsets builds its percentage model from the previous cell's discharge curve stored in memory. A new Ni-MH cell has a different internal resistance and voltage profile, so the IC's stored reference no longer matches reality. The phone reads voltage at a point it associates with 60%, but the new cell is actually at 80% — or vice versa. One complete discharge cycle down to auto-off, followed by a full charge, forces the IC to rewrite its curve against the actual cell behaviour.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eNi-MH cells have a steep voltage drop near the end of their discharge curve. If the fuel gauge IC is still calibrated to the old cell, it underestimates how close the new cell is to its cutoff voltage. Under load — a call, backlight, or keypad activity — the cell voltage drops fast enough to cross the protection circuit's cutoff before the percentage reading catches up. The phone shuts down hard with the display still showing 20–30%. Run one full discharge cycle to auto-off and recharge fully; this recalibrates the IC to the correct voltage-to-capacity mapping on the new cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409471799386,"sku":"BWCS-ER788SL-1","price":23.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43409471832154,"sku":"BWCS-ER788SL-2","price":26.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43409471864922,"sku":"BWCS-ER788SL-3","price":29.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ER788SL-1.webp?v=1779579784","url":"https:\/\/batteryweb.com\/products\/sony-ericsson-788-replacement-battery-48v-750mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}