{"product_id":"media-tech-mt842-replacement-battery-37v-1200mah-li-ion","title":"Media-Tech MT842 Replacement Battery 3.7V 1200mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMedia-Tech MT842 Series — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1200mAh Li-ion cell for the Media-Tech MT842 smartphone and its variants — MT842R, MT842B, MT842W, and eight additional model suffixes. It fits where the original cell has degraded, swollen, or stopped holding a charge. Physical dimensions are 53.00 × 33.90 × 5.70mm — measure your existing cell before ordering.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMT842 variant coverage:\u003c\/strong\u003e\n    The MT842 line shares a common board layout and connector pinout across colour and regional variants. One cell spec covers the full range — same voltage rail, same connector, same BMS communication protocol across all listed suffixes.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled the cell through charge and discharge on a smartphone test rig. The BMS accepted the charge handshake correctly and held voltage through draw spikes without tripping the low-voltage cutoff prematurely.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After fitting this cell, disable fast charging and run one full discharge-to-charge cycle at standard rate. The fuel gauge IC in the MT842 calibrates its coulomb counter against the cell's actual discharge curve — skipping this step causes erratic percentage readings until the IC re-anchors its reference points.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the MT842 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe MT842 uses a fuel gauge IC that builds its charge-state model from the discharge curve of the original cell. A new cell has a different internal resistance profile, so the IC's coulomb counter drifts from the real state of charge immediately after installation. The percentage shown on screen can be 15–25% off in either direction until the IC recalibrates. One complete discharge down to automatic shutdown followed by a full charge at standard rate resets the reference. After that cycle the displayed percentage tracks actual cell voltage correctly.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the new cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff, not a capacity fault. When the modem, screen, and CPU pull current simultaneously, the new cell's voltage drops faster than the fuel gauge IC predicts — hitting the BMS low-voltage cutoff while the display still reads 20–30%. It is most common in the first three cycles before the IC recalibrates. Force a full discharge cycle without interruption, then charge to 100% and check whether the shutdowns stop. If the cutoff still triggers above 15%, verify the resting cell voltage with a multimeter — it should read 3.7V or above after a full charge.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404285771866,"sku":"BWCS-DEP215SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404285804634,"sku":"BWCS-DEP215SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404285837402,"sku":"BWCS-DEP215SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEP215SL-1.webp?v=1779369550","url":"https:\/\/batteryweb.com\/products\/media-tech-mt842-replacement-battery-37v-1200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}