{"product_id":"tomtom-gps-9821x-replacement-battery-37v-650mah-li-ion","title":"TomTom GPS-9821X Replacement Battery 3.7V 650mAh Q6000021","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTomTom GPS-9821X — 3.7V Li-ion Replacement Battery (Q6000021)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 650mAh Li-ion cell replaces part number Q6000021 in the TomTom GPS-9821X portable navigator. It restores power to the unit when the original cell can no longer hold a charge or causes unexpected shutdowns. Dimensions are 60.00 x 30.50 x 4.50mm — measure your original before fitting if you are unsure.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eGPS-9821X and GPS-9821X PDA\/Handheld fit:\u003c\/strong\u003e\n    Both model variants run the same 3.7V single-cell architecture with the same connector pinout and BMS communication protocol, so one cell covers both listings.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the Q6000021 replacement through full charge and discharge cycles on the GPS-9821X platform. The BMS accepted the cell without fault flags, and voltage at full charge held at 4.2V within spec.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eCold-start satellite acquisition after swap:\u003c\/strong\u003e\n    After fitting this cell, power the GPS fully on outdoors before driving. A full power interruption forces a cold start — first satellite fix takes 5–10 minutes. Subsequent warm starts drop to under a minute once almanac data is cached.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eGPS-9821X shutting off without warning at low battery\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe GPS-9821X uses a voltage-threshold system to gauge remaining charge. After a new cell is fitted, the device's fuel gauge is uncalibrated against the new cell's discharge curve. This means the low-battery warning indicator and the actual cutoff threshold fall out of sync — the unit can shut off abruptly before the visual warning fires. Run two full charge-to-discharge cycles to allow the threshold to recalibrate. Shutoffs should stabilise once the device has mapped the new cell's curve down to the 3.0V cutoff floor.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSaved routes and POIs missing after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSome TomTom GPS-9821X units store active route data and recent POIs in battery-backed volatile RAM rather than flash. A full power removal — which battery replacement causes — clears that RAM entirely. Saved favourites stored in non-volatile flash survive the swap, but unsaved routes and recent destinations will not. Export any routes you need to keep via TomTom HOME or MyDrive before removing the old cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43377736810586,"sku":"BWCS-TM821SL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43377736843354,"sku":"BWCS-TM821SL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43377736876122,"sku":"BWCS-TM821SL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-TM821SL-1.webp?v=1778771896","url":"https:\/\/batteryweb.com\/products\/tomtom-gps-9821x-replacement-battery-37v-650mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}