{"product_id":"allstar-z818l-replacement-battery-37v-1800mah-li-ion","title":"Allstar Z818L Replacement Battery 3.7V 1800mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAllstar Z818L \/ Z818G (Straight Talk) — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1800mAh Li-ion battery for the Allstar Z818L and Z818G smartphones sold through the Straight Talk network. It replaces the original cell when the phone no longer holds a charge or fails to power on. Capacity figure is 6.66Wh at rated voltage.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eZ818L and Z818G compatibility:\u003c\/strong\u003e\n    Both models share the same battery bay dimensions (72.74 × 53.41 × 4.67mm), the same 3.7V nominal voltage rail, and an identical connector pinout — one cell fits both 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 the bench. The BMS accepted a standard 5V charge input without triggering over-voltage cutoff, and the protection circuit tripped correctly at the low-voltage threshold before cell damage occurred.\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 complete one full discharge-to-charge cycle before resuming normal use. The fuel gauge IC in the Z818L is calibrated to the old cell's discharge curve — skipping this step causes the phone to read incorrect percentages until the coulomb counter resets against the new cell.\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 Z818L after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff issue, not a faulty battery. The Z818L's modem and screen together draw a current spike the fuel gauge IC maps incorrectly against the new cell's discharge curve. The phone's protection circuit reads a voltage sag as critically low and cuts power before the percentage counter reaches zero. One full discharge cycle — draining to automatic shutdown, then charging uninterrupted to 100% — lets the coulomb counter rebuild an accurate state-of-charge map. After that cycle, shutdowns at 20–30% stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone showing 1% or jumping percentage erratically after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC stores learned capacity data from the original cell. When a new cell goes in, that stored data is wrong — the IC reports whatever the old curve predicted, not what the new cell is actually doing. Erratic jumps of 10–15% or a stuck reading near 1% are both symptoms of the same uncalibrated state. Charge the phone to 100% without interruption, use it until it shuts off automatically, then charge back to 100% in one session. That single full cycle forces the fuel gauge IC to recalculate against the new cell's actual discharge curve.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404321226842,"sku":"BWCS-ZTN986SL-1","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404321259610,"sku":"BWCS-ZTN986SL-2","price":33.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404321292378,"sku":"BWCS-ZTN986SL-3","price":37.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ZTN986SL-1.webp?v=1778773940","url":"https:\/\/batteryweb.com\/products\/allstar-z818l-replacement-battery-37v-1800mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}