{"product_id":"srf-startrall-4-replacement-battery-37v-1600mah-li-ion","title":"SRF Startrall 4 Replacement Battery 3.7V 1600mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSRF Startrall 4 — 3.7V Li-ion 1600mAh Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V Li-ion replacement battery rated at 1600mAh (5.92Wh) for the SRF Startrall 4 smartphone. It slots into the Startrall 4 battery bay and restores power to the device when the original cell has degraded or failed. Dimensions are 60.20 × 56.12 × 4.70mm — confirm against your existing cell before installing.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eStartrall 4 fitment:\u003c\/strong\u003e\n    The Startrall 4 uses a compact 3.7V single-cell Li-ion configuration. This replacement matches that voltage rail and physical envelope, so the battery connector seats correctly and the BMS communicates with the phone's power management IC.\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 under a simulated screen-on load. The BMS held cutoff at the correct low-voltage threshold and accepted a full charge without the protection circuit tripping early.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration after install:\u003c\/strong\u003e\n    On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated 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 Startrall 4 after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a voltage cliff under modem or screen load that the IC wasn't expecting, so it reads 25% but the cell voltage has already dropped below the cutoff threshold. The phone shuts down to protect the cell, even though the percentage shown looked safe. One full discharge-charge cycle with fast charging disabled resets the coulomb counter and brings the reported percentage back in line with actual cell voltage.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone warm near the battery during the first charge after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA new cell starts with higher internal impedance than a broken-in cell. The charge IC pushes current into higher resistance, which converts more energy to heat than usual. This is normal for the first one to two charge cycles and settles as the cell impedance drops. If the phone stays warm beyond the third full charge, check that the charge IC isn't locked in a high-current mode — drop to a 5V\/1A charger and monitor temperature at the back of the phone above the battery bay.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404323684442,"sku":"BWCS-ZTN909SL-1","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404323717210,"sku":"BWCS-ZTN909SL-2","price":31.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404323749978,"sku":"BWCS-ZTN909SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ZTN909SL-1.webp?v=1779369779","url":"https:\/\/batteryweb.com\/products\/srf-startrall-4-replacement-battery-37v-1600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}