{"product_id":"fujitsu-loox-400-replacement-battery-37v-1250mah-li-ion","title":"Fujitsu Loox 400 S26391-F2607-L50 Compatible Battery 3.7V 1250mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eFujitsu Loox 400 \/ 420 \/ N500 Series — 3.7V Li-ion Replacement Battery (S26391-F2607-L50)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 1250mAh Li-ion battery fits the Fujitsu Loox 400, 410, 420, and N500 series PDAs and Pocket PCs. It replaces OEM part numbers S26391-F2607-L50, PL400MB, PL400MD, and PL500MB. The cell slots into the same battery bay as the original and connects to the same BMS contacts on the device board.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLoox 400 \/ 410 \/ 420 \/ N500 compatibility:\u003c\/strong\u003e\n    These models share the same 3.7V battery rail, physical form factor, and BMS handshake protocol, which is why one cell covers the full range. The connector pinout and thermistor line are identical across all variants listed.\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 Loox-class device, confirming the BMS accepted the cell without fault flags and that charge termination triggered correctly at full capacity. Voltage under load remained stable across the discharge curve.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eRAM data protection before swap:\u003c\/strong\u003e\n    The Loox series holds open files, calendar entries, and application state in volatile SRAM powered directly by the main battery. Sync all data to your host PC or ActiveSync connection before pulling the battery — anything unsaved to flash will be lost the moment power drops.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Loox 400 won't boot after a new battery is installed\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Loox boot sequence checks for a minimum voltage threshold before the CPU initialises. A new cell shipped in storage can arrive at 3.0V or lower — below what the device needs to complete a cold boot. If the unit shows nothing when you press the power button, the battery is not flat or faulty; it just needs a charge cycle first. Connect the device to the cradle or AC adapter and let it charge for at least 30 minutes before attempting to power on.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBattery capacity dropping faster than expected during wireless sync sessions\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWireless radio and backlight together pull significantly more current than the Loox draws in standby or basic PIM use. If the battery appears to drain quickly, the cause is almost always an active sync session running with full backlight brightness — not a cell defect. Check that auto-backlight timeout is set to 30 seconds or less in Power Settings. For scanning workflows, disabling Wi-Fi between sync windows can extend active use time without replacing hardware.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43415947247706,"sku":"BWCS-FL420SL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43415947280474,"sku":"BWCS-FL420SL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43415947313242,"sku":"BWCS-FL420SL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FL420SL-1.webp?v=1779758396","url":"https:\/\/batteryweb.com\/products\/fujitsu-loox-400-replacement-battery-37v-1250mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}