{"product_id":"toshiba-e400-replacement-battery-37v-1000mah-li-polymer","title":"Toshiba E400 Compatible Battery LAB503759C 3.7V 1000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eToshiba E400 \/ E410 — 3.7V Li-Polymer Replacement Battery (LAB503759C)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1000mAh lithium-polymer cell that replaces the LAB503759C battery in the Toshiba E400 and E410 pocket PCs. These early-2000s PDAs rely on a single flat Li-Po cell to power the processor, RAM, and display. When the original cell degrades, the device loses charge quickly or won't hold enough voltage to boot.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eE400 and E410 platform fit:\u003c\/strong\u003e\n    Both models use the same battery bay dimensions and the same 3.7V single-cell Li-Po arrangement. The connector pinout and BMS communication protocol are identical across the two, so one cell covers both units 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 an E400 unit. The BMS accepted the cell without fault flags, regulated charge termination cleanly at 4.2V, and held the low-voltage cutoff at the expected threshold without premature shutdown.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eRAM state before you remove the old battery:\u003c\/strong\u003e\n    Sync all open data to the host PC before pulling the original cell. The E400 stores active application state and unsaved contacts in volatile SRAM — that data disappears the moment battery voltage drops to zero. A full ActiveSync before the swap takes 60 seconds and prevents data loss.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the E400 won't boot after a battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eA freshly shipped Li-Po cell typically arrives at 30–50% state of charge — enough for storage, not enough for the E400's boot sequence. The device checks for a minimum voltage threshold before committing to a full boot. If that threshold isn't met, the unit either shows a low-battery warning and halts, or shows nothing at all. Connect the E400 to its charger for at least two hours before attempting the first power-on after a battery replacement.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eE400 calendar and contacts missing after the new battery goes in\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe E400 keeps its operating system in ROM, but open records, calendar entries, and installed third-party apps live in volatile SRAM. SRAM requires continuous power — even a brief gap during a battery swap is enough to wipe it. If data is already gone, connect to ActiveSync immediately and restore from the last backup. Going forward, perform a full sync before every battery removal to avoid repeating the loss.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43415953506394,"sku":"BWCS-E400SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43415953539162,"sku":"BWCS-E400SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43415953571930,"sku":"BWCS-E400SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-E400SL-1.webp?v=1779758425","url":"https:\/\/batteryweb.com\/products\/toshiba-e400-replacement-battery-37v-1000mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}