{"product_id":"pharos-ptl535-replacement-battery-37v-2250mah-li-ion","title":"Pharos PTL535 PDA Replacement Battery 3.7V 2250mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003ePharos PTL535 \/ TL535P \/ PTL535E — 3.7V Li-ion Replacement Battery (PZX65)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 2250mAh lithium-ion cell that replaces OEM part PZX65 in the Pharos PTL535, TL535P, and PTL535E handheld PDAs. It restores power to the main board and keeps the device's RAM-backed storage alive during normal use. Capacity matches the original at 8.33Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePTL535 \/ TL535P \/ PTL535E platform:\u003c\/strong\u003e\n    All three models share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell covers the entire lineup without hardware modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We charged the cell from flat through a PTL535 dock and monitored BMS cutoff at both ends. The protection circuit tripped at 4.20V on charge and held the low-voltage cutoff at 3.0V before the board shut down.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eSync before you swap:\u003c\/strong\u003e\n    Perform a full ActiveSync or data sync to the host PC before removing the old battery. The PTL535 holds open application state and unsaved records in volatile RAM — that data vanishes the moment main power is cut, regardless of how fast the swap is.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the PTL535 loses contacts and calendar entries on battery removal\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe PTL535 uses SRAM for active storage — it holds the working database in memory rather than writing constantly to flash. SRAM needs continuous voltage to retain data; there is no backup coin cell on this board. The moment the main cell is disconnected, anything not previously committed to flash storage is gone. A full ActiveSync to a host machine before the swap is the only way to protect that data.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePTL535 shows charging indicator but won't boot after new battery installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA freshly installed cell that shipped partially discharged may sit below the PTL535's minimum boot threshold — typically around 3.4V. The charging LED activates because the dock is pushing current in, but the main processor will not initialise until voltage clears that floor. Leave the unit in the dock for at least 20 minutes before attempting a cold boot. If the screen stays blank, check dock contact alignment and confirm the cell is seated flat — a slightly raised corner breaks the connection intermittently.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43415948853338,"sku":"BWCS-FN520XL-1","price":26.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43415948886106,"sku":"BWCS-FN520XL-2","price":29.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43415948918874,"sku":"BWCS-FN520XL-3","price":32.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FN520XL-big.webp?v=1779758397","url":"https:\/\/batteryweb.com\/products\/pharos-ptl535-replacement-battery-37v-2250mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}