{"product_id":"cosmed-pony-fx-nta2531-replacement-battery-74v-3400mah-li-ion","title":"COSMED Pony FX NTA2531 Compatible Battery 7.4V 3400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCOSMED Pony FX NTA2531 — 7.4V Li-ion Replacement Battery (A-410-750-002)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.4V, 3400mAh Li-ion replacement battery for the COSMED Pony FX NTA2531 portable spirometer. It replaces OEM part number A-410-750-002 and fits directly into the Pony FX used for pulmonary function testing in clinical and field diagnostic settings. Capacity is 3400mAh (25.16Wh) — matched to the OEM specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePony FX NTA2531 fitment:\u003c\/strong\u003e\n    The Pony FX uses a dedicated battery bay with a keyed connector tied to the device's BMS handshake. This cell matches the voltage rail, physical footprint (66.65 × 37.00 × 19.50mm), and communication profile the firmware expects at startup.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the Pony FX power-on self-test and full charge sequence. The BMS accepted the cell without flagging a battery fault, and the charge IC brought the pack to full capacity without capping short on the first pass.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation self-test protocol:\u003c\/strong\u003e\n    After inserting the battery, allow the Pony FX to complete its full power-on self-test cycle without interruption. The device runs a BMS verification routine at boot — cutting power mid-sequence registers a false battery fault that persists until the next clean reboot.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Pony FX flags a battery fault after a fresh cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Pony FX BMS stores the last known battery state and compares it against the new cell's reported parameters at boot. A replacement cell starts with a blank charge history, so the firmware may flag a mismatch on first power-on. This is not a defective cell — it is the BMS running its learn cycle. Run one complete charge-to-full followed by a controlled discharge, and the firmware updates its reference data. After that cycle, the fault flag clears and the battery indicator reads accurately.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCharge indicator stalls below 100% on first charge\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn a new Li-ion cell, the Pony FX charge IC applies a conservative current limit until it has mapped the cell's internal resistance. This causes the charge indicator to slow significantly above 90% and sometimes appear to stall. The cell is still charging — the IC is completing a conditioning taper. Leave the device on charge until the indicator confirms full; do not disconnect early. After the first full charge cycle, subsequent charges progress at normal speed through to 4.20V per cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43381447458906,"sku":"BWCS-CMP250MX-1","price":38.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43381447491674,"sku":"BWCS-CMP250MX-2","price":44.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43381447524442,"sku":"BWCS-CMP250MX-3","price":48.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-CMP250MX-1.webp?v=1778900875","url":"https:\/\/batteryweb.com\/products\/cosmed-pony-fx-nta2531-replacement-battery-74v-3400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}