{"product_id":"philips-defibrillator-heartstart-mrx-replacement-battery-148v-6000mah-li-ion","title":"Philips Heartstart MRx M3538A Replacement Battery 14.8V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003ePhilips HeartStart MRx — 14.8V Li-ion Replacement Battery (M3538A)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 14.8V, 6000mAh Li-ion battery replaces the Philips M3538A and fits the HeartStart MRx defibrillator, HeartStart MRx Monitor, and Laerdal Monitor. It also cross-references OEM part numbers M3536A, M3535A, 989803129011, and M5055. Voltage and capacity match OEM specifications exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHeartStart MRx and Laerdal Monitor compatibility:\u003c\/strong\u003e\n    These units share the same 14.8V battery bay, BMS handshake protocol, and connector pinout. One cell pack covers all listed models without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge and discharge cycles on the HeartStart MRx platform. The BMS completed its handshake, accepted the charge cycle without fault, and reported correct state-of-charge after the first full conditioning cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap self-test protocol:\u003c\/strong\u003e\n    After installing this battery, let the HeartStart MRx complete its full power-on self-test without interruption. The device runs BMS verification at startup — cutting power during this sequence triggers a persistent battery fault that won't clear 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\"\u003eDevice not completing boot sequence after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe HeartStart MRx runs a multi-stage BMS learn cycle on first power-up with a new cell. If the cell voltage sits below roughly 13.5V after storage, the device may stall mid-boot or display a battery fault before the self-test completes. Connect the device to the AC adapter before powering on — this lets the charger raise cell voltage to an acceptable threshold while the BMS initialises. Do not disconnect AC power until the self-test finishes and the device shows a green ready status.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCharge indicator not reaching 100% on the first charge cycle\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe HeartStart MRx charge IC applies a conservative upper voltage limit on cells it hasn't profiled yet. On the first charge, the display may plateau at 85–95% and hold there. This is the charge IC capping current while it maps the new cell's internal resistance. Run one full charge-to-discharge-to-charge cycle and the charge IC recalibrates — subsequent charges will reach 100% and hold correctly.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43381429010522,"sku":"BWCS-PHM353MD-1","price":325.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43381429043290,"sku":"BWCS-PHM353MD-2","price":387.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43381429076058,"sku":"BWCS-PHM353MD-3","price":434.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-PHM353MD-1.webp?v=1778900788","url":"https:\/\/batteryweb.com\/products\/philips-defibrillator-heartstart-mrx-replacement-battery-148v-6000mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}