{"product_id":"petzl-e36nao-replacement-battery-37v-2600mah-li-ion","title":"Petzl E36NAO Replacement Battery 3.7V 2600mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003ePetzl Nao \/ Nao+ \/ E36NAO — 3.7V Li-ion Replacement Battery (ICR18650-35)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 2600mAh (9.62Wh) Li-ion cell that replaces the ICR18650-35 in the Petzl E36NAO, Nao, and Nao+ headlamps. These headlamps are used in mining, caving, and technical outdoor work where consistent light output matters. A degraded original cell causes the headlamp to step down output early — swapping this cell restores full driver performance.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNao series compatibility:\u003c\/strong\u003e\n    The E36NAO, Nao, and Nao+ all run the same 18650 cell format with the same voltage rail and connector. Petzl's reactive lighting driver in the Nao+ communicates charge state over a single-cell BMS handshake — this cell meets that spec 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 the Nao+'s reactive lighting driver at full output. The BMS held voltage above the driver's 3.0V cutoff through a full discharge curve with no premature stepdown.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eSingle-cell replacement note:\u003c\/strong\u003e\n    The Nao series uses one 18650 cell, so there's no multi-cell balancing concern here. What matters is not mixing this new cell with a partially discharged old one if you have a spare pack — always run this cell as the only power source from a full charge to avoid confusing the headlamp's charge indicator.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePetzl Nao+ reactive driver stepping down output before the battery indicator warns you\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Nao+ uses a reactive lighting driver that continuously adjusts brightness based on ambient conditions. When the cell voltage sags under high-draw conditions — typically below 3.4V — the driver steps output down before the low-battery LED triggers. This isn't a fault; it's brownout protection keeping the driver stable. A worn cell with high internal resistance sags faster, so you see the stepdown much earlier in the charge cycle. A fresh cell at 2600mAh holds voltage above 3.4V for significantly more of the discharge curve, keeping the driver in its upper output range longer.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eHeadlamp flickering or cycling through modes at end of charge\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIf the Nao or Nao+ starts flickering or rapidly cycling modes near the end of a charge, the cell voltage is dropping below the driver's minimum threshold and recovering slightly — causing the driver to restart repeatedly. This happens with aged cells whose voltage bounces around 3.0–3.1V under load. It's not a driver fault and the headlamp isn't broken. Switch to the lowest output mode immediately to stabilise the driver, then recharge — if it happens at the start of what should be a full charge, the cell needs replacement.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43377466081370,"sku":"BWCS-PTE360FT-1","price":36.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43377466114138,"sku":"BWCS-PTE360FT-2","price":42.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43377466146906,"sku":"BWCS-PTE360FT-3","price":47.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-PTE360FT-1.webp?v=1778767154","url":"https:\/\/batteryweb.com\/products\/petzl-e36nao-replacement-battery-37v-2600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}