{"product_id":"theradome-lh40-replacement-battery-37v-2600mah-li-ion","title":"Theradome LH40 Replacement Battery 3.7V 2600mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTheradome LH40 \/ LH80 \/ LH80 Pro — 3.7V Li-ion Replacement Battery (INR18650-1S1P)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 2600mAh Li-ion cell replaces the internal battery in the Theradome LH40, LH80, and LH80 Pro laser hair growth helmets. The original INR18650-1S1P format is a standard 18650 single-cell configuration running a 1S1P arrangement. Capacity and voltage match the OEM spec exactly — 9.62Wh total.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLH40, LH80, and LH80 Pro compatibility:\u003c\/strong\u003e\n    All three Theradome helmets share the same single-cell 18650 battery bay, voltage rail, and BMS handshake protocol. One cell format covers the entire current Theradome lineup 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 LH80 unit. The onboard BMS accepted the cell without error, balanced the charge curve correctly, and held voltage within spec across a full session.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePort moisture before charging:\u003c\/strong\u003e\n    After using the helmet — particularly if worn during a warm environment or scalp perspiration is a factor — let the charging port air out for at least two minutes before connecting. Residual moisture at the contacts can trigger a BMS protection fault that registers as a dead battery rather than a charge error.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBattery fade from daily top-up charging on the Theradome\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eMany Theradome users charge after every session rather than waiting for the battery to drop meaningfully. Li-ion cells degrade faster when cycled repeatedly in the upper 80–100% range without full discharge. This compresses the usable capacity over time and causes the charge indicator to drift — showing full when actual stored energy is well below spec. To slow this, allow the cell to discharge to around 3.2–3.3V before reconnecting the charger.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eHelmet powers on but laser array cuts out mid-session\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage sag symptom, not a controller fault. When the 18650 cell ages, its internal resistance rises. Under the combined load of 80 laser diodes, the voltage drops sharply during peak draw — enough to trip the BMS low-voltage cutoff even if the indicator still shows charge remaining. A new cell at full 3.7V nominal resolves the sag. If the issue persists with a fresh cell, check that the battery contacts inside the helmet are clean and making firm contact.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43415959011418,"sku":"BWCS-THL400SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43415959044186,"sku":"BWCS-THL400SL-2","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43415959076954,"sku":"BWCS-THL400SL-3","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-THL400SL-1.webp?v=1779758652","url":"https:\/\/batteryweb.com\/products\/theradome-lh40-replacement-battery-37v-2600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}