{"product_id":"waygate-replacement-battery-74v-3900mah-li-ion","title":"Waygate LI-138 7.4V Inspection Battery Replacement 3900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eWaygate LI-138 — 7.4V Li-ion Replacement Battery (LI-138)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V 3900mAh Li-ion pack replaces the OEM LI-138 battery used in Waygate handheld non-destructive testing instruments. It fits portable ultrasonic and radiographic flaw detectors used for weld inspection, material analysis, and structural integrity checks in field conditions. Voltage is 7.4V nominal; capacity is 3900mAh (28.86Wh).\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNDT instrument compatibility:\u003c\/strong\u003e\n    Waygate flaw detectors require a battery that meets a strict BMS handshake on power-up. The LI-138 form factor, connector pinout, and cell voltage curve match what the instrument's power management circuit expects — a mismatch here causes an immediate power fault before the boot screen loads.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this pack through probe initialisation sequences and sustained ultrasonic pulse cycles. The BMS held within normal cutoff thresholds during the high-current transient at probe power-up, and cell voltage stayed stable under continuous sensor load.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePre-deployment calibration cycle:\u003c\/strong\u003e\n    After installing this pack, run a full calibration cycle through the instrument menu before taking it to site. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings on the first measurement session, even with a fully charged cell.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBMS cutoff when the probe module powers up\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWhen a Waygate flaw detector initialises its probe, the instrument draws a short but sharp current spike — often 2–3× the steady-state load. If the battery's BMS has a low peak-current threshold, it interprets that spike as a fault and trips the output. The instrument sees this as a sudden power loss, not a battery error, so the screen goes blank rather than showing a warning. This pack's BMS is rated to handle probe initialisation transients without tripping. If the instrument still cuts out at probe power-up, check the probe connector for resistance — a corroded pin increases inrush current.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eInstrument won't recognise the pack after months in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage. If the pack drops below roughly 2.5V per cell (5.0V total), the BMS enters a sleep state and blocks charge input — the instrument shows no battery detected and the charger reports no connection. To recover, apply a trickle charge at 0.1C using a compatible Li-ion charger that supports a pre-charge or recovery mode; this brings cell voltage back above the BMS wake threshold. Once the pack reads above 6.0V, normal charging resumes. Do not attempt recovery with a fast charger — the BMS will reject the charge request before cells are stable.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43303967752282,"sku":"BWCS-WDM138SL-1","price":303.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43303967785050,"sku":"BWCS-WDM138SL-2","price":363.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43303967817818,"sku":"BWCS-WDM138SL-3","price":407.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-WDM138SL_1.webp?v=1777520735","url":"https:\/\/batteryweb.com\/products\/waygate-replacement-battery-74v-3900mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}