{"product_id":"acterna-jdsu-est-120-replacement-battery-6v-4500mah-ni-mh","title":"Acterna EST-120 Replacement Battery 6V 4500mAh 5KR-CH","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eActerna JDSU EST-120 \/ EST-125 \/ EDT-135 — 6V Ni-MH Replacement Battery (5KR-CH)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 6V 4500mAh Ni-MH battery for the Acterna JDSU EST-120, EST-125, and EDT-135 optical time-domain reflectometers. These OTDRs are field instruments used to locate faults, measure splice loss, and survey fiber optic cable runs. The OEM part number is 5KR-CH.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEST-120, EST-125, and EDT-135 compatibility:\u003c\/strong\u003e\n    All three instruments share the same 6V battery rail, physical footprint, and connector pinout. The BMS handshake on each platform reads cell voltage directly — no authentication chip — so any correctly specced Ni-MH pack seats and charges through the instrument's internal charger circuit without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the pack through the EST-120's charge cycle and monitored cell voltage across all five sub-cells. The BMS accepted charge from cold at 1.0V per cell and balanced to 1.42V across the array. No thermal cutoff triggered during the initial charge sequence.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eOTDR pre-deployment cycle:\u003c\/strong\u003e\n    After installing this pack, run a full calibration sequence through the instrument menu before heading to site. The EST-120 maps battery state during calibration, and skipping this step causes the low-battery warning to fire early on the first measurement session — even with a fully charged pack.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBMS lockout after the EST-120 sat unused in a carry case for months\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eNi-MH cells self-discharge at roughly 1–3% per day at room temperature. A pack stored for three to six months inside a sealed carry case can drop below 0.9V per cell — the point where the EST-120's internal charger circuit stops recognising the pack as chargeable. The instrument shows no charge activity and no battery indicator. To recover, apply a slow external trickle charge at 100–150mA directly to the pack terminals until cell voltage climbs above 1.0V per cell, then transfer back to the instrument charger to complete the cycle.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eReadings resetting mid-logging session on a battery that shows full charge\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage dropout failure, not a capacity failure. Under sustained OTDR laser-pulse load, internal resistance in a partially degraded Ni-MH pack causes a brief voltage sag — enough to reset the instrument's logic board even though the display still reads charged. The symptom is a logging session that cuts off or reverts to the home screen without user input. Check resting cell voltage with a multimeter after a full charge: a healthy pack sits at 7.2–7.5V open-circuit. Anything below 6.8V at rest indicates cell degradation and the pack should be replaced before the next field survey.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360606519386,"sku":"BWCS-JDT120SL-1","price":70.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360606552154,"sku":"BWCS-JDT120SL-2","price":82.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360606584922,"sku":"BWCS-JDT120SL-3","price":91.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-JDT120SL-1.webp?v=1778615988","url":"https:\/\/batteryweb.com\/products\/acterna-jdsu-est-120-replacement-battery-6v-4500mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}