Keysight N9923-90001 User’s Guide241Working with the Lithium-Ion BatteryCharging the BatteryThe battery in your FieldFox will have either 4 or 5 LED segments.Charging the BatteryWhen you receive your FieldFox, the lithium-ion battery is partially charged toapproximately 30% to 40% to preserve battery life. Allow four hours to fullycharge the battery internally, or three hours by using the external batterycharger (N9910X–872). A fully charged battery will power your FieldFox forabout four hours. It is NOT necessary for you to charge the battery.The FieldFox circuitry ALWAYS prevents the battery from discharging to a levelthat is damaging. However, if the battery is completely discharged, theFieldFox may not turn ON. If this occurs, the battery can still be charged eitherinternally or externally.Because a lithium-ion battery has no memory effect, you can charge a batteryat any time regardless of the current charge status. However, this could impairthe accuracy of its internal charge-remaining indicator. When the Max Error isgreater than 10%, the battery should be reconditioned. Learn more in“Reconditioning Battery” on page 244.Internal Charging with the AC/DC AdapterInternal charging time for a fully deplet ed battery is approximately 4 hours withthe FieldFox either ON or OFF.5-segmentGaugeChargeRemaining4-segment Gauge Charge Remaining5 segments ≥80% 4 segments ≥75%4 segments 60% to 79% 3 segments 50%,to 74%3 segments 40% to 59% 2 segments 25% to 49%2 segments 20% to 39% 1 segment < 25%1 segment < 20%Read the safety information in “For the AC/DC Adapter” on page 250.
