LMR Master™S412E User Guide : General Information : Battery Replacement
 
Battery Replacement
The battery can be replaced without the use of tools. The battery compartment is located on the lower left side of the instrument (when you are facing the measurement display). Refer to Figure: Battery Compartment. To remove the battery:
1. Slide the catch toward the bottom of the instrument.
2. Tilt the top of the door away from the unit.
3. Lift out the battery door.
4. Remove the battery pack from the instrument by grabbing the battery lanyard and pulling out.
Replacement is the opposite of removal. The battery key side (slot below the contacts) must be facing the front on the unit and slides in first. Press the battery inward firmly to seat the contacts, then reinstall the door.
Note 
When inserting the battery, the battery label must face the back of the instrument, and the guide slot on the battery must be below the contacts. If the battery door does not latch closed, the battery may be inserted incorrectly.
Battery Compartment
The battery that is supplied with the LMR Master may need charging before first use. The battery can be charged while it is installed in the LMR Master by using either the AC‑DC Adapter or the DC adapter, or outside the LMR Master with the optional Dual Battery Charger. Refer to Battery Symbols for a description of battery symbols used on the LMR Master screen.
Note 
Use only Anritsu Company approved batteries, adapters, and chargers with this instrument.
Anritsu Company recommends removing the battery for long‑term storage of the instrument.
To ensure an improved battery life, do not charge the battery above 40ºC.
Press Shift+8 > Status to view the Battery Temperature in the Status window.
If the battery temperature exceeds the limit, disconnect the AC power supply and allow it to cool down and perform a power cycle before resuming operation.
Caution
When using the Automotive Cigarette Lighter Adapter, always verify that the supply is rated for a minimum of 60 watts at 12 VDC, and that the socket is clear of any dirt or debris. If the adapter plug becomes hot to the touch during operation, then discontinue use immediately.