Should the batteries get hot?

No, the batteries (Part #: RF16 or RF46) should not get hot. If this happens, the battery pack may be defective, or the module's circuit board may have failed. Install another fully charged battery pack in the module. Then, perform the module functional test found in RF Service Procedure Module Testing (RFS001). If this test fails, or the battery pack gets hot, contact ANKOM Technology at https://www.ankom.com/contact/technical-services or by calling (315) 986-8090 for assistance.

Note: It is normal for the batteries to warm up when charging while using the battery charger (Part #: RF25).