Backup Battery

[lancegoddard]

Preparing for first start of Rotax 912iS with SVD700 and EMS221. A week ago the backup battery ran the SVD700 when turning off master switch. Now it shows battery missing. Removed it and used voltmeter with tiny probes to check the voltage and it shows zero. What would cause this? I assume it is no longer chargeable with zero voltage.

 

[Dynon]

Measuring the voltage directly at the battery won't always show a voltage since the battery has some circuitry for protection there. When it's plugged into SkyView, go to SETUP MENU > LOCAL DISPLAY SETUP > DISPLAY HARDWARE INFORMATION. What do you see under the Battery status section, both the voltage and the charge status, both before and after the aircarft is started?