FX-3 Ignition Battery Failure

[Cactus Charlie]

I have written on this forum, and on others, about the importance of testing the emergency ignition battery. Simply changing it at condition inspection does not mean you will have a good battery for the next 12 months.

At run-up I run an emergency ignition battery test for about 10 seconds while monitoring the voltage. The rate of voltage decay is a good indicator of battery condition. A one second selection of emergency ignition is not sufficient to show battery condition.

I periodically plot the voltage seen during the ignition test. It will typically show a slow deterioration in battery performance as the battery ages. I change the battery based on this test data rather than time in service. Sometimes they will last about 18 months. Sometimes I reject them in less than 12 months.

My most recent ignition test showed severe degradation in battery capacity even though the battery had been in service for less than 2 months. This was a PowerSonic battery and the vendor has agreed to replace it under warranty.

Please test your emergency ignition battery at least on the first flight of the day.

 

[ve6yeq]

Do you have the manufacture date for the failed battery? The documentation suggests limited shelf life especially if not float charged.

 

[Cactus Charlie]

Do you have the manufacture date for the failed battery? The documentation suggests limited shelf life especially if not float charged.

I looked the date code before I fitted the battery. It concerned me but I decided I may have misinterpreted it. I'll check it again when I remove it.