Or maybe the back up battery is on the edge of needing replacement?Think I may have figured this out. Only took a few months. About a week ago the same issue occurred again. Back up battery test required message even though it is less then a year since the last one. So yesterday I had the same issue still there and I took off on a 2 hour flight. In flight while drilling through some of the set up pages came across a “ back up battery voltage low on shutdown” message. Then after getting my chutes repacked fired up to fly home and message was gone. My theory is that the backup battery needed a good long flight to recharge. Not sure if that is printed somewhere or if it is institutional knowledge. Just throwing it out there as to why the issue may appear and then disappear on its own.
I am on the original 2014 battery and passed the annual test in July. I never use the bu battery for fiddling on the ground and have a lithium main battery so bus voltage is always high enough to keep the bu battery fully charged. Do not know if this helps extend bu battery life or not, but will continue the same practice in the future.Could be, but I am on my third one in 9 years. Not sure what the life expectancy is.
Yes, it does. Batteries deteriorate more with less than a full charge....Do not know if this helps extend bu battery life or not...
I would think when the battery comes close to nearly being totally discharged (around 10.5 - 11 volts?).Slight drift if I may please. On most aircraft I deal with the voltage on screen while in flight will be 14.2 to 14. V. I have a customer with an aircraft showing 13.8V max while flying. Not knowing the charging circuit can one assume that his backup will take much longer to fully charge. The manual suggests a charging time of up to four hours, but under what circumstances will it take four hours?