Backup Battery Charge Low alerts

[jsalak]

Last couple of flights I have been getting a lot of audio alerts 'MESSAGE' with no accompanying text in the message list on the display. Looking at the exported alert file I find a bunch of BACKUP BATT LOW CHARGE alerts that set and immediately clear. These are a bit of a nuisance as there is not much I can do inflight to change or charge the battery. Is there some reason the message does not simply latch for the remainder of the flight (power on cycle)?

Here is an example of two from a list of 15 that occurred over a 16-minute period.

15:34:40​	TEXT	SHOW	alertBACKUP BATT LOW C
15:34:40​	AUDIO	PLAY	SYS_MESSAGE
15:34:40​	AUDIO	PLAY	SYS_MESSAGE
15:34:40​	TEXT	HIDE	BACKUP BATT LOW CHARGE
15:34:45​	TEXT	SHOW	alertBACKUP BATT LOW C
15:34:45​	AUDIO	PLAY	SYS_MESSAGE
15:34:45​	AUDIO	PLAY	SYS_MESSAGE
15:34:46​	TEXT	HIDE	BACKUP BATT LOW CHARGE

 

[Rhino]

If you don't want to fix your battery problem, you could just disconnect it. That would make the messages go away. What software version are you running? Are you still running a single D1000?

 

[RB-RV9A]

After this last update mine is doing the same warnings. I have a HDX

 

[Rhino]

This started immediately after the upgrade? What version did you upgrade to?

A practice I've continued since I started working electronics and computers is never to immediately install new updates. Bugs can unfortunately be included. Not saying that's necessarily what this is. Just sayin....

 

[RB-RV9A]

after this very last update. Can’t recall the version number.

 

[jsalak]

I don't think it is a battery problem. If the voltage was in fact low and triggered the alarm, it would remain displayed. I have had a low battery state in the past and the alarm remains on the message list until the charge state is high enough to hide the message. If you look at the time index you will see the alarm sets and clears in the same 1 second time tick. I have no idea if there is any signal conditioning on the battery voltage check or how often the task runs, but setting and clearing within 1 second is not consistent with a battery charge/discharge profile. In the past I have observed this error triggering just before an auto-reboot occurs. 16.7.0 fixed the auto-reboot problem, which started shortly after I updated to 16.6.0. Not in any hurry to move to 16.7.4 based on the change list.

 

[Rhino]

It could be the battery if it's having difficulty holding a charge. Other than that, I would guess you may have some sort of spurious issue going on, maybe a loose wire or hardware failing. That's the only reason I can think of for a recycle of the error in one second, other than a software glitch. If the battery was failing, you'd tend to think the error would last longer. According to the manual, that message means "The backup battery connected to the SkyView display has a low charge but is not in use." It doesn't explain exactly what they mean by "in use", but presumably they're referring to it not being on backup power. Given that it just popped up out of nowhere, and that it only happens in flight, I wouldn't really suspect a software issue, but you never know. Were I you, I'd start by checking, disconnecting and reconnecting the wiring to the battery. If inflight vibrations are causing that though, everything may still, physically, appear normal. Then I'd contact Dynon to see what they think.

 

[jsalak]

I suspect it is a software issue and most likely related to the battery charging part of the code. Battery voltage is reading 12.08, a bit low but not bad enough to be triggering low voltage alarms.

 

[Raymo]

12.08 volts is a bit low for the backup battery. Have you tried running a battery test?

 

[Rhino]

BACKUP BATT LOW C isn't really a voltage alarm, per se. It just means the voltage isn't sufficient to charge the backup battery, 12.25 volts minimm. Technically, the battery still charges below that level, but at a rate that is considered insufficient.