SV Power Loss

[NASA515]

On Monday, I was cruising at 4500 ft, enroute TIW - 0S9, when the screen went blank.  SV ver 10.1 - RV-12.

I observed the  EFIS 5 amp fuse on the center panel was blown.  I replaced the fuse; the system rebooted and returned to normal operation.  It remained normal for the remainder of the flight.

It was a very hot day (for the PNW), with ramp temps in the 90s and OAT at 4500 ft in the mid 80s.

I downloaded the flight data (as I do for every flight) and reviewed the voltage and amp data - with no anomalies noted.  The electrical system showed a plus 2.2 amp charge before and after the event.

On contemplation after the event, it occurred to me that the display should have switched to back-up battery power after it lost ship's power.  No?

The back-up battery operation was, is, and has been normal.

Bob Bogash
RV-12
N737G

 

[Dynon]

Yes, the backup battery should've taken over, and SkyView, even with the battery installed and when charging, doesn't pull that much current. When you replaced the fuse, and resumed/ended the flight, are you saying that it DID go to the backup battery successfully when you shut the master? We may have more questions for you shortly.

 

[NASA515]

I don't know that it ever went to the backup battery.  It quit, went blank, I changed the fuse, and it rebooted and came back on-line.

I don't know if it was being powered by ship's power or the backup battery, but I assume it was ship's power.

Yes, the amps being pulled was high, much higher than what I have seen as normal.  It declined towards the end of the flight to about 1.0 amp +/- 0.2 amp.

I plan to work on the airplane tomorrow and do some battery checks, etc, and maybe test fly the airplane and watch the current draws.

But - if there were something wrong with the alternator, battery, voltage regulator, or some other airframe system pulling amps - it WAS the EFIS 5 amp fuse that blew.

Bob Bogash
RV-12
N737G

 

[NASA515]

Oh, Yes - to answer your question - when I shut down at the end of the flight, it transferred to the back-up battery like it always does.

It did not transfer in flight.

Bob B.

 

[NASA515]

Did a lot of checks today and a test flight - all normal.

Also downloaded the Dynon diagnostic file, if someone should ever want to check it out.

Bob Bogash
RV-12
N737G

 

[Dynon]

We have an alternate theory here. When you initially turned on your SkyView that flight, was it by pushing button 1 (ie, you turned it on to have it ready for engine start) or with the master? The theory here is that you turned it on using the backup battery, and the fuse actually blew when you subsequently turned on master power (it still shouldn't have - SkyView isn't designed to pull that much power). If that's the case, you then had some dozens of minutes of power from SkyView's backup battery, depending on its charge.

In any case, we'd very much like a data log from you. I'll PM you the instructions.

 

[William_Ince]

We have an alternate theory here. When you initially turned on your SkyView that flight, was it by pushing button 1 (ie, you turned it on to have it ready for engine start) or with the master? The theory here is that you turned it on using the backup battery, and the fuse actually blew when you subsequently turned on master power (it still shouldn't have - SkyView isn't designed to pull that much power). If that's the case, you then had some dozens of minutes of power from SkyView's backup battery, depending on its charge.

In any case, we'd very much like a data log from you. I'll PM you the instructions.

Can you please PM me also on those data log instructions, in the event I ever need to send them to you? Would like to know how to do it in advance.

Thank you.

 

[NASA515]

I successfully sent the Data Log file and the Diagnostic File as requested.

Was wondering if you guys had gotten around to reading them and whether any useful info was elicited.

Bob Bogash
RV-12
N737G

 

[NASA515]

During shutdown today, SV failed to transfer to standby battery power. Do you want another diagnostic file?

Bob Bogash
RV-12
N737G

 

[bbtapb]

This reminds me of a feature request... EMS display items: backup battery % remaining and status. Pleeeeeeeez

 

[Dynon]

I'm wondering if your battery is depleted from your previous fuse event. How long have you flown since the fuse event happened?

A more robust battery status is what we were originally aiming at when we added the rundown test but for technical reasons we had to give it up.

 

[William_Ince]

This reminds me of a feature request... EMS display items: backup battery % remaining and status.  Pleeeeeeeez 

That's a great suggestion. . . .   

 

[swatson999]

This reminds me of a feature request... EMS display items: backup battery % remaining and status.  Pleeeeeeeez 

That's a great suggestion. . . .   

Not as straightforward to compute battery state of charge (SOC) as one might think, though...

 

[dynonsupport]

We have looked into it and with our battery chemistry it is not feasible to give an accurate state of charge. We had a smart guy try for over a month, and over time, temperature, and more, it's just not possible to give an accurate number. Telling you you have 30 minutes left when you only have 15 is probably worse than not knowing at all.

The system does have a warning of "LOW BACKUP BATTERY" that will occur in the messaging system. This will appear when running off master or the battery. If you didn't have this when you started up, then you should have a battery that would have lasted at least a few minutes.

The battery charges at a rate of a about 1/3- which means if your engine has been running for 90 seconds, you should have 30 seconds of backup. Thus, it's really hard to fly the plane and have the backup be so dead that it won't last through the 30 second countdown. Thus, in Bob's case, something else is likely up.

 

[NASA515]

Had another blank screen shutdown on Monday - after 2 one hour flights.  Burned another diagnostic file if you want it.

Yesterday, did two SV power-on's in the hangar, followed by two master power-off's.  In each case, SV went to Batt pwr for 30 secs normally.

Went flying for about an hour, and on shutdown, it was normal.

I plan to do the full battery rundown check to see how much juice the batt has left.

As for a juice remaining indicator, my experience with those things is they are worthless - laptops, cameras, etc.  One minute it shows a lot of power remaining, then 2/3, then it conks out on you.  It seems those batteries die quick.

It's also one of the things that makes me mistrust all electric cars.  I can see the thing telling you that you have 20 miles remaining and then croaks in the middle of the freeway during rush hour....

Bob Bogash
RV-12
N737G

 

[mmarien]

The system does have a warning of "LOW BACKUP BATTERY" that will occur in the messaging system. This will appear when running off master or the battery. If you didn't have this when you started up, then you should have a battery that would have lasted at least a few minutes.

Good to know. When the topic was brought up I thought that a battery gauge showing remaining power would be a nice thing. But then how many times would I get to use it. I don't fly around much without the alternator working so the battery level is not a concern. Nice to know there will be a warning if the backup battery is very low. A guy can take the normal precautions and not have a failed alternator for the first little while. or charge the battery first I guess. :

 

[Dynon]

Burned another diagnostic file if you want it.

Bob: Yes, please send us that log in the same way you previously did. Make sure to reference this thread when you send it. Thanks!

 

[NASA515]

SV has been failing to transfer to Standby Batt after power loss.  The first time, as noted above, occurred in flight, when the SV fuse blew.  The other times have been during normal on the ground shutdown.  Yesterday, it failed to transfer during several on the ground tests, and then again, during shutdown after a flight.

This first happened once or twice, then fairly frequently.  Now it is failing to transfer almost all the time.  I do not believe my SV will transfer should I experience another in-flight power loss.

I checked the SV Backup Batt Status via the Menu screens.

The Batt Status showed as CHARGED  12.78 volts

Ship System Voltage at the time was 13.6 volts

It could be just a bad backup battery, or it could be something else.  12.78 v represents a fully charged battery per the Instl Guide Pg 9-4.  I am unable to perform the 60 minute Batt Test since it will not go into the 30 second power off countdown where the Test Bat button selection appears.

I have forwarded another Diagnostic File per your request.

Bob Bogash
RV-12
N737G
175 hrs TT

 

[dynonsupport]

Bob,
Are you really getting 12.78V on your backup battery? You should never be able to get more than 12.30V. So if you are, something is up for sure.

 

[NASA515]

I've sent a bunch of private messages, diagnostic files, and screen shots per your request.

Had an interesting day today, with a SV crash and reboot after engine start, and data param resets, and memory loss, and loss of assorted flight segments.

I agree - "something is up for sure."

Bob Bogash