LARGE RED CROSSES DYSPLAY on EFIS :(

[Jean-Pierre Jacob]

1 or 2 seconds after engine start, 90% of EFIS parameters are red crossed. I need to launch the engine start procedure (Rotax 912 iS) up to 5 times before EFIS works. Sometimes I even need to launch the EFIS using its built-in emergency battery.

Has anyone ever encountered similar symptoms? If so, I'd be most grateful if you could please help and share a procedure to try and isolate the fault.

Kind regards,

Jean-Pierre Jacob, FRANCE

 

[airguy]

Do the EFIS parameters show up prior to cranking the engine, and then come up with red crosses after cranking? If so, that's probably voltage drop associated with the starter causing that - and that can be fixed. First thing is to identify the problem that is causing the symptom.

 

[Jean-Pierre Jacob]

Do the EFIS parameters show up prior to cranking the engine, and then come up with red crosses after cranking? If so, that's probably voltage drop associated with the starter causing that - and that can be fixed. First thing is to identify the problem that is causing the symptom.

 

[Jean-Pierre Jacob]

Do the EFIS parameters show up prior to cranking the engine, and then come up with red crosses after cranking? If so, that's probably voltage drop associated with the starter causing that - and that can be fixed. First thing is to identify the problem that is causing the symptom.

The situation is exactly as you describe. Since the battery was changed yesterday, I suspect it could be a cause for a voltage drop. With your indications, I'll speak again with the mechanics who performed the job on my aircraft and check if this could be the cause for this. Thanks for your help

 

[swatson999]

You mean the main aircraft battery was just changed? And what is the state of charge of the backup battery?

 

[Jean-Pierre Jacob]

Yes, the main battery was just changed and the backup battery good (tested 15 days ago)

 

[swatson999]

Yes, the main battery was just changed and the backup battery good (tested 15 days ago)

OK, did you fly for an hour or so and charge the backup battery after it was tested? (It may have been run down low enough to not hold the system up during start, when the main battery bus voltage drops during cranking, which is *normal*).

 

[sunfish]

Jean - Pierre, it sounds to me like your battery is not sufficiently charged. I assume you have switched off the “start power” switch before restarting the Skyview, so the battery is charging. Is the new battery a lithium one by any chance?

 

[swatson999]

Let's try this...from the installation manual:

SkyView displays require a minimum of 10V, and during engine start, it’s common for the electrical system to temporarily drop below 10V. If an SV-BAT-320 backup battery is not installed, SkyView may shut off / reboot. If you wish to monitor your engine prior to engine start, an SV-BAT-320 backup battery should be installed so that the SkyView display can switch to the SV-BAT-320 when its power inputs are not receiving at least 10V. The SkyView display will switch from SV-BAT-320 to ship’s power when its power inputs receive voltage above 10V.

A discharged backup battery will act just like one that's not there. And, from the user's manual:

Charging a completely discharged [backup] battery may take up to 4 hours.

It doesn't usually take that long, but an hour or two is not unreasonable. AND, without a backup battery, depending on your engine/starter demands, it's quite likely that the voltage to drop below 10V during start.

Go fly for a while, check your backup battery charge by looking in the menus afterwards, and make sure it's above 12.25V first.

 

[Jean-Pierre Jacob]

Thank you very much for your precious advice

 

[Jean-Pierre Jacob]

Jean - Pierre, it sounds to me like your battery is not sufficiently charged. I assume you have switched off the “start power” switch before restarting the Skyview, so the battery is charging. Is the new battery a lithium one by any chance?

I changed my Lithium battery to a lead battery; I hope this is a good option, especially when it comes to security?
Thanks for your advices