Minimum power configuration

[edwalker]

I have a motorglider with SV system consisting of a single D700, integrated xpdr, ads-b and autopilot. I also have a separate radio, variometer, ASI and altimeter panel for soaring which is independent of the SV system. When I change to the soaring configuration I'd like to be able to power the SV down to the minimum current draw to preserve my battery capability. If I turn it completely off I lose the xpdr and flight timers.

The plane has two independent 14 amp-hour batteries, which can be selected independently, so I always have a fresh battery for an air restart. For the purposes of this discussion consider that there is only one 14 Ah soaring battery. I can run this soaring battery fairly low on a good day if the SV is running. Two questions:

1) I understand that I can dim the screen manually, but are there any other power saving options I'm not considering? The primary goal is to preserve xpdr function and extend battery life.

2) If I shut the system off at the breaker it will run on the backup SV battery for about an hour. Is that an option I should try to avoid? Thanks for your help.

 

[airguy]

The transponder takes it's power separately from ships power, not the Skyview battery - so #2 will leave you with a functioning screen but no transponder.

 

[Dynon]

1) Well one bit of good information is that SkyView will charge the backup battery whenever the bus voltage is above 12.25V (this is normally when you have an alternator/generator charging the aircraft battery, so that SkyView doesn't the dump charge from your aircraft battery into your backup battery when you're engine's off). So if your aircraft batteries are above 12.25V, and your SkyView battery isn't, the SkyView battery will charge. Although this is seemingly just moving charge from one device to another, there is some inefficiency in the conversion, and so you'll get less overall available power across all your avionics if your SkyView battery's charging.

2) The battery wasn't really designed for this use case, but it will work. We'd recommend not leaving the SkyView battery discharged for long periods of time. In other words, charge it back up as soon as practical after a flight that depletes it. The best (and only ways) of doing this is to power SkyView with >12.25V on its main power inputs. The battery charge status can be viewed in SETUP MENU > LOCAL DISPLAY SETUP > BATTERY BACKUP STATUS