[Rick6a]

The Dynon wiring harness includes a keep alive circuit. I ordered the D100 with the back up battery option and is said to be able to power the EFIS for at least 1-1/2 hours in the event of an external power failure. That seems PLENTY of time for me to find a place to land. Still, should I hook up that keep alive circuit anyway and if so, where? For instance, would it be good practice to route the keep alive circuit directly to the PC680 aircraft battery via an in-line fuse?

 

[vlittle]

The Dynon wiring harness includes a keep alive circuit. I ordered the D100 with the back up battery option and is said to be able to power the EFIS for at least 1-1/2 hours in the event of an external power failure. That seems PLENTY of time for me to find a place to land. Still, should I hook up that keep alive circuit anyway and if so, where? For instance, would it be good practice to route the keep alive circuit directly to the PC680 aircraft battery via an in-line fuse?

Rick, do not hook this circuit up if you are using an internal battery. I found the original bug in the D10A that will cause your main battery to eventually discharge if you hook this up. I think the bug still exists, and the fix is to not use the keep-alive.

 

[az_gila]

Connect it...

I think it's to keep internal clocks running when you are not flying, and keeps the internal battery charged...

These are Dynon's words for the D-180...

A very low current power input which is only used if both Master and External Backup Power are not applied. Keep Alive draws just enough current to keep the clock running and keep the optional battery charged. It draws less than 1 milliamp of current when not charging the internal battery. When charging a completely dead internal battery, the Keep Alive line can draw an average of 0.6 amps at 12 volts for 18 hours. If you have the internal battery and do not wish the FlightDEK-D180 to draw current from your plane’s battery, you do not need to connect Keep Alive. The internal battery will maintain charge without Keep Alive connected as long as the master switch power is turned on for at least 1 hour per month.

gil A

 

[Jamie]

I had the same problem as Rick. I had it wired to my battery bus and one day I went out to fly and my battery was down to 10 volts (was still able to start the engine). Knowing about this issue, I simply pulled the fuse on the keep-alive circuit. No problems since.

If I were you, I would just wire it to your battery bus but leave the fuse out. You always have the option of using the circuit later if you see a need.

 

[bjustus]

I didn't hook mine up either. Don't like the idea of it sucking juice all the time. One of the main reasons for it, (keeping the clock going) is a non-issue if you have your GPS talking to the Dynon. If hooked up to a GPS it syncs to the GPS clock at power up.

 

[David-aviator]

Rick, do not hook this circuit up if you are using an internal battery. I found the original bug in the D10A that will cause your main battery to eventually discharge if you hook this up. I think the bug still exists, and the fix is to not use the keep-alive.

I don't think it is a bug, it's normal.

I have a keep alive circuit for the D10A and memory feature in the engine computer. These items will take the Odyssey battery down in about 10 days. If I don't fly, I hook up a charger after 5 or 6 days.

 

[N941WR]

Interesting comments. I've left my plane in the hangar for over a month with both the EFIS D100 and EMS D10 Keep Alive connected w/o any starting issues.

BTW, I made the mistake of labeling one of my CB's "Keep Alive" and that is something non-aviation type passengers don't want to see in an airplane someone built in their basement.

I usually tell them not to pull that CB no matter what happens!

 

[Ironflight]

I'm hoping that the drain isn't that bad, as I hooked up the keep-alive in Louise's plane for both the D10A and D180, since I saw the wires on the drawing.....the plane will have been sitting three weeks by the time Louise gets to it this weekend - I sure hope the new battery isn't dead!

Paul

 

[Dynon]

So, there WAS a bug in the way that the software charged the internal batteries that, would, in rare cases, cause the keep alive line to pull current, slowly but consistently, until there was no more that your battery could give.

However, with our latest firmware (downloadable from http://www.dynonavionics.com/docs/support_software.html), this issue has been fixed.

Now, hooking up the "keep alive" line means that your aircraft's battery will occasionally be used to top off the internal battery if it's installed. If your internal battery is completely dead (say, after playing with your EFIS on the ground w/ master off), this could use as much as 5 amp hours off your aircraft battery (in a 12V system) to fully charge the battery back up.

Our Li-ion batteries don't really self-discharge over short periods of time like NiCd or NiMh batteries do, so once the battery is topped off, it should basically stay there unless you operate the EFIS. So with normal usage, you'd expect the battery to be pretty much full all the time and not require charging from the keep alive circuit.

But, if having power taken from your battery is something that you want to avoid entirely, simply don't connect the keep alive line. The battery will still charge whenever the EFIS has power coming to it while you fly.

Note that if you do not have the internal battery installed, you can connect the keep alive line to keep the clock going. This draws negligible power - just enough to run the clock.