Strange Power Problem with EFIS D-10A

[jwachman]

I have completed fitting and EFIS D-10A, an EMS D-10 and an HS34 to my Zenith CH 701. I use an EXP Bus to control my electrics, and have had these devices connected to the Main Bus, so that they all get power for start. All has been working perfectly. But, and there is always a but...
Over the last couple of days, I have not been able to get the EFIS to come on line. The EMS works, but the EFIS just fashes ever now and then.

The fault finding - If i disconnect power to the EMS, then the EFIS will boot up just fine. If I then add power to the EMS/HS34 (which are wired together for power) all works fine. But if I put power on the EMS/HS34 and then the EFIS, the EFIS won't boot up.

I am only using the battery, which indicates 11.4 v. I charge the battery to keep it topped up.

This is not an issue with connections, as I have checked these.

It appears that it may be linked to the power left in the battery. (I am charging it overnight to check again tomorrow).

Is this a known issue if power is low?

Many Thanks

PS. I am VERY impressed by the Dynon system. I bought the wiring harnesses for the EMS and EFIS, and spent many hours reading the forums to clear some of the (self induced) issues I faced. Thanks for your great work.

Cheers

Jon Wachman

 

[dynonsupport]

So all of our products are supposed to come on at 10V. We've recently found a problem, that affects a few units out there, that cause them to not power on until around 12V, give or take a little bit. This only affects units that do not have the internal battery installed, and your unit should come on at normal aircraft power (14V when the engine is cranking).

I'm guessing that having the other items on is dragging the battery voltage down just below the threshold where the EFIS is able to turn on. I'll note that 11.4V represents a fairly discharged battery.

We have a software fix that's due to be deployed in our next update, which doesn't have a firm date yet, but will be out shortly in concert with the autopilot.

 

[jwachman]

Dear Dynon Support.
First, thank you for your quick reply.
Your expalnation aligns exactly with the symptoms I have noted. When I charge the battery back to full, them problem doesn't occur. I have also added a fix that seperates the power on for the EFIS, thus allowing me to have the EMS functional for start, but bring the EFIS on line after start.
I do look forward to the final fix when it is released, but understanding the problem has put my mind at ease for now.

PS. GREAT PRODUCT!! Keep up the good work.
PSS. I have not had any issues with the harnesses I have purchased (EFIS and EMS).