EFIS D-100 power-down anomaly

[rvmills]

My EFIS D-100 is shutting off early during the 30 second shutdown cycle when I turn the battery switch off, and has me scratching my head. This appears to have started since updating to v 5.0, and installing the AP-74 and Servos, but I do not know if it is related. Here's the set-up:

- D-100 (w/ BU Batt), powered via a dedicated CB on the avionics buss.
- D-10A (w/BU Batt), powered via a second dedicated CB on the avionics buss.
- AP-74 and 2 SV-32 Servos, powered via a third dedicated CB on the avionics buss.
- D-100 Keep Alive, powered via a fourth dedicated CB to hot Batt.

I recently sent the D-100 back to you after my v 5.0 update failed, and it came back with 5.0, and all indications are normal in flight. AP is functioning, and everything on DSAB is good to go.

As I shut down the aircraft, when I turn the avionics master off, the D-100 and D-10A both begin their 30 second shutdown timer as they did before. However, if I turn the Battery master off during the 30 second countdown, the D-100 shuts off immediately. The D-10A continues it's countdown to zero, then shuts down, as it did before the 5.0 update and the AP install. That's the way the D-100 used to behave as well...this is a new phenomenon, and the batt sw never had this effect before.

Suspecting the D-100 backup battery (which was drawn down to zero during my earlier 5.0 update issues), I tried to bring the D-100 up on backup batt with Batt and Av masters off, and it booted up just fine. I did note that the clock was wrong...first time I've noted that. I've flown the airplane a few hours since the AP install, so I think the BU batt should be fully charged now.

So my questions are:

1. Given that the power wiring hasn't changed for the D-100 (the only change I made to the D-100 wiring during the AP install was to tie the AP-74 and servos into the D-100 DSAB A/B wires...power wire was not touched), is there anything you can think of that would cause this behavior?

2. Could it ba an issue with the charge state of the BU batt (and is there any way to check that state...maybe via a menu, vs. pulling it out and checking it with a meter)?

3. Given that the clock was wrong, could there be something up with Keep ALive that could cause this?

4. While I troubleshoot this, and until I figure it out, am I causing harm to the D-100 if I shut off the Batt master and the EFIS shuts down as described (I can wait the full 30 secs for the EFIS to shut off before turning the batt off, but I'd like to make sure I don't have another issue going on).

Thanks much!!

Cheers,
Bob

 

[dynonsupport]

Bob,
It can take 20+ hours to charge a battery. So if you discharged it during the 5.0 update, it may not be back yet.

You can check the status of the battery right on the unit. It's an info item, "vmeter" and the internal battery is the "I" item.

A dead battery is below 14V, and a good one is above 16V.

If you have keep alive, the unit may have decided that it doesn't have a backup battery anymore and isn't trying to charge.

Try killing all power to the unit, which means all master power and all keep alive power (either pull the KA fuse or pull the connector off the back). Now turn the unit back on. Check the voltage on the internal battery and see if any voltage is listed, and if it increases. It should go up pretty fast if it's down in the 14V range.

All that being said, if the D100 will turn on when off on just the backup battery, but will not stay on after master power is killed, well, that's really odd.

You mention "battery master" as the thing that causes the D100 to die. What is this on your plane? If the D100 is running off battery before this is turned off and then turns off when you shut this off, all I can think of is that it's somehow causing the D100 to try and power something else in the airplane which is causing it to die and turn off. This may be why your clock is wrong too- you may be getting a full reset at some point. Try and figure out exactly what causes the clock to reset, this will be a real clue.

 

[rvmills]

Thanks for the late Friday (holiday) reply!

I'll check the voltage tomorrow, then do the following (see if I followed ya):

Turn Battery switch off (that's what I called the Batt Master, it's just the on/off switch for the switched battery buss) and the Av Master off, and pull the CB for the KA.

Then turn the EFIS on via the internal BU battery, and check the voltage of the BU batt.

Then turn the EFIS off, and then turn all back on (Battery sw, Av master sw) which should fire up the EFIS. I'll leave the KA CB pulled, and see if the BU Batt voltage increases.

If it does, then I'll reset the KA CB, and see if the BU batt voltage continues to increase. If it does not, perhaps what you said about the EFIS thinking it does not have a BU batt is true...is there anyway I can "re-train" it to recognize the BU batt?

To clarify, the EFISs do not power up or down with the Battery switch. They power up when I turn on the Avionics Master switch. They both also power down (start the 30 sec timer) when I turn off the Av Master. The only new glitch is that once I turn off the Av Master and the 30 sec timer starts, if I turn off the battery sw, the D-100 dies (but the D-10A continues the timer till it shuts down at zero...the way it always did, and the way the D-100 used to.

Not sure I understand how the D-100 could be asked to power another item in the plane...it's power wire goes only to it's own CB, which is connected to the avionics bus.

I will also reset the clock, and see if it loses time only when it dies via this battery switch anomaly, or if it also loses time if I let it's 30 second shutdown timer complete it's cycle.

It's definitely an odd one. I did a panel upgrade before adding the AP, and it worked normally before the upgrade, and normally after the upgrade (with the current wiring as described). This issue just popped up after adding the AP. However, I did not change the battery switch wiring, or the D-100 power wiring during the AP install. Each EFIS and the AP get their power via separate CBs, and they all go through the Av Master switch, and not the batt switch, though the batt switch must be on for the Avionics buss to power up with the Av Master switch, of course.

I'll let you know what I can find out, and thanks again for the quick reply!

Cheers,
Bob

 

[dynonsupport]

Bo,
Your test is right.

The unit checks for a battery each time it goes from having no power to having any power. So if you have KA, it only checks when you first apply KA. So just cycling KA once should cause it to re-learn.

 

[rvmills]

DS,

Well I did some testing today, and it was interesting. It appears to be the way my KA is wired, but I'd like to bounce it off of you. Here's what I did:

Turned on the D100 and D10 with everything hooked up as it was (including KA) to get a baseline.

On that power-up, I brought up the voltmeter info, and it showed the I batt with 16.5 V...so it wasn't a low charge state. Also on that power-up I reset the clock to correct time, for the follow-on checks.

Shut all down, and let the timers on the D100 and D10 go to zero (I didn't turn off the batt sw early, so the D100 timed down to zero and shut down).

Powered up again, and the clock had kept time.

Next I powered down, but this time turned the battery off before the two EFIS clocks got to zero (like a normal shutdown flow). The D100 shut off immediately, as noted in the original post, and the D10 counted to zero.

Powered up again, and the clock had lost the time.

Shut all down and then pulled the KA CB.

Powered up, reset the clock, and repeated the same two power down procedures as above. On the first shutdown (letting both timers go to zero before switching battery off), the clock kept time, as expected.

On the second shutdown (turning battery off before timers reach zero) the D100 did not shut off immediately, and counted to zero! And the D100 kept the time when I powered up again.

AH HA! The premature shutdown only occurs when I have the KA CB in, and KA connected to the D100. I apparently have the KA power wire going to either the cold (switched) side of the battery master (instead of the hot side), or that power wire is run to the switched batt buss. Kind of defeats the purpose of having a KA line run, eh! Ran out of time to crawl under and look, but will do so next time out.

2 quick questions:

No harm in flying with the KA CB pulled, correct? The BU batt will save the clock, as long as the EFIS is run regularly (I believe I've read at least an hout per month)...correct?

In your experience, could killing the KA circuit during the EFIS 30 sec shutdown cycle cause this premature shutdown, and resulting clock loss? Just want to make sure I don't have any other issues to look for, and kinda interested in why killing the KA during shutdown would do this...just kind of curious, in a systems sense.

Thanks much, and I'll report back with the bottom line after I trace the KA power wire.

Cheers,
Bob

 

[dynonsupport]

Bob,
That is super weird. You should be able to kill/make KA as much as you want with the unit on (on master or the battery) with no difference in operation. I can't even theorize how what you are seeing is happening. The software literally doesn't know if KA is there, so it can't react to a change. Somehow the change in KA is causing the main power supply to shut down, which is truly odd.

One option is to just leave KA disconnected. If you have an internal battery, this will keep the clock alive, and as you say, an hour a month of flying will keep the battery charged. KA isn't doing much for you in your situation, and as a general install procedure, we wouldn't recommend it in a new install.

If you want to keep working at it, put a voltmeter on the KA line and see what it's doing at different phases of your switching sequence.

 

[rvmills]

Thanks, figured it was an odd ball. I'll retrace where all the KA CB wires are going. Had some help with that piece, so it may even go to an incorrect pin on the DB25. I may just remove the wire and the CB, but kind of want to solve the mystery, especially if it prevents others from doing the same thing! Will let you know what I find out next week. Thanks again!

Cheers,
Bob

 

[rvmills]

Mike and Nick (at DS):

Here's a recap of our discussion today, with a follow-on after today's flight. Please pass this to Nick as he troubleshoots KA issues and battery draining issues.

I traced and tested my KA circuit, and it is providing power to Pin 2 on the DB25 with the battery off (as it should be) so I believe that piece is wired correctly.

My tests on this shut down anomaly are four-part, as follows:

1. KA CB pulled (disconnected). Turn Avionics Master off, let D100 and D10A 30 sec timers expire, then turn off Battery Switch.

2. KA CB pulled. Turn Avionics Master off, then turn off Battery Switch before 30 sec timers run out.

3. Same as 1, with KA connected (CB in).
4. Same as 2, with KA connected.

The results below are for three different test attempts:

A. Last week, when D100 BU battery showed 16.5V
1. Normal Shutdown, timers go to zero with Batt SW on, clock kept time
2. Normal Shutdown, timers go to zero with Batt SW off, clock kept time.
3. Normal Shutdown, timers go to zero with Batt SW on, clock kept time.
4 D100 shuts down when Batt Sw is turned off (during 30 sec cycle), clock loses time (resets to 0000Z).

B. This morning, after the airplane sat for 2 days with KA CB pulled out, the D100 BU Batt had dropped to 13.4V. The tests showed the following:
On all 4 tests, the D100 dropped off line before the 30 sec timer ran out. It did not matter if I had the KA CB in or out, and it did not matter whether I turned the battery off early in the 30 sec cycle or not. In each case, I watched the voltage on the BU Battery drop from 13.4 to 12.0 in about 5-7 seconds, then the D100 would shut off, while the D10A completed it's 30 sec cycle. I did note that on tests 3 & 4 (KA CB in), I could see a faint flashing around the edges of the D100 after it shut down, and during the 30 sec cycle as displayed on the D10A. When I tried to start the D100 by pressing the soft key, it did not work with the KA CB out, but would work with the KA CB in (in which case it would only last for a few seconds, then go dark). Seems like a classic case of a very low battery, but I have no idea why it would drain so fast...then again, another factor may be that my D100 BU Battery drained fully last month when I had the 5.0 update failure, so it may not be holding a charge well, and may need to be replaced altogether.

C. After we spoke, I flew for a 1.5 today, and upon return, the D100 BU Batt showed 15.4V (D10A showed 16.2V). I ran the tests again, and it behaved exactly like it did last week...ie normal shutdown on tests 1, 2 and 3, and premature shutdown of the D100 only in test 4...with KA on, and turning the batt switch off before the 30 sec timer was done (and the clock lost its time again). By the time I was finished running the tests, the D100 BU batt had dropped to 14.8V (.6V loss), while the D10A BU batt had only dropped to 16.1V (.1V loss)(FWIW).

I really have no clue why the batt switch would do this, given that KA is not wired to it, and KA seems to be wired correctly. From our discussions, it appears that KA may be causing a drain problem after 5.0 updates, and I know you are working it. However, my D100 BU battery drained this week with KA disconnected.

Another data point is that Dan, the RV-9A guy we conference-called with, has a D180 master & D100 slave, and has seen his BU battery (in the D180 master) drain as well. He even switched the D100 BU batt into the D180, and then that one drained too (while in the D180 Master), much as mine did. My BU Batt problems are also in my Bus Master, but I have not switched the batteries to see if the D100 drains a second battery (I want to keep one BU Battery alive!!)

One thought for a test...would you be willing to send me a fresh BU battery, which I will place in my D100. Then I will disconnect the KA completely, and watch to see if the D100 (Bus Master) BU Batt drains quickly. Nick mentioned a possible software patch test, and I'm happy to do that as well. If a fresh battery and the patch (or disconnecting KA) solves the problem, and the BU battery does not drain prematurely, I will of course buy the fresh BU battery (at a substantial discount, since it'll be a "used" battery, of course!)  Just kiddin'!

Apologies for the long post, just wanted to provide Nick with the data as he works on the software. Please let me know if there are any more tests you'd recommend running.

Thanks much for the good discussion today!
Bob

 

[dynonsupport]

Bob, as discussed yesterday your battery going from 13.4V to 12V quickly is totally expected when it is down in that voltage range. 13.4V on that battery is almost all the way discharged so you are just seeing its last breath. What we will focus on is why it got discharged. But your battery is not the problem, the thing that drained it is what we need to focus on. Once we nip this, your battery will charge and be happy. These batteries last for a very long time in our EFIS.

We are actively working on some things here and will be in touch.

 

[marc.dahlet]

Hello,
Excuse me, but I have exately the same problems : immediate power-down when switch off, and loss of the hour. Internal power is very low (13.2 V after 1h30 flight; may be 0 before flight..). Is it usefull to change the internal battery ?
Thanks
Marc

 

[dynonsupport]

Not change it, but charge it. It will take 10+ hours to fully charge to 16V when that low. Also, are you running the latest version of firmware?

 

[marc.dahlet]

thankyou fo answering
Yes, I run firmware 5.0.
The question seems perhaps ridiculous, but : what's the best procedure for full charging the internal battery ?
Marc

 

[dynonsupport]

Just have it on external power for a bunch of hours. In an aircraft, hooking a battery charger up to the battery helps. You can even turn off the EFIS by holding the left button and the battery will continue to charge behind the scenes - as long as it has power coming into it.

 

[marc.dahlet]

This afternoon I watched the charge of internal battery: 0 Volt!
My last flight was a week ago and at the end of flight (1h30), the charge of the internal battery was 13.2 V, but EFIS D100 shut down immediately when switched off.
Why it that the battery completely empty?
Is there any internal consumption even when the unit is off?
Do you think the battery is still good, or is it permanently out of service?

 

[dynonsupport]

Marc,

Take a read through this post. We may have a solution to the problem you may be having.