PFD and MFD rebooting after engine starts

[Keith M]

It began intermittently, but then the PFD and/or MFD rebooted after every engine startup on my DA40 TDI. My maintenance organization diagnosed a weak battery and replaced it yesterday. However, the reboots still occurred, so the thought was that maybe the new battery hadn't been charged for long enough. I departed for my base airfield in the hope that the alternator would complete the charge. I noticed that the ammeter was reading 29 amps throughout the 50 minute flight, so something was drawing a lot of current. After landing, I waited 25 minutes then started the engine again and the PFD rebooted. All the starts were within a couple of turns of the engine, and the starter motor didn't sound laboured.

If the new battery isn't faulty, any suggestions as to what else could be causing this?

Thanks, Keith

[pietromarx]

That's a lot of amperage; my DA40 (with the Lycoming) draws 10-11 amps on average throughout a flight (without pitot tube heat on) regardless of lighting, etc. The battery is presumably being charged at the same time, too.

Your new battery should be bench-charged before installation in any case (if the instructions need it).

To me it sounds like you have something else doing some serious electrical draw. Are you vacuuming or blow-drying during the flight? )

[Rich]

Keith, what's your normal current load? As I understand it, the TDI is a 12/14 V system, so I would expect it to normally draw roughly double what my 24/28 V DA40 does,which is 10-ish amps in daytime, depending on what I've got running at the time.

[Keith M]

Rich and Peter, in addition to the standard G1000 avionics, it has ADF, DME and TAS 600, and I was flying with the strobe on and the KAP 140 engaged, so maybe only 8-9A was for charging. The maintenance organisation have admitted that they mistakenly charged the new battery for about one third of the time specified by the manufacturer, so I'll give it a longer flight, when I can find the time.

[ThomasD]

FWIW, the only time that I have had over 20 amps drawn in my DA40 is when I had a flat battery (ground power to start). But after 1/2 hour in the air the current dropped to usual ~ 9amps.

[Keess]

This seems to be a problem for al the thielert ones. The cause seems to be a significant voltage drop during the start. Obviously the starter of the diesel engine draws a lot current from the battery. This causes the voltage to drop a lot. That's why the garmin restarts. There is a to fix this problem.

http://support.diamond-air.at/fileadmin ... supply.pdf