Battery dies after 39 hrs, on a new DA40 NG

[ledio.ago]

Hi there. Proud owner of a new DA40 NG. I was gone for two or so weeks over the holidays, and the plane didn't fly during this time. I got back today, and there was no power when turning the master on. Got some help from the local shop that helped me find the external power port so I could charge the battery, but the voltage had dropped from 24V to about 17V, putting it in red. I had left nothing on; everything was turned off, and I can't explain how the batter can be drained, given it is new.

Has anyone seen this?

[chili4way]

That is unusual if the battery was in good condition and fully charged before you left for the holidays. Did you have anything plugged into the 28V power port (that looks like a car cigarette lighter)? That's the only thing the battery powers in a DA40NG when the Electric Master is off.

Speaking of which, just plugging in the external power/GPU will not charge the battery in a DA40NG. The Electric Master also has to be turned on. This is also a good opportunity to confirm that the GPU provides ~28V. You do NOT need to turn on the Engine Master.

If this persists, you should discuss options with a Diamond Authorized Service Center.

[SJM]

Hello Ledio, I remember reading something about being careful to not leave the over head (map) light on because that will drain your battery. Not the same with the flood and dome light switches but they should be fully checked to see that they are in the off position of course. Ditto, on the gpu being plugged in to the fuselage does not charge the battery. Best of luck!!

[Bryce]

I had my Concorde battery go T.U. on me after about 60 hours on my brand new DA62 this past summer. Warrenty claim with Concorde made me whole, but it was a PITA (took 4 weeks to get reimbursed) and am lucky it happened at home and not while on a trip.

[vincent99]

As a point of comparison, mine sat for ~4 weeks over the holidays (outside, but Arizona) and I was surprised it was down to 24.0v yesterday. It still turned over fine though.

[MarkO]

My battery also became weak shortly after delivery. It lasted about nine months, and then the maintainer did a deep cycle charge. That gave me a few more months, but then I replaced it, and I haven't looked back since. I was getting less than 17 volts, but the engines still started ok.

[ledio.ago]

Thank you for the response!

The GPU was attached for several hours, and yes, the master had to be turned on during this time. I had to go to work, but it reached 21.4V after 1.5 hours, up from 17.3V. I could have probably tried to crank it, but I had no time. I returned late in the afternoon, but the shop was closed and had disconnected the GPU. I turned the master on, and nothing ...

I contacted Diamond. It's probably a bad battery that needs to be replaced. The battery warranty covers it. I'll find out more in the next few days and post it here.

[ledio.ago]

Hello Ledio, I remember reading something about being careful to not leave the over head (map) light on because that will drain your battery. Not the same with the flood and dome light switches but they should be fully checked to see that they are in the off position of course. Ditto, on the gpu being plugged in to the fuselage does not charge the battery. Best of luck!!

Well, you have to close the circuit, I think, by turning the master on for the battery to charge, and it was. The voltage meter measured 21.3 by the time I had to leave.

[ledio.ago]

Well, even after the trickle charging for a few hrs, up to 24V, as soon as you unplug it, the battery starts draining rapidly.

I used a GPU to start it and flew it to a service center to investigate it and probably replace the battery under warranty. During the flight, the voltage and AMPS readings were normal. Once the GPU was plugged in, everything came back to life, G1000, lights, ... and started immediately. Once it was turned off, though, the voltage started to drop.

Waiting for the service center to confirm a bad battery or anything else.

[MarkO]

Sounds just like mine - new battery