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Re: Oxygen Concentrator

Posted: Tue May 31, 2022 11:29 pm
by dmloftus
Rich wrote: Tue May 31, 2022 10:58 pm The accessory plug is 28V, directly connected to the hot bus.
Hi Rich,
Really? The cigarette lighter adapter? No 12V regulator inline with it? While I've never used it, seems dangerous at 28V as people would be plugging in auto accessories that are meant for a max of 16V and frying them. I noted the 2A max but never checked the actual voltage. Just assumed it was 12V like a car. You mention 'directly connected', does it have it's own breaker? I'd look myself, but my plane is at Southtec, north of Charlotte.

So if it is actually wired directly to 28V, would it be wise to rewire it and run thru an open breaker slot so it can handle 5A?

Re: Oxygen Concentrator

Posted: Tue May 31, 2022 11:44 pm
by Rich
dmloftus wrote: Tue May 31, 2022 11:29 pm
Rich wrote: Tue May 31, 2022 10:58 pm The accessory plug is 28V, directly connected to the hot bus.
Hi Rich,
Really? The cigarette lighter adapter? No 12V regulator inline with it? While I've never used it, seems dangerous at 28V as people would be plugging in auto accessories that are meant for a max of 16V and frying them. I noted the 2A max but never checked the actual voltage. Just assumed it was 12V like a car. You mention 'directly connected', does it have it's own breaker? I'd look myself, but my plane is at Southtec, north of Charlotte.

So if it is actually wired directly to 28V, would it be wise to rewire it thru an open breaker slot so it can handle 5A?
There's a fuse. Wiring from the AMM. Fuse is in the engine compartment. The socket is placarded with the correct voltage.
Screen Shot 2022-05-31 at 16.35.30.png

I think newer DA40s may not have this at all, however.

Re: Oxygen Concentrator

Posted: Wed Jun 01, 2022 12:56 am
by blsewardjr
You may need more than 5 amp. From the Imogene G5 manual -

“Ensure that the automobile power socket is adequately fused for the Inogen One® G5 power requirements (minimum 15 Amp). If the power socket cannot support a 15 Amp load, the
fuse may blow or the socket may be damaged.”

Re: Oxygen Concentrator

Posted: Wed Jun 01, 2022 3:07 am
by dmloftus
Thanks Rich and Bernie. Checking the G5 manual, it claims maximum power consumption of 120W. So that's about 4.3A at 28V. 5.0A if running directly off a 24V battery.

Rich, If I calculated worst case, the Hot Bus would not also require inclusion of a diode drop?

Re: Oxygen Concentrator

Posted: Wed Jun 01, 2022 3:25 am
by Rich
dmloftus wrote: Wed Jun 01, 2022 3:07 am Thanks Rich and Bernie. Checking the G5 manual, it claims maximum power consumption of 120W. So that's about 4.3A at 28V. 5.0A if running directly off a 24V battery.

Rich, If I calculated worst case, the Hot Bus would not also require inclusion of a diode drop?
The socket is placarded against use in flight. Many of us (me included) have ignored this limitation and used it to power portable avionics of one sort or another. But for a load like this I’d suggest removing that plug from the hot bus and wiring it (or a replacement) to its own breaker off either the essential or main bus. As an example, I had it removed altogether and installed a Stratus USB power plug in its location, connected to the avionics bus.

This assumes the G5 will run off 28 volts. Otherwise you’ll need a DC-DC down-converter in there somewhere.

Re: Oxygen Concentrator

Posted: Wed Jun 01, 2022 3:37 am
by dmloftus
Thanks Rich. I agree it's safer on a breaker. In an earlier post, someone mentioned Inogen Aviator that has a DC-DC brick for the G5 capable of up to 32V. Interestingly enough, I'm looking through the AMM for the wiring diagram you clipped above and I notice a DA40 version on page 2779 that shows a 10A fuse for the accessory plug! How would I know which of these wiring diagrams would apply to my specific airframe? If Diamond installed a 10A on one version and a 3A on another, could the wiring be identical and leave me the option of just installing a larger fuse? I can always have my shop reroute the source to the breaker if the rest of the wiring and socket can support 10A.
page2779.JPG
P.S. I noticed there is another wire coming off J2410-E (that powers the accessory port) that goes to schematic DA4-9234-50-16 referencing 23308B18. If you track that to the other page, it may actually power a GNS430 in some variant. Crazy that they power an accessory plug and a GPS off a 10A fuse, not protected by a breaker!

Question remains whether accessory plug and wiring could handle 10A, or even 5A

Re: Oxygen Concentrator

Posted: Wed Jun 01, 2022 4:52 am
by Rich
David, you’ve now discovered one of the conundrums of the AMM - which of these diagrams applies to me :scratch: The AMM contains multiple instances where prior and later revisions of some diagrams are all included. The page you’ve come across is long obsolete. You’ll notice that the 10A fuse feeds more than just the auxiliary socket. The additional feed allowed bypassing the avionics bus and powering the GNS430 and GMA340 directly off the hot bus, via a switch located who-knows-where. Obviously this doesn’t apply to your plane (or mine).

I’ve had to wade through the various diagram chains to determine which diagrams (and versions thereof) apply to my plane.

The relevant fuse is located in one of three holders accessible at the top of an enclosure against the right side of the firewall in the engine compartment. It requires removing the upper cowl for access. The three holders are clearly marked. I use the no-longer-applicable AUX holder to hold a blown fuse for doing maintenance that requires disabling power to my Surefly.

Re: Oxygen Concentrator

Posted: Thu Jun 30, 2022 11:05 pm
by dmloftus
I now have a dedicated 7.5A breaker to an upgraded 28V lighter plug to power an Inogen One. Anyone else looking to purchase an oxygen concentrator, maybe negotiate a quantity discount?

Re: Oxygen Concentrator

Posted: Fri Jul 01, 2022 1:48 pm
by chili4way
I did the math for my flying and decided a concentrator wasn't the right solution for me. My Mountain High O2 system meets my needs, and I almost always fly using it on long XC trips at 13,000'-15,000' with two people. Still, the idea of 'unlimited' supplemental oxygen and never needing to worry about finding a place (or the expense) to refill the tank is attractive.

I think a concentrator is a great solution for one-way solo ferry pilots because it can be taken on commercial flights, and the battery pack is sufficient for most such missions.

Re: Oxygen Concentrator

Posted: Fri Jul 01, 2022 2:57 pm
by Soareyes
I recently flew with my oxygen concentrator from Florida to Oregon and back. Some of the multi-leg days were 7-8 hours of flying in the mid to upper teens and running the concentrator at levels 4-6 so a good test of battery consumption. On the longest, highest flying day my double battery got down to 38% power remaining. I would estimate that one double battery was good for one person for probably ten hours of use. We have two units so my wife and I each have our own.

Having an "unlimited" supply of oxygen was a big psychological difference. No hesitation to put it on early, fly higher, leave it on longer and no wondering how much hassle it was going to be to fill the tank. Fill it up in the hotel at night.