Peter looks like an amazing project. Could be bought for $1000-1500 in the US however albeit without the voltage switching. Might have to be just for the satisfaction of having done it!
Could be bought for $1000-1500 in the US however albeit without the voltage switching.
…and not even a shade of the level of quality workmanship, either, I’ll bet you! Indeed, a job like this must be done for the pride of craftsmanship – “satisfaction” could be too small a word, but I can’t think of a better just now.
Yes – I did it as a fun project.
It would be very hard to production engineer, to reduce the cost. Many years ago I used to build custom power supplies as a business. One spends a lot of money on major parts and saving a bit of labour just doesn’t make much difference.
Plus that IP67/68 box is very expensive and there is no way to reduce that. I used that box because this guy (an A&P/IA) is freelance and often has to work outdoors for political reasons, so it could get caught in the rain. The downside is that effective cooling is not possible; there is an internal fan but obviously the air can’t get out. So you could not do 40A continuously. It will run for maybe 30-60 mins before the temperature switch cuts out (depending on ambient). At say 10-15A it will run for ever. One would have to bolt a big finned heatsink on the side of it…
If one was making these in say 100+ batches then one would build the whole thing, switching PSU included, onto one PCB, and chuck it inside a box made of bent-up ally. That is probably how the $1500 units are done. Unfortunately one should not skimp on quality when building something like this because there could be 100k’s worth of avionics powered from it… Also I bet the $1500 boxes will not have a really good overvoltage trip. What they would have is a trip within the switcher, but not an extra one after it. Fortunately switchers rarely fail into overvoltage; they normally just blow up and you get no output 
But any programmable switcher could …..
A metal IP67/68 box could help a lot with the cooling issue – but would obviously be more expensive yet – even if commercially available at all, in small quantities
PS “bent-up ally” forces my memory of one Mr. Tito
Mine is metal Diecast ally.
Hi achimha, hi everyone,
did you decide for a ready made GPU? Maybe it´s an unnecessary gadget but I´m considering to get a ready made GPU sooner or later just for the reason to become a bit more acquired to all avionics adjustments and import updates.
An offer I found that seems right for my TB20GT was e.g. from “AeroPac, CONTINUOUS POWER SUPPLY 24V – 25 AMPS switchable between 12V, 14V and 28V available”.
I´m a bit in doubt (about the reliability of this unit) not to wreck my avionics because in some of the German (PuF) “Pilot und Flugzeug”-forum threads site it appeared to me that some made some unpleasant experience…
Does anybody have an acutal recommendation or contact?
Do not buy anything from Aeropac, that would be my #1 advice. I have never seen worse products than from this company. They are completely incompetent and what they fabricate is dangerous.
It’s OK to post that but you need to keep photos etc as evidence, in case they see the posting.
I have seen units from this company at some German airports, e.g. EDME. The covers on the units used to be orange and have recently become red, it seems. I do not have personal experience with them.
Achimha, Peter, I´d suggest to communicate with achimha via PM (or phone) personally and we do not run into trouble here therefore…
