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Power supply for testing

RVG8tor

RVG8tor

Well Known Member
Yesterday I spent most of the day updating and configuring my panel and manged to drain the battery to 9 volts.

I have a 15 amp Radio Shack power supply, there must be some way I can use this, instead of draining the battery then charging over and over. So my question is how to do this? If anyone has some ideas please let me know, I tried a search of "power suppl panel testing" and really did not get a direct answer.

My thought is to hook up the power supply like it was the alternator, Ground the black terminal from the supply to the aircraft and attach the red terminal to the bus feed wire. Would this work, should I use some form of fuse other than the internal fusing of the power supply. I really need hour learning this equipment so I need to do something. I would even entertain the purchase of another supply if it would do the job.

Thanks
 
Just get yourself an Odyssey batter charger and leave it connected while you are doing your checks or charge it when you are done. I would not use an inexpensive RS power supply to power your high $$$ avionics stack :eek:

Keeping the battery in the system while the equipment is powered is important to keep the voltage output smooth and constant (acts as a large filter capacitor).
 
RVG8tor said:
My thought is to hook up the power supply like it was the alternator, Ground the black terminal from the supply to the aircraft and attach the red terminal to the bus feed wire. Would this work, should I use some form of fuse other than the internal fusing of the power supply. I really need hour learning this equipment so I need to do something. I would even entertain the purchase of another supply if it would do the job.
Click to expand...


Walt's suggestion will work fine, but what you suggest is very similar to what I do when building up a Technically Advanced Aircraft (where I need LOTS of power-on testing time). I use a 50 Amp Pyramid power supply, and hook it in to a special connection on the alternator feed. This is part of the aircraft wiring harness, so that I can use it for software testing and maintenance checks throughout the airplane's life. Doing this allows you to put off buying a battery early in your build if you so desire (I like a newer battery when it comes time to do engine starts), since you may well be doing power on testing a year in advance of NEEDING a battery.

Just another solution.

Paul
 
Battery Tender

The Deltran Battery Tender does a great job of automatically maintaining the charge on my battery. I leave it plugged in all the time and forget about it. For me, it has been a worry-free way to test avionics without ever discharging the battery.

The Battery Tender always seems to do what you want it to without user intervention. It doesn't even care if you temporarily disconnect it from AC power. When power is restored it just goes back to work. I've never seen it get confused in any scenario. It never undercharges or overcharges.

I can't speak for other brands, but I'm happy with my Battery Tender. For its purpose, I'm happier with it than any of my Apple products!

How's that for an unpaid endorsement?


M
 
I bought one of these http://www.startpac.com/53025-12.php back when I was building. It was an item at a charity auction at the NBAA convention that year and I don't remember what I paid for it. It has worked quite well and the company has been great to work with when I had a problem with it recently. They fixed it and treated it as a warranty fix even though the unit is about four years old. That is great customer service. It does require a standard three prong aircraft external power plug and might be more $$$ than you want to spend, but it is the right tool for the job.
 
Amps

Good point, Paul.

The Battery Tender doesn't generate enough current to maintain the battery power with all the gizmos turned on, but I got my panel working by testing one or two systems at a time, and it's more than adequate for that.

If you turn on everything, the charger can't keep up, but as soon as you shut the systems down, the charger goes to work topping off the battery again.

M
 
Have an tender

I was using a battery tender last night but the voltage slowly trickled down as I had things on for several hours. Heck the battery was at 9.9v when I shut it down, it has been about 10 hours on the Tender and the voltage is only back up to 11.5V.

@ Paul,

When hooking up the power supply to the alternator feed line, do you have a battery hooked up, my thinking is this might be a good idea, but then maybe not. My alternator feed runs though an ANL, rated for 60 amps though it is marked 40 amp. Should I put in a lower amperage ANL. I know the power supply has an internal breaker that will protect it.

Thanks for all the help guys, I am slow so I need hours with the book in hand, as I read I like to touch what I am reading about, I am more of tactile learner. Besides it is so cool to see the multi-thousand dollar toys work!
 
I too have the 15a Radio Shack power supply (for sale now). It worked great for powering up my system. I hooked it up to my main buss as if it were the alternator. No problems. I didn't want to use the battery as I was messing around too much and was afraid I'd cook something for sure. The internal fuse of the power supply never blew, but I am sure it would do well to protect the $$ avionics.
 
RVG8tor said:
When hooking up the power supply to the alternator feed line, do you have a battery hooked up, my thinking is this might be a good idea, but then maybe not. My alternator feed runs though an ANL, rated for 60 amps though it is marked 40 amp. Should I put in a lower amperage ANL. I know the power supply has an internal breaker that will protect it.
Click to expand...


Generally, I use this system without a battery during construction - the power supply is designed for powering 12 volt electronic systems for testing, so it does the job just fine. I do hook it in upstream of my main circuit protection (I use a 50 amp breaker to protect for a main bus short), but the power supply has internal protection.

I started my first plane using a 10 Amp supply, but as the systems grew, the load got too much - I have never regretted buying the larger supply - I use it all the time!

Paul
 
Pure DC

The main thing is your electronics need pure DC. Most chargers "chop" the incoming AC, resulting in very dirty DC. I would resist using any charger to power any electronics without a battery in the circuit. Even DC power supplies can be pretty dirty unless you have one that is specifically designed for electronics.
 
If your comfortable with power supplys

Check out http://www.mpja.com/
They sell mostly surplus supplies I saw many there that would do the job.
Just make sure you do not use a 'battery charger' without a battery in the circuit to clean it up!
Avoid any supply with a listed 'minimum load' for bench purposes
 
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

As another option, I followed the above article. It was fairly easy to do with an old computer lying around. However, a few months ago, I needed to buy a new higher power computer power supply, so I bought a $30 500W supply, added a 10W resistor and cut some wires together. It was internal circuit protection unlike a battery. It's designed to work with computer motherboards and CPUs, so i figured it was good enough for avionics.

Jae
 
Shack 15 amp seems to work

Here is what I did, I ran the ground terminal from the power supply to the ground bolt on the firewall, all ground tabs hook here. The red I ran through an in-line fuse to the terminal off the battery contactor, it has the fat wire that runs to breaker busses. Of course this by passes the battery contactor, but if I open the battery switch current flows to the battery. I am getting a good steady 13.6V at the bus.

So with the battery open this should protect things yes, no maybe? One of you mentioned dirty power, the voltage seems to be pretty steady and did not fry my Dynon equipment, I had not turned on any radios yet . I stopped what I was doing with the power supply to get my phone jacks installed.

Basically this Radio Shack it meant to be used to bench test DC equipment.
 
Originally, I went with the large Odyssey charger for doing my avionics testing and learning. I then (inevitably) left the master on overnight. Fried the charger.

I then bought the Radio Shack power supply and hook it up as you say. No problems ever since, but then again haven't left the master on again (yet!).:D

Jeremy Constant
 
ham radio power supply

I just recently received my G3X equipment and won't be able to work on the airplane install for 6 weeks or so due to work constraints. However, I want to connect the wiring harness to all the equipment on my table at home and get familiar with pushing buttons, etc.
I'm planning on either bringing home a spare PC-680 battery and charger that I have at the hangar, or moving my Astron 35 amp power supply from my ham radio setup.
I think that either way I will have a good source of clean 12 v (ok..13.8 from the Astron) power to power up the equipment.
 
Converted PC power supplies put out at most 8 Amps on the 12 volt line. I used one for the 12 volt line I have running throughout my house but then as I put more items on it, it topped out at about 7 amps and then the voltage just dropped. I then ordered one of these units. Adjustable voltage (12-15) and up to 25 amps. $40 and free shipping. Whereas the converted PC power supply could not keep up with load additions, this unit never misses a beat.

s350-1.jpg
 
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