Paul Eastham
Well Known Member
This worked for me, but TRY THIS AT YOUR OWN RISK 
Last weekend my airplane was on display at Yuri's Night at NASA Ames (an annual party to celebrate space exploration) -- an event that lasts from 2PM to 2AM. I thought it would be cool to let people see all the avionics/Dynons running during the day, and of course my fancy LED position lights and strobes at night.
Certainly my battery wasn't going to last 12 hours running all that stuff, so I looked for other options. My Battery Tender only puts out 750mA, not enough for the estimated load of 10A.
I found this page on the web about how to convert your old PC power supply to a lab power supply. I had a pretty nice one lying around...It took about an hour to open it up, install a large power resistor (cost: 55 cents), and cut all the leads (I only brought out the 5V and 12V leads, I can add the others later). Worked like a charm! The only minor problem was that the power supply was rated to 15A at 12V, but the voltage was already starting to drop at 10A -- there may be multiple circuits to provide the aggregate 15A. But 10A was enough for what I wanted to do.
Once on location at the exhibit, I hooked the ground lead to the firewall and fished the other to the spot where my alternator connects. I fed both of these wires in via the exhaust outlet area, without decowling. Please check your electrical system carefully for the proper spot to patch in. Also check if you're energizing anything dangerous! On my airplane, this allows the contactors to be off and the battery totally disconnected. But the starter will be hot, so I put a cover over the starter switch and cordoned off the prop area just in case. I doubt the power supply would move the prop much before it fried out, but who knows...
Another warning would be to watch out for overheating on the power supply and any exterior lights you are running, since there is no airflow. My tail position light lens went a bit opaque from the heat.
It was worth it, though, for cool shots like this:
Some more photos from the event are here.
Last weekend my airplane was on display at Yuri's Night at NASA Ames (an annual party to celebrate space exploration) -- an event that lasts from 2PM to 2AM. I thought it would be cool to let people see all the avionics/Dynons running during the day, and of course my fancy LED position lights and strobes at night.
Certainly my battery wasn't going to last 12 hours running all that stuff, so I looked for other options. My Battery Tender only puts out 750mA, not enough for the estimated load of 10A.
I found this page on the web about how to convert your old PC power supply to a lab power supply. I had a pretty nice one lying around...It took about an hour to open it up, install a large power resistor (cost: 55 cents), and cut all the leads (I only brought out the 5V and 12V leads, I can add the others later). Worked like a charm! The only minor problem was that the power supply was rated to 15A at 12V, but the voltage was already starting to drop at 10A -- there may be multiple circuits to provide the aggregate 15A. But 10A was enough for what I wanted to do.
Once on location at the exhibit, I hooked the ground lead to the firewall and fished the other to the spot where my alternator connects. I fed both of these wires in via the exhaust outlet area, without decowling. Please check your electrical system carefully for the proper spot to patch in. Also check if you're energizing anything dangerous! On my airplane, this allows the contactors to be off and the battery totally disconnected. But the starter will be hot, so I put a cover over the starter switch and cordoned off the prop area just in case. I doubt the power supply would move the prop much before it fried out, but who knows...
Another warning would be to watch out for overheating on the power supply and any exterior lights you are running, since there is no airflow. My tail position light lens went a bit opaque from the heat.
It was worth it, though, for cool shots like this:
Some more photos from the event are here.
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