DC-DC working! I’ve got the pow-ah

July 2, 2007 by Rob.

I’m unimpressed with my Astrodyne DC-DC converter, but at least it is working now. Thanks to Chris R’s shunts, I was able to determine when the converter is working. It is very sensitive to being drawn down into overload protection by spikes in demand. For example, when the vacuum pump starts up.

My frustrations with the Astrodyne include:

1. cannot handle short surges (like pumps starting up) in demand without overloading
2. “power on” LED on even if unit is overload shutdown but connected to 12 VDC system
3. overload shuts down the unit instead of just current limiting
4. unit requires power off and about 15 minutes of rest before recovering

If the auxiliary battery is not fully charged then the converter seems to always shutdown. This makes sense because just recharging the battery was pulling 10 amps. I installed a switch and relay so that I unload the converter from the cabin when the pump starts up.
Here is the converter in it’s new home. This is not as protected as I would like, but it makes for easy access when I need to tinker with it.

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