Originally Posted by jehan12413
I just found some dc-dc converters on ebay, I'm looking at a Vicor V1-251-09 200v to 12v model and am wondering if anyone is familiar with this one. I sent a request to the seller for the datasheet but while I'm waiting I figured I would post it here .
I have these exact Vicor DC-DC units, and I got them on ebay from Troy Gaud at Azure Dynamics. He does not have a data sheet for them; he will send you the generic VI 200-Series Vicor data sheet, which does not in fact have this part number listed anywhere on it.
The -09 suffix signifies that these converters were a from a custom run by Vicor for Solectria/Azure made around 2007. They vary a little in spec from a standard VI-251-xx converter, as they are listed at 200V nominal input voltage, and the part# call-out would normally be 150V. Vicor will not discuss the specs of these units with anyone not from Azure, (ask me how I know...) but Troy told me that according to the Azure engineers, they are good down to about 130V, and up to a little over 250V input. They are also in fact "IU" suffix-class, which means -40 to 85 degrees C operating range, and 200W max output. I also have the -09 series matching Booster units, which allow you to run several booster bricks off of one 200 Series control unit. I haven't installed them yet, but I'll be using 4 or 5 boosters and a control unit, for either 75 or 90 amps of max current at 13.2V. Just what a late-model car needs.
These DC-DC converters can be trimmed up to 13.2V output by installing a trim resistor. If you only have 200-Series units, and no boosters, you can match them in trim and still use them together, as Jack Rickard has documented. His implementation, complete with a schematic and some thoughtful instruction, is here:
Don't use Jack's resistor values on the VI-251-09! The correct one is 422K, from Section 5 of the Vicor Manual. You could also put in a pot and trim the output manually. In any case, it is instructive to just RTFM:
I actually think this unit and the matching booster are superb quality equipment, particularly for the price, and the ones I got from Troy were brand new. They are in fact the very units you will find if you open up the Azure Dynamics DC-DC converter, and at $50 versus the hundreds they cost new, you really can't go very wrong. My understanding is Azure has "hundreds" of them to sell...
Not a shill for Vicor or Azure Dynamics, though both have been nice to me on the telephone...