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Nuts & Volts
25 September 2012, 1301
I need a DC/DC that will run my El Moto. Tried two different Vicor units and the first was either DOA or I killed it. Second one just limits output to 0A for some reason. Using a 12V LiPo battery at the moment, but don't have a easy way to charge it.

My system is 70V-88V operating range. I need 12-14V output and between 100 and 200W. I won't to keep the weight and size of it really smaller. I can get a 300W Sevcon for $220 that is 2lbs, but I think there are options out there that are cheaper, more efficient or smaller.

Let me know if you have any extra units sitting around or can get me a sweet deal :D

-Kyle

frodus
25 September 2012, 1355
I have an extra vicor (the one you turned me on to). I'm thinking maybe we need an inductor on the input to keep current from flowing from the dc-dc into the controller.

Also have the surepower ones available.

__Tango
25 September 2012, 1358
You probably know this already, but the vicors have protection in them that will disable them when a short occurs. You have to remove all power for them to come back. That feature has saved my bacon a couple of times, but the first time it happened i thought i killed it or that it died on its own.

Nuts & Volts
25 September 2012, 1620
Thanks Frodus, I may make an offer for that one. I'm kinda afraid I will kill another one, so I need to figure out why I suck with those before I get another one of those.

The Surepower are a good options, overpowered for me and heavy/bigger than I want. But good price and I know it will work. That and the Sevcon will be on my list if no holy grail of DC/DCs show up for me. Sevcon is 2lbs, versus the Surepower's 5lbs, and its smaller. I'm too picky

I solder the sense leads to the the output. Then (off the bike on a spare pack) I connect V- to Battery V- and V+ to Battery V+. When I measure the output I only get about 6V and its buzzing like its current limiting. Does it need a load to read 12V? Will a resistor properly load it?

The new unit I have is this one (here (http://www.ebay.com/itm/261064157877?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649)) and it should work up to ~95V if it has the same percentage range as this one (http://www1.futureelectronics.com/doc/VICOR%20CORPORATION/VI-910954B.pdf)which most vicor's seem too.

frodus
25 September 2012, 1929
Thanks Frodus, I may make an offer for that one. I'm kinda afraid I will kill another one, so I need to figure out why I suck with those before I get another one of those. Sounds good, I have the Vicor here and ready, and I can re-order you a DC-DC.


The Surepower are a good options, overpowered for me and heavy/bigger than I want. But good price and I know it will work. That and the Sevcon will be on my list if no holy grail of DC/DCs show up for me. Sevcon is 2lbs, versus the Surepower's 5lbs, and its smaller. I'm too picky Yeah, a bit larger and heavier I know...too bad there's not something cheaper that is smaller. If you DO find something, post here and let us know.


I solder the sense leads to the the output. Then (off the bike on a spare pack) I connect V- to Battery V- and V+ to Battery V+. When I measure the output I only get about 6V and its buzzing like its current limiting. Does it need a load to read 12V? Will a resistor properly load it?
Probably needs a load. Load it with a 12V light bulb.
Read this? Some stuff in there to try. This wasn't intended as a standalone DC-DC for a vehicle, needs some filtering and spike protection.
http://cdn.vicorpower.com/documents/applications_manual/fas_trak_apps_manual.pdf

__Tango
25 September 2012, 2044
Kyle, which vicor are you looking for? we have a surplus shop close by that i haven't visited in a while that tends to carry used vicor converters for cheap (so you won't worry about destroying another one. :) ). If you're interested, let me know and i'll stop by to take a look.

Nuts & Volts
26 September 2012, 0642
Travis, yea I think the problem is I just don't fully understand how these devices want to work, just how I want them to work.

Tango, Anything with >150W output at 12V-14V output. I am also cool with paralleling two 75W units as well. Input needs to work from 63V to 87V in my application. Most Vicor's have a wide range input. I'm willing to pay up to like $70 for a Vicor because of its many advantages over other units (weight, size efficiency, etc.). I would have to know its working before I get it because I am unsure if the ones I have are DOA or not.

I will try to test my 61V unit out again soon.

frodus
26 September 2012, 0904
I have a 75w 55-100v in 12v out and a 150w 66-160v in 12v out. I won't be using them. I paid 20 for the 75w and 50 for the 150w I think. If you want one of them let me know and I'll sell it for cost with usps flat rate included.

Nuts & Volts
26 September 2012, 1805
Travis, I will most likely take the 150W unit off your hands. I want to do a little bit more testing with my current 61V unit before I jump to a new one. I'll PM you if I decide to go for it.

frodus
26 September 2012, 2050
Sounds good. You know where I got it and what I paid. I'll throw in a matching heatsink and bussmod. Would rather someone used it than keep it.