# Iota AC/DC Converter as DC/DC Converter



## J-Ro (Aug 9, 2012)

Hi Guys,

I bought a DLS-45 about 2 months ago and have been having problems getting the thing to output enough voltage to run my 12v system.

I googled it to see if i could find any hints and found that somwhere in the last several months Iota changed the design of their AC/DC converters to disallow a DC source...

Does anyone have any experiance with modifying a new DLS-45 to re-allow a DC input? I plan to have some of the electrical engineers at work take a look at it but I'm hoping maybe theres already some experiance floating around out there?

Thanks!


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## kennybobby (Aug 10, 2012)

In what mode do you have the charging plug set? What are you running and how many amps does your 12 V system need to run?

It could be a defective unit--may need to test it on the bench and verify it is known to be good before tapping in to the dc bus.


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## EVfun (Mar 14, 2010)

If new ones no longer works on DC they most likely have a voltage doubler front end. If that is bypassed it is possible it will run on about 200 to 300 volts DC.


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## iruraz (Sep 4, 2012)

EVfun said:


> If new ones no longer works on DC they most likely have a voltage doubler front end. If that is bypassed it is possible it will run on about 200 to 300 volts DC.


I need a dc/dc converter. I looked Iota's website. DLS-
240-55 is 750W ac/dc converter. Can I use it with 320V battery pack for my 12V accessories? Or How can I use it with 320V because they don't mention about dc input?

Regards.


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## J-Ro (Aug 9, 2012)

I got a few minutes to probe around in the converter and found that it does look like there is a voltage doubler circuit. Down stream of the rectifier theres about 315 to 320 vdc.

I still plan to dive the thing further but would love some suggestions on where to look. My goal is to still use it as a dc/dc converter on my 144v pack since I cant return the thing at this point.


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## iruraz (Sep 4, 2012)

@J-Ro, is there any progress?


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## Coulomb (Apr 22, 2009)

So if there is a voltage doubler in there, it should look something like this (borrowed from another post):










[ Edit: ignore the 96 V; the original drawing was to answer whether a typical power supply would work with 96 V input. ]

So you could leave the diodes in, but it would seem better to just remove them all and replace two (say D1 and D4) with links. Perhaps one of the links could be another NTC thermistor, to soften the current spike when you connect pack voltage across the capacitors. But you would want to replace the upper half-voltage capacitor with one full-voltage capacitor. (And you may as well remove the lower one.) The actual capacitance value would not be critical; you have the battery to smooth things out; this would just be supplying current spikes that the inductance of your leads is not going to be able to provide. About 100 uF should be fine, rated at well over your pack's voltage when fully charged. I'd also replace the switch with a link.


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## Stiive (Nov 22, 2008)

Could use a transformer to boost/lower voltage first? DC input wouldn't create any flux and therefore no secondary output voltage.

Post a pic of the unit?


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## J-Ro (Aug 9, 2012)

I decided for fun I would try emailing iota's tech support. They told me the following:

"The change was a different transformer. We selected a multi tap transformer that can go either 120v or 240v for ease of production between the two product lines. The 120v tap does not perform with DC input. The 240v tap will work with 250-380vdc"

I hope ti dig into this in the next day or two here. ..I finally got my water cooling system completed for my controller


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## iruraz (Sep 4, 2012)

J-Ro said:


> "The change was a different transformer. We selected a multi tap transformer that can go either 120v or 240v for ease of production between the two product lines. The 120v tap does not perform with DC input. The 240v tap will work with 250-380vdc"


@J-Ro thanks for revealing IOTA 's secret


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