# DC-DC Inverter Short



## TStrain (Feb 15, 2016)

Hey there,

I picked up a used truck that was converted a few years ago (2008-2009) this past weekend, and after cleaning it up I wanted to make sure everything worked before I ripped out the batteries to find a new pack.

Needless to say, when I put the power to the charger, sparks came out of the DC-DC Inverter. I immediately cut power, and removed it from the system. After taking it out, it appears that water was leaking in through the canopy that wasn't sealed properly (I know the charger and inverter shouldn't be in there but I didn't check it before.)

I've attached a few pictures, think it's repairable? Should I just spend the $200 and pick up a new one?

Thanks!


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## dcb (Dec 5, 2009)

this comes to mind.
http://www.angelfire.com/electronic/funwithtubes/Restore_cap.html


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## TStrain (Feb 15, 2016)

hey DCB,

Took a read through that. It actually wasn't sitting for more than a year even. All the other electronics worked just fine, it was only the way that the DC-DC was positioned and the leak that allowed it to have water in it, so i'm not sure I have to go through that process.

I should have mentioned though, I'm really comfortable taking all the components of an EV and hooking them up to work, but taking apart a component and changing out capacitors is new to me. I think I did it in high school once? I do own a solder iron though so I'm one step in the right direction 

Just not sure whether something like this would be as simple as changing out a few capacitors and resistors? Is there any place that will fix this?

Thanks.


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## WolfTronix (Feb 8, 2016)

From the pics, it looks like the FET driving the primary on the fly-back transformer died.

Probably had a drop of water on the gate and drain which caused it to turn on, saturated the transformer, then popped the FET, and most likely the fuse.

I would start there, check the fuse and replace if needed, and replace the FET.

And check if the FET driver survived. 

Everything else would probably be OK.

Hope that helps, 
Wolf


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## TStrain (Feb 15, 2016)

That does help. Actually helped enough that a friend with more knowledge than me understood. That being said, I took it apart further, and then discovered the attached pictures. I fear that this is worse than I originally thought as there is a physical hole in the board itself.

From what I see (and I've cleaned it up a bit) is that the smaller "coil" (I have no idea the technical term) burnt through the board some how.

My buddy has offered to fix it for me, do we still think this is fixable?

Thanks again!

Travis



WolfTronix said:


> From the pics, it looks like the FET driving the primary on the fly-back transformer died.
> 
> Probably had a drop of water on the gate and drain which caused it to turn on, saturated the transformer, then popped the FET, and most likely the fuse.
> 
> ...


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## WolfTronix (Feb 8, 2016)

From the pics, it looks like that damage to the PCB is not that bad...

It looks like you had some arcing between some traces when the field in the inductor collapsed.

I have fixed worse. 

http://www.wolftronix.com/amc230_514/index.html


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## TStrain (Feb 15, 2016)

Ok, so I went through that repair of yours... wow. I enjoy tackling problems, but that was intense (and way over my head). Nice work.

So if I do take this on and start removing some of the bad parts, is there a place you'd recommend getting the faulty parts. As I said, I'm new to tinkering with PCB's at any level, but I can't break it anymore than it is!

Thanks again.

Travis


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## WolfTronix (Feb 8, 2016)

I am not sure what country you are in, but in the USA the big three component supplies are:

DigiKey.com
Newark.com
Mouser.com

And if you want to waste more time...
I have a bunch of repairs on my site, but they are mostly pics I take during the repairs, only a few have write-ups and videos:
http://www.wolftronix.com/EV.htm

Enjoy,
Wolf


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## TStrain (Feb 15, 2016)

Well my parts arrived a few days ago and I started swapping a few out. A friend put me onto this article (http://www.evdl.org/pages/iotamods.html
), so I decided I may as well upgrade if I'm doing all this work... Problem is that I swapped the MOSFET and the bridge rectifier (that was where the hole was caused by once I had take it apart). I put in the two new CL-30 inrush limiters and applied a bit of power, it's still shorting somewhere. Guess I'll need to take a bit more of a look. Whatever made it short in the first place is still there...


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## Moltenmetal (Mar 20, 2014)

Not worth it in my view.

Open frame devices like that should not be used in an auto environment anyway.

If I had mine to do over again, I'd go with a decent sized aux battery, no DC/DC, and a small separate charger for it running in parallel with the main pack charger. That approach would have been more than adequate and would have saved me quite a few dollars.


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## WolfTronix (Feb 8, 2016)

This style of DC-DC converter (universal mains to 12V) is not ideal... and a much better automotive DC-DC converter is recommended.

However, I would encourage you to still try and fix it as a learning experience.

The way I see it, when the magic smoke comes out, its an opportunity to figure out why. 

I bet next time you after you take out some components, you will check if anything down stream is also shorted... 
Before putting the new parts back in. 

And always make sure you know what path the current took, that way you can determine if any other components might have been damaged/weakened by the excessive current/voltage path.

Some times it can be unexpected, like when a sil pad cracks with age, allowing current to flow into the heat spreader/sink:


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## TStrain (Feb 15, 2016)

I am going to continue trying. I've never messed around with something like this and you don't take on a project like an EV conversion without a sense of adventure.

Part of me was just hoping that it was a simple fix and I'd get away with it.  My hopes weren't too high.

Moltenmetal - Do you run one without? I don't think I'd be able to as I have a lot of electronics to run on this car. There will be a soundsystem (I can't get away from this... it' s a need), as well as a double din deck, and my commute is 85 KM without any other side trips. I don't want to risk the car going dead with a full pack but no 12 volt.


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## novaal (Oct 1, 2015)

Is the first picture the bad inverter? Are you connecting your battery pack to that box?

The label shows it to be AC-DC not DC-DC


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## TStrain (Feb 15, 2016)

That is what it was used for in a truck that I bought. When I powered up the truck for the first time in a while, it shorted.

I chatted with a guy from Seattle who helped out a lot in sending me this: "That looks a lot like a rebranded Iota DLS-55. I've got several of them new in the box, but the first one I modified according to the following instructions blew an internal soldered-in fuse at first connection (of course I happened upon these for free right after I ordered my Belktronic converter), and I haven't attempted again. 
http://www.corbinstreehouse.com/blog/2011/02/plug-bug-iota-dc-dc-converter-fix/
http://www.evdl.org/pages/iotamods.html "

You are correct that it was designed for AC, but apparently could be re purposed as DC. Not really meant for EV's, but it did work for 6 years for the previous owner with no issues.


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