# Stealth EV combination charger and DC / DC converter



## PocoJoe (Feb 18, 2021)

Stealth EV 3.3KW 108V Aircooled Charger+1KW DC/DC Converter


Shop the Stealth EV 3.3KW 108V Aircooled Charger+1KW DC/DC Converter and other products by Stealth EV. Click here to shop now...




stealthev.com





Hello... this charger has nice specs and integrates a DC/DC converter. I cannot find any reviews but am intrigued. Does anyone have any experience either with the product or the company?

Thanks in advance!

Joe


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## john61ct (Feb 25, 2017)

Yes very interesting.

I wonder if the DC-DC output is available, while the AC-DC rectifier is operating concurrently 

both at their respective max rated full power.

If the design is "charging is a separate cycle from discharging" as is normal for EV

that would be a deal breaker for me.

*__*
Note in general the design principle of "high DC voltage storage and backbone transmission coupled with distributed Point-of-Load buck conversion" has become widely adopted in military, aviation and high-end technology systems in industry, health care etc.

See MIL-STD-704B 1975 for its origins

270-280Vdc is common, but also 300+

My point being for DIYers, sometimes surplus gear of *very* high quality rectifiers and DCDC comes out super cheap on eBay

Google 
Vicor
Nemic Lambda Power Supply
Advantest T2000 
CKA 3750/S 

for some examples.

48V is a very common target for the down-conversion, and of course 12/24V easily reached from there.


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## Qckslvrslash (Oct 29, 2019)

The stealth ev unit is just a rebranded Ovartech. Stealth EV is a registered reseller of them. I am using one of these in my build but have yet to finish my wiring. 









6.6KW OBC+1.5KW DC-DC Converter Liquid-cooled - ovartech


6.6KW OBC+1.5KW DC-DC Converter Liquid-cooled 85-265VAC/200-420VDC input 200-420VDC/13.8VDC output IP67 Download Specifications: Ovartech Liquid-cooled 6.6KW OBC+1.5KW DCDC CAD662DF400-12152 Data Sheet



www.ovartech.com


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## PocoJoe (Feb 18, 2021)

Thank you both! Qckslvrslash, is your model user configurable via CAN? Can’t find much documentation on their web site. Thank you.
Joe


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## Qckslvrslash (Oct 29, 2019)

PocoJoe said:


> Thank you both! Qckslvrslash, is your model user configurable via CAN? Can’t find much documentation on their web site. Thank you.
> Joe


There is a bunch you can control over CAN. I can try and cover more once I dig into the programming part of the build. But I am not doing anything too wild setup wise. If you contact them they may be able to give you more info on it.


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## Qckslvrslash (Oct 29, 2019)

You can also read Zeva's review here on the charger they tested








Ovartech


Hi all, A quick community service announcement: Earlier this year I got contacted by a Chinese company called Ovartech, whose website lists a range of chargers and DC/DC converters for electric vehicles. I couldn't find any independent reviews of the company or their products on Google, but...




www.diyelectriccar.com


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## PocoJoe (Feb 18, 2021)

I received an email from Frank at Ovartech over the weekend. He told me that the company is now only making 400V and 750V chargers. He did not specifically say anything about the combination charger and dc/dc converter being in production, so I was not able to ask if the dc/dc convertor was available for charging my auxiliary 12V battery during charge cycles. He did indicate that all the chargers that the company makes are standalone programmable.

Thanks for the information everyone. 

Joe


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## john61ct (Feb 25, 2017)

I'd like to know the range of adjustable output voltage for the 400V model.

Lots of components have 300V limits, others 360V

Vicor has flexible and *very* robust lines of DCDC converters VI-26xand VI-J6x standard input is 375Vdc

325 to 345Vnominal for the pack


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## Qckslvrslash (Oct 29, 2019)

john61ct said:


> I'd like to know the range of adjustable output voltage for the 400V model.
> 
> Lots of components have 300V limits, others 360V
> 
> ...


Clicking on the spec sheet of the model I linked OBC output voltage is 200-420VDC same is true of the input to the DCDC

And based on Zeva's testing it would suggest what they say spec wise is accurate. Even on efficiency numbers


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## Qckslvrslash (Oct 29, 2019)

PocoJoe said:


> I received an email from Frank at Ovartech over the weekend. He told me that the company is now only making 400V and 750V chargers. He did not specifically say anything about the combination charger and dc/dc converter being in production, so I was not able to ask if the dc/dc convertor was available for charging my auxiliary 12V battery during charge cycles. He did indicate that all the chargers that the company makes are standalone programmable.
> 
> Thanks for the information everyone.
> 
> Joe


I suspect this is more a language barrier issue. Having dealt with numerous Chinese companies for electronics in the past this is often the issue. Their website still lists many different products from combines OBC+DCDC, OBC, DCDC, and slow chargers. There was a time a while back where ovartech made lower voltage chargers in the 100V range, so Frank may be referring to that. I also got mine back in early January so it would be pretty abrupt for them to stop production of something numerous companies are using and reselling, especially since the R&D work is done.


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## john61ct (Feb 25, 2017)

Qckslvrslash said:


> OBC output voltage is 200-420VDC same is true of the input to the DCDC


Fantastic, that's a very flexible unit!


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## EVchargers (Mar 1, 2021)

PocoJoe said:


> I received an email from Frank at Ovartech over the weekend. He told me that the company is now only making 400V and 750V chargers. He did not specifically say anything about the combination charger and dc/dc converter being in production, so I was not able to ask if the dc/dc convertor was available for charging my auxiliary 12V battery during charge cycles. He did indicate that all the chargers that the company makes are standalone programmable.
> 
> Thanks for the information everyone.
> 
> Joe


Hi Joe, sorry I did not explain to you very clear. We discontinued the low voltage products for a while because of the demand dropped many, most of the low voltage products are liked by DIY customers, our OEM customers all are using high voltage.
StealthEV has the low voltage products that made by us, they buy bulks from us, so we still keep the production for them only.


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## Qckslvrslash (Oct 29, 2019)

EVchargers said:


> Hi Joe, sorry I did not explain to you very clear. We discontinued the low voltage products for a while because of the demand dropped many, most of the low voltage products are liked by DIY customers, our OEM customers all are using high voltage.
> StealthEV has the low voltage products that made by us, they buy bulks from us, so we still keep the production for them only.


Is 400V considered low voltage now? Or is it like I suspected where the 108V and 144V chargers were discontinued?


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## cejota3 (Aug 15, 2019)

Hi Joe,
I've used the 144V version of the Stealth charger/DC-to-DC unit in one of my conversions, and it has worked great for me. The value was very good, as its price was very close to (and in some cases less than) the total cost of a separate charger and DC-to-DC converter of similar specs; and then you get the packaging/space-saving benefits of it being an all-in-one unit. I've also found Matt at Stealth to be helpful, fair, and responsive. Just about a year of regular use now and no complaints at all. You should be able to get all the info you need on it from their website.
An important word of advise is that it only works when controlled by CAN, which is true of many "better" chargers, so just make sure you have that base covered, usually through a sophisticated BMS system. For me that was by using an Orion BMS2 (which I'd also recommend). The two integrate very well together.
C.J.


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## john61ct (Feb 25, 2017)

For geeks comfortable with basic programming, CAN parsing and control using DIY microcontrollers is not rocket science.

Ideally all the specs and command strings are documented

the reverse engineering part does require experience.


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## PocoJoe (Feb 18, 2021)

“Hardware eventually fails. Software eventually works” - Michael Hartung

The battery pack I’m assembling is small by present standards... a 20 kW pack. Still, very dangerous: see ResearchGate for a review of EV car fires.

I’d like to understand the failure modes more thoroughly before buying into the illusion of control. 

For comparison, another hobby of mine is espresso- there is a lot of energy in a boiler, and in one famous incident in England in 2010, an explosion injured six people. Espresso machines have three safeties to prevent this ...a primary based on temperature, a secondary based on pressure, and finally fail safe plugs that pop if overpressure exceeds design limits. Still, if a thin walled boiler ages and weakens, and the water level runs low, you get a large volume of steam at pressure (nearly empty boilers are more dangerous than overly filled boilers.... the energy is in compressed gas, not in incompressible liquid).

I don’t want to ‘eventually’ get the charge cycle of my LiPo pack right. It’s worth it to me to buy quality (and it appears the Orion2 is an example) and pay to have it properly configured by someone who has practical experience with a specific canbus controlled charger.

Ideally, I’d like a dead man switch on the chager and traction contacters that would cut the charger at at absolute over voltage, and disable pack discharge at an absolute under voltage... with thumb switches that set those voltages... anybody built one already?

THANKS FOR ALL YOUR HELP!


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