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TC-Charger DC/DC Converter TDC-IY-108 – 1 kW - how to connect

6K views 19 replies 6 participants last post by  pdove 
That picture is pretty self-explanatory. There is enable signal for which you need to apply another source of +12v. I assume it references the chassis for the negative, but it would be good to see the pinout for that entire connector to confirm.

It is kind weird to design a DC-DC that will require the same votlage to operate as the one it outputs! But that's the Chinese engineering for you.
 
But logically it must be unimportant for the dc converter where the 12V comes from. It doesn't know if it's provided by the bms or the battery itself.
Except I use the CAN interface (which I'm not) so the BMS can tell the converter to start.
But it has to work without CAN I guess.

Also this connector is 4x1 but mine is 2x2.
This is what really freaks me out because I can't find any plan where there is the connector which is on my converter...
These chinese manuals really tick me off
Yes, it can be a 12v battery, as long as the negative is tied to the chassis of the converter itself. The only reason I specifically talked about it is the fact it's rather silly for EVs to carry 12v batteries. The whole point of DC-DC converters with 12v output is to power the 12v equipment from the main battery.
 
It is standard in many if not most production EVs, but what is the point of it ? There is no standard equipment that would produce significant peak loads that the DC-DC wouldn't be able to handle directly. Not having to run main power contactor(s) just to power DC-DC when vehicle isn't running ?
 
That's the common design pattern, but it doesn't need to be that way. So like you suggested there is a legitimate interest to interrupt HV in case of a crash, fine... but if the DC-DC is buried into the pack, along with BMS, then there is no HV coming out of the pack.
 
You need to remember why disconnecting the HV is important, and legitimate. Idea is that on production EVs battery pack is enclosed into a self-contained, somewhat armored shell and is installed in a predictable location, such as vehicle's underbody. So if the rescue team needs to chew through the vehicle to get to the occupants, as long as they stay outside of the battery box, there is a reasonable expectation that no HV will be supplied to any other part of the vehicle. It's not 100% either, but it's a lower risk. Inside the battery box you can do whatever you want though, since no matter how you look at it, battery box remains under HV even when contactors are open.
 
Tell me what it is after a 60g crash....
In engineering we talk about these things in terms of "failure modes." Please articulate which failure modes you anticipate that are either absent altogether or significantly altered by addition of DC-DC the way I described. There are already lines in the system, both High and Low voltage that can be impacted by a crash. There are already additional devices that can be impacted. There are batteries themselves that can be impacted. You're not worried for example that BMS would get confused and close the contactors when they should be open ? Or how about BMS getting electrically and/or mechanically damaged and applying HV say to CAN lines ?
 
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