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  #11  
Old 10-30-2010, 12:09 AM
RoughRider RoughRider is offline
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Default Re: Precharge, what is it, why do I need it, how do I do it.

Quote:
Originally Posted by sjc View Post
I can't see the schematics in the original posting. Are they still visible to others?
i cant see them

would someone upload them again??
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  #12  
Old 11-14-2010, 09:47 PM
surgy surgy is offline
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Default Re: Precharge, what is it, why do I need it, how do I do it.

yeah, i cant see any schematics either and i need to learn about precharging.
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  #13  
Old 11-15-2010, 12:31 PM
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Default Re: Precharge, what is it, why do I need it, how do I do it.

From what I can tell, the photos have been taken down at the source. Since they were only linked to and not hosted directly by the forum server, there isn't much we can do from this end.

It also seems the original contributor hasn't been posting since 2009
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  #14  
Old 11-15-2010, 01:00 PM
surgy surgy is offline
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Default Re: Precharge, what is it, why do I need it, how do I do it.

Fair enough. Could someone please explain in detail how you would wire the pre-charge resistor? is it just another power cable going to the controller with a resistor connected in-line?
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Old 11-15-2010, 02:35 PM
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Default Re: Precharge, what is it, why do I need it, how do I do it.

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Originally Posted by surgy View Post
Fair enough. Could someone please explain in detail how you would wire the pre-charge resistor? is it just another power cable going to the controller with a resistor connected in-line?
surgy,

The manual for your controller will have a wiring diagram. And you can go to controller company websites and download manuals which will show you. And you can use the search feature on this web site to find threads and posts about it. And this thread, a sticky, I think talks about it. http://www.diyelectriccar.com/forums...off-25318.html

But I do think some basic diagrams should be here in the EV Information section.

Regards,

major
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  #16  
Old 11-15-2010, 09:43 PM
CaptConan CaptConan is offline
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Default Re: Precharge, what is it, why do I need it, how do I do it.

I'm trying to find a relay for the precharge circuit that can "block" the pack voltage (144) but work (close) off of the 12V system. I was hoping to just use an automotive relay for this but from what I can find these are only rating up to about 50 VDC or so. I don't want to have to pay to get another ev200 just to switch 5 amps at 144volts. What is everyone else using for parts?
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  #17  
Old 11-16-2010, 01:23 PM
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Default Re: Precharge, what is it, why do I need it, how do I do it.

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Originally Posted by CaptConan View Post
I'm trying to find a relay for the precharge circuit that can "block" the pack voltage (144) but work (close) off of the 12V system. I was hoping to just use an automotive relay for this but from what I can find these are only rating up to about 50 VDC or so. I don't want to have to pay to get another ev200 just to switch 5 amps at 144volts. What is everyone else using for parts?
Hi Cap,

I don't have a part for you, but a suggestion. Put a contactor like the EV200 in the negative (or mid pack) battery line turned on by the keyswitch. Then when it is turned on, it precharges thru the resistor across the contacts of the positive line contactor. After a few seconds, or when a precharge indicator lamp goes out, have a switch (like on the drive position of the gearshifter) which closes the positive contactor. That way the precharge is off when the keyswitch is off. And the high voltage accessories (DC/DC) can come on ahead of the precharge.

Different controllers can require different precharge circuits. There is no one-size-fits-all diagram.

major
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  #18  
Old 11-16-2010, 01:57 PM
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Default Re: Precharge, what is it, why do I need it, how do I do it.

Right Major, thats pretty much the route I was planning to go, just acquiring parts right now as I'm doing a custom controller and all... what I wanted to get away from is buying ANOTHER ev200 which appear to run about 70-80 bux. There has to be a non-solid state relay out there that can handle 5 amps, block high voltage, and only require 12V to energize. I imagine this fictitious part costing me about $15 or $20. It's just a matter of finding it.
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  #19  
Old 11-16-2010, 08:33 PM
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Default Re: Precharge, what is it, why do I need it, how do I do it.

Well I found two that fit spec, but neither one seems to be for sale anywhere...

http://www.fujitsu.com/downloads/MIC...ays/ftr-j2.pdf

http://relays.tycoelectronics.com/datasheets/ev41a.pdf

I think I should be okay with a relay rated at 125vdc. The current I am "making" is only for a short time anyway and then it's done after a few seconds. Any objections from the field?
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  #20  
Old 12-01-2010, 06:23 PM
bluefxstc bluefxstc is offline
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Default Re: Precharge, what is it, why do I need it, how do I do it.

I
I am using a Mercury switch like these for my heater and am thinking about using one to enable my precharge resistor. I am thinking about using my interior lights to turn on the relay. That way anytime I open the door the precharge is enabled. I would just have to leave the door open for a couple of seconds to make sure it is charged which shouldn't be much of a problem. I tend to fasten my seatbelt before I shut the door so it should be enough time. Given the current the mercury switch will handle (16 amps at 125 VDC) I will probably use a lower resistor value which will make it faster. Also due to the construction of the switch (dipping contacts into liquid mercury which freezes at about -38C) I don't think arcing is as big a problem as it is with a standard contactor.

http://www.surplussales.com/Relays/mercury_con.html

Last edited by bluefxstc; 12-01-2010 at 06:36 PM.
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