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  #1  
Old 10-07-2012, 05:07 AM
spoland spoland is offline
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Default How to chose contactor

Hi,

I'm planning on using a Kostov K9" 220V and a Soliton Jr for a conversion. The Soliton has a built-in main contactor, but I want to use an external contactor to break the batteri circuit in the middle to remove the voltage from the engine compartment.
According to the Kostov specs it has an sustained current of 180A when delivering 32 kW at 220V while the peak current is 500A giving 78 kW.
Can anyone advice me on how to choose a contactor for this? I saw a 600A contactor which was 2,3 kg, enormous! Or will a 200A contactor be sufficient since the peak current will occur very selldom?
I guess the contact voltage will not be an issue since the circuit will be open when the contactor closes and opens, and no voltage will be present over the contacts (unless a emergency break is done while driving).

/ Peter
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  #2  
Old 10-07-2012, 10:49 AM
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Roy Von Rogers Roy Von Rogers is offline
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Default Re: How to chose contactor

This is what you need, but you may also look for a BRB (big red button) manual disconnect switch instead.

http://www.ebay.com/itm/Kilovac-EV20...item43af8d50ee

Roy
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Old 10-07-2012, 12:26 PM
spoland spoland is offline
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Default Re: How to chose contactor

Quote:
Originally Posted by Roy Von Rogers View Post
This is what you need, but you may also look for a BRB (big red button) manual disconnect switch instead.

http://www.ebay.com/itm/Kilovac-EV20...item43af8d50ee

Roy
Thanks Roy, that's more like it!
A little expensive though. Over $200 in Europe.
I want a contactor so I can connect it to the stock fuel pump relay which shuts down in case of a crash.

/ Peter
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Old 10-07-2012, 12:41 PM
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Default Re: How to chose contactor

In Europe there is GWL/Power - DC Contactors
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Old 10-07-2012, 01:23 PM
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Default Re: How to chose contactor

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Originally Posted by WarpedOne View Post
In Europe there is GWL/Power - DC Contactors
Yes, that's the one that weighs over 2kg for a 600A version. I could'nt find any detailed specs for it so I am wondering what would happen if I used the 400A version or even the 200A version (which are both smaller and cheaper).

BTW, I found some specs on a similar or same relay, cant say.
http://www.bcrelays.com/Contactor.HZJ-600A.pdf
It says it is rated for 600A at 27 VDC and the electrical life is 2500 operations.
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Old 10-07-2012, 02:13 PM
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Default Re: How to chose contactor

Don't know about those 27VDC, but 2500 cycles are at full 600A load.
If you don't switch it at full load/current, it will live longer, much longer.
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Old 10-07-2012, 02:33 PM
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Default Re: How to chose contactor

27V means 27V... It is probably designed for 12V and 24V battery systems only, so it's useless in an EV.

DC is difficult to break because the arcing does not stop as there is no zero point like in AC. For this reason, the ratings for a DC contactor are much lower than for a physically similar AC contactor.

Both voltage and current ratings are extremely important, as well as the fact that those ratings are for DC. Then, in addition, random Chinese products need to be tested in order to verify that the data given is correct.
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Old 10-07-2012, 03:38 PM
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Default Re: How to chose contactor

Quote:
Originally Posted by spoland View Post
Thanks Roy, that's more like it!
A little expensive though. Over $200 in Europe.
I want a contactor so I can connect it to the stock fuel pump relay which shuts down in case of a crash.

/ Peter
Good idea - I like to see an inertia switch (which is often in series with the fuel pump relay) shut down power to the controller and any additional contactors in the battery circuit.

I strongly recommend that any additional contactors installed in the battery circuit either be the Tyco/Kilovac EV200 or the equivalent from GigaVac (which was started by former Kilovac engineers when Kilovac bought out by Tyco, btw). DO NOT USE contactors with low DC voltage ratings (ie - for golf carts, yachts, etc.) or, worse, ones intended for use with AC.

If the cost of the right contactor is a bit too much to swallow over there then a more budget-friendly approach is to put an appropriate DC-rated fuse in series with the positive line inside each battery box (I like Ferraz-Shamut [now Mersen] A50QS series fuses).

Good controller choice, btw...
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  #9  
Old 10-08-2012, 12:55 AM
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Default Re: How to chose contactor

Quote:
27V means 27V... It is probably designed for 12V and 24V battery systems only, so it's useless in an EV.
Thanks for pointing it out. They don't list the voltage at all, just amperage.
So, EV200 it is.
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  #10  
Old 10-11-2012, 05:32 AM
Jamie EV Jamie EV is offline
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Default Re: How to chose contactor

Good to know there's an affordable contactor...every other one I've seen is either underrated for voltage, power or both OR is like 300 dollars.
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