# Contactors, connectors and fuses, oh my......locations



## swoozle (Nov 13, 2011)

I'm realizing I went a little overboard on the "disconnect the big, bad battery pack from everything else."
I have one of these,






, a couple of these







and a couple sets of these








Oh, and a fuse of course. 
So do I need them all and where do I put them?

One Kilovac contactor on the positive cable before the controller, obviously.
I've read here that a second on the ground is good, too. Does it matter if I put it in the middle of the pack (27 cells before, 21 after) in the trunk? That would be the initial key-on contactor, to be followed by the positive one after precharge.

Does it matter if I put the main fuse in the middle of the pack as well?

I kind of like the convenience of the BEP switch, how about that on the ground side at the main pack connection for routine maintenance?

And are there any disadvantages to throwing the Leviton single pole connectors in there as well? I kind of like the peace of mind of being able to see the ends of the cables separated when I'm seriously working on things. And those connectors are large, well-fitting metal pieces. There's a certain satisfaction in feeling those cam-lock together.


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## Ziggythewiz (May 16, 2010)

How much you should have, and where depends on your pack configuration. A contactor on each leg will isolate the controller when unpowered. 

Also, don't call the negative leg ground. It should not be.

It's good to have fuses on each leg as well (as close to the batteries as is reasonable), and one in the middle would be good also.

I'm not familiar with the Levatons, what do you use them for?


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## swoozle (Nov 13, 2011)

They are Leviton single pole cam-lock connectors, high current capacity. The particular ones I have are 400A constant current capable. Essentially a replacement for the more typical Anderson connectors.

http://www.leviton.com/OA_HTML/Sect...308A627FEE5AFD3B2C4A15F6441EF6F866B0DB81BFA81


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## PStechPaul (May 1, 2012)

We are now using these connectors on our circuit breaker test sets, and they are quite nice, and fairly reasonable in cost at about $20 or so. Here is their line:
http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=37742&minisite=10251

We used to use the Superior Electric connectors, which wre rated at 250A. But they were like $50 or more, and really not as good.
http://www.newark.com/jsp/search/br...ions=false&ref=globalsearch&_requestid=136183


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## ricklearned (Mar 3, 2012)

Ziggythewiz said:


> ........
> 
> It's good to have fuses on each leg as well (as close to the batteries as is reasonable), and one in the middle would be good also.......


I thought I read somewhere that damage to some BMS's can occur if there is a disconnect in the middle of a pack. I currently don't have a BMS but might want to add one in the future, especially if I separate the pack halves, ie front and back. Does anybody know if a middle of the pack disconnect is an issue with some BMS's?


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## dtbaker (Jan 5, 2008)

PStechPaul said:


> We are now using these connectors on our circuit breaker test sets, and they are quite nice, and fairly reasonable in cost at about $20 or so. Here is their line:
> http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=37742&minisite=10251



these don't appear to be designed for disconnect under load.... are they?


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## PStechPaul (May 1, 2012)

No, they are not designed for disconnect use. The Superior Supercon connectors were originally designed for theater lighting and they were plugged in or removed for various effects, like color changes. But that was for a tungsten load. For anything with transformers or motors there is inductance and you can draw a huge arc and so they cannot be used. However, if you can pull it out fast enough, it might work.

I couldn't find anything on those old stage lighting connection boxes. Now it seems they use these:
http://www.ebay.com/itm/Leviton-Cle...245?pt=LH_DefaultDomain_0&hash=item51a0658af5










The twist-lock types are designed specifically NOT to disconnect easily.


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## Ziggythewiz (May 16, 2010)

ricklearned said:


> I thought I read somewhere that damage to some BMS's can occur if there is a disconnect in the middle of a pack. I currently don't have a BMS but might want to add one in the future, especially if I separate the pack halves, ie front and back. Does anybody know if a middle of the pack disconnect is an issue with some BMS's?


A fuse is an emergency disconnect. If it blows you probably have bigger problems than the BMS.


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