# contactor for 150v accessories question



## Ziggythewiz (May 16, 2010)

Don't know the synchro, so not sure how it would affect it (don't understand the difference between one or 50 contactors in series if they turn on at the same time), but for redundancy it's better to put a second contactor on the negative leg instead.


----------



## dladd (Jun 1, 2011)

Ziggythewiz said:


> Don't know the synchro, so not sure how it would affect it (don't understand the difference between one or 50 contactors in series if they turn on at the same time), but for redundancy it's better to put a second contactor on the negative leg instead.


it's not redundancy I'm after, it's power to my heater and DC/DC. The controller would only see one contactor, the main one that is controlled by the Synkromotive controller. I don't want my 150v accessory fuse block powered on all the time, so I want to put a on/off of some type between the 150v battery + and the 150v fuse block I have. Currently, it's switched by the main contactor. 

I'm wanting to put a second contactor powered off the battery side terminal of the main contactor for the sole purpose of powering on the accessories. This second contactor's 12v coil would be powered by the 12v accessory key switch position.


----------



## frodus (Apr 12, 2008)

Are you wanting to drive the coils of the Accessory contactor with the synkromotive, or a 12V signal from the ignition somewhere?

Can you draw out what you're thinking?


----------



## dladd (Jun 1, 2011)

frodus said:


> Are you wanting to drive the coils of the Accessory contactor with the synkromotive, or a 12V signal from the ignition somewhere?
> 
> Can you draw out what you're thinking?


I'm wanting to drive the accessory contactor with a 12v signal from my ignition switch. It is my intent to make it independant from the controller. The only connection is on the battery side of the main contactor, which would be invisible to the controller I think, right? 

sorry I'm not good at explaining this... I'll see if I can draw up a picture.


----------



## dladd (Jun 1, 2011)

here we go,


----------



## frodus (Apr 12, 2008)

Great pic, thanks.

I think you're missing a battery pack fuse... on the 150Vbat side. You need that. That protects the pack from shorts. If that is there, and you short the Acc.Contactor, it'l blow the battery fuse. The issue arrises though, is that you have a different current going to the fuseblock, and it's lower current than the pack fuse. If the wire is sized for the Accessory current (lets say 30A) and you short before the fuseblock, or somehow you ground out something at the acc.contactor, the pack fuse won't clear, and that wire in between the two contactors will overload.

I'd fuse it according to the fuse on the fuseblock, or eliminate the main fuse in the fuse block and put it before the contactor in between the two.


----------



## dtbaker (Jan 5, 2008)

frodus said:


> Great pic, thanks.
> 
> I think you're missing a battery pack fuse... on the 150Vbat side.


also missing a circuit breaker w/ manual pull.... really a good idea in case contactors get welded together and you need to cut power. Also good to have one disconnect EVERYTHING from main pack for extended storage, or when you are working on things.


----------



## dladd (Jun 1, 2011)

There is currently a breaker in the battery circuit, right in the middle of the pack, with a pull cord I can yank from the drivers seat. There is no fuse. An upcoming project is relocating some batteries and I plan on adding a fuse at the second pack at that time (and keeping the breaker as well). In the meantime (it may be a few weeks/months till I get around to moving the batteries) do I need to add a fuse in addition to the breaker that's already there?

Thanks!


----------



## frodus (Apr 12, 2008)

no fuse?

Does the breaker disconnect without binding the cord? does it open correctly?


----------



## charliehorse55 (Sep 23, 2011)

I wouldn't use an EV200 contactor for this role, it's massive overkill. A $5 MOSFET can easily switch the 30A or so that you will need for your accessories, and it's solid state. 

I would fuse the wire going between the main contactor and the accessory switch. As frodus pointed out, you should always have a fuse protecting a wire from melting. Unless you want to wire the accessory circuit with your drivetrain gauge cables you will need a fuse. 

MOSFET (Okay, it's $10!) http://canada.newark.com/internatio...8pbf/n-ch-mosfet-250v-93a-to-247ac/dp/08R4843


----------



## dladd (Jun 1, 2011)

frodus said:


> no fuse?
> 
> Does the breaker disconnect without binding the cord? does it open correctly?


When I pull the cord (or flip the breaker at the lever) it disconnects (opens). I've never tried it under load.


----------



## charliehorse55 (Sep 23, 2011)

dladd said:


> When I pull the cord (or flip the breaker at the lever) it disconnects (opens). I've never tried it under load.


As long as breaking capacity of the unit is well above your load current it should work fine.


----------



## frodus (Apr 12, 2008)

charliehorse55 said:


> As long as breaking capacity of the unit is well above your load current it should work fine.


What I meant is not about the rating, but of the mechanical way he's running the remote pull-cable....

i.e. does the cord allow the breaker to open under load without interfering.


Dladd,

You could use a mosfet, or a 12V relay with DC rated contacts:
http://www.onlinecomponents.com/te-connectivity---p-b-brand_kuep-3d35-24.html?p=12108600


----------



## charliehorse55 (Sep 23, 2011)

frodus said:


> What I meant is not about the rating, but of the mechanical way he's running the remote pull-cable....
> 
> i.e. does the cord allow the breaker to open under load without interfering.


If he can open it at idle, why it would anything be changed when you are pulling it under load?

Am I missing something?


----------



## frodus (Apr 12, 2008)

Nevermind..... 
I was thinking that the handle moves if it breaks.... but it doesn't. It will trip regardless of if there's something impeding the movement of the handle.... like the mechanical linkeage of the pull-cable.


----------



## dladd (Jun 1, 2011)

so, other than being overkill, it sounds like it's a functionally sound way to go. I can pick up a 10awg wire with an inline automotive style 30amp ATC fuse at the hardware store to connect the contactors together, is that acceptable for 150v? I'm not sure if fuses care about voltage or not... As you can probably tell, I'm more of a mechanical guy.  I have to be honest, I don't have any idea how I'd implement that mosfet or relay shown above... looks like they need to be plugged into, or soldered onto something.


----------



## frodus (Apr 12, 2008)

a 12v fuse doesn't have to clear much of an Arc when it breaks, a 150V fuse does. A fuse does care what voltage you're at.....so yeah, you'd need something rated for that voltage. 

If you already have the EV200, just use it. It'll be overkill but it'll work just fine.


----------



## EVfun (Mar 14, 2010)

frodus said:


> a 12v fuse doesn't have to clear much of an Arc when it breaks, a 150V fuse does. A fuse does care what voltage you're at.....so yeah, you'd need something rated for that voltage.


I would add that it needs to be rated for the pack *DC* voltage. AC voltage crosses zero volts 100 or 120 times a second making arcs much easier to stop.


----------

