[PeterH]

Hi there,

I've been searching the web and searching these forums for the past few days looking for an answer.

I've been unable to find hard info on a DC circuit breaker that can interrupt safely, 1000 amps at 160VDC.

I found several discussions and even a few pics but so far, no valid part numbers. I've heard of airpax and GE breakers rated for 500 or 1000 amps at 250 VDC but haven't yet found any available parts.

Does anyone have valid part numbers for currently available breakers suitable for an EV? I have the parts for an "anderson loop" but I'm really uncomfortable with the idea of such a slow interruption of that much current in a runaway situation.

Thanks,
Pete

[Yukon_Shane]

Hi Pete,

I'm not sure if this will help you or not but this is the breaker I'm using:

http://www.kta-ev.com/Airpax_Circuit...3-3-b4-250.htm

It's continious rating is 250 amps but if you look at the trip delay curve (assuming I'm reading it correctly) it seems to indicate that this breaker will hold 1000 amps (500 percent greater then it's rating) for somewhere between 2 and 10 seconds before triping.

That says to me that it will safely interupt 1000 amps at 160V.

[PeterH]

Hi Shane!

Thanks for the info. Would you happen to have any pics of how you have it installed?

That is what I've been looking for... Wonder what the diff is between the single and the two ganged breakers...

Think I'll be ordering one shortly.

Peter

[PStechPaul]

Most 600VAC industrial breakers can be used on 250VDC. New ones are very expensive but surplus and used items are cheap. Here is a 2 pole 250A breaker for $70 "buy it now".
http://www.ebay.com/itm/CH-Westingho...item519499fe52

You can wire the poles in parallel for greater current but that may drop the voltage rating to about 1/2.

Some breakers have an undervoltage trip or shunt trip which will either require a voltage to be applied in order to close, or will trip the breaker when a voltage is applied.

If a large, fast rectifier is placed across the load, it will eliminate almost all arcing so you can use a device with a lower DC voltage rating.

In any case you should also have a fuse in series. Breakers and switches can fail closed. Fuses generally cannot.

Here is a three pole 350A breaker designed for up to 500VDC and interrupting capacity of 10,000A:
http://www.ebay.com/itm/GE-General-E...item35bc1f0197

Here is one with a shunt trip. Not specified for DC, but should be OK if you wire all poles in series.
http://www.ebay.com/itm/ITE-250-Amp-...item53eaa0e617

[ricklearned]

I just bought one of these. This thing is about 10 inches long. I am going to mount it behind the emergency brake lever on my VW. If that proves to cumbersome, it can be actuated by a cable remotely. I could but it in the battery boxes where the rear seat used to be.

[Yukon_Shane]

Originally Posted by PeterH

Hi Shane!

Thanks for the info. Would you happen to have any pics of how you have it installed?

That is what I've been looking for... Wonder what the diff is between the single and the two ganged breakers...

Think I'll be ordering one shortly.

Peter

Hey Peter,

I've attached a few pictures of my installation. I found mounting this breaker a bit tricky. Essentially what I did is just used the terminal bolts to connect the breaker through my Lexan mounting plate. This obviously won't work if you're mounting the breaker to a metal mounting point though. There are two threaded holes on the front of the breaker on either side of the switch arm but they didn't seem to be very large and I wasn't confident that they would hold.

I mounted a disconnect cable through one of the threaded holes on the top plate and ran that cable into the vehicle cab. Works great but I do have to pop the hood to turn the system back on.

To be clear I didn't actually purchase this breaker from KTA; the breaker, and disconnect switch assembly all came from CanEV. I used the KTA link in my post because they had a good image and some quality documentation. That's not to say that KTA isn't a reputable company, I just haven't done business with them before.

[dladd]

Originally Posted by Yukon_Shane

Hey Peter,

I've attached a few pictures of my installation. I found mounting this breaker a bit tricky. Essentially what I did is just used the terminal bolts to connect the breaker through my Lexan mounting plate. This obviously won't work if you're mounting the breaker to a metal mounting point though. There are two threaded holes on the front of the breaker on either side of the switch arm but they didn't seem to be very large and I wasn't confident that they would hold.

I have that same breaker, and mounted it with the two small holes on the front. It's mounted to a sheet of heavy gauge sheetmetal and is quite sturdy. Here's a view from the trunk, it's on the far right of the photo. The specs say this breaker is good for 20+ seconds at 500a, and 4+ seconds at 1000a, both of which are much more than my battery pack can put out... I'm set to a 500a limit in my controller and have had no problems. If you put two of these breakers in parallel, it doubles the current limits (so 500a continuous, 1000a for 20 seconds). The handles must be mechanically linked if doing this.

I don't yet have a pull cable hooked up like Shane does, but I plan to soon. I actually have an old 8' long manual choke cable that I plan to use, just haven't done it yet.

[PStechPaul]

Originally Posted by dladd

I have that same breaker, and mounted it with the two small holes on the front. It's mounted to a sheet of heavy gauge sheetmetal and is quite sturdy. Here's a view from the trunk, it's on the far right of the photo. The specs say this breaker is good for 20+ seconds at 500a, and 4+ seconds at 1000a, both of which are much more than my battery pack can put out... I'm set to a 500a limit in my controller and have had no problems. If you put two of these breakers in parallel, it doubles the current limits (so 500a continuous, 1000a for 20 seconds). The handles must be mechanically linked if doing this.

If you parallel two breakers, make sure you run two separate cables so the current is better equalized. And it will still probably not be exact so you might expect 800-900A rather than 1000. Linking the handles is a good idea, although the trip action may not apply enough force to trip the other breaker, because of the "trip free" mechanism. But if one breaker trips, the current will quickly shift to the other and it will trip also. The linked handles mostly allow easy switching by hand.

[ricklearned]

I like the remote cable actuator for the emergency shutoff that Shane showed in his pictures. I am doing the high voltage wiring on my conversion during the next week and I may put the big Anderson shutoff further back where the back seat was. I am planning on putting some batteries there when I order my next phase of 36 cells.