# Source for Emergency Disconnect Switch



## green caveman (Oct 2, 2009)

Apologies if this is in the wrong forum, it's not really technical, but I'm not sure where else it should go.

Can anyone suggest a source for a high amp DC manual disconnect - just a big manual switch in the main battery line? They're referenced in the "sticky" thread, but the parts suppliers (on the right ad bar) don't seem to have them listed.

Does it have a better name/description that would help me on a web search?

Thanks,


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## Jimdear2 (Oct 12, 2008)

green caveman said:


> Apologies if this is in the wrong forum, it's not really technical, but I'm not sure where else it should go.
> 
> Can anyone suggest a source for a high amp DC manual disconnect - just a big manual switch in the main battery line? They're referenced in the "sticky" thread, but the parts suppliers (on the right ad bar) don't seem to have them listed.
> 
> ...


green caveman,

Follow the link below then scroll down until you find the ED series disconnect (Big Red Button). You can click on the link for the disconnects and down load a PDF spec page.

http://curtisinst.com/index.cfm?fuseaction=cdatasheets.dspListDS&CatID=7&siteID=1

Their disconnects come in two types the ED series which is a disconnect only and the SD series which is a manual disconnect AND main contactor combination. Perfect for the underhood service disconnect, it kills two birds for less money, the each switch seperatly. I bought a SD300 with mag blowouts and aux contacts. Worth ever penny.

The ED series comes in both a single conract pair and double contact pair so thoses with split packs have a way to disconnect both packs with one Big Red Button. 

I'm not associated with Curtis and Albright. I just think the BRB and the combo contactor/ disconnect arem nice products.


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## chansen (Mar 13, 2009)

i used a cheap fork type manual switch close to the pack and remoted it with a cable to a small pull-handle in the car. (good conversation piece for my ICE passengers too!) I bought the cable/handle on ebay and it has a little cool emergency stop icon on the handle. I may have a spare you can have for free. This keeps the pack voltage out of the cabin.


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## Stunt Driver (May 14, 2009)

If asking for under hood switch - it is ok to bring voltage there.

Budget depends on convertion plans and currents. Mine tops out at 200A, but normally stays within 100A. I have used one from HF, was $3 on sale.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92688

It is rated for 100A which is an normal average for mine, but I have measured voltage drop on it at ~250A and it was minor, within 0.2v. I believe it is safe to use for budget convertion. I have it under hood just in case something goes wrong while I'm there, digging and experimenting.

As for cabin control - contactor is the way to go, just switch off ignition if something goes wrong, and you're good.


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## gdirwin (Apr 7, 2009)

How about this one:
http://rechargecar.com/product/ev-ez-safe-disconnect









You would have a cable from the inside (on a big red button) that would run to this disconnect - this keeps all of the HV stuff under the hood and not in the cabin...


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## green caveman (Oct 2, 2009)

chansen said:


> i used a cheap fork type manual switch close to the pack and remoted it with a cable to a small pull-handle in the car. (good conversation piece for my ICE passengers too!) I bought the cable/handle on ebay and it has a little cool emergency stop icon on the handle. I may have a spare you can have for free. This keeps the pack voltage out of the cabin.


The "fork type manual switch" must have better name and a manufacturer and would be fine. Without a name it's hard to find.

I like the idea of the handle in the cabin to pull it, keeping high voltage elsewhere. 

I kinda like the idea of an e-stop and contactor combined - easier to install, all in one spot, etc.etc. but I also like the idea of two devices. If something really bad happens to the contactor there's still something to pull/push to cut the power.

Stunt Driver has an interesting solution. Those are readily available. The specs are a little low, but since it's just the volume of metal in the current stream it may be OK. I don't know how well it would perform as an e-stop. If everything goes to heck opening one of those switches might be a little scary - might not even happen if the power is full on.


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## green caveman (Oct 2, 2009)

gdirwin said:


> How about this one:
> http://rechargecar.com/product/ev-ez-safe-disconnect
> 
> 
> You would have a cable from the inside (on a big red button) that would run to this disconnect - this keeps all of the HV stuff under the hood and not in the cabin...


Nice, but pricey, but probably worth it for a life/safety component if nothing equally good is available.


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## few2many (Jun 23, 2009)

How about one mounted right under the cabin, attached by cable to the parking brake lever.


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## Jimdear2 (Oct 12, 2008)

Looking at all of these ideas I don't see one of them that is a purpose built real honest to goodness *EMERGENCY DISCONNECT* switch.

Most of them would melt into a fused and shorted chunk of metal if you ever had to disconnect a circuit that was carrying a big load of amps if/when your controller might fail full on. We all know that might happen, thats why they want an emergengy disconnect. 

The knife switch (I think that is what Chansen is describing) and the Cheapo battery shut off switch that Stunt Driver came up with, were both made to disconnect a circuit when it was carrying no or low voltage/current. They are both fine for service disconnect when there is no load on them but I wouldn't want to trust my life (or someone elses) to them. There are people on this forum who have had a runaway, it sound scary

Before I would use it I would like to see the test sheet on the Anderson connector disconnect that Gdiewin came out with. I would want to know what current at what voltage will it break FOR SURE without shorting closed, before I would trust my life to it. 

A circuit breaker like the Airpack or the Curtis Albright emergency disconnect switches are are made to break a circuit that is under load. They have the test results to prove it. I'm sure that there are others devices out there as well.

These switches are like car insurance you may never need it, but if you do you want the best availabe. This is not a place to cheap out.


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## jackbauer (Jan 12, 2008)

I used a kilovac ev200 main contactor. Rated to open once at 320v 2000amps. So if something happens i just switch off the key. Job done. If you wanted to be 110% just use a second kilovac connected to a normal nc industrial emergency stop button placed on the dash or nearby. I got mine for $75usd.


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## Jimdear2 (Oct 12, 2008)

Jack,

What most people seems to be missing is that the idea behind an emergency stop is it is for *EMERGENCIES.* 

This should be something that everyone recognizes and even a child can be taught to use. 

It should be placed where everyone can see it It shouldn't be hidden or complicated or require more the one simple move to operate.



jackbauer said:


> I used a kilovac ev200 main contactor. Rated to open once at 320v 2000amps. So if something happens i just switch off the key. Job done.


Jack,

That will work as a standard disconnect. The important information here is the Open Once specification of the contactor. 



jackbauer said:


> If you wanted to be 110% just use a second kilovac connected to a normal nc industrial emergency stop button placed on the dash or nearby. I got mine for $75usd.


The Big Red Button connected to a contactor idea is even better. After all you don't want the guy who is peeling you out of a burning car to hesitate while looking for a emergency battery disconnect.

Although, I personally, prefer a mechcanical emergency disconnect, thats just one of my quirks. I use my tractors in compitition and I wrote (am writing) the rules for the classs, so mechanical disconnects are required. 

For those of you building cars or trucks, there are international standards for battery pack disconnects that are recognized by emergency service personal. They are trained to use them to protect themselves. You should investigate those rules see if they apply in you locality.


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## green caveman (Oct 2, 2009)

Jim,

I'm with you on this one. I've pushed a few E-Stops in earnest in my life, once when my finger was caught in a belt, and been very glad that they were there, accessible, and worked.



Jimdear2 said:


> It should be placed where everyone can see it It shouldn't be hidden or complicated or require more the one simple move to operate.


I've built industrial equipment where you have two start buttons at arms length on each side of the machine - this means the operator can't have their hands in the machine when it starts.

You still need an accessible E-Stop and, with the hands occupied, that leaves you with few body parts to hit it with. The primary choice was to place it so that with a flex of the hips you could hit the big red button.



Jimdear2 said:


> That will work as a standard disconnect. The important information here is the Open Once specification of the contactor.
> 
> The Big Red Button connected to a contactor idea is even better. After all you don't want the guy who is peeling you out of a burning car to hesitate while looking for a emergency battery disconnect.


I don't think that the "Open Once" contact is a good idea. You wouldn't what to hesitate because after you hit it the car won't run/time to repair/whatever. If something's going wrong, or you suspect that something's going wrong - hit the E-Stop.



Jimdear2 said:


> Although, I personally, prefer a mechcanical emergency disconnect, thats just one of my quirks. I use my tractors in compitition and I wrote (am writing) the rules for the classs, so mechanical disconnects are required.


Most safety specs require E-Stops to be mechanical. I've had people suggest that you run an E-Stop through a PLC or computer control, which is not allowed (and a bad idea).

As far as I know, knife switches are used to connect/disconnect under load. So it should be possible to find one that is designed to disconnect while loaded and rated for enough amps.

I haven't found an industrial E-Stop with high enough current rating. If someone has link/part number that would probably be a good source.

I still don't really know how I feel about the mechanical and electrical contactor being the same. If the stories about potentially welded contacts are true, I'd want to be sure that the E-Stop and the normal closure are not the same contacts. But that may be a little more paranoid that I need to be.


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## jackbauer (Jan 12, 2008)

I'd love to be able to buy a true ev emergency disconnect. My issues is that what we are all afraid of is a failed controller going full on. Should that happen the current will be very very high. Any of the so called emergency switches I have seen on this and other threads will turn into a plasma ball if opened under serious load. Don't believe me? Buy one and connect it to an industrial dc arc welder wind it up to 500amps and hit the switch.!!! Be sure to take precautions and post a video. And thats only about 50v max!

I accept the points made not trying to be argumentative just pointing out that whats available on the market is just not suitable. Just today i was messing about powering the shunt field on my motor from 48v. Only draws 2 amps at that voltage. Disconnected the wire from the battery and drew a 1 inch arc!


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## green caveman (Oct 2, 2009)

jackbauer said:


> I'd love to be able to buy a true ev emergency disconnect. My issues is that what we are all afraid of is a failed controller going full on. Should that happen the current will be very very high. Any of the so called emergency switches I have seen on this and other threads will turn into a plasma ball if opened under serious load. Don't believe me? Buy one and connect it to an industrial dc arc welder wind it up to 500amps and hit the switch.!!! Be sure to take precautions and post a video. And thats only about 50v max!
> 
> I accept the points made not trying to be argumentative just pointing out that whats available on the market is just not suitable. Just today i was messing about powering the shunt field on my motor from 48v. Only draws 2 amps at that voltage. Disconnected the wire from the battery and drew a 1 inch arc!


Good point. So the E-Stop should be rated at least as highly as the fuse in the circuit. If you have a 500 Amp fuse, you need a 500 Amp+ disconnect.

Do arc welders have E-Stops?


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## jackbauer (Jan 12, 2008)

green caveman said:


> Good point. So the E-Stop should be rated at least as highly as the fuse in the circuit. If you have a 500 Amp fuse, you need a 500 Amp+ disconnect.
> 
> Do arc welders have E-Stops?


No i was just being a smart ass! What I should have said is that to test that a switch can break a dc circuit under load connect it to the output of a dc arc welder , turn the welder on then operate the disconnect. Typical arc welders run about 50v dc on no load so if it cant break that power safely its useless at high ratings.


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## green caveman (Oct 2, 2009)

jackbauer said:


> No i was just being a smart ass! What I should have said is that to test that a switch can break a dc circuit under load connect it to the output of a dc arc welder , turn the welder on then operate the disconnect. Typical arc welders run about 50v dc on no load so if it cant break that power safely its useless at high ratings.


No, I understood the first time. I was just hoping that disconnect was required in the high-amp low voltage side that would work for an EV.

Solar installations have high amp disconnects, but they are pretty expensive. I think that they are typically breakers, just like the 15A home circuit breakers but 300A+.


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## Overlander23 (Jun 15, 2009)

I know not everyone can do it (because of choices and design), but it's also a good reason to have a clutch. The clutch can disconnect the motor from the drivetrain, and just doing that will reduce current to the point where something like a contactor or Anderson disconnect should work without welding, imo.


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## Woodsmith (Jun 5, 2008)

Probably something wrong with this thought but...

There is a main fuse that should be able to break safely at over load current.
Could an emergency shut off simply put a dead short in the circuit to force the fuse to blow?
To reset the break just open the circuit and replace the fuse.


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## green caveman (Oct 2, 2009)

Overlander23 said:


> I know not everyone can do it (because of choices and design), but it's also a good reason to have a clutch. The clutch can disconnect the motor from the drivetrain, and just doing that will reduce current to the point where something like a contactor or Anderson disconnect should work without welding, imo.


Or put it into 5th and hope you blow the fuse? I might think of the clutch, but I doubt that my son would - at least until he has some more driving experience. Then turn the key while the motor is trying to shake the itself to bits - that's all pretty scary?

To keep it in perspective, there are many ways to kill or injure yourself on the road, in EV's or ICE. Many you have no control over. You need a succession of failures, runaway, welded contactor, fuse doesn't blow, forgetting the clutch, etc. for the E-Stop to become important (or at least the Amperage of the E-Stop to be important). So it's not a very likely condition.

It's just that, since you can buy a electrical contactor for ~$70 I would have expected that a simple (but high current) mechanical switch would have been available for under $100. The most cost-effective choice does seem to be the Curtis/Albright combined contactor/E-Stop, but that brings power into the cabin and might still have a problem if the contacts are welded.


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## DC Braveheart (Oct 12, 2008)

I'm going to show my ignorance here ... in a runaway situation your controller has failed in such a way that it's not pulsing the voltage to the motor and your full pack voltage is going into the motor, right? In that case, as your motor tries to reach it's max speed (which is limited by the pack voltage) doesn't the backward EMF created by the increased speed cause the current to drop? I think that's why a motor's torque drops after a certain speed (since torque is proportional to current). So with less current flowing a contactor or other physical disconnect is less likely to weld itself if (when) it arcs when you open it if the motor is running away?


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## Jimdear2 (Oct 12, 2008)

Overlander23 said:


> I know not everyone can do it (because of choices and design), but it's also a good reason to have a clutch. The clutch can disconnect the motor from the drivetrain, and just doing that will reduce current to the point where something like a contactor or Anderson disconnect should work without welding, imo.


Sorry, but if you shove in the clutch of a EV that is in runaway, you won't need to worry about disconnects. You need to worry about how much the new motor will cost. Removing the load may reduce the current but it will allow the voltage to rise and voltage equals RPM. From what I've read it happens so fast you would be unable to release the clutch in time to save the motor.

It will for sure stop the car though. Hopefully there will not be a short, plasma event and resultant fire.

Series DC motors in controller runaway will wind up until they explode if the load is removed.

If a controller fauils FULL ON:

Unless you have a disconnect of some kind, your motor will continue to run until you can get the power off, batteries go dead, something melts or you hit something. Again from what I've read you cannot stop the vehicle with the brakes if you are in your low gear.

As far as at speed try this, think of your car at full throttle, then holding the throttle down slam on the brakes.m Sound like fun? 

I like Jacks idea of a of a contactor (like the KiloVac - one time 320 volts 2000 amps) with a NC emergency stop button wired into the operating coil circuit. It seems the best of a lot of ideas. Better to trash a contactor then a expensive motor.


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## green caveman (Oct 2, 2009)

Jimdear2 said:


> Unless you have a disconnect of some kind, your motor will continue to run until [...] something melts.


At some point everything acts as a fuse?



Jimdear2 said:


> I like Jacks idea of a contactor (like the KiloVac - one time 320 volts 2000 amps) with a NC emergency stop button wired into the operating coil circuit. It seems the best of a lot of ideas. Better to trash a contactor then a expensive motor.


I think that it works, and you can switch the Kilovac many times at lower currents, so it works as a non-terminal E-stop if you just fell of the jack stands. But you still have all your hopes in the contactor.

I'd like to find a knife switch to go along with that. Mainly I'd like the knife switch under the hood so that I have some positive visual indication that the circuit isn't made. You could then put a pull into the cabin. If everything else has failed you might as well pull it. Given the type of day you're already having if you got to that stage, it probably isn't going to work, and your winning lottery ticket will be lost in the ensuing fire.

Problem is, the only knife-switch I can find are 12v-type battery disconnects, say these. Given Stunt Driver's experience, they would probably work but they are a little small.


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## Overlander23 (Jun 15, 2009)

For me an emergency disconnect comes down to an emergency. I've got three contactors (one Kilovac EV200 controlled by a 12v cutout in the cabin and the two contactors built into the Soliton-1 run off of the ignition circuit), a couple of fuses, and an Anderson disconnect handle as power handling points. That's a lot to go wrong all at once... 

So while depressing the clutch to lower current and risking motor failure is certainly not an option I like, at least it's a last ditch one.


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## green caveman (Oct 2, 2009)

Overlander23 said:


> For me an emergency disconnect comes down to an emergency. I've got three contactors (one Kilovac EV200 controlled by a 12v cutout in the cabin and the two contactors built into the Soliton-1 run off of the ignition circuit)


What I also like about the Kilovac is that it takes < 2W to hold the contact. I was looking at some. I was looking at some that took 10W or more. That would be about 10% of your mileage if you had three of them in there.


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## Jimdear2 (Oct 12, 2008)

Everybody,

It appears that there is no one perfect Emergency Disconnect system for all EVs. I really didn't expect there would be one fitzall, that was also reasonably priced;

BUT I HAD HOPES.

For up to 96 -100 volts and 500 or so amps. 

Up to that point there seems to be the Albright Emergency Disconnects With the problem of bringing the power into the passenger compartment or needing to create a remote operating system (I did that, so it is possible).

Then there is using a/the contactor as a remote emergency disconnect the contactor being opened by a dedicated Big Red Button.

For all voltages and currents;

There are also posssible knife switches. I didn't see any proof that these exist and they would have the same problem of bringing high voltage into the passenger compartment or making a DIY remote system

Their are some pricey circuit breakers, but again you need to mount them in the passenger compartment or create a remote operating system.

I'm still not convinced that the Anderson connector is a good answer as a EMERGENCY disconnect. You would have to pull it apart very fast to break an arc from big current.

Above 100 volts and 500 amps;

The only thing I was able to find was a few BIG circuit breakers some of which can be remotly operated using equipment supplied by the manufacturer, others (all?) could be remotly operated with a DIY system, usually a pull cable. The problems with those is some of them were HUGE and all of them had HUGE prices.

I think that those that participated in this discussion now recognize the need for a visible and dedicated Emergency Disconnect and are aware of some options 

Thats Progress.


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## Overlander23 (Jun 15, 2009)

Erm, not quite. Even if they were pulling 10W each, that's 30/30000=0.1% of my pack capacity (if I ran the contactors for an hour... and drove far enough in an hour to deplete the pack, of course).



green caveman said:


> What I also like about the Kilovac is that it takes < 2W to hold the contact. I was looking at some. I was looking at some that took 10W or more. That would be about 10% of your mileage if you had three of them in there.


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## jackbauer (Jan 12, 2008)

Good points Jim. My problem with the albright / curtis is that they are designed for low to medium voltages on things like airport electric trucks , golf carts etc. I fully intend to fit a second kilovac myself. 

My seat of the pants guess would be that to open a high power dc circuit quickly and safely would require an oil or nitrogen jet quenched breaker. Big size and big bucks. Look at the massive fuse carrier used as a disconnect in the white zombie. And they have used it at full load and it lit up the car like flashbulb. My other gut feeling is that anyone with an ev of over 96v who opens one of those curtis disconnects at full load will create more trouble then solve.

What I would like to see is a video of one of these units being operated at say 144v 500amps. I'll hapilly do it if a supplier provides a unit ????


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## Amberwolf (May 29, 2009)

Even the knife switch would still work under load if it had a spring force against it of sufficient drive to open the gap far enough fast enough to prevent the plasma ball. 

I think this is what is used on emergency disconnects on high-power main transmission lines for AC power delivery (yes, AC vs DC but should still work in principle).
________
LIVE SEX WEBSHOWS


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## sharon (Jul 31, 2009)

Think what you are looking for is this switch


green caveman said:


> Apologies if this is in the wrong forum, it's not really technical, but I'm not sure where else it should go.
> 
> Can anyone suggest a source for a high amp DC manual disconnect - just a big manual switch in the main battery line? They're referenced in the "sticky" thread, but the parts suppliers (on the right ad bar) don't seem to have them listed.
> 
> ...


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## Jimdear2 (Oct 12, 2008)

sharon said:


> Think what you are looking for is this switch


Sharon,

Thank you for making us aware if your companies copy of the Curtis Albright emergency disconnect.

It is always good to know of other suppliers.

Please when you make us aware of components like this, publish a price list or make us aware of a reseller who will.

If you read the thread carefully you will note that we were looking for over 100 DC volt and over 250 amp disconnects, circuit breakers and switches, Does your company have such a unit? Please make us aware of it if you do

Thanks


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## green caveman (Oct 2, 2009)

Overlander23 said:


> Erm, not quite. Even if they were pulling 10W each, that's 30/30000=0.1% of my pack capacity (if I ran the contactors for an hour... and drove far enough in an hour to deplete the pack, of course).


I just figure that if you're pulling 400Wh/mile, if the holding current for the contactors are taking 40W then you're pulling 440Wh/mile - 10% more.


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## 69bug (Sep 17, 2009)

I like the clutch style disconnect of the Forkenswift project.
http://www.youtube.com/watch?v=RBQWXyxSTyU
Pretty simple operation... clutch is re-cabled to act as a disconnect.
_Skip to around the 2 minute mark in the video_.

I don't care for the clutch to be the disconnect, just from habit of driving manuals I would be disconnecting every-time I had to shift. Maybe a big red T handle you pull instead.

The disconnects are rather inexpensive. $24.99 I purchased a set to fit 2/0 cables but here are the 4/0 for 600 volt / 350 amps


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## green caveman (Oct 2, 2009)

69bug said:


> The disconnects are rather inexpensive. $24.99 I purchased a set to fit 2/0 cables but here are the 4/0 for 600 volt / 350 amps


Sort of related. Can someone please explain to me the limits of connectors and switches. I've always assumed that it's heat and so therefore power related. So in the example above, the connector should be good for 350*2=700 amps at 300V.

I really ask this in regard to fuses. I've always assumed that fuses just melt - so power. However, some of the big fuses I've seen claim "up to 600V", which, therefore makes no sense to me. Would it be reasonable to de-rate these, so to get a fuse that will blow at, say 100V 600 Amp (to make the calculation easy), should I get a 600V 100A fuse? Are the big fuses smarter than I give them credit for, or are they just fusible links like their little cousins?


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## EV-propulsion.com (Jun 1, 2009)

Green, To answer your fuse question- fuses are voltage rated for the amount of voltage they can break without arc jumping the fusible link section. A 100 amp fuse will blow at over 100amps at 12volts or 600 volts-voltage rating does not change the current limiting. *But, *if you blew a fuse rated at 12 volts using 600 volts (or even 36 volts possibly), the voltage may arc across the gap and continue the circuit- also causing alot of heat-to the point of a possible plasma ball.
Also keep in mind, there is a big difference in fuses rated for DC compared to AC- _be_ _sure to get the proper one_. That goes for all components too- DC rated parts are much more robust- Thats why these emergency disconnect switches are not up to the task of breaking large currents at high voltages-consider Jack's example of an arc welder (that is usually no more than 50 volts) and the distance the arc can jump!
There really isn't a disconnect available up to the task-we use the kilovac for an emergency disconnect, possibly an anderson disconnect would be the best if you could seperate it far enough apart quickly.
Mike
www.EV-propulsion.com


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## green caveman (Oct 2, 2009)

Mike,



EV-propulsion.com said:


> A 100 amp fuse will blow at over 100amps at 12volts or 600 volts-voltage rating does not change the current limiting.


I'm missing a piece of technology here. If I take a standard, say automotive fuse, it's just a piece of wire in a glass tube. As far as I understand it, it just melts. The only thing that blows that fuse is power. If it's a 100V 10A fuse it should take 1000W (P=IV, 100*10 = 1000) to blow it. If I only put in 12V, it still takes 1000W so now we have 1000/12=83A to blow it.

Where did I go wrong?



EV-propulsion.com said:


> Also keep in mind, there is a big difference in fuses rated for DC compared to AC- _be_ _sure to get the proper one_. That goes for all components too- DC rated parts are much more robust- Thats why these emergency disconnect switches are not up to the task of breaking large currents at high voltages-consider Jack's example of an arc welder (that is usually no more than 50 volts) and the distance the arc can jump!


Good point, but I would not have thought that to be true of fuses.



EV-propulsion.com said:


> There really isn't a disconnect available up to the task-we use the kilovac for an emergency disconnect, possibly an anderson disconnect would be the best if you could seperate it far enough apart quickly.
> Mike
> www.EV-propulsion.com


I've been waiting for a chance to frivolously cite this eBay auction. Really unrelated to the point above (or any other point). I just find big industrial stuff interesting:

600 AMPS CONT.


95KV
7.5 KV NOM
8.25 KV MAX
25000 AMPS 3 SEC
40000 AMPS MOM
600 AMPS CONT. CO7 A.C.C.C.


Of course, mounting it might be a problem.


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## jackbauer (Jan 12, 2008)

Fuses are current operated devices not power operated. Mike , have you guys actually done any tests on the disconnects? or know of anyone who has?

Just today I had a scare. Doing some static tests and the throttle stuck wide open because it snagged a wire. Fortunatly i had power on the shunt field so the motor didnt overspeed so i just switched off the ignition which opened the kilovac. Motor was only drawing 27amps so doubt it caused any harm.


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## EV-propulsion.com (Jun 1, 2009)

Yes, Jack is right, fuses (and circuit breakers) are strictly current based. Your example of a 10 A fuse will blow(melt) at say 11 amps at 12 volts or at 100 volts. 
I also might add that if you do find a disconnect switch rated for high voltage, pay attention to the ampere rating- a 300volt, 50adc switch will also not work-the continous current of an EV would overheat these contacts and possibly start a fire.
Ratings are very important, read them carefully.
I use the kilovac as a disconnect, in the thinking that in you ICE car, if the throttle stuck, the only way to stop it would be to turn off the key. Since I try to make a vehicle standard to the auto industry and peoples habits, I use the key to break the circuit, just like Jack has done in his situation (a reflex habit from his ICE days maybe?) 
Depending on how it was stuck on (mechanically or electrically direct) if the fuse was sized right, possibly using a fast blow fuse just above your maximum current, standing on the brake should create a current rise to blow the fuse. Of course if the thottle cable was stuck, the current would not rise above your max current, so then turn off the key... 
Jack, we haven't tested any disconnects, nor have any knowledge of anyone. 
Your a brave soul to offer!
We are, like many, unfortunately relying on manufacturers specs. Luckily in many years we have never seen a "stuck on" controller...then again, years ago we didn't have controllers like today.......
Mike
www.EV-propulsion.com


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## dimitri (May 16, 2008)

green caveman said:


> I'm missing a piece of technology here. If I take a standard, say automotive fuse, it's just a piece of wire in a glass tube. As far as I understand it, it just melts. The only thing that blows that fuse is power. If it's a 100V 10A fuse it should take 1000W (P=IV, 100*10 = 1000) to blow it. If I only put in 12V, it still takes 1000W so now we have 1000/12=83A to blow it.
> 
> Where did I go wrong?


You are missing understanding of Ohm's law, not technology  According to Ohm's law P = I x V , which can also be written as P = I x I x R , or more commonly known I2R. So, fuse blows when current reaches the level when I2R reaches melting point of the fuse material, irrelevant of the voltage.


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## Jan (Oct 5, 2009)

dimitri said:


> You are missing understanding of Ohm's law, not technology  According to Ohm's law P = I x V , which can also be written as P = I x I x R , or more commonly known I2R. So, fuse blows when current reaches the level when I2R reaches melting point of the fuse material, irrelevant of the voltage.


It's just as valid to write: P = V/R X V = V2/R. No, current. Only voltage.


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## Overlander23 (Jun 15, 2009)

Typically, a unit's wattage rating is given in how many watts it consumes per hour of operation. A contactor is essentially a big relay. A low voltage (12v)/low current circuit operates an electromagnet in the contactor that mechanically pulls a set of contacts closed to allow the high voltage/high current side to flow. The amount of power required to maintain the low side, for an hour, is what you're quoting (be it 4w or 10w). This power is normally drawn from the 12v accessory battery, or the main traction pack through a DC->DC converter.

So, the holding current has nothing to do with the efficiency of the high voltage side of the contactor. And there's certainly nothing about the holding rating that would indicate consumption on a per mile basis. Only we EVers would care about miles... everyone else just cares about consumption over time (with one hour being the relative standard).

Whenever you see a wattage rating (except for a watt/mile figure) you're looking at watts per hour.



green caveman said:


> I just figure that if you're pulling 400Wh/mile, if the holding current for the contactors are taking 40W then you're pulling 440Wh/mile - 10% more.


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## green caveman (Oct 2, 2009)

Overlander23 said:


> Typically, a unit's wattage rating is given in how many watts it consumes per hour of operation.


You're right, thanks for pointing out the error in my logic, one less thing to worry about.


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## dtbaker (Jan 5, 2008)

jackbauer said:


> Just today I had a scare. Doing some static tests and the throttle stuck wide open because it snagged a wire.


I had a throttle wire fray and stick once a couple months ago... with accel full on! Lucky I had time to react and pull 'kill switch'. I went for the kill rather than the key so the steering wheel would not lock....

kill consists of a $10 generic choke cable connected to a big fat circuit breaker. see pix at
http://www.envirokarma.org/ev/gallery/090216_cbcable04.connect.htm

so... I have a big fuse inline at mid-pack, ignition switch with inertia switch, and manual pull kill to circuit breaker.


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## green caveman (Oct 2, 2009)

Probably more than you need to know about fuses and, of course, it just confirms what all the smart people on this list already know...

This from Kim at Ferraz Shawmut, Inc. 
http://us.ferrazshawmut.com




A fuse will open due to the heating effects of current. It doesn’t matter what the voltage is until the fuse starts to open.

Here is a picture of a typical fuse [Below]:

An overcurrent will heat the element and it will start to melt at the notches (see red arrow[Don't know where that went, but it just pointed to the hole in the fuse]). Once the element has completely melted through a notch, an arc will form across the gap. This is where the voltage is very important. The arc will continue until the gap is too large to sustain it (we call the amount of element consumed by the arc burn back). The higher the system voltage, the longer the arc can be sustained, the longer the element must be (this is why 600V fuses are longer than 250V fuses). If your system voltage is only 250V or 120V, the fuse will start to melt at the same point, but the arcing time will be much less.

This is all under AC, under DC the rules are different. If your fuse isn’t label for DC, it shouldn’t be used under DC.

For your application, I would use a Class J fuse, like our AJT. It is rated at 600VAC and 500VDC, and is available from 1A to 600A. It is UL listed and is the most current limiting fuse under 600A.

The attached pdfs are from our advisor, the entire application section is at the link below.

http://us.ferrazshawmut.com/oem/resources/literature/Advisor%20Circuit%20Protection%20Applguide.pdf


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## EV-propulsion.com (Jun 1, 2009)

Nice to get a recomendation from a fuse manufacturer, now the bad news, a 500 amp AJT fuse cost about 250.00...+ a holder.........
BUT, that would be the proper fuse...
Mike
www.EV-propulsion.com


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## dtbaker (Jan 5, 2008)

EV-propulsion.com said:


> Nice to get a recomendation from a fuse manufacturer, now the bad news, a 500 amp AJT fuse cost about 250.00...+ a holder.........
> BUT, that would be the proper fuse...
> Mike
> www.EV-propulsion.com



??? the 500a/300v ferraz fuse is $56 at kta...
http://store.kta-ev.com/circuitbreakersfusessafetyswitches.aspx

and no 'holder' is probably required... I did put a sleeve made from old bike innertube over it to help contain spatter or hot bits in case it ever does blow.


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## Jimdear2 (Oct 12, 2008)

Everybody,

We seem to be missing an important point for the purpose of an emergency disconnect.

The safety of others. Emergency personal have been instructed to disconnect electrical power at the disconnect before attempting rescue out of an electric vehicle. The locations for these disconnects are published and distributed by the OEM. 

Since we DIYers cannot do this, the disconnect should obvious and should be easily reconiziable for what it is. 

BIG RED BUTTON/HANDLE

Anyway enough preaching.

I have seen the circuit breaker , Airpack is one brand I believe, used as a disconnect with a manual remote operation and think it is a good way to solve this problem for all voltages vehicles as long as the breaker is properlty sized. I have seen breakers advertised with factory equipped remote operation

DTBAKER and others have gone this way. DT says that the cable cost $10.00 US but what did the circuit breaker cost? Bet it was more then a hundred bucks, unless he got lucky.

The Curtis Albright type disconnect or equivalent should be good for below 100volt EVs

What I'm leading up to is; when we are asked for a list of components a proper breaker or disconnect should be recommended. A point should be made that a EV owner should make the location of the disconnect on his vehicle obvious and also known to local emergency agencies.

Finally, has anyone seen any information on just what voltage/current an anderson connector can break when used to interupt a live circuit. I'm going to go look for a OEM website with specs. If anyone has information, please post it. 

I would hate to see someone hurt because they depended on something to perform a function it is not designed to do. I would also hate to see what a liability lawyer would do to an EVer who hurt someone because they depended on it and finally I would hate to see what the insuarance companies would do to DIY EVs after someone won a multi million dollar lawsuit


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## EV-propulsion.com (Jun 1, 2009)

DT, Yes that fuse is cheaper, but it is not the AJT fuse recommended by ferraz ....btw that's not our price I just did a quick search on the web (we are still looking for an economical choice). Remember, there are many different classes of fuses, (read the 49 page guide green caveman has a link to) some more appropriate than others. The Ferraz recommended AJT fuse is for 600v, in DC motor applications...the other fuse you point out is 300volts for semiconductor protection- a totally different animal- but maybe acceptable, just not what was recommended by ferraz....hence a different price
Mike


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## dtbaker (Jan 5, 2008)

Jimdear2 said:


> The safety of others.
> Emergency personal have been instructed ...
> BIG RED BUTTON/HANDLE


amen to that, which is why I installed an inertia interlock on main contactor circuit. In case of crash, contactor would open traction battery circuit regardless of whether Response Crew notices my red pull labelled 'kill'. I actually am suggesting to my State DMV that part of the registration process for EV is to develop a standardized marking, and 'expected' location for manual disconnect as well as requiring inertia switch. BUT, New Mexico does not have ANY physical inspection of cars for registration, so no real way to enforce this at the moment.



Jimdear2 said:


> DTBAKER and others have gone this way. DT says that the cable cost $10.00 US but what did the circuit breaker cost?


for my voltage/amps I got a GE dual pole for $162. The $10 cable is just a good way to make it a MANUAL disconnect reachable by driver and hopefully Emergency Personel even though it *shouldn't* be required in a crash. If I was using higher voltage or bigger controller, I probably would go with the single pole airpax for about $175. I like the idea of a circuit breaker that can act as a over-amp auto break should the fuse fail AND a manual trip.



Jimdear2 said:


> Finally, has anyone seen any information on just what voltage/current an anderson connector can break when used to interupt a live circuit.


I would guess it *could* break whatever current it is rated to carry, but would arc like a mother, and you'd have to build a slide/cable to be sure to separate by more than your voltage could ever arc... like an inch or so.


as much as I hate restrictive laws, I do agree that we probably ought to seek and promote 'reasonable' safety standards for inspecting/registering DIY EVs before the OEMs feel threatened and make up requirements we can't meet.


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## sharon (Jul 31, 2009)

Thanks for comments.

It is similar to Albright emergency disconnect.

This 250 amp disconnects is USD26 each delivered (international air mail).




Jimdear2 said:


> Sharon,
> 
> Thank you for making us aware if your companies copy of the Curtis Albright emergency disconnect.
> 
> ...


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## Jimdear2 (Oct 12, 2008)

sharon said:


> Thanks for comments.
> 
> It is similar to Albright emergency disconnect.
> 
> This 250 amp disconnects is USD26 each delivered (international air mail).


sharon,

$26.00 delivered is a very attractive price. I'm sure that now that people are aware, you may receive some purchase requests.

Please let us know if your company should happen to develope a disconnect that will handle the higher voltages and currents, up to 350 volts and 1000 + amps.

You might also want to place a post in the sales forum. 

Have a great day,
Jim


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## jackbauer (Jan 12, 2008)

Fair point Jim. A bit like others here my opinion on the emergency services is that the disconnect should happen automatically just like fuel pump cuttof in an ICE vehicle. To that end i'm fitting two kilovacs and everything will be routed through a land rover crash switch. I may even fit two. One front one back and a standard nc industrial mushroom emergency stop button that everyone would recognise.


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## sharon (Jul 31, 2009)

Thanks Jim, It is a good idea, i will place a post in the sales forum. 

For this emergency switch, rated voltage is 80V, but it can be used for 96V,120V,144V,156V sytem without problem. But when used on 350volts system, the Electric life will be shortened. For current, rated current is 250A continuous, but can handle much higher currents short term, so are fine for breaking the traction circuit directly in most EV systems. For "1000 + amps" you mentioned, what is the normal working amps ?




Jimdear2 said:


> sharon,
> 
> $26.00 delivered is a very attractive price. I'm sure that now that people are aware, you may receive some purchase requests.
> 
> ...


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## dtbaker (Jan 5, 2008)

jackbauer said:


> ... disconnect should happen automatically just like fuel pump cuttof in an ICE vehicle.


exactly, the inertia switch I used I think is a fuel cutoff from a ford product... they are only rated for 12v, so you use it to interupt the 12v keyed power to your main contactor solinoid and the circuit opens just like yu turn the key off.


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## Stunt Driver (May 14, 2009)

Not everyone can buy parts, that are good for all possible voltages and currents, that is why I think using normal contactor (rated up to you max current) and a fuse (rated just above your max current) will work just perfect, without any overcomplication or paranoya.

Big red button breaking signal voltage to main contactor - would be nice to have outside of car, preferably driver's side, near hood cover. This is standard for Rally vehicles in my place atleast (12v batt can cause much smoke too). That button would be used by emergency guys.

Now, for driver himself, shutting off ignition should work just perfect, and if controller stuck open, and motor is at low RPM - fuse would blow by the time you'll be ready to disconnect anyway.
I am using forklift contactor, that has 1 inch between open contacts.


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## dtbaker (Jan 5, 2008)

Stunt Driver said:


> Now, for driver himself, shutting off ignition should work just perfect,


not when key 'off' locks steering wheel.... Kill switch should be inside, reachable by driver and NOT kids on the street itching to push big red buttons.


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## Jimdear2 (Oct 12, 2008)

Stunt Driver said:


> Not everyone can buy parts, that are good for all possible voltages and currents, that is why I think using normal contactor (rated up to you max current) and a fuse (rated just above your max current) will work just perfect, without any overcomplication or paranoya.
> 
> Big red button breaking signal voltage to main contactor - would be nice to have outside of car, preferably driver's side, near hood cover. This is standard for Rally vehicles in my place atleast (12v batt can cause much smoke too). That button would be used by emergency guys.
> 
> ...


Stunt Driver,

I've been looking at two things here. One is the best equipment/procedure to perform the emergency disconnect. 

The other is to start an awareness that we need to have a clearly visable, easily recognizable, simplely operated, High Voltage circuit disconnect in/on the vehicle. 

The cost of the Big Red Button along with an iniertia switch wired in to your main contactor operating circuit is probably less then $50.00 - $60.00. This set up would probably be sufficient in 90% + of situations.

What I want to stress is that every DIY EV should have a BIG RED BUTTON or it's equivalent. We need to prove that we are responsible people producing safe vehicles. 

All it's going to take is one persons poorly built EV hurting an emergency worker with High Voltage to start a cascade of laws and lawsuits that could end the DIY EV or so restrict it that it is impossible to build one.

Think about it.


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## green caveman (Oct 2, 2009)

dtbaker said:


> exactly, the inertia switch I used I think is a fuel cutoff from a ford product... they are only rated for 12v, so you use it to interupt the 12v keyed power to your main contactor solinoid and the circuit opens just like yu turn the key off.


Do you have any more details. It sounds to be a good idea.



dtbaker said:


> I actually am suggesting to my State DMV that part of the registration process for EV is to develop a standardized marking, and 'expected' location for manual disconnect as well as requiring inertia switch. BUT, New Mexico does not have ANY physical inspection of cars for registration, so no real way to enforce this at the moment.


I have to strongly object to any situation that increases interaction with the Motor Vehicles Division - at least here in New Mexico. Of my last four interactions with the MVD (over the past year or so) three have been resolved only after I contacted the state governor's office for help. The fourth transaction I just gave up on. I have nothing good to say about them, and there should be no attempt to expand their bureaucratic reach. 

While I think that my experience is extreme, I don't think that it's State specific or that many people have good things to say about these organizations who's goal, let's face it, it to collect revenue for the States. If you can find some other appropriate agency I might be supportive, but not the MVD.


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## dtbaker (Jan 5, 2008)

Jimdear2 said:


> The cost of the Big Red Button along with an iniertia switch wired in to your main contactor operating circuit is probably less then $50.00 - $60.00.


agreed on manual 'kill' + inertia switch... but the price is likely to be $150-175 for big manual circuit breaker with adequate rating, and another $60 for inertia switch interrupt to contactor soliniod. I spent some time looking for a big 'mushroom' rated for 120vDC at 500amps, and couldn't find anything much less expensive than the single-pole Airpax at $175.

HHHmmm, Although I guess maybe if the kill were a big anderson connector in a slide mechanism it might be cheaper... but missing the double coverage of the circuit breaker aspect.


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## dtbaker (Jan 5, 2008)

green caveman said:


> Do you have any more details. It sounds to be a good idea.


the inertia switches can be ordered from KTA-ev.com, or probably yanked from most ford products in the junkyard. Usually located under a panel in the trunk. All you have to do is wire it in between your incoming keyed 12v+ and your contactor solenoid. if it trips, its as if you turn off key.

Check out this page that shows the physical location of mine...
http://www.envirokarma.org/ev/gallery/090301_final_assy00a.htm It's the thing with the red top (reset button)



green caveman said:


> I have to strongly object to any situation that increases interaction with the Motor Vehicles Division - at least here in New Mexico.


They are pretty bad in NM... I am only saying that we SHOULD have physical safety inspection for ALL vehicles to get the clunkers off the road, with reasonable specific requirements for EVs... but echo your doubt that NM MVD can handle that.


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## jackbauer (Jan 12, 2008)

Again just my gut feeling here but as far as i know the prius battery disconnect is buried under the back seat. I'm sure priuss (is that a word!) crash and people get cut out of wrecks etc. I would agree with something like a red painted fuse carrier or some such in the engine bay for emergency crews. I just dont like having a "plasma generator" in the pasanger cabin and as mike said earlier in my experience of the stuck throttle this week i just went straight for the key. Pure instinct. Most modern vehicles will not engage the steering lock until the key is actually REMOVED from the ignition switch. At least thats the case in my 96 bmw.


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## Stunt Driver (May 14, 2009)

dtbaker said:


> not when key 'off' locks steering wheel.... Kill switch should be inside, reachable by driver and NOT kids on the street itching to push big red buttons.


 
I can't recall any cars that would lock wheel just after key is turned to OFF. My `85 fiero also that way. There may be rare exceptions

As for location - if worst comes to worst - would you expect emergency crews to reach inside crashed car for the switch on you dash, if they know it is under high voltage?


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## dtbaker (Jan 5, 2008)

Stunt Driver said:


> I can't recall any cars that would lock wheel just after key is turned to OFF. My `85 fiero also that way. There may be rare exceptions
> 
> As for location - if worst comes to worst - would you expect emergency crews to reach inside crashed car for the switch on you dash, if they know it is under high voltage?


...I just checked, my steering doesn't lock unless key is removed... make sense, and good to know. But the inside/outside manual disconnect is sort of a ::very remote:: thing where it would be most likely for the traction pack circuit to have been opened either from a disconnected cable if a battery rack is smashed, or the main fuse, or the inertia switch, or the circuit breaker, or the driver turning key, or grabbing kill switch...

ER hesitation to cut open a door for fear of high voltage seems less likely than hesitation from cutting and putting sparks all over the ground that could be covered with leaking gasoline.

I just think it makes more sense pulling a manual kill button/pull where the driver can reach it, than on the outside where the driver CANNOT reach it and curious passerbys CAN.

Perhaps the standard that makes sense is to require that HV cables are located centrally under the car to reduce any risk of cutting/shorting with the 'jaws of life', and that kill button/pull are located 'near' the hood latch in the cabin.


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## Stunt Driver (May 14, 2009)

for the last point - looks like proper location of fuses would help.


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## jackbauer (Jan 12, 2008)

I'm just gonna say here that most conversions have front and rear battery packs. So even if i have a kill switch in the engine bay i have hot cables running the length of the car. Don't get me wrong i'm all for safety but sometimes its best to stop and think.


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## dtbaker (Jan 5, 2008)

jackbauer said:


> I'm just gonna say here that most conversions have front and rear battery packs. So even if i have a kill switch in the engine bay i have hot cables running the length of the car. Don't get me wrong i'm all for safety but sometimes its best to stop and think.


what's your point? If you break the circuit anywhere, it won't be 'hot' to the motor, and the whole circuit would be dead unless shorted midstream. 

I suppose if someone managed to run a metal saw through both leads of the 2/0 cable running from front/back that run under the center of the car in the old exhaust tunnel, and the rear pack cables were still in place then they might get a short from the pack in the back... which is why I put my big in-line fuse in the rear pack. If the front is dead via button or contactor, the rear would be covered from worst case short with fuse.


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## jackbauer (Jan 12, 2008)

I guess what i mean is that for ultimate safety the system should have a front and rear disconnect to totally isolate all hv wiring. Assuming our concern here is for people trapped in a crashed vehicle.


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## green caveman (Oct 2, 2009)

jackbauer said:


> I used a kilovac ev200 main contactor. Rated to open once at 320v 2000amps. So if something happens i just switch off the key. Job done. If you wanted to be 110% just use a second kilovac connected to a normal nc industrial emergency stop button placed on the dash or nearby. I got mine for $75usd.


eBay Auction for used contactors for $40:
*Kilovac Czonka III Relay 200AAANA Contactor EV*


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## Evilsizer (Jan 25, 2010)

didnt see this posted so i figure why not...
http://www.evequipmentsupply.com/pr...irect)|utmcmd=(none)&__utmv=-&__utmk=52943528

sounds like what we need, but the question is how much force for it to activate?


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## jackbauer (Jan 12, 2008)

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250438313613&ssPageName=STRK:MEWAX:IT


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## green caveman (Oct 2, 2009)

Will any of the inertial fuel shutoffs work? Say this:

FORD TAURUS SHO FUEL SHUT OFF BUMP SWITCH

Any benefit to buying a switch from an SUV, sports car, ???

Are there any trick I should know about reusing these? Does the orientation matter?


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## jackbauer (Jan 12, 2008)

Any inertia switch should work. It should be a normally closed contact that pops in a crash. You'd have to work out the correct location by trial and error. ie hit it a tap to see which side should face forward.


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## PorscheFan5 (Mar 24, 2015)

All,

I would like to post a few questions to this thread. I realize that it has been a while since the last post, however new products have/can be available.

Background: I am working on my 2004 Boxster conversion and am currently looking at the Emergency disconnect...My system is 144V DC, 1000A controller. Expect the operating current to be around 300-500A DC.


Have procured a Ez-Safe Disconnect from Recharge car - DPST with Anderson 350 connectors. This one is solid however have difficulty in finding the mounting location to easily get to it from the cockpit. Also this is a dual pole so can be used for maintenance disconnect (at no load) and can be mounted near my main contactor in the rear trunk...Has anyone used this? Where did you install it?
Now to the emergency disconnect. Has anyone looked the Gigavac HBD41 master disconnect switch? EV-Propulsion carries it and has a continuous current (400A) overload current 1 minute (2000A) and nominal voltage (1000vDC) ratings that I could use. Refer - http://www.ev-propulsion.com/disconnects.html .

I could potentially mount this in series with my batteries so switching this will open the circuit and no power would be supplied to the controller. Also this could be mounted inside the cockpit with the contacts on the outside (bottom of the car) where the battery wires are passing so as to be able to easily reach and break the circuit.

Would like to get thoughts from the knowledgeable people on this board. Thanks!


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