DC Circuit breaker 400 amps+

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pdhsolar
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DC Circuit breaker 400 amps+

Post by pdhsolar »

Hi, Does anyone know where I can purchase a 400 amp DC circuit breaker for my EV (which is almost complete)?

I am running 144 volts from the traction batteries (45x120Ah Sky Energy).

EV works use to sell them, but now they are not online.....

Any help would be apreciated.
Thanks,
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DC Circuit breaker 400 amps+

Post by acmotor »

Is this what you were looking for ?

http://www.evworks.com.au/index.php?category=3
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DC Circuit breaker 400 amps+

Post by pdhsolar »

Hi, Thats a contactor which operates via a 12v supply.

I am looking for a manual DC circuit breaker that can handle 400 amps so that I can manually turn off the DC side when I need to.

Thanks anyway. Image
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DC Circuit breaker 400 amps+

Post by lithbattboss »

I am actually in the process of ordering a 400amp circuit breaker for an EV project this week. However it is an industrial circuit breaker and wouldn't be suitable and would be too expensive for use in an electric car. I say it wouldn't be suitable for an electric car since this is for my big electric boat project which only runs a 48V battery/motor system supplying three 5kW electric boat motors.

Unlike an electric car, the boat does not require a main contactor. The 400A circuit breaker is the main circuit protection and has a shunt trip fitted which will automatically trip the circuit breaker should the battery become excessively over discharged thus providing protection for the batteries from possible damage which could otherwise occur due to deep discharge.

In addition an emergency stop button will also be connected to the shunt trip mechanism in case of an emergency aboard the boat eg, fire etc. so as to instantly isolate the battery bank supply at the push of a button without having to be close to the circuit breaker lever.

If you are looking for a circuit breaker to act as protection and act as a manual isolation switch for the voltages normally used in electric cars you will need to expect to pay big dollars for such a high current rated circuit breaker rated for DC. I don't get much change out of $2000 dollars for my breaker and I would expect that a breaker to suit your requiremnts would cost considerably more.
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DC Circuit breaker 400 amps+

Post by acmotor »

LBB, you don't need to look too far or spend too much for a very capable contactor e.g..... kilovac ev200.

These are less than $200 (I paid $65) and would be VERY suitable for a marine environment being totally sealed in the contact department. (and not an ignition source which is mandatory in the marine world anyway)

Re manual switch... but why ????? when you can have a 12V ignition switch operated contactor. In fact the modern EV safety expectation is that the ignition switch (and 12V system) cuts everything off. i.e. inertia switch and charger also operate the contactor !
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DC Circuit breaker 400 amps+

Post by 300zxev »

Doesn't the current NCOP14 state "manual disconnect of HV required" ... AKA circuit breaker with in cabin choke cable ??? ...
I believe the NCOP is under review and could possibly migrate to contactor disconnect sufficient ... but isn't this only in the pipeline ...

So to answer the original question ... I have used Airpax circuit breakers which are rated at 160V 800A trip ...

You can get them here
http://www.kta-ev.com/catalog.html

Or Google the model number

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DC Circuit breaker 400 amps+

Post by evric »

The circuit breaker acts as a fuse and a manual disconnect, all in one.
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DC Circuit breaker 400 amps+

Post by lithbattboss »

evric wrote: The circuit breaker acts as a fuse and a manual disconnect, all in one.


Yes exactly. I like this feature. It doesn't require an external power source to energize it and make it work.
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DC Circuit breaker 400 amps+

Post by pdhsolar »

Thanks Guys,

The idea is to use the circuit breaker as an emergency on/off located on the battery box (which can be reached from the drivers seat). The main reason is for that extra peace of mind just in case the contactor gets stuck in the ON position. I will still be able to shut down the high voltage DC by the simple flick of a switch. It is unlikely to happen, but I prefer to be on the safe side. Who would have thought Toyota would have had an issue with the Prius???
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DC Circuit breaker 400 amps+

Post by lithbattboss »




To answer both acmotor and 300zxev there are several reasons for my choice of the circuit breaker.
I guess alot of it comes down to my years of experience in the electrical industry and particularly in the UPS industry working on huge UPS's and their asscoiated large battery banks and the protection methods used in this industry. These methods have been tried and proven as reliable over many years.
A contactor is never used as the battery bank switching device for a UPS battery bank. The contactor requires power to energize the coil whereas the circuit breaker does not thus making it fail safe and since it acts like a resetable fuse it serves more than one function.

The circuit breaker can be locked with a padlock thus preventing unauthorized use which will be a good feature to have for my e-boat when it is moored and not used.

The better circuit breakers which have a good reputation in the industry for their reliability allow you to fit several accessories such as undervoltage release trips, shunt trips, trip indicators etc. allowing automatic or remote control of the circuit breaker.

The breaker I will be using is typically used in the mining industry and is amongst the best available which is also why it is very expensive.

Normally on a large lead acid battery bank an undervoltage release is used which automatically trips the breaker when the batteries are discharged to provide automatic protection of the battery bank from damage due to excessive discharge.

Since my boat will be powered by lithium batteries I can't use this method due to the very flat discharge curve. This is why I will use a shunt release instead with 12V (or 24V) being supplied from the genset starting battery.

LiFeTech lithium batteries provide a 5V TTL signal (OLV) when the batteries are discharged. This signal will be used via the shunt trip coil in the circuit breaker to automatically trip the breaker when the batteries are depleted thus ensuring deep discharge protection.

So the circuit breaker act as-
1) Short circuit protection
2) Provides manual isolation for battery replacement/maintenance
3) Provides automatic protection of the batteries in case of deep discharge.

Usually a battery circuit breaker with a B-curve is used for DC/battery applications but in UPS installations it is most common to just use a regular C-curve breaker but to use a 3 pole breaker and break the +VE supply line twice and the -VE supply line once.
This is what I will be doing on my electric boat project.

You can see the battery circuit breaker fitted in the top right shelf of this UPS battery installation in a government building in Sydney.
(see attached photo below)

The Airpax breakers are OK as a budget circuit breaker but they aren't as versatile as the Terasaki breakers (which I have many years of experience with) since they don't allow you to fit accessories such as undervoltage and shunt trip coils.

The battery circuit breaker I will be using for my e-boat project is a Terasaki Tembreak S400CJ with rated fault current level of 36kA which is more than sufficient protection for the lithium battery bank which will power this boat.

The Terasaki short form Circuit Breaker catalogue is here-
http://www.acdc.co.za/downloads/Terasak ... %20WEB.pdf

Image
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DC Circuit breaker 400 amps+

Post by lithbattboss »

pdhsolar wrote: Thanks Guys,

The idea is to use the circuit breaker as an emergency on/off located on the battery box (which can be reached from the drivers seat). The main reason is for that extra peace of mind just in case the contactor gets stuck in the ON position. I will still be able to shut down the high voltage DC by the simple flick of a switch. It is unlikely to happen, but I prefer to be on the safe side. Who would have thought Toyota would have had an issue with the Prius???


It is not quite as easy as you think!
Have you seen the size of a circuit breaker rated at 800A? It is quite large and you certainly can't turn it off in an emergency with a "simple flick of the switch" (as you put it).
It takes considerable force.
You would be best using my method and you can fit a shunt trip release mechanism. That way the breaker can be fitted anywhere in the vehicle. You just wire an E-Stop button from the breaker to some convenient location such as on the dashboard etc. So all it takes is just a quick momentary press of the button in an emergency situation and the breaker trips thus totally isolating the battery pack.
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DC Circuit breaker 400 amps+

Post by acmotor »

Counting the safety numbers....

Prius 12V "ignition key" and inertia sensor (etc) battery pack contactor backed by a DC rated fuse.
>> 2,000,000 and counting (and new revision of NCOP14, and all other commercial EVs/hybrids ?)
Toyota's current problems are not related to this.

..and...
Ancient big red mechanical buttons (and old versions of NCOP14)
..... some on the backyard conversions, but now relagated to history.

Contactors fail as often as mechanical switches, but both mostly when underrated for the application.

You don't need a padlock for an ignition key last time I looked !
A removable fuse is sooooo superior to a padlocked CB if you really want to be safe when working on the gear. IMHO
LBB's arrangement still sounds good though.
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DC Circuit breaker 400 amps+

Post by 300zxev »

lithbattboss wrote:

It is not quite as easy as you think!
Have you seen the size of a circuit breaker rated at 800A? It is quite large and you certainly can't turn it off in an emergency with a "simple flick of the switch" (as you put it).
It takes considerable force.
You would be best using my method and you can fit a shunt trip release mechanism. That way the breaker can be fitted anywhere in the vehicle. You just wire an E-Stop button from the breaker to some convenient location such as on the dashboard etc. So all it takes is just a quick momentary press of the button in an emergency situation and the breaker trips thus totally isolating the battery pack.


The Airpax is rated at 800A trip ... I have 2 of these in parallel and they are quite easy to turn off with a choke cable ... For the record though, I am designing the cutoff for both NCOP revisions ... ... I have a LV red button which cuts the pack in 3 via contactors (run from the ignition) and also the 2 circuit breakers via a choke cable. (never can be too careful ...)

lithbattboss ... no doubt you might have a superior circuit breaking option and the experience to back it up, but is that really an option for the DIR'er ?
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DC Circuit breaker 400 amps+

Post by antiscab »

300zxev wrote:
So to answer the original question ... I have used Airpax circuit breakers which are rated at 160V 800A trip ...

You can get them here
http://www.kta-ev.com/catalog.html


is this the breaker you refer to?:
Airpax JLE-1-1-53-3-B4-250...Single section w/toggle handle...compact...160 VDC max...For controller systems up to 800 Amps...2 lbs       $175.00

because 800A is the breaking capacity.
trip current is 250A

so says the manufacturers website.

800A is generally not sufficient breaking capacity for the majority of traction batteries capable of giving more than 250A continuous.

what is likely to happen is if it trips under significant load, it will arc. the a CB arc, its rather hit and miss as to whether the circuit actually breaks. the CB is also toast afterwards (so no reset possible).

a set of gigavac (or EV200 is you can still get the cheaply) breakup contactors will be more reliable.

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DC Circuit breaker 400 amps+

Post by antiscab »

oh wait,
silly me,

found the data sheet

breaking capacity is 10kA (if voltage applied is less than 3msec?)

not sure where the 800A rating came from.

interesting that at ~500A, trip time is between 22 and 150 seconds.

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DC Circuit breaker 400 amps+

Post by 300zxev »

In the data sheet I have ... Airpax model number JLE-1-1-53-3-B4-250

The 3 stands for ... 160Vdc 800A
the 250 stands for ... Current Rating 900 Ampres

The 53 stands for DC long delay on trip
if you see the graph for the 53 it shows 250% of the rated current for 10secs before trip


All I know is i've seen one of these successfully in a 400A setup ... and i'm using 2.
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DC Circuit breaker 400 amps+

Post by acmotor »

300zxev wrote:
The Airpax is rated at 800A trip ... I have 2 of these in parallel and they are quite easy to turn off with a choke cable ...


I would have thought that a choke cable is about 1,000,000,000 times more likely to fail than a correctly rated contactor ! Image

But yes, as a BACKUP system it is fine when there are big sparks to play with.

Don't confuse the breaking capacity of contactors/CBs in AC or ms DC with their capacity to break thousands of amps DC in a fault condition in an EV.
The 10kA or 30kA breaking capacity is not realisable in DC situations.
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Post by hipo_ev »

Just reread other suggestions and they are the same lol. Sorry.

acmotor wrote: Don't confuse the breaking capacity of contactors/CBs in AC or ms DC with their capacity to break thousands of amps DC in a fault condition in an EV.
The 10kA or 30kA breaking capacity is not realisable in DC situations.

These Airpax circuit breakers are specifically rated in DC - so I would expect their interrupt breaking capability to be accurate - if it isn't, it would be a HUGE liability for Airpax to even list them.

300zxev wrote: In the data sheet I have ... Airpax model number JLE-1-1-53-3-B4-250

The 3 stands for ... 160Vdc 800A
the 250 stands for ... Current Rating 900 Ampres

The 53 stands for DC long delay on trip
if you see the graph for the 53 it shows 250% of the rated current for 10secs before trip


All I know is i've seen one of these successfully in a 400A setup ... and i'm using 2.

One thing to point out though, is that the one suggested above (JLE-1-1-53-3-B4-250 ) is not rated at 800A, but rather only rated at 250A. It has a slow delay before breaking which makes it break at high amps, but the higher the amps, the quicker it breaks.

An 800a load through it would cause it to break in approx 5 seconds and it would break after about 10s at 500a. Still that is prolly suitable for 75% of EVs being made, but if you live on the top of a hill (or drive up a hill during your commute) and more than 500A is drawn for 10s continuously it will break and you will stop.

At least that is how I understand the data specs for that particular circuit breaker :p

If you drive up long hills, or are looking to build a high performance EV that draws more then 250A continuosly for any long period of time, you may need to consider something that is rated at 400A, like the Airpax JTEP-2-1-53-3-B1-400 or JTEP-2-1-53-3-B1-400 - which are both rated at 400A continuous, and can support 500a for almost 2 minutes and 800a for approx 20s before breaking.

hipo_ev



EDIT: If an EV store buys them in bulk (ie. 50 or more at a time), they can be had for less then $300 each - which is a HUGE savings compared to almost $600 for one.
Last edited by hipo_ev on Fri, 05 Mar 2010, 11:01, edited 1 time in total.
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