DC and AC circuitbreaker>>>?

MAGICPIE3FOCUSPOWER · Jan 27, 2015

Hi All! 8)

I am a little bit confused while looking for some circuit breaker.
What is/are the difference(s) between AC and DC circuitbreaker?

Thanks for help!

striker54 · Jan 27, 2015

See this video https://www.youtube.com/watch?v=Zez2r1RPpWY

You need a solar dc breaker to avoid the arc of dc current to damage the contacts of the circuit breaker

MAGICPIE3FOCUSPOWER · Jan 27, 2015

Thanks mate! I will have a look when I am home.
Youtube is blocked at work 8) :mrgreen:

Doctorbass · Jan 27, 2015

MAGICPIE3FOCUSPOWER said:
Hi All! 8)

I am a little bit confused while looking for some circuit breaker.
What is/are the difference(s) between AC and DC circuitbreaker?

Thanks for help!

AC is alternating current and every time it cross the 0 volt when changing polarity this blow the arc that the Dc current like to produce. Normally the design of a DC fuse and breaker are different and more complicated. if you use a 32V max fuse ( found on the 12V car) to cut 100V dc there is a risk of when the fuse blow, the arc that is created continue to live for few second and it make everything to melt around due to the intense heat.. this can cause a fire. this is not a problem with AC because the voltage change and cross zero witch blow the arc 120 times per second.

Dc fuse and breaker have longer gap between the contact and this reduce the arc problem.

you can get some decent quality circuit breaker here for DC up to 150V

some popular are the Airpax of 80V.. but there is also some 150vdc one.

Some have screw and some have already the bullet connector!!

MidNite Solar DC Circuit Breaker MNEPV
http://www.cafr.ebay.ca/itm/8A-10A-...-Breaker-disjoncte-Solar-Charge-/271147082582

Airpax:
http://www.ebay.com/itm/Airpax-LELK1-1REC4R-32969-80-V-DC-BREAKER-80A-/111394715244

Doc

MAGICPIE3FOCUSPOWER · Jan 27, 2015

Thanks for your info! 8)

Wauuww I have viewed the video :shock:

Yup no AC circuit breaker for me :mrgreen:

Thanks for help all 8)

sn0wchyld · Jan 27, 2015

Doctorbass said:
MAGICPIE3FOCUSPOWER said:

Hi All! 8)

I am a little bit confused while looking for some circuit breaker.
What is/are the difference(s) between AC and DC circuitbreaker?

Thanks for help!

Click to expand...

AC is alternating current and every time it cross the 0 volt when changing polarity this blow the arc that the Dc current like to produce. Normally the design of a DC fuse and breaker are different and more complicated. if you use a 32V max fuse ( found on the 12V car) to cut 100V dc there is a risk of when the fuse blow, the arc that is created continue to live for few second and it make everything to melt around due to the intense heat.. this can cause a fire. this is not a problem with AC because the voltage change and cross zero witch blow the arc 120 times per second.

Dc fuse and breaker have longer gap between the contact and this reduce the arc problem.

you can get some decent quality circuit breaker here for DC up to 150V

some popular are the Airpax of 80V.. but there is also some 150vdc one.

Some have screw and some have already the bullet connector!!

MidNite Solar DC Circuit Breaker MNEPV
http://www.cafr.ebay.ca/itm/8A-10A-...-Breaker-disjoncte-Solar-Charge-/271147082582

Airpax:
http://www.ebay.com/itm/Airpax-LELK1-1REC4R-32969-80-V-DC-BREAKER-80A-/111394715244

Doc

hey doc do you know if you can parallel those DC breakers to handle higher amps? ie 2x the 60A breakers for 120A?

MAGICPIE3FOCUSPOWER · Jan 28, 2015

I am thinking the same, I will use two switches for higher current

striker54 · Jan 28, 2015

sn0wchyld said:
hey doc do you know if you can parallel those DC breakers to handle higher amps? ie 2x the 60A breakers for 120A?

yes you can and yes you should.

MAGICPIE3FOCUSPOWER · Jan 28, 2015

Also should a circuit breaker enough to replace a fuse.
Or it is recommended to use a extra fuse inline?

Thanks! 8)

Alan B · Jan 28, 2015

While there is a range of performance for each fuse and circuit breaker design, they are similar and rarely would one need to use both.

Paralleling generally works but the current might not split perfectly equally so the full rating could end up being a bit less than 2x.

Look at the data sheets, a breaker will carry larger currents for a while, depending on temperature. You may not need two in parallel.

Watch the polarity on DC breakers, it needs to be right for the ARC to extinguish quickly.

Doctorbass · Jan 28, 2015

I paralleled a lot of fuse and it work just perfect. they blow when they have to and they hold when they have too. As for circuit breaker I never paralleled any but this is my actual plan for my Max-E.

The actual max battery current is 130A and I should rarely sustain that level for more than 10 sec ( ex: for acceleration)

I have bought one 100A ( trip at 125A after 52 sec) and two other that I might parallel if the 100A trip or trip too often.

The two other are one 50A and one 60A ( aprox 110A parallel) and about 150A trip after 52 sec.

I wiil test.

Before for a 12kW ebike I was using 3 parallel 40A fuse (the 12V car fuse) and they did their job as they should And I think that the fact that there is many in parallel is a way to blow the arc progressively because I never had arc problem at 24s lipo and even 30s lipo for these 12V fuses.

Doc

MAGICPIE3FOCUSPOWER · Jan 28, 2015

Thanks!

Do you have to use a precharge resistor when using DC circuitbreaker?
Or it is just overkill?

Doctorbass · Jan 28, 2015

MAGICPIE3FOCUSPOWER said:
Thanks!

Do you have to use a precharge resistor when using DC circuitbreaker?
Or it is just overkill?

Yes Precharge must be installed. Breaker or fuse don't replace precharge.

Doc

striker54 · Jan 28, 2015

Doctorbass said:
MAGICPIE3FOCUSPOWER said:

Thanks!

Do you have to use a precharge resistor when using DC circuitbreaker?
Or it is just overkill?

Click to expand...

Yes Precharge must be installed. Breaker or fuse don't replace precharge.

Doc

Actually, adaptto guys say that a precharge is not needed if we use a breaker.

Doctorbass · Jan 28, 2015

striker54 said:
Doctorbass said:

MAGICPIE3FOCUSPOWER said:

Thanks!

Do you have to use a precharge resistor when using DC circuitbreaker?
Or it is just overkill?

Click to expand...

Yes Precharge must be installed. Breaker or fuse don't replace precharge.

Doc

Click to expand...

Actually, adaptto guys say that a precharge is not needed if we use a breaker.

Well it depend on what we are talking about... the first time you connect the battery to the controller YOU MUST have a precherge, temporary or permanent. Then the adaptto controller is always connected to the battery and alwys seeing full battery voltage, but it's because it have a sleep mode wich is great! but not all controller does

dnmun · Jan 28, 2015

you can turn the BMS on and off if you need a switch to turn off the battery. then you can use a little 7 cent DIP switch instead of a DC breaker.

MAGICPIE3FOCUSPOWER · Jan 28, 2015

Thanks for your nice tip!

But this time I dont any bms :oops:

Also a extra is fuse is needed when using a breaker?

spinningmagnets · Jan 28, 2015

Read this build article, it uis my "go to" reference for the electrical system. there is a build thread link in the article if you want more detail, but the highlights are featured:

http://www.electricbike.com/custom-build-gallery-teklektiks-dual-motor-yuba-mundo/

MAGICPIE3FOCUSPOWER · Jan 28, 2015

Thank you very much!!! 8)

I see you are using 330 ohm precharge resistor is 150 ohm also suitable?
Due I have some 150 ohm 10W laying around :mrgreen:

sn0wchyld · Jan 28, 2015

MAGICPIE3FOCUSPOWER said:
Thank you very much!!! 8)

I see you are using 330 ohm precharge resistor is 150 ohm also suitable?
Due I have some 150 ohm 10W laying around

100ohm would be fine for most setups... and 3w is generally enough too. pretty sure that's whats on my current build

dnmun · Jan 29, 2015

i would expect even a 1/4W resistor would work if it is in the 200-300R range. it doesn't make heat.

MAGICPIE3FOCUSPOWER · Jan 29, 2015

Thanks!

I will box a box with those 1/4W resistors for in future projects! 8)

Thanks for help all!

madin88 · Jan 29, 2015

Doctorbass said:
striker54 said:

Actually, adaptto guys say that a precharge is not needed if we use a breaker.

Click to expand...

Well it depend on what we are talking about... the first time you connect the battery to the controller YOU MUST have a precherge, temporary or permanent. Then the adaptto controller is always connected to the battery and alwys seeing full battery voltage, but it's because it have a sleep mode wich is great! but not all controller does

shouldn't an AC braker be able to precharge (a bit)?
I think of if many electrical gadgets are connected to sockets in the house and the braker will be closed. I believe there would be a BIG spark if it wouldn't do some kind of precharge..

MAGICPIE3FOCUSPOWER · Jan 29, 2015

Maybe this help?

crea2k · Jan 29, 2015

Some AC circuit breakers also do DC too, you just need to check the spec.

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