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Resettable Circuit Breaker - Voltage Drop

clarkpeacock

clarkpeacock

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Jun 6, 2020
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Hi all

Thought I would just share this in case it helps save a little time for anyone else!

I have had problems recently with my Victron Multiplus 24/3000 repeatedly going into low voltage shutdown when driven fairly hard - circa 80 Amps for 2-3 minutes while the washing machine heater is running. Less than 2000 watts, so well within its capabilities.

After much checking and tearing out of non existent hair, it turned out to be the 200A resettable Circuit breaker - 26V input, 16V output, and it wasn't even getting very hot! Once the Multiplus shut down, voltage was restored, washing machine restarted, and the cycle begins again.

I have now replaced the breaker with a 200A mega fuse - problem solved.

I have read before that these cheap circuit breakers are not very good, and I can now agree! Throw them away and get a decent fuse instead ?

Here's the offending article

Screenshot_20210823-090810.png

Now replaced with this

Screenshot_20210823-091221.png
 
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Short_Shot said:
Reminder that this is only a problem for the cheap ones. I experienced the same way back in my early car stereo days.

The "name brand" breakers don't have this issue and you don't necessarily need to go the fuse route.
Click to expand...

That's a good point. I did look at replacing with a Durite breaker at £30 UKP, but figured that a fuse was a simpler and safer bet!
 
While I largely agree, cheap fuses have problems similar to cheap breakers. So that's another one to watch out for. Low cost fuses have been shown to have voltage drops and bad ratings many times.

Of course the choice ultimately depends on preference at the end of the day and there's something inherently more trustworthy feeling about the tried and true single use fuse.

No matter what, you never need to question whether a used fuse will work the same way the second time - because it won't work at all!
 
clarkpeacock said:
Hi all

Thought I would just share this in case it helps save a little time for anyone else!

I have been problems recently with my Victron Multiplus 24/3000 repeatedly going into low voltage shutdown when driven fairly hard - circa 80 Amps for 2-3 minutes while the washing machine heater is running. Less than 2000 watts, so well within its capabilities.

After much checking and tearing out of non existent hair, it turned out to be the 200A resettable Circuit breaker - 26V input, 16V output, and it wasn't even getting very hot! Once the Multiplus shut down, voltage was restored, washing machine restarted, and the cycle begins again.

I have now replaced the breaker with a 200A mega fuse - problem solved.

I have read before that these cheap circuit breakers are not very good, and I can now agree! Throw them away and get a decent fuse instead ?

Here's the offending article

View attachment 61280

Now replaced with this

View attachment 61281
Click to expand...

If you have LFP battery then Class T fuse is the minimum I would use.
Better are NT and NH fuses.
ANL and Mega fuses do not have the necessary Amp breaking capabilities.

That breaker are also jokes. (the cheap ones and the originals too).
This is a usable breaker:
https://www.outbackmarine.com.au/noark-200a-500v-dc-circuit-breaker-2-pole
 
Short_Shot said:
While I largely agree, cheap fuses have problems similar to cheap breakers. So that's another one to watch out for. Low cost fuses have been shown to have voltage drops and bad ratings many times.

Of course the choice ultimately depends on preference at the end of the day and there's something inherently more trustworthy feeling about the tried and true single use fuse.

No matter what, you never need to question whether a used fuse will work the same way the second time - because it won't work at all!
Click to expand...
The one I have bought is branded 'Littelfuse' which is the same as the one Victron sell as their own (at four times the price!) So hopefully will be good. Like you say, if it fails, it has permanently failed, so in my mind should be safer.
 
Go with the tried and true. Heinemann/Eaton GJ breakers, or Carling. Both were/are used by Trace Engineering and Outback Power and can be found at reputable solar distributors.
 
I struggled with selecting one of these beakers too. Too cheap to be true usually means too cheap to be good. I watched a video Will did on his own install and noticed he used the Tocas breaker. I got one but haven't installed it yet and the return window on Amazon is still open. The thing is only intended as a convenient safety valve for the inverter. My main "oh f**k" device is a 300 amp class T fuse near the battery. I have an industrial grade 250 amp DC breaker but it's almost the size of a VHS cassette and I was avoiding using it because of the size.
 

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I recommend the Bussmann brand for these breakers. I believe they only go to 150 amps so that puts you in a fuse.
 
My inexpensive 80 amp breaker keeps throwing after 10 mins of AC at only 27amps!!!

1631361049153.png
 
Brett V said:
I struggled with selecting one of these beakers too. Too cheap to be true usually means too cheap to be good. I watched a video Will did on his own install and noticed he used the Tocas breaker. I got one but haven't installed it yet and the return window on Amazon is still open. The thing is only intended as a convenient safety valve for the inverter. My main "oh f**k" device is a 300 amp class T fuse near the battery. I have an industrial grade 250 amp DC breaker but it's almost the size of a VHS cassette and I was avoiding using it because of the size.
Click to expand...

T Tocas is the worst.

Throw that thing away or return it ASAP!
 
@cwilken your breaker looks just like the one in this video. And the T-Tocas craptastic ones as well :


Note the first comment below the video urging folks to use UL approved ones.

I really wish @Will Prowse would remove the Tocas crap from whatever pages he has posted from which people keep taking it as a recommendation.

Critical safety components is not the place to save $2 over a brand name IMHO.
 
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I removed it and ordered a fuse block instead and a separate high amp battery switch. I am returning it to amazon so the vendor knows it is a problem.
 
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Really good breakers for high current DC use

Carlingswitch...............Magnetic/Hydraulic

Rebranded as:
MidNite Solar MNDC series
Blue Seas
Anchor Marine
almost the exclusive use in aircraft including Boeing, Rockwell, Cessna, Piper.....everybody who is “whose who in avaition”

and others

Circuit Breaker International................. Magnetic/Hydraulic

Rebranded as:
MidNite Solar MNPV series
Outback Solar

Bussman........Buss Industries........... Thermal ( no where near as good as Magnetic/Hydraulic)

Rebranded as:
Blue Seas
Anchor Marine

and many others
 
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JoeHam said:
@cwilken your breaker looks just like the one in this video. And the T-Tocas craptastic ones as well :


Note the first comment below the video urging folks to use UL approved ones.

I really wish @Will Prowse would remove the Tocas crap from whatever pages he has posted from which people keep taking it as a recommendation.

Critical safety components is not the place to save $2 over a brand name IMHO.
Click to expand...
The Toca's are fine. States that they meet S.A.E. J1625, J1171, UL1500 compliancy. Should look up the certs for it.

Even the dirt cheap ones seem to work great:

I've had them trip just fine. I don't see what the problem is.
 
JoeHam said:
@cwilken your breaker looks just like the one in this video. And the T-Tocas craptastic ones as well :


Note the first comment below the video urging folks to use UL approved ones.

I really wish @Will Prowse would remove the Tocas crap from whatever pages he has posted from which people keep taking it as a recommendation.

Critical safety components is not the place to save $2 over a brand name IMHO.
Click to expand...
Oh, that circuit breaker in the video isn't a Toca's. You are mistaken. That's a piece of garbage! We talked about this years ago. Those are dangerous. The Toca's are fine.
 
time2roll said:
I use Bussmann Hi-Amp. Amazon has them.
Click to expand...
I have a "48 volt" battery that really goes up to 58 volts. All of the higher quality breaker switches go up to 44v or 48 volts in the self ratings. I prefer one that goes to 60 volts. Some people say they like AC like breakers but I don't know how they mount them without a box and using minimal space. Ive decided to have a separate fuse and battery isolator switch.
 
cwilken said:
I have a "48 volt" battery that really goes up to 58 volts. All of the higher quality breaker switches go up to 44v or 48 volts in the self ratings. I prefer one that goes to 60 volts. Some people say they like AC like breakers but I don't know how they mount them without a box and using minimal space. Ive decided to have a separate fuse and battery isolator switch.
Click to expand...
Yes my mind was on the OP 24/3000 victron.
 
Will Prowse said:
My current favorite surface mount marine grade breaker is Stinger breakers. They are fantastic, and can handle higher voltage than Bussman.
Click to expand...
They look pretty well made but I would be very happy to see a video with one of these that is heated up with a 50% amp load for 10 minutes then subjected to a 75% capacity and then a 100% capacity spike. I predict that when they are hot they will throw much lower than advertised!!! Im not really sure these are designed to respond well to constant load situations and still have any accuracy. I just removed my 80 amp breaker switch for a HD battery switch and fuse as my breaker kept going off at low values when it was hot!
Also when I looked at these Stinger breakers I think they only went up to 48 amp. A lot of us who use 48 amp systems are really using 55-60 amp systems so we cant be sure of what can go wrong outside of the called out parameters.
 
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cwilken said:
They look pretty well made but I would be very happy to see a video with one of these that is heated up with a 50% amp load for 10 minutes then subjected to a 75% capacity and then a 100% capacity spike. I predict that when they are hot they will throw much lower than advertised!!! Im not really sure these are designed to respond well to constant load situations and still have any accuracy. I just removed my 80 amp breaker switch for a HD battery switch and fuse as my breaker kept going off at low values when it was hot!
Also when I looked at these Stinger breakers I think they only went up to 48 amp. A lot of us who use 48 amp systems are really using 55-60 amp systems so we cant be sure of what can go wrong outside of the called out parameters.
Click to expand...
No, Stinger has higher amperage models. I am using a 150A model right now. They do not fall apart in high moisture environments unlike other "marine grade" breakers that fail miserably.

Yes, I will test them. I use them on my packs right now 24/7, and they are fine. I will try to pull some certificates and see what their listings are when I get home. I do not understand why people would like a bussman more than a tocas. I think they have the same certificates. I would trust a third party laboratory test more than any personal experience.
 
The one thing that i worry about with Lithium batteries is the available short circuit capacity. The amps are huge at dead short circuit. Really good breakers have a A.I.C. rating....That is not the trip amps, the A.I.C. rating is the Amp Interrupt capability. When that massive dead short happens the current can be very massive, way beyond the trip capability. With a 200 a.h. battery it can be in the thousands of amps. The A.I.C. rating of the breaker must be greater than the maximum amps available. When that unsuspected short happens the entire breaker welds. It is catastrophic. The breaker almost always welds closed.

Do chinese breakers even have a A.I.C. rating? I have never seen a Chinese one that does. They may have one but it is not in the published specs. Well the CBI breakers (Soweto, South Africa) do have a published A.I.C. rating as well as the Schneider and Seimens, (Germany) do but these are industrial rated breakers. It is required in industry as well as breakers for household use, normally 10,000 amps for branch breakers and up to 70,000 amps for main breakers.

It is not required for “car stereo breakers”
 
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