diy solar

diy solar

Resettable Circuit Breaker - Voltage Drop

clarkpeacock

clarkpeacock

New Member
Joined
Jun 6, 2020
Messages
83
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
 
Last edited:
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.
 

Attachments

  • Tocas.jpg
    Tocas.jpg
    94.5 KB · Views: 3
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.
 
Last edited:
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.
 
Last edited:
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
 
Last edited:
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.
 
You must log in or register to reply here.

Similar threads

P
Voltage Drop On Batteries
Replies
15
Views
994
philatio
P
Back
Top