hot breaker

[dgd]

Mofawayesu,
It appears you have the breaker wired correctly and as VIC detailed.
I took a pic of my MNDC box with 100A, 80A and 60A breakers and indeed the 100A type at the front has two nuts and washers. Note the 80 A behind it has a different stud mounting.
The cables to the breakers are multi-finestrand #4 and the lugs are deeply crimped on the cable.
I know you have probably checked this but you say yours are soldered but you are very sure its a good solder joint?  I agree with VIC and would recommend you also deep crimp the lugs.

ZB,
I was surprised after your heating confirmation so I went to check my breakers. The 100A one was outputting 74A to the battery and the 80A breaker had 34A output.
I felt both and they were at ambient temperature which is about 18degC.
Then I realized they were all Outback breakers as supplied by Able Solar. I thought these were identical to the MN breakers but maybe not.

dgd

[Vic]

dgd,

Thanks for the clear photo.  The second and third breakers are the style that has the formed metal "platform"  thing that I was trying to describe before.  Am certain that those are the Carlingswitch breakers that MidNite sells as the MNEDCs.   That is either a newer design,  or perhaps just used on MNEDC breakers with the high current ratings.   This style may dissipate heat better,  and would allow one to torque the nuts tighter (IMO).

Have used the MNEDC 80.  or 100 A breakers on a Load Bank,  and sure do not recall  significant heating of the breakers or the terminal studs.  Am in town now,  so cannot confirm the design of those EDCs or the heating.

zonblue,  thanks for running tests.  IR Thermometers sure do come in handy in many applications.   Vic

[zoneblue]

Mine is 100A, without the plates, from naws last year. I cant see the sticker side, but i have 80A one just like it which is labelled,

CA1-X0-17-775-321-L
AMP 80
MAX Volts 150 120
hertz dc 50/60
delay 36
trip amps 108
circuit 80
mexico 1239R

The hot spot is near the LINE terminal, with the battery on the LINE side.

[mofawayesu]

Zoneblue, I'm glad then I'm not the only one!  My breaker is definitely more hot on the line (battery) side than the other - like yours. I'm curious if you're also seeing .3-.4 vdc voltage drop across the breaker when it's hot as well.

Vic/dgd, Yes, mine are the 'older' style without the platform.  They were purchased in Canada 18 months ago. 

On the two breakers I have, not all the posts were snugged up tight with the first nut, but that was one of the first things I noticed when I started to try to fix this, so they are now.  It looks like the new style only comes with one nut, so this shouldn't be a problem I'd hope.

By 'deep-crimp', are you suggesting one of those hammer/vise type crimpers?  Those are small enough I could get someone to bring one over on a plane someday.  Unfortunately, battery shops that would have the right tools here are several hours drive away. 

Vic, you're right about the breaker/wire size mismatch.  My intention was to eventually replace those #6 input cables with #4 to match the breaker, but at the time of wiring the epanel, I didn't have any more #4 cable, so used the #6.  Thanks for the reminder!

[mofawayesu]

Westbranch,  it would be nice if parcel/mail were reliable here!  Hardly anyone uses the postal service here for anything but paper mail because anything of value is so consistently stolen. 

We have enough contacts with people coming this direction that we can usually get something handcarried here on a plane in a matter of 2-3 months or so - you learn to plan waaaay ahead!

[mike90045]

This is a small (half briefcase size) hydraulic crimper.  Ebay, Ships from Canada
    Hydraulic-Crimping-Tool-Kit-8-Ton-Electric-Wire-Crimper  US $70.00
http://www.ebay.com/itm/230847642864?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
seller SAROHS   http://www.ebay.com/usr/sarohs?_trksid=p2047675.l2559
Hexagonal die sizes (mm2) â€" 4,6,8,10,16,25,35,50,70
Hexagonal die sizes (converted to AWG) â€" Ranges from 12 to 2/0

It has worked well for me, on a 48V system which has lower currents than 24v systems (1/O wire)

[Westbranch]

here is another link at ~ $35
http://www.ebay.com/itm/10-Ton-Hydraulic-Wire-Battery-Cable-Lug-Terminal-Crimper-Crimping-Tool-9-Dies-/380780092529

I also got the one Mike listed,  and it works fine, just use the smaller of the dies when you do the size conversion.  Some 'straddle' the AWG conversion number and the larger one will not crimp tight enough.

[zoneblue]

I will check the voltage drop next sunny day.  I wonder if rewiring in the reverse direction will make any difference? They are supposed to be unpolarised, but hey, it is in backwards afterall. If its anything like  tenths of volt, thats just ridiculous.

[dgd]

Mofawayesu,

I don't think there should be any heat associated with the breakers. Just that small voltage drop of .3 to .4 volt at 40 amps would mean 10 watts of power being dissipated
This would lead to a real hot breaker in very little time and definitely poses a fire risk.
If its the breaker making the heat then its faulty, likely burned up switch contacts making a resistance to current flow. The only solution is to replace the breaker.
If the cable is hot then it could be a loose connection, anything from the lug not being tightly bolted down to a badly contacting cable inside the copper lug.

I would recommend changing the cable with one that has the copper lugs crimped.
If you do not have a crimping tool then use a flat faced metal punch (about 1/4 inch or 6mm face) and use a use a sledge hammer to drive it into the back of the lug to create a deep deformation of the copper lug into the cable.
Do not solder or heat the lug/wire.

If after trying the new cable, making sure it is real tightly connected to the breaker, there is still heat coming from the breaker then the breaker needs replacing. Until you get a replacement just forget about the breaker (its useless anyway) and wire the circuit without it. If you have a fuze available (T class type 100 to 200 amps) then put this in circuit for safety.

dgd

[zoneblue]

Thats not the conclsuion i get to dgd. My breaker was criimped correectly from the word go, and has had a very gentle life. It being the silly season, i dont know when i get to it, but will definately check the other unused breaker at some point, and also a polarity swap.
When you felt the temp on yours, did you check the area near the line terminal? And was the one carrying 70 amps the one with the plate or the one with out?

I seem to recall a thread previously about these breakers, but cant find it...

[dgd]

ZB,

After reading your earlier posting about breaker heating I have almost continually monitored my breakers in MNDC.
I have felt all the cables and connections and absolutely no excess heat.
The three Carling type surface mount breakers are also just at ambient on both terminals and the back and body sides are cool.
The closest one in my pic is 100A and uses the two nuts on each post. Today at 1pm there was 62A at 28.7v through it and I could not detect even the slightest heat and no voltage drop over the breaker terminal posts. Cable is #4 to Classic 150.
The middle one is 80A and is the flat plate type post with one nut/lockwasher. It was at 29A at 1pm, 28.7v and again no voltage drop. Terminals and cables were cool at ambient.
Cable is #4 to Classic 250.

These 3 breakers as mounted in the MNDC are not tight together, there is a small air gap between each..
All 3 have  commoned together outputs using a solid copper bar with the output cable on the 100a breaker using a short length of #2 with connects to +ve input on 250A breaker post that connects to bank via 1 metre of #0/2
All of these cables and connectors run cool at ambient. I cannot detect excess heating anywhere in this connection chain of cables.

But all of this is just as I expect it to be.
These breakers are not AFAIK thermal  types.
I just can't understand how a breaker should heat up as that means resistance which nobody wants between Classic output and battery bank.

dgd

[zoneblue]

Well all i can say is what i measured. It also makes no sense to me, because these breakers are a magnetic hydraulic design. If and when we get to the bottom of this perhaps ill sacrifice one to a biopsy.

Do you have yours LINE to battery, or LINE to classic?

[Vic]

Yes,  these PM MNEDC breakers are Magnetic-Hydraulic types.

There is a solenoid winding for the magnetic function of the breaker,  this,  the contacts,  and all of the interconnections DO have some resistance.   But agree with dgd,  that a number of watts dissipated in the breaker should not be required,  and would result in quite a lot of heat to dissipate ...

Begin to wonder if these breakers are real MN -- Carling units ...


FWIW,  Vic

[dgd]

Do you have yours LINE to battery, or LINE to classic?

9:34m and 47.5A through 100A breaker and I cannot detect any warming. Maybe I need to get an IR thermometer to be 100% sure but the finger feel test shows nothing.

I didn't think polarity line vs load mattered with these but in my setup the LINE is to battery and LOAD to the Classic.

dgd

[mike90045]

Maybe I need to get an IR thermometer to be 100% sure but the finger feel test shows nothing.

If the pad of your finger can't feel it, the back, near your nail, is very good for checking small thermal differences.  BUT check with the front of the finger first, 'cause you can really burn the back side very easily.