Can Someone please explain the math to actual amps being pulled from the battery to an inverter?

[McKravitts]

Well if you want to take it to that then what I meant was it doesn't account for everything, we need the unified field theory to do that and even that is in question these days.

My statement was "everything when determining fuse size or type for an inverter". That a far cry from everything.

Ohms Law has a few centuries of success. It's been referred to as simply a definition of conductance which is the reciprocal of resistance.
I've successfully designed several circuits using just ohms law and Maxwell’s equations.

 

[robbob2112]

CBI, also Carling Tech. Both relabeled by Midnight.

Magnetic breaker trips instantly when enough current flows, e.g. > 5x rating.
With a magnetic core held back by spring, in silicone oil, at modest overload it moves slowly until it makes field strong enough to trip.

You can find diagrams online.

I think they can protect motors and the like better than thermal overload. Also are not affected by ambient temperature or rise due to electrical connections.

Testing Magnetic-Hydraulic circuit breakers

I've built myself a circuit breaker tester. I assembled three transformers into a 3-phase wye auto-transformer, and by means of a breaker and cord/plug it can be repurposed into a current multiplier. A breaker connects X1 to H2 and H3, providing 4.7x current boost on X2 paralleled with X3...

diysolarforum.com

I wonder how the would work down near freezing.

 

[robbob2112]

My statement was "everything when determining fuse size or type for an inverter". That a far cry from everything.

Ohms Law has a few centuries of success. It's been referred to as simply a definition of conductance which is the reciprocal of resistance.
I've successfully designed several circuits using just ohms law and Maxwell’s equations.

Just busting your chop and seeing if I could irritate you too.

 

[Hedges]

I wonder how the would work down near freezing.

Not very well. But at what temperature does silicone oil freeze?
I think this shows -25C or -60C it is just more viscous.

https://www.shinetsusilicone-global.com/products/type/oil/detail/about/index2.shtml

 

[robbob2112]

Not very well. But at what temperature does silicone oil freeze?
I think this shows -25C or -60C it is just more viscous.

https://www.shinetsusilicone-global.com/products/type/oil/detail/about/index2.shtml

Apparently not much different than at normal temperatures Depending on the exact composition used. If you still have your test rig might be interesting to see if a breaker in the freezer overnight changes much

 

[Hedges]

I have it, except breaker panel is now on 3-phase setup. Need to wire a different QO panel to test some QO240, make sure they aren't counterfeit.

For these magnetic-hydraulic, they are DIN rail mount and take wires on both ends so it should be ready to go.

To make an AC breaker tester just wire 120V through a heating element (Variac and heating element to be adjustable) and through transformer primary windings. Use circuit breaker under test to short the secondary. Voltage steps down, current steps up. That can make it reasonable to put 60A or 75A through a breaker under test, with 15A through primary. (wired as isolation transformer gives 4x, as auto-transformer 5x, assuming primary configured for 480V and secondary for 120V)

 

[12VoltInstalls]

wonder if that is real world measurement

There are vids of loaded discharges online.

math shows that we could easily have a fire in the time it takes the class T to blow.

Not arguing- just food for thought.
Class T contains powdered ectoplasm or freeze-dried albino unicorn eggs that snuffs the arc. The blow-cycle is less important to me when envisioning ‘something’ that causes a bms-frying plasma continuity.
I’m not saying do as I do. However, I feel like I’m quite adequately protected from my batteries.
I’m way overkill with 2/0 to the inverter with an ANL and 1AWG to the busbar with 125A Class T’s on each battery. Each battery has a 100A bms. I don’t think I can create more than ~60A from each battery with a 2000W inverter, though the inverter load could theoretically hit 175A it never does.
You can be safe with ‘proper’ cables too.

 

[robbob2112]

There are vids of loaded discharges online.

Not arguing- just food for thought.
Class T contains powdered ectoplasm or freeze-dried albino unicorn eggs that snuffs the arc. The blow-cycle is less important to me when envisioning ‘something’ that causes a bms-frying plasma continuity.
I’m not saying do as I do. However, I feel like I’m quite adequately protected from my batteries.
I’m way overkill with 2/0 to the inverter with an ANL and 1AWG to the busbar with 125A Class T’s on each battery. Each battery has a 100A bms. I don’t think I can create more than ~60A from each battery with a 2000W inverter, though the inverter load could theoretically hit 175A it never does.
You can be safe with ‘proper’ cables too.

What I meant by real world was also if it measured at 7000amps or if it was calculated somehow? I can't imagine many folks have a 7000 amp shunt or other way to measure current at that level tucked away in their garage? I.e. might it be a few thousand amps one way or the other?

 

[Hedges]

I've only got a 2000A probe lying around, and that is for AC not DC.

A piece of 4/0 cable should make a pretty good 7000A shunt, if operated briefly enough to not heat it much. 0.4%/degree C.
Busbar would be better, controlled locations for 4 connections.
But for a wire, I think two ring terminals, stack current connections with ring terminals on one side, sense ring terminals on other side. Or current feeds ends, use split bolt to connect sense somewhere further in.

 

[robbob2112]

Briefly enough would mean fractions of a second. I think a solid chunk of copper 3 inches wide and an inch thick would be what is need. And it would need to be long enough to get a good reading for the ohms before you start. So probably a foot or two.

I know in the Navy I had to calibrate a 3000amp shunt for the airframes shop a few times. It was as big as my wrist and curved back and forth, I bet the length was a couple of meters.

If you want to do it with cables, the math says 31 4/0 cables or 19 350kcmil.

Of course that is to carry it continuously verse just an impulse while your battery blows up in your face.

 

[McKravitts]

Just busting your chop and seeing if I could irritate you too.

I don't mind if you irratate me, just be careful to not make yourself look dumb.

 

[Checkthisout]

I don't mind if you irratate me, just be careful to not make yourself look dumb.

Now I remember why I had you blocked.

 

[McKravitts]

Now I remember why I had you blocked.

Do me a favor and block me again.