My 2/0 cables are getting hot

[Carl Boyd]

I'm still waiting on clarification for the temperature units. I have a theory but don't want to sound dumb.

Not sure what you're wanting, but temp of the cables were around 80-90 degrees fahrenheit.. I bought a victron lynx distributor today..

 

[Carl Boyd]

Hey which brand and amp of a mega fuse should I use ?? What about the littlefuse brand ??

 

[Rocketman]

Three items:
First do you have a shunt on your system to see how much power is being pulled from the batteries. I use the Victron Smartshunt (or BMV712). This way you can know what is happening to the batteries and know their charge level. That could help solve part of the mystery.

Second, do you have a clamp digital multimeter? This is a great tool to know how many amps are running in a wire.

Third, I just looked up what Victron asks for as far as wire size for that size of inverter. They want two 1/0 wires or if over 10’ two 2/0 wires. A single 2/0 wire is much smaller than two 1/0 wires.

1/0 has 53mm2 (millimeters squared)
2/0 has 67mm2
3/0 has 85mm2
4/0 has 107mm2
So two 1/0 wires is about equal to a single 4/0 wire.

 

[timselectric]

I would bet money on connection points.

 

[Just John]

Hello, 4 of my 2/0 cables gets warm to hot like 80 degrees or so, even blew the 300amp anl fuse. The 2/0 cable from the battery positive to the battery cutoff switch
doesn't even get warm, cutoff switch doesn't get hot. The 2/0 cable from the negative busbar to the inverter get pretty warm but from the negative side of the battery
to the busbar doesn't. The inverter get pretty warm like 80-90 degrees also but I'm not sure how hot they get normaly.
I have 600ah of batteries and 800 watts of solar 400w on each controller, 1 has 4 renogy 100w panels series/parallel the other has 2 200w hightec panels in series.
I haven't tried turning off the solar (not that is should matter, I think) and use the inverter and batteries to see if the cables still gets hot.
The inverter it's self has 2 grounding wires hooked to it a 10 gauge and even a 6 gauge battery cable. None of the other cables even get close to warm.
The setup is for a 50amp RV, the 3 wire output of the inverter is running to a 50amp transfer switch on the generator side and hot leg 1 is jumpered to hot leg 2.
The transfer switch doesn't seem any hotter on the generator than the shore power side. I'm not running any a/c's or big amp draws at the same time or anything but
after a few hours the cables get hot and the anl fuse smells like it's burning. Is the 300amp anl fuse too small, I ordered a few 300amp anl fuses and even
an extra 400amp fuse also. Does anyone have any ideas why only those 4 cables and fuse gets hot???
Thank You!!!

The main positive and negative cables don't get hot, but everything connected to the fuse/busbar does?

I can tell you where I would start looking for a poor crimp, or bad connection.

 

[HRTKD]

Hey which brand and amp of a mega fuse should I use ?? What about the littlefuse brand ??

I'm using the Victron MEGA fuses and fuse holder for the circuit to my Victron Multiplus. They are available on Amazon, coming from Inverters-R-Us. I was unable to find the same items directly on the Inverters-R-Us website. I ordered a fuse holder and a 5 pack of 200 amps fuses last week. It arrived in four days as I recall. I don't know that all fuses fit all fuse holders, so I went with the same brand of both.

 

[Checkthisout]

I had that same fuse holder and returned it to Amazon for the same reason. It has a coating on it that creates high resistance and gets hot. It was a "windynation" brand.WindyNation ANL Fuse Holder + ANL Fuse (2pcs 150A Fuse) https://www.amazon.com/dp/B079ZJY92...t_i_YT6773YFC2B0YHHA9QTQ?_encoding=UTF8&psc=1

Went with this one instead: Spartan Power 100 Amp ANL Fuse & Holder Kit https://www.amazon.com/dp/B075CV5MG...t_i_7DAN4BCFBQ2JP0J9F1WM?_encoding=UTF8&psc=1

It was a very irritating issue to diagnose. I diagnosed it by taking a different straight fuse of the same amperage i orderd and bolting it to the cables without the Holder and retesting. There was absolutely no temperature rise.

Edit: also, your "breakers" are junk too. Same issue. They blow well before their rating and get hot while in operation. Junk them.

Funny, I had the exact same components you do when I started out and had the exact same problems.

Pre-emptively, that inverter is garbage too. If you're still within the 30 day window return that too.

 

[JRH]

you guys have the best pics/diagrams. Gotta figure out how to do that.

I like the expression that blue dog has….a cool critter..

 

[wmgeorge]

Are you sure they are copper cables, not aluminum cables?