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4/0 wire to inverter getting hot

corn18

corn18

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So I doubled up my 4/0 wire from the batteries to the Lynx distributor and they stay ambient now even at 325A. The single 4/0 wire to the inverter (3 ft total run) is getting hot at max load. Not super hot, but warmer than I would like. Would love to double it up but the MPII 12V 3000 lugs will not accept two 4/0 lugs without modification. Best I can do is 2/0 x 2. I would much rather just shave one mm off the side of the 4/0 lugs and double up the 4/0 cable vs. running 2 x 2/0.

This is what 2 4/0 lugs look like on the MPII:
mpiilugs.jpg
 
SparkyJJO said:
I'm the crazy idiot who would shave the edges of the lugs slightly so they fit.
Click to expand...
I'm not sure how crazy it is. The contact area on the Lynx Distributor is just the size of the nut under the lug. Even after some modification, the contact area on the MPII would be a lot larger. Always bugged me that the contact area on the Lynx was so small for the positive lugs. The negative lugs contact directly to the bus bar. The top of the mega fuse does as well. But not the output lug.
 
Somting like this ??
Is this a solution for you ?
 

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Measure the voltage drop and that will tell us a lot. How warm is warm? And what is the type/rating of the cables.
 
Quattrohead said:
Measure the voltage drop and that will tell us a lot. How warm is warm? And what is the type/rating of the cables.
Click to expand...
I'll have to measure it next time I am out there.

Cables are 4/0 welding cables and lugs from Windy Nation rated 105C.
 
Grind off the sides and roll with it, or find a different lug. They make the latter, sometimes the price is not right, usually it will be a tad thicker. The amount of material you remove is not going to be that significant, and at any rate you will be maximizing the surface contact to the conductor. The screw lugs on the post above would work as well. It will likely separate into two fins once you grind off the edges. A compromise but a reasonable one.
 
corn18 said:
Not super hot, but warmer than I would like.
Click to expand...

It is the nature of electricity that things get warm when in use.
If you can keep your had on it without discomfort then your OK.
Hot spots are something to watch for however.
 
corn18 said:
So I doubled up my 4/0 wire from the batteries to the Lynx distributor and they stay ambient now even at 325A. The single 4/0 wire to the inverter (3 ft total run) is getting hot at max load. Not super hot, but warmer than I would like. Would love to double it up but the MPII 12V 3000 lugs will not accept two 4/0 lugs without modification. Best I can do is 2/0 x 2. I would much rather just shave one mm off the side of the 4/0 lugs and double up the 4/0 cable vs. running 2 x 2/0.

This is what 2 4/0 lugs look like on the MPII:
View attachment 225040
Click to expand...
These might fit better side by side.

Panduit lugs

They offer "narrow tongue" versions
 
DPC said:
It is the nature of electricity that things get warm when in use.
If you can keep your had on it without discomfort then your OK.
Hot spots are something to watch for however.
Click to expand...
You could go grab a temperature gun at Home Depot and that would give you a good read on the surface temp.
 
Another good option is the FLIR camera for for smart phones. They are about $200 but you can see hotspots easier.
 
High temperature cables just means that the insulation can handle running at higher temps. This allows more current to flow through the same copper cross section (with more power loss ) and "deal with" the cables running hotter.

Don't take this as criticism, but people tend to under estimate just how difficult and perfect things have to be to really make a 4 / 0 crimp that is really optimal. The really pro shops wake up each morning and qual everything by make some and cutting them open to inspect vs just assuming that life is ok.

For substantial cables, I use battery cables usa, but there are a number of places that make good quality cables. I have seen a couple of them on ebay - but I don't buy anything from ebay or amazon.

Quality Copper Battery Cables Made in the USA! - BatteryCablesUSA

www.batterycablesusa.com www.batterycablesusa.com
 
325 amps? this is a vehicle?

Aluminum lugs for copper wire? Why not get copper lugs?
not an issue at all to file down the lugs so they fit in that tight spot.
Could you just put both wires into one big lug and bolt on once? err, I guess that would make working on it hard.
Looks like they both touch the same plate. OR double stack them?
 
corn18 said:
So I doubled up my 4/0 wire from the batteries to the Lynx distributor and they stay ambient now even at 325A. The single 4/0 wire to the inverter (3 ft total run) is getting hot at max load. Not super hot, but warmer than I would like. Would love to double it up but the MPII 12V 3000 lugs will not accept two 4/0 lugs without modification. Best I can do is 2/0 x 2. I would much rather just shave one mm off the side of the 4/0 lugs and double up the 4/0 cable vs. running 2 x 2/0.

This is what 2 4/0 lugs look like on the MPII:
View attachment 225040
Click to expand...
Couldn't you just slightly oval the holes to spread them enough? Seems you would still get full contact pressure 🤔
 
Is there not enough room to reverse the first lug and then place the other lug on top?
 
SparkyJJO said:
So, did 8 people like my post because they like the idea of shaving the edges of the lugs, or did they like my post because they agree that I'm a crazy idiot? :unsure: :LOL:

View attachment 225178
Click to expand...
If i was working in a remote location and needed to make it work, trimming the edges would suffice just fine.
If doing this at home with all resources at hand, id spend $30 and get the narrow Panduit lugs so my OCD would settle down.
 
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