positive wire get a pretty warm to touch

oldcat

Solar Enthusiast
ok im runing- 66-amps with 0/2 wire 9 foot of wire on a 12volt 4
crown 205 batterys about 15 min the red pos wire gets prtty warm is this normal or not?????.....thanks
 

OffGridInTheCity

Solar Addict
I have some 'warm' wires in my solar setup and put some temp sensors on them. In particular I have 4 x wires in 1" (or 1.5") flexible conduit and where the come into the control box they routinely hit near 58C/136F in summer - e.g. I can hold my fingers on it. Its 4AWG multi-strand 8ft length carrying up to 80amp per pair (charge controller -> battery). After 2 years of this - they seem fine. Discussions I've had with other 'folks' seem to indicate that 58C (as long as wire is rated for it) is not that alarming.

Suggest you measure the temp. Wire will have a heat maximum as part of it's spec. Of course warm/hot wire also means 'some' power loss - but in my case I just live with it.

I'm just sharing my personal example - not telling you what's OK or not OK :)
 

smoothJoey

Get offa my dock
ok im runing- 66-amps with 0/2 wire 9 foot of wire on a 12volt 4
crown 205 batterys about 15 min the red pos wire gets prtty warm is this normal or not?????.....thanks
Is the wire hot all the way down or is hot at a joint with a downward gradient away from the joint?
I run 66 amps on 2 awg without noticing much heat.
By the numbers 6 awg should be able to carry that current just fine but I oversized.
Is the wire pure copper?
My guess is even if its aluminum it should be fine at that amperage.
How are you measuring the amperage?
 

Hedges

I See Electromagnetic Fields!
66A is around 1/4 of 2/0 wire ampacity, so 1/16th the heating. At maximum current, expect 90 degree wire from 30 degree ambient, a 60 degree rise. At 66A and 1/16th the heating, expect only 4 degrees C rise.

Warm where? Entire length of wire, or just near one end?
Use a DMM to check voltage drop between cable lug or cable strands and the terminal it is clamped to, etc.
See if there is excessive voltage drop across any particular connection. Also along length of wire.
 

GXMnow

Photon Sorcerer
If the whole length of the wire is just "warm" you are probably fine. Is it cooler near the end connection, or hotter? Most wire current ratings are based on the temp rise. 60C will feel warm, but it not a problem. If the ends of the wire are hotter, that may be a sign of a bad connection at the end. Normally a large lug, bolted to a buss bar, will be cooler than the length of wire. So in that case, you are all good. But if the connector is hot, and it is only warm down the wire, then you need to repair the bad connection. a 2/0 cable is rated at 145 amps at just a 60C temp rating, so I think you have a bad connection if 66 amps is making it warm.
 

OffGridInTheCity

Solar Addict
In my case, the conduit is warm the whole way. I think 80a is pretty much the max for 4awg over 8ft and there are 4 wires (2 different charge controllers / 160a total) in the one conduit. Its copper multi-strand but not the 'fine strand' of welding wire. I think the conduit also contributes to things being warm. An electrician installed it 'per code' - but you know, he's gone and I'm the one living with it :)
 

oldcat

Solar Enthusiast
i believe it my battery switch it getting pretty warm where the wires go in... my wire is 100 copper wielding cable i crimp and solder so it deefinelty not that. what battery switch do you all reccomend ...
 
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smoothJoey

Get offa my dock

HRTKD

Boondocker
The switch is rated for 275 amps. It should be able to handle the current.

Most likely it is your crimp or your connection. Very few of us are soldering a crimp. A well done crimp, using a quality lug, has no need for soldering.
 

Hedges

I See Electromagnetic Fields!
I agree with "should" but not "Most likely"
I consider off-brand products not performing to spec most likely.

Try removing the switch, using a bolt to clamp your two ring terminals together (nothing between them, not even a washer).
If it doesn't get hot, fault was with the switch.

Consider construction of that switch. It holds the ring terminal between two nuts. That's a no-no according to our understanding of best practices.



1625243310700.png

Compare to Blue Sea. I can't make out the exact design, but it has a flange nut bearing on something that isn't a nut.

1625243468362.png
 

oldcat

Solar Enthusiast
I agree with "should" but not "Most likely"
I consider off-brand products not performing to spec most likely.

Try removing the switch, using a bolt to clamp your two ring terminals together (nothing between them, not even a washer).
If it doesn't get hot, fault was with the switch.

Consider construction of that switch. It holds the ring terminal between two nuts. That's a no-no according to our understanding of best practices.



View attachment 54792

Compare to Blue Sea. I can't make out the exact design, but it has a flange nut bearing on something that isn't a nut.

View attachment 54793
 

oldcat

Solar Enthusiast
i was the battery switch i put on a blue sea switch. you cant run no more than 30amp continous through that china battery switch....
 
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