Load and heat

[weq92f]

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So...I've got this bus bar where everything connects. All the power grabbers and the power adders (alt, batt) all connect to the bus bar.

While playing with my fan setup today I happened to notice my bus bar has some heat in it at full load (elec fans, A/C, blower on high, lights on bright). Measured the heat at about 150F on the bus bar. I was feeding the bus bar from batt with 4AWG but changed that to 2AWG today. After doing this I had more total voltage at the batt than before (14.5VDC) so I'm sure the 4AWG cable wasn't enough, however the heat in the bus bar didn't really change.

The bus bar has these ratings:

* Continuous amperage of 130 amps AC, 150 amps DC
* Maximum voltage rating 300 V AC, 48 V DC

My alt is 140amp and my estimate of the amperages being pulled through there were below 150, the max rated for this bus.

What are your thoughts on this heat...I'm sure it's been running this way since the day I rewired everything. All power leads off bus bar are fused with either in line or fusible link.

-Kevin

[Dead Parrot]

Is there a temp spec with the buss bar? If the bar is in the engine compartment, under hood temps are probably higher then 150* anyway.

If the buss bar terminals allow, might move the heaviest load to the same terminal as the Alt wire so that load isn't flowing through the bar. Put the heavier loads in the middle with the alt and the lighter ones on the outsides. Minimize the bit of bar carrying the heaviest load.

[weq92f]

Originally Posted by Dead Parrot

Is there a temp spec with the buss bar? If the bar is in the engine compartment, under hood temps are probably higher then 150* anyway.

If the buss bar terminals allow, might move the heaviest load to the same terminal as the Alt wire so that load isn't flowing through the bar. Put the heavier loads in the middle with the alt and the lighter ones on the outsides. Minimize the bit of bar carrying the heaviest load.

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I'm not finding a temp spec for it. I'll rearrange the leads in this manner as it does seem logical. I'm running 6AWG from the alt to bar which I believe should be adequate.

Good point about the engine compartment heat however I'm certain the leads also have a bit of heat in them...at least the heavy electric fan leads to the relays do.

Thanks much,

-Kevin

[weq92f]

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I placed the 3 electric fan leads along with the Alt lead on the same lug in the middle of the bar and distributed the remainder on the other lugs. This changed things for the better in terms of how the system reacts to high draw fans kicking on and the in dash volt gauge now reads much closer to actual at-the-battery volt readings. This gauge thing may have been the result of changing the 4AWG batt to bar cable to 2AWG.

Thanks again,

-Kevin