Hot negative battery lead....

[Stumpknocker]

I have on several occasions, seen the negative terminal on a battery get so hot they would blister you in a second or so. Once in a car, yesterday in a boat. No wiring issues, just a weak battery unable to crank the engine. Do they normally do this when under load? I mean HOT.

 

[Reel Poor]

Re: Hot negative battery lead....

Yes ...Its normal if the battery is weak,starter draging, or bad connections. You should only notice this under "excessivly high" amp. loads.

 

[Moody Blue]

Re: Hot negative battery lead....

Sound to me like either wrong gauge cable or bad connections either at the battery or the starter.

 

[jlinder]

Re: Hot negative battery lead....

I have another idea. The battery is fine, the connection/wire is bad.<br /><br />You crank, and the bad wire/connection has a 4 vold drop across it. 150 amp draw (I am of course guessing at what these numbers could be).<br /><br />This is 600 watts in a small area, and only 8 volts to the engine. Seems like a bad battery, and the 600 watts really heats up the wire.<br /><br />Take the wire off the battery. Look for corrosion, espically where the wire could be corroded just up from the crimp on connection. If suspicious, replace the wire or crimp connector. (If you do, make sure the crimp is good, and sealed with adhesive lined heat shrink).<br /><br />Clean the battery terminals good. Reconnect and see what you have.<br /><br />Want to test this theory? Take a voltmeter. One lead on the battery post (not the crimped lug), the other on the engine ground. Crank the engine. How many volts do you read? Should be pretty low, in the 1 volt range or so.

 

[demsvmejm]

Re: Hot negative battery lead....

Originally posted by Jack L:<br /> I have another idea. The battery is fine, the connection/wire is bad.<br />...<br />Take the wire off the battery. Look for corrosion, espically where the wire could be corroded just up from the crimp on connection. <br />

This would not be an issue if the connection was soldered, and sealed.<br />

 

[jlinder]

Re: Hot negative battery lead....

I was waiting for that one, but I am not going for the bait

 

[18rabbit]

Re: Hot negative battery lead....

Originally posted by David L. Moore:<br /> This would not be an issue if the connection was soldered, and sealed.

I think soldering the battery cable to the battery post is an excellent idea.<br /> <br /> <br />Back to the original question; no, presuming a good connection, the battery should not be that hot. The heat at the post is indicative of the internal temp of the battery...unless you are in the process of soldering your battery cable to the battery post.<br />

 

[Stumpknocker]

Re: Hot negative battery lead....

The last time on the boat, yesterday actually we had a battery with approx 30-40% charge trying to crank a 305 V8 Mercruiser. The negative terminal was scalding hot. The battery was removed to be charged and another put in its place. Engine cranked right away and the hot temps did not occur on this replacement battery. I guess it goes with a weak battery under lots of load. I just never grabbed that terminal and found it hot before the boat and once on a Chrysler v6 a couple of weeks ago. The battery that overheated that time was defective. No good under load and I use it for supplying power to a portable livewell that draws about 1 amp. Seems to last for hours at that rate of draw even as a bad battery.

 

[demsvmejm]

Re: Hot negative battery lead....

Originally posted by 18rabbit:<br /> I think soldering the battery cable to the battery post is an excellent idea.<br />

We all know that is not what was intended. And it is not a good idea. <br /> Soldering the clamp onto the cable IS a good idea however. Albeit a controversial method of making a secure connection impervious to corrosion.

 

[levittownnick]

Re: Hot negative battery lead....

If one terminal is hot, it has a poor connection (assuming the proper gauge wire is used). Jack L has excellent advice. Changing to a new battery solved the problem because the connection was moved. It is not an indication of the state of the older battery. A side note is that the poor connection could limit or prevent charging.<br />A hot terminal is a bad connection. I'll bet my shirt on it (it's an old shirt anyway).

 

[Bondo]

Re: Hot negative battery lead....

Originally posted by levittownnick:<br /> If one terminal is hot, it has a poor connection (assuming the proper gauge wire is used). Jack L has excellent advice. Changing to a new battery solved the problem because the connection was moved. It is not an indication of the state of the older battery. A side note is that the poor connection could limit or prevent charging.<br /> A hot terminal is a bad connection. I'll bet my shirt on it (it's an old shirt anyway).

I'll second that Bet........

 

[Perfidiajoe]

Re: Hot negative battery lead....

I would say that is the problem(bad connection), or at least part of the problem, which was most likely corrected w/ the new battery installation. As Yogi said "This is like whipping a dead horse to death"