j.kenzie@sbcglobal.net

With respect Martin, I don't think current alone, through properly sized wires, makes it warm. You are right that an unfused load shorted to ground would make things hot, not warm, and that is possible. I think high resistance plus normal current flow is more likely.

M. Requin

Dave, in it's normal (i.e. unused) state current does not flow through the post, so if there is heat, there is current flowing, which means a path to ground exists that should not be there. The resistance of this path determines the amount of heat generated. Ohm's law is what you should think about here.

lrpman

FYI, Baking Soda and water will clean the heck out of the terminals and not destroy the car. Been using it for over 40 years.
PS spot on diagnoses of what was wrong, nice job!!!

Alan

Sorry this is all complete bull****... he'd been driving the car...

Quite a lot of current flows though the wires on the jump post when running because it is series with almost all the current flow in the car circuits. Almost everything that is connected to the central electric panel (virtually all the fuses and virtually all the relays) is fed via this point. Most power that flows from the battery or alternator to power the car goes via this point. The only large current flows that don't go though this point are the starting current, the charging current and the ABS/PSD current.

Its not surprising it would get slightly warm normally depending on these current loads - however if there is significant resistance in the connections it will get much hotter particularly at the connection point.

Alan

M. Requin

Well, I certainly stand corrected! Thanks, Alan.

85fortheDrive

Okay, so I've decided to do a back-to-front analysis of the integrity of the main wiring in the car. As Alan mentions in his post, I have had voltage blips for some time, though they are consistently inconsistent. At any given moment, I have suspected battery, wiring harness, alternator, lights, stereo system, and my ex-wife. Given the age of the car and its history of having lived both in Fargo, ND and Tucson, AZ, the wiring may well be fatigued. @Dr. Bob --> I did purchase the plastic post cover a few years ago, but the car was used for years without one.

I guess the way to proceed is to clean the contact points at battery, starter, jump post and alternator. Then have a little beer. Then check resistance between various segments of the wiring - got a multimeter for that. Then have a little beer.

I have already scrubbed ground points throughout the inside and exterior of the car. Given what Merlin suggests, I'll put some dialectric grease on the back ground connection.

If anyone has other suggestions, I'm all for it. Already grateful for the help so far.

dr bob

I test for voltage drop with a long test lead and a voltmeter set on volts. This is one time when an analog meter is sometimes better than a digital, since the needle reads quickly. Anyway, put the meter in parallel with the segment you wish to analyze, and you can see how much voltage is changing. More load on the segment means more voltage drop, so hard charging and starter loads will give bigger numbers. The longest run with the most connections is the 30 bus in the CE panel to the battery positive. The alternator sits in the middle of that kind of, as it connects to the starter at the forward end of the primary battery cable, then the jump post, then the CE panel if you are looking forward from the alternator. Point is, a little sleuthing with the meter and long test leads will help you discover where your resistances are. Remember that engine to negative battery terminal drops include the engine ground cable and the battery ground cable, and their connections. Charging and starting are the loads there.

85fortheDrive

Okay, so I cleaned up the connections at the post (which were already pretty clean) and cleaned the hatch ground contacts. I then connected the multimeter with the car not running:

14.3V straight from battery to ground
14 V from jump post to ground

started the car

13.8V from post to ground

waited for a few minutes and then turned on the headlights

14.2... 14.8... 15.3... 15.7... then over 16V at the post. I finally shut the car off after it got to 16.4V.
Why would the voltage keep climbing like that?

dr bob

Voltage regulator in the alternator is the culprit on the overvoltage.

dr bob

But, 14.3 at the battery is high with the engine not running. Plus the battery voltage actually dropped some with engine running? But jump post voltage climbs... Saturation on the alternatpr windings is somewhere around 16V typically. Got a good battery in your meter? My H-F special DMM was showing wicky readings when I pulled it out of the storage drawer, 'cured' by putting in a new meter battery. Now reads same as the Fluke DMM.

Mrmerlin

get another DMM to check these readings anything over 14.5 will quickly boil the battery this can be confirmed by lifting the battery cover and smelling for acid vapors .
If in fact you do have the alternator giving 16V then the regulator is damaged

j.kenzie@sbcglobal.net

Hi Tim,
I agree with Stan. I know it's a virtually new alternator, but there should not be 16 volts anywhere around it, and the voltage regulator is part of the alternator. Does the newly cleaned jump post still get hot? If you don't have another voltmeter, just check your battery voltage in another car. It should be 12.4 to 12.8 without the car running. See what your voltmeter reads on your wife's car battery. Good luck.

Alan

As everyone has said - somthing is up with your meter - the battery steady state voltage should never be that high... I'd suspect the meter first, may just be worth getting a decent quality additional one... if you can't trust your diagnostic tools you have nothing...

Alan

85fortheDrive

Well two points for Bob on the faulty MM note. I borrowed a neighbor's DMM and tested from jump post to ground and it hovered steadily around 14.3v while mine started there and climbed past 15v.

So, that's one problem resolved. Now back to the original issue.

Landseer

I'd have never suspected that.

Jeez, there are some smart people on this board.