Electrical puzzler...

I'm glad you located the defective ground strap,
yes the lights should get brighter,

Your not always,going to measure a big noticeable difference in amp draw, when correcting a deffective ground or other circuit, and like I stated, its going to sound a lot more complicated than it is, but youll need to track it down, generally with a meter and pulling fuses to isolate the offensive circuit
 
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DorianL said:
I would suspect that the draw would be much greater if the lights had a short somewhere, no?
Click to expand...

Yes ...... that's correct somewhat!

But picture the short as a resistor, possibly corrosion in a connection. Some current is going
thru both the short and the light, so the brightness of the light depends on the resistance of
the short. Therefore this all hinges on how much resistance is in that short, it could go all the
way from negligible effect to a direct short. In which case that would mean the light might not
even be visible.
short-circuit.jpg
 
Here's a question for you. Let's say that the headlights draw 10 Amps. And there a short somewhere close to it that's also drawing current. Wouldn't the draw upstream be higher than 10 Amps?
 
Hm.

Voltage drop on positive of alternator is at 0.6v
Voltage drop on negative side of alternator is at 0.3v

  • battery positive post to alternator b+ stud= 0.5 volt with maximum charging load applied (all accessories turned on)
  • battery negative post to alternator metal frame = 0.20 volt
Click to expand...

We're getting closer. I'll clean up the batter connections. They don't looks so good.

IMG_4675.JPG
 
Mmm. Poking around the internet I just found out that my battery connectors are supposed to be temporary ones.
 
I took the Ghi-ghi for a 30 min drive.

All at 1500 rpm

Lights off: 13.8v voltage
Lights on: 13:5v
Battery at fuse box at front of vehicle: 12.5v
Voltage drop + : 0.6
Voltage drop - : 0.3
 
I figure that voltage drop may clear up when I put in better terminal connectors.

That idle voltage at batt junction looks low
 
electrically conductive corrosion protective grease
dielectricgr.jpg


http://garage.grumpysperformance.com/index.php?threads/battery-charger-for-the-shop.928/#post-55689

http://garage.grumpysperformance.com/index.php?threads/current-draw.11310/#post-51485

http://garage.grumpysperformance.com/index.php?threads/battery-or-alternator.10003/#post-43220

http://garage.grumpysperformance.co...trical-wiring-for-a-tbucket.10038/#post-39055
 
CORRECTION

Negative alt drop: 0.2v
Positive alt drop: 0.1v

I checked all the fuses. No draw with circuits off

"This house is cleeeaaannn!"

Anyway, I still am going to install new batt connectors.
 
DorianL said:
Here's a question for you. Let's say that the headlights draw 10 Amps. And there a short somewhere close to it that's also drawing current. Wouldn't the draw upstream be higher than 10 Amps?
Click to expand...
Yes, the total current upstream would be the the two currents added together. It's a parallel circuit, therefore the more branches you add (such as a short) the more current total coming from and going back to the battery.

current-in-parallel-circuits-2.jpg
0.05 amps + 0.15 amps + 0.1 amps = 0.3 amps

.
 
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They seem so - my idiot lights seem to be brighter as well. I think that ground strap (thanks Richard :D) was the issue.

Interestingly, it was one of the few things I did not install myself. It was installed by the engine-builder. When I brought the car in for a tune up, he mentioned that the ground strap was missing and that his crew added one. He also said that neglecting having one could lead to all kinds of gremlins. Well when I removed the strap, I noticed that they split the eye loop at the end of the strap because it was too small to fit over the stud - and because of this, when it got torqued, it was nearly twisted loose. This is a rookie mistake! Second, and far worse - they neglected to grind off the paint and get down to bare metal :mad::mad::mad: Who does this???

Thanks Indie - I am happy to give this a rest till next weekend. Now it almost seems every time I test something I get a different reading - fatigue and mistakes, I guess.
 
Here's a question for y'all.

When I check the battery while running I get at 1500 rpm 13.8 with no accessories and 13.5 with all accessories. So I presume it's always charging. That's good

However the voltage at the far end of the car where the fuse box is at the front, I seem to be one volt lower, or nearly

Is that normal?
 
Interesting... the plot thickens!

I am beginning to suspect the Alt - this really surprises me and was last on my list as the Alt is a $300 Bosch unit less than three year old. I thought it would last a while. Maybe the rear-end smack compromised it? Of maybe it is the poor ground strap that precipitated its demise?

Anyway I went ape testing everything and found roughly normal reading... until, the idiot light came back on! And it comes on intermittently.

I took the KG for a drive and the idiot light started to glow vaguely. This time I had my DMM in the car. I went from at healthy 13.8v to 13.4v when the idiot light came on (1500 rpm).

With idiot light still on and headlights turned on my voltage dipped down to 13.0v (still 1500 rpm)

Pulled over at idle (800 rpm) my voltage dipped 12.2v with headlights on.

I then tested the voltage drop: unchanged at the Alt's b+ and case-

Here's what is interesting. With headlights on at 1500 rpm, I had 15 Amps of draw on the battery but <1 Amp from to alternator TO the battery!

One last detail. While driving the idiot light glowed faint and constant but dimming slightly on acceleration. Firm slowing down to a stop, the idiot light would waiver bright and dim almost like gas gauge needle sloshing about.

I read somewhere (and someone also mentioned above, IIRC) sticking brushes.

I just find it soooo unlikely that a new, quality Bosch unit could fail so soon.
 
Ira, I've seen a fair share of brand new electrical parts fail, sometimes it doesn't work straight from the box. You can see voltage regulators last a couple years or I've seen some still working 50 years later. Warranties build confidence in the brand, not guarantee how long they should last.
 
chromebumpers said:
Ira, I've seen a fair share of brand new electrical parts fail, sometimes it doesn't work straight from the box. You can see voltage regulators last a couple years or I've seen some still working 50 years later. Warranties build confidence in the brand, not guarantee how long they should last.
Click to expand...

Is it just me, or is this not as it used to be when things were built to last?
 
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