Voltage drop
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Pro
Joined: Feb 2009
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From: North Port Florida
Voltage drop
This is just a hopefully FYI.I"ve been fighting a voltage difference between the battery and inside the driver's compartment. I had corrected the high resistance of the B+ 12 volt from the battery to the starter , then Alt. The terminals that go on the starter have to be sanded w/400 paper till they shine. Then coated w/grease. I added a #6 ga. wire from the Alt. to the B+ at the pos batt post, included a 175 amp circuit breaker. This got the starter spinning and the underhood voltage increased two or three tenths on the digital guage. But I still had low voltage in cockpit. So, I did the same sanding on the cable going to the underhood fuse box and the pass compartment B+ FUSE panel post. What I want to stress is that none of these terminals or nuts looked bad at all. But after all the cleaning, I have 13.8-14.2 volts inside at the digital guage. First time in 14 yrs. of searching. I think this was the problem that was turning on the active handling warning light? But, I`ve been wrong about that before. Sorry this was so long winded, but I thought this may help someone else out of a bizarre problem on their C-5. Happy Trails everyone.
Thread Starter
Pro
Joined: Feb 2009
Posts: 651
Likes: 33
From: North Port Florida
Drifting
Joined: May 2008
Posts: 1,695
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From: Denver, NC
A helpful hint. A voltage drop test would have identified every spot that needed help. If you went from the + battery post (post not cable) to any other point in the positive cable run and saw a voltage while the circuit was active, that would indicate the section you were testing had high resistance for some reason. The only time you should see voltage is between the + and - battery posts, and at the load (each side of a bulb for example). All wiring and connections should have no resistance and report zero on a meter when tested. Real world is that there are small voltage drops here and there but we have to mitigate them because they can quickly add up.
So if you want to see how much of a drop you have between the post and the cable, one lead goes on the post, one on the cable. Going from the battery post to the starter post, you would be testing every connection and wire from the battery post to the starter post. This way you can quickly identify where a high resistance is causing a voltage drop.
So if you want to see how much of a drop you have between the post and the cable, one lead goes on the post, one on the cable. Going from the battery post to the starter post, you would be testing every connection and wire from the battery post to the starter post. This way you can quickly identify where a high resistance is causing a voltage drop.
Last edited by Ed Ramberger; Mar 16, 2022 at 09:57 PM.
Thread Starter
Pro
Joined: Feb 2009
Posts: 651
Likes: 33
From: North Port Florida
A helpful hint. A voltage drop test would have identified every spot that needed help. If you went from the + battery post (post not cable) to any other point in the positive cable run and saw a voltage while the circuit was active, that would indicate the section you were testing had high resistance for some reason. The only time you should see voltage is between the + and - battery posts, and at the load (each side of a bulb for example). All wiring and connections should have no resistance and report zero on a meter when tested. Real world is that there are small voltage drops here and there but we have to mitigate them because they can quickly add up.
So if you want to see how much of a drop you have between the post and the cable, one lead goes on the post, one on the cable. Going from the battery post to the starter post, you would be testing every connection and wire from the battery post to the starter post. This way you can quickly identify where a high resistance is causing a voltage drop.
So if you want to see how much of a drop you have between the post and the cable, one lead goes on the post, one on the cable. Going from the battery post to the starter post, you would be testing every connection and wire from the battery post to the starter post. This way you can quickly identify where a high resistance is causing a voltage drop.
