[Shop-talk] electrical problem with truck

[Jack Brooks]

Glad to hear it is finally charged and that the solution was simple!


Major sidetrack follows…….

This reminds me of my change over from a generator to an alternator in my 1960 Triumph TR3.  I installed a 30A non-regulated alternator from a Honda Civic. The old generator peaked at 17A, so it was a nice upgrade.  I had the alternator checked out by an old fashioned alternator shop.  It worked perfectly.  He sold me an electronic regulator, that was small enough that it could hide under the housing for the old Mechanical OEM regulator, but also activate my charge light (the one that stays lit until the generator/alternator is charging) which made it a perfect fit.

I wired everything up carefully, but after starting it, the alternator light would not go out, hence no charging, so I brought the alternator back to have it checked out again. The alternator was good.

I wired, tested and rewired this system 3 or 4 times. Finally in exasperation, I punched the throttle and as the revs climbed, the charge lamp extinguished.  I repeated this procedure and it consistently would not start charging until the revs reached about 2,600 rpm.

What I figured out from talking to a lot of people was that Hondas spin backwards, opposite from every other modern engine manufacturer.  Apparently the alternator can take a magnetic set.  In this case, this magnetic field was reversed and needed to be overcome before the alternator could start charging.  About 8 years later, it now starts charging at about 2,200 rpm, so slowly but surely the magnetic memory in the alternator is being reversed.

As was John’s exercise, it was a very frustrating path to resolving what should have been a simple installation. It does work great now though.  It’ll run the headlights and windshield wipers easily at idle which the old generator struggled with and has me thinking about seat heaters for those cold winter days with the top down…….

Jack
p.s. – I used a Civic alternator for a few reasons,
1.      it was only 30A, so I had very few wires to change out,
2.      the alternator shaft was the same size as the generator shaft on the TR3, stunning right?  and
3,      it was free!


From: Shop-talk <shop-talk-bounces at autox.team.net> On Behalf Of john niolon
Sent: Thursday, August 12, 2021 2:33 PM
To: shop-talk <shop-talk at autox.team.net>
Subject: Re: [Shop-talk] electrical problem with truck

well, that's three days or so I'll never see again... started over on the diagnosis... A fellow ford guy in Canada mentioned something about the alternator exciter wire being used when alternator was larger than 80 amps. I didn't use one... I called EZ-wire tech guy and we discussed it. He assured me that with a one wire unit the exciter wire wasn't used (it gets itself excited [https://www.ford-trucks.com/forums/images/smilies2/biglaugh.gif] ) As we talked he asked what my battery voltage was when the alternator was above 1500 rpm and I told him in the 13 volt range. Then he asked what my alternator voltage was and it was 14.6 or so... He said just to check it and bypass all the wiring to run a wire straight from the alternator to the battery +... I asked him if it cured the problem should I just leave it in place... he said sure , that way you are getting charging voltage straight from alternator

So I built a #4 cable and installed it from alternator to battery +... guess what ??? 14.6 at alternator and 14.6 at the battery... All this high tech diagnosis... was just an exercise... At least I know that all my connections and terminals and electrical stuff is good and well grounded and blessed ., I think I'm gonna call him back tomorrow and get him to explain EX-wires reason for not having that direct charge wire in the first place. Thanks  for sticking with me trying to figure this out and for all the information, ideas, suggestion, CWAGs and un mentioned comments about how I can be so dumb and yet so good looking at the same time...

john


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