Battery dies but alternator tested OK?

[jumpsoffrock]

So it seemed my battery was losing juice, so I thought simply I'll start the truck and run it a little which then I'll be ok.

I jump it to start and drive it around the block(15 minutes), once I get back the battery is more dead than before.
Remove alternator and have it tested, it passes test.

Could this problem be caused by the little box that's mounted on the radiator support? How would one go about testing that unit to see if it's bad or good?

Thank you very much.

[C10 - C90 Bill]

The little box on the radiator support is the Voltage Regulator. It's best to just buy a brand new one. I was buying high quality Borg-Warner ones for my '72 C-10 and kept burning them out. Finally switched to a Solid-State Regulator and it cured my problem. Some will say to switch to a One-Wire Alternator, which eliminates the Regulator, but I like to keep them original. I've been running the Solid-State one for about 9 or 10 years now, with no trouble.

Although no guarantee, that will most likely fix your problem.

Bill

[jumpsoffrock]

Ahhh, ok, that's just what I needed to know. I may be changing to an electric fan and adding a power inverter so I can get some 120V receptacles on my truck, and with that being said I was already eying a new alternator.
I will probably switch to a 1-wire not because I don't care about originality, but rather it just makes sense.

Thank you for the help.

[mrolds88]

1 wire alternators are good for tractors that don't have accessories. If you want to get rid of the external regulator, just get a later 70's or early 80's GM alternator and be done with it. They are simple to retrofit and you can go to any auto arts, anywhere and pick up a replacement. Heres a good way to do it.

http://www.wallaceracing.com/alt-conversion.html

[jumpsoffrock]

Originally Posted by mrolds88

1 wire alternators are good for tractors that don't have accessories. If you want to get rid of the external regulator, just get a later 70's or early 80's GM alternator and be done with it. They are simple to retrofit and you can go to any auto arts, anywhere and pick up a replacement. Heres a good way to do it.

http://www.wallaceracing.com/alt-conversion.html

Well nuts, i just got a 1-wire off of ebay. ( emailed seller to try and cancel transaction....after some more reading, there are apparently more downsides to a 1-wire than I thought) Thank you for the enlightenment.

Can you tell me what the difference is from a 1-wire as compared to the "later 70's or early 80's GM alternator" that you mentioned?

What is the bad part of having accessories and a 1-wire alt?

Thank you very much.




Bill--can you get me the model number or part number and manufacturer of your solid state that you use? Thank you

[mrolds88]

As far as differences, externally they look the same. Internally though they are different. Here's an article that should help you out. http://madelectrical.com/electricalt...hreewire.shtml With wanting to add accessories and such, a lot of the 1 wire alternators don't start charging until a certain rpm.

[C10 - C90 Bill]

Originally Posted by jumpsoffrock

Bill--can you get me the model number or part number and manufacturer of your solid state that you use? Thank you

Message sent.

Bill

[franken]

Why not get a voltmeter and check the voltage rather than replacing random parts?

[jumpsoffrock]

^I don't know how to do that, or what the readings will tell me. What do I need to look for to see if my voltage reg is bad, now knowing that the alternator is good, and that my brand new battery is good?

Thank you very much.

[jumpsoffrock]

So I have some new info.

When I start the truck and run at 1500rpm, the alternator is NOT charging, the voltage at the BAT terminal is the same as battery, which is 12.XX volts. Voltage at the "F" or 2 terminal is 7-8v. Voltage at the white wire which is terminal 1 or "R" is none.


However, once I use a jumper from the white wire to the BAT terminal, I hear the voltage reg click and the alternator starts working, because new voltage readings at BAT terminal and battery are in the 14.XX range!

Does this mean a voltage regulator is bad?


Thank you all very much.

[cerial]

1 upgrade to an internally regulated. 144 alternatiors put out more amps at idle then the old 10 and 12 do.
2 check your wiring. I just went through mostly the same thing checking installing and such. Turns out I had a blown fused link. I have since simpflied my system.

All you need to run a 3 wire is one sensing wire to the junction block where you most draw is(horn relay stock), a wire going to the battery, and a idiot light wire. You can jump the idiot light wire and connect it to the sensing wire actually for a 2 wire hookup if you don't mind not having the light come on at startup.

I personally don't touch externally regulated alternatiors. They are simply not needed until you get into ambulance sucking draw. My current system is 2 90 ish amp alternatiors powering 2 batteries. My next engine will be fitted with 2 144 and put out more amps then alternatiors the size of a milk jug.

[jumpsoffrock]

Basically I didn't know that my new alternator was internally regulated and my wiring was wrong. I--on a whim--decided to mock up my wiring "as-if" I had an internally regulated alt only because I had ran out of ideas and research was sending my in circles.

That solved my problem. I have bypassed the external reg and now everything works like a charm.

Here was the flaw in my hypothesis: All 1 wire alts are internally regulated; all 3 wire alts are externally regulated.

I'm not sure where I surmised this from, but that INCORRECT statement is what was making my electrical system not work....not the actual parts themselves.

Funny/stupid lessons to be learned.


Thank you to everyone who chipped in!