truecountry
Senior Member
my bad too i should have looked it up ....before i post sorry
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cummins 6bt alternator problems
- Thread starter truecountry
- Start date
willie59
Administrator
truecountry
Senior Member
well good news i got to work today , thought about how this thing is wired ,,, changed out lil square relay and be damn its charging... 13.5 what or why someone did this to this truck is beyond me .... i did notice after shut down the engine my fluke meter started dropping voltage down to 12.0 so i still have something draining batteries... i still thing its the relay thing doing that too ,but ill have to trace every wire and see where they lead and maybe with yalls help fix that problem.... again thanks
truecountry
Senior Member
ok i must ask this why couldnt i do away with both relays in pics and use one Universal starter solenoid like on most equipment
willie59
Administrator
If you got it to charge, all we need to know is what the wiring connections are at the alternator.
truecountry
Senior Member
just 1 to batt terminal on alt but that factory wire goes to the last pic i showed above the bosch relay single wire in conduit at my thumb but see the added a red wire it goes to square lil relay then other side has 2 factory wires and a added wire to lil relay its like they are using lil relay as a coil .... remeber in post 25 the top pic is old relay thats the only thing i changed today
truecountry
Senior Member
the lil off the wall relay is only thing i changed
willie59
Administrator
I think the relays are "muddying the water" at the moment. Let's stay with the alternator for now. Remember, your alternator is known as a "one wire" alternator, meaning, all it takes is a wire/cable from the battery post of the starter connected to the largest post on the alternator. When the engine is running, the alternator is excited by the voltage on the cable, it produces a charge, and sends this charge to the battery cable at the starter. When the engine is not running, the diodes (rectifier plate) inside the alternator prevent a current drain feedback which would discharge the battery. Question; if you hook it up like this, what does it do? If it charges...great. But does it create a current drain when not running? This is simple to check; with the engine not running, disconnect the wire at the alternator, connect a simple test probe light in-line between alt post and cable terminal. If the light glows, you've got a current drain, probably from bad rectifier plate in alternator. This is the way it's supposed to be hooked up. Give it a try and let us know what happens.
truecountry
Senior Member
ok but remeber i got a new alt had problems , only 11.8 charging.... took a alt i tested running off a running appentice 310 knuckle boom with same engine cummins 6bta it ran 11.8 charging.. the new alt is on the running appentice charging 13.8 the old is on the one we are talking about now is 13.4... i see what you are sayying but why did the lil relay change things .. no way can a tested i saw output alt go from 13 volts to 11.8 with just a relay change
truecountry
Senior Member
i will do what you said i need to know
willie59
Administrator
The most obvious way a new relay changed things is that the relay was faulty, and [someone] wired a "one wire" alternator through a relay???, for what reason...who knows. I'm only saying what is supposed to be there, a one wire alternator should only have one wire, why it's rigged some other way???:beatsme I'm just trying to get back to the basics of what should be. If, in fact, for some reason I can't explain, it requires a relay, we'll figure that out later. Right now...I just want to know if it works the way "it's supposed to".
truecountry
Senior Member
me too ,,,atco im running the 310 cutting logs part time and being a tech full time,,, im stressed im sorry,,, workplace has down sized and im asked to saw logs with 310 and radioed if anything breaksdown ..... guess i need to leave work at work
willie59
Administrator
The most important thing in being a maintenance tech is to avoid the rabbit trails. Most all problems will have rabbit trails that you can chase and scratch yer head over and they ain't no rabbit there. Keep it simple. Logic is closer to reality than is scratching your head. We don't know (for sure) what the wiring three ring circus is. On the other hand, we do know what the one wire alternator should be.
texascadillac42
Well-Known Member
Just a thought, but if this alternator was setup to be externally regulated (2nd gen Dodges with the Cummins used an externally regulated alternator on the 6BT) it might be worth it to take it to an alternator shop, have them convert the alternator to internally regulated for $40, then run a hot lead to the batteries and be done with it. At least an alternator shop could tell you if the alternator is internally or externally regulated, or if it needs anything special to charge.