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470 smokes alternator belt and kills engine

Bt Doctur said:
I think your meter may be giving you a false reading, even at a 40 A load a belt should not slip
Click to expand...

Yeah, shouldn't bog down at all at 20 amps! It's a pretty reliable meter and when I put it on my 2005 mustang it's less than 3 amps with no accessories so I'm pretty confident on its accuracy.
 
only other thing I can think of is that the alt has some type of internal wiring fault.Once it has battery voltage on the output post its like fighting itself. But you said it did work with a remote battery and you cant have it both ways. working with a remote but not working with the ships wiring. The output voltage with nothing connected is wrong. Now an alt that requires a regulator will run wild if not connected to a battery source such as the 34 volts you measured when you remove the battery cable from the battery.

Do your test with the remote battery again but use the ground from the ships battery not the engine block, verify battery voltage and then touch to alt output. battery voltage should increase slightly. If your normal at this point, connect the ships + battery to the remotes+ battery with a 14 Ga wire.
Report back results
 
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1dsarver said:
I do have 2 batteries. At first I just ran the alternator wire to battery 1 but then realized that battery 2 would not charge if hooked up that way
Correct!

so I switched it to the solenoid so it would charge on either both or 1 or 2.
It's best to NOT select BOTH/ALL when charging.
You will want the alternator to sense only the battery that is being charged.
(see ** below)

It makes sense not to run them on both other than in an emergency situation
Correct again!

but other than a portable battery charger how do you charge battery 2 if the alternator is not connected to the solenoid and just to battery 1?
If managing your batteries manually, you will select one bank or the other.
** Or...... install an ACR or a VSR and let it do that for you.

BTW it had the alternator issue all along when it was hooked to battery 1 only.

In a 12 vdc system, you will have a Positive and Negative sides only...... (technically, although the term is used loosely, there is no ground in a 12 vdc system).

The charge lead from the alternator will connect to the "common" cable terminal at the starter motor's solenoid.
The MBSS (main batter selector switch) will determine which battery you crank from, which battery will receive the charge rate, and which battery powers the hull harness.

Also, if this is what they call a single wire alternator, it is most likely a Delco 10si.
A 105 Amp 10si will cut back on the charge rate quickly..... in other words, it is unlikely that this alternator will produce 105 Amps.... at least not for any duration.

Going to the #8 charge lead was a good idea.
However, you will also want to increase the size of the short alternator-chassis-to-engine-block Negative cable.


As for battery choices, you will want a good cranking battery on MBSS #1, and a bank of Deep Cycle batteries on MBSS #2.
Good cranking amps for #1, and a large amount of Amp Hours for #2.

Either MBSS selection will draw/charge from/to the bank that has been selected! In other words, all 12 vdc demands will be taken from the selected battery bank.

Crank from #1, warm up engine and charge #1.
Then switch to #2 and go out boating.
This keeps the #1 starting bank in Reserve, as it should be.


An exception to this would be a main engine bay bilge pump's float switch.
To power this float switch, you will connect it directly to the rear MBSS terminal #2, of which will be directly connected to your House Load Batt Bank (of large Amp Hour Deep Cycle batteries).
Doing this will allow you to turn the MBSS OFF when you leave the boat unattended in the water, and will prevent an accidental power shut-off to the float switch.
Click to expand...
 
I can't stress enough how bad this advice is. That's not how alternators, or the 1,2, BOTH, OFF switch works. How this poster manages to keep from frying alternators is beyond my understanding.
First of all, before you go switching batteries with the 1,2, BOTH, OFF switch with the engine running, be sure that it is the "make before break" type.
Secondly, alternators don't "cut back" they are either charging or not. They charge according to engine speed...spin it faster; it puts out more amps.
Anyway, no clue what your issue is. Hope it's just a bad ground or something.
 
Most all MBSS today, and even if going back years, are make-before-break.
What the OP does NOT want to do, is to pass through the OFF position with the engine running, UNLESS the MBSS is equipped with a field protection circuit.


Alternators do cut back on the charge rate.
And yes, RPM is a factor...... however, the alternator's charge rate is determined by the regulator's ability to sense the battery voltage, battery SOC and/or the load on the battery.


"[FONT=q_serif]The output voltage of the alternator depends on several things. One is how fast the shaft turns the output windings through a magnetic field - this pushes electrons in the wires - and another is the strength of that magnetic field which is produced by another set of windings called a field coil. A regulator can adjust the current in the field coil and thereby control its magnetic field level, and thus govern how much magnetism the output windings see."

[/FONT] "The current flowing through the rotating solenoid (rotor) is the decisive factor for regulating the output generated by the alternator. This current is used to alter the magnetic field. It is controlled by the alternator regulator based on the battery voltage, which has been measured in advance."


Although we will often see this used in a misnomer fashion, "ground" is a term used in industrial and residential AC current, as in Earth Ground!
Technically speaking, 12 vdc systems use positive and negative paths.
 
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