When idling, the voltmeter shows this:
The hand held meter:
With the ignition on but not running:
The hand held meter:
With the ignition on but not running:
Trying to find the electrical draw that drains the battery...
- Thread starter Kern Dog
- Start date
I wonder why the alternator is charging so much.
The battery is less than a year old. The battery cables are in good condition, I have adequate grounds but it seems that this starter needs 12.6 volts or better to spin properly.
Changing starters is not a 15 minute job on this car. It means left header removal, well at least unbolting and swinging it away from the block enough to create a window. The tubes are not necessarily close to the starter but they block access. This means 4 spark plugs and wires, the dipstick tube maybe, flange and collector gasket maybe.
The car hasn't spun over this fast in awhile. I don't trust it though. There is still a draw to the battery that doesn't show up by using the test light to the negative terminal.
Randy and RJ Renton (Possibly others as well) both mentioned that an alternator diode could be bad. Would that possibly explain the high rate of charging?
The battery is less than a year old. The battery cables are in good condition, I have adequate grounds but it seems that this starter needs 12.6 volts or better to spin properly.
Changing starters is not a 15 minute job on this car. It means left header removal, well at least unbolting and swinging it away from the block enough to create a window. The tubes are not necessarily close to the starter but they block access. This means 4 spark plugs and wires, the dipstick tube maybe, flange and collector gasket maybe.
The car hasn't spun over this fast in awhile. I don't trust it though. There is still a draw to the battery that doesn't show up by using the test light to the negative terminal.
Randy and RJ Renton (Possibly others as well) both mentioned that an alternator diode could be bad. Would that possibly explain the high rate of charging?
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If an alternator diode is bad (open) the alternator will charge but at low output (amps delivered) and depending on the load, the voltage will be nominal (14.0 v +/-) under light load but low 12.0 v, under heavy load. If the voltage produced is high, a possible cause is a bad voltage regulator or if a one wire system, a bad internal regulator. In a GM alternator, the "diode trio" produces the field voltage internally, independent of the main diode bridge. The voltage and current applied to the rotor, determines the output voltage of the alternator. It seems as if everyone checks the output voltage but no one seems to check the voltage applied to the brushes of the alternator (early round back unit- only one field wire) or both brushes of an isolated field alternator ('70 and newer unit both wires).
If an alternator diode is SHORTED, the output will be low AND cause the battery to discharge over a short time.
Low output can also be caused by low drive RPM (drive to driven ratio) when changing over to a serpentine belt system. Just my opinion of course.
BOB RENTON
If an alternator diode is SHORTED, the output will be low AND cause the battery to discharge over a short time.
Low output can also be caused by low drive RPM (drive to driven ratio) when changing over to a serpentine belt system. Just my opinion of course.
BOB RENTON
Thanks. It seems that I'm no further ahead than I was a week ago.
What I do know is:
With full charge, the starter seems to work fine but it does quickly drop in speed after 10 seconds.
Below maximum charge, the performance of the starter drops off real fast.
The Ford solenoid is not defective.
What I do know is:
With full charge, the starter seems to work fine but it does quickly drop in speed after 10 seconds.
Below maximum charge, the performance of the starter drops off real fast.
The Ford solenoid is not defective.
Derwud
Well-Known Member
Is this cold or hot starts? I had to wrap my Starter and Headers to get my car to start reliably when hot.
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Out of curiosity, what is the terminal voltage MEASURED AT THE BATTERY before -during-after cranking and how long (time) was the cranking event? Is it possible to measure the specific gravity of the electrolyte in all cells? Realizing, that if you have a maintenance free battery, you will not be sble to do so. IF the battery's terminal voltage is less than 10.5 volts during cranking, it is an indication, to me, it seems as if the battery has a sulfated (or partially sulfated) cell, which can supply, at least innitially, a high current drain. Have you tried to substitute the battery? What was the size (AWG #) of your supply cables and their actual length? To me, its a voltage drop problem, either caused by the wiring or the supply source. Just my opinion of course.
BOB RENTON
It is strange.
Cold starts and hot starts are similar: Slow cranking. Medium temperature starts are fairly easy.
I don't understand why it is that way.
Terminal voltage before cranking has been tested several times and when it is at 12.5 and above, the starter spins fine.
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With regard to your assumption relating to the wire size: where does the 3% voltage drop @ 45 amps figure come from? The starter motor draw when cranking the engine is approximately 450 amps with 9.5:1 compression ratio hot. The amperage will be greater when the engine is cold.
First example: # 2 AWG X 16 ft.
Resistance is 0.156 ohms/1000 ft Assume total length of cable is 16 ft which results in ~ 0.00156 ohms.
By ohm's law E (voltage) = I (current) x R (resistance)
Voltage drop = 45 amps x 0.00156 ohms = 0.0702 volts
Voltage drop = 450 amps x 0.00156 ohns = 0.702 volts
Second example: # 1/0 AWG X 25 ft
Resistance is .0983 ohms/1000 ft Assume total length of cabke is 25 ft which redults in ~ 0.0098 ohms.
Voltage drop = 45 amps x 0.0098 ohms = 45 x 0.0098 = 0.441 volts
Voltage drop = 450 amps x 0.0098 ohms = 450 x 0.098 = 4.41 volts
These calcs just show wire loss. Terminal resistance unless crimped AND soldered will add 5-10% loss plus the final connection loss, 1-2 %.
If smaller wire sizes are used, voltage drop will be greater at high current draws.
One additional consideration is the starter motor itself. IF the starter motor's armature has a bad winding (shorted to ground) or a shorted commutator (where the brushes ride) bar, current draw will be excessive eith arcing at the brushes or a bad field coil winding (assuming its not a permanent magnet motor). Just my thoughts.
BOB RENTON
I did mention before that the cable to the starter is a 1/0 stranded wire. It is less than 16 feet. I bought 18 feet with one end professionally crimped and ended up cutting off about 2 feet of it.
I was just out there and with the battery at 12.8, it spun over and started quickly. After a brief warm up, restarts were quick but I can still hear the starter strain a bit. The pitch of the noise when a starter is fast or slow is distinctively different. It is much higher when the rate is faster.
Years ago when I had Chevrolets, the starters in the small block engines often needed shims to get them aligned. A brand new starter could grind and drag of the starter wasn't positioned properly. The Mopar starters don't have that problem since they have that centering nose on them.
I was just out there and with the battery at 12.8, it spun over and started quickly. After a brief warm up, restarts were quick but I can still hear the starter strain a bit. The pitch of the noise when a starter is fast or slow is distinctively different. It is much higher when the rate is faster.
Years ago when I had Chevrolets, the starters in the small block engines often needed shims to get them aligned. A brand new starter could grind and drag of the starter wasn't positioned properly. The Mopar starters don't have that problem since they have that centering nose on them.
Just check on that Greg....my mini starter had a little wiggle-room for adjustment, and it made a difference. Agreed that the factory starter doesn't have much adjustment,, but some mini's do.
Thread title must be a bit misleading then.
"Trying to find the electrical draw that drains the battery..."
Is this your starter?
Tuff Stuff Mini Denso Gear Reduction Starter Gray 1965-83 Chrysler 225-
440
Tuff Stuff Mini Denso Gear Reduction Starter Gray 1965-83 Chrysler 225-
440
Yeah, I think so. It is buried behind headers and a torsion bar. I'm not anxious to change it out but for now, that is a possibility.
Kern this has turned into Saga.
It is strange that it turns over the slowest when the engine is cold. With it up to temp, it spins over nicely.
Cold engine, cold oil, and a tight bearings provide for increase in mechanical resistance. Warn it up and things start to loosen up. Get it hot and the starter will start to suffer. Sorry to say but from all that has been described I fear the starter my be your issue. Called a good friend who races and uses the mini's for the extra room. Sometimes they just take a dump and act up. Other times it is just a bad ground, but he has had to replace more than few over the years.
I know that is not what you want to hear but I can't wrap my head around any one common thing, except that starter.
I know that is not what you want to hear but I can't wrap my head around any one common thing, except that starter.
Hey....If I can take apart these cars and put them back together, I can change a starter. It sucks but I do want to drive the car more.
Ugh. I thought this was fixed a week ago.
I haven't priced a Ford solenoid lately, but I have seen the contact burned from a high draw, which then results in more resistance=slower cranking. If you bypassed the solenoid and it "cranks faster that it has in a long time" - sound like part of the problem.
Not quite...After I wrote that, I also wrote that when I reconnected the cable and started the car from inside, it turned over just as fast. It seems that this starter needs full battery voltage to work properly. I've been charging the battery each day to get the battery topped off.Ugh. I thought this was fixed a week ago.
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With regard to the mini-starter, as I've mentioned previously, is a permanent magnet motor. ALL armature current flows thru it. IF the armature coil's insulation is starting to fail as a result of the close proximity to an exhsust heat source, after replacement of the starter with a new (NOT rebuilt) unit, you must protect it from its surroundings with shielding. Electric motor insulation degradation, due to extreme heat, is cumulative. A percentage of degradation occurs each time the thermal value of the insulation is exceeded. Motor insulation and qualified by letters relating to temperature. For example, class B, F, H corresponding to tempersture rise over ambient, with class H being the best highest thermal rating. The different insulation materials vary from paper to fiberglas, to nomex. The varnish covering the individual wires used in the motor's armature windings also varies from formvar to synthetic blends. IF the armature coil wire's insulation is degrading, either to ground or each other, more armature current will result and less armature torque will be produced... resulting in slow cranking speed.
It is unlikely that a "rebuilt" starter will be completely re-wound with new insulation and wires. It will be cleaned, have new brushes installed, but not brush holders, maybe a new "bendix", bearings lubricated, and "tested" (for what--current draw under load, RPMs, insulation resistance to ground ?) and will the published result be included with the individual "rebuilt" unit....not likely. So...are you, the purchaser, getting the best value for your $$$ ? Its up to the individual. For my money, I'll opt for the new unit, regardless of the price, install it, and enjoy the use of the car....not worrying about if it will start or not. Just my opinion of course.
BOB RENTON
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