Hot Rods generator question for the Jr. stock guys

What you're missing is that a generator regulator does compensate for weather, it has a temperature sensitive armature hinge inside.

This is one reason it's not adviseable for the average DIYer to try adjusting the voltage output of a generator regulator, the battery first has to be fully charged (if it was fully charged, then he wouldn't be trying to adjust the output ... right? Hm.) ... then drawn down a little bit, but first, everything has to be stabilized to the "normal" operating temperature for a 1/2 hour or so, then a correction applied to the voltage output for the prevailing ambient temperature, and then try to adjust it to between 14.6 and 15.4 volts, while making an allowance for the effect of the anti-magnetic metal cover after replacement.

Nobody wants to do that. They are really touchy, too. Just trying to tweak it with the "golden screwdriver" doesn't end well. The problem is made worse usually by corroded grounds and cables anyway etc, nobody ever cleaned the regulator points, etc. Easy to see why Alternators took overnight.

What I found looking at old school automotive battery chargers, is they must have had it figured out 100 years ago. The current starts out high and tapers down while the voltage starts out low and ramps up as the battery accepts a charge. They "sized" the charger's transformer to charge at a certain set point and this limited the end voltage at the far end, I think. Right around the "absorption" or bulk charge voltage. However they did it, if you monitor the voltage while it charges a battery you can see it tracks pretty close with the recommended charge tables.

Where the temperature comes into play, set it at 6 amps in July and it will boil it out pretty quick once it is fully charged. The current will be negligible but the voltage will spike to 17+ volts.

In the wintertime though, the battery is much harder to push voltage through. A charger won't peg the voltage that high not right away anyway, and if it gets cold enough, real damn cold, 16 volts won't hurt a thing for a few hours. So for the average poor ******* in Saskatoon in January who didn't own a garage and needed to get to work and it's -25° F below, he could hook it up and leave it for a day or two or longer no problem I expect. At the 2 amp setting it would barely float. Those "dumb" chargers were a lot smarter than I thought, though they will boil a battery dry if neglected in warm weather.

Here's a temperature compensation chart for Ford regulators, notice too the Generator charges nearly a full volt higher than an Alternator at 25° F

Another factor too, we tend to use digital voltmeters today with a different impedance than the old school ****og voltmeters. ****og voltmeters are less accurate but that's what they used at the time to make those voltage charts, it may be that a digital voltmeter will read too high on some of this stuff. It damn sure will read gibberish when measuring directly at a mechanical voltage regulator.

 

"...A smaller pulley will turn the generator FASTER."

Yup. That's why Ford used them in '64. When a cam was added
to the lo-po 289, the extra 1000 rpm or so caused the armature to
Lucas itself.

 

That makes sense, thanks for the good explanation, I’ll be honest and say I’ve probably never checked a charging system in the cold, usually in a warm shop! I have however adjusted mechanical regulators successfully. Thanks again


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Question how long do you set in staging lanes do you have electric fuel pump, water pump ,fans and other electoral equiptment do you restart car? Another question when setting voltage regulators do you recheck after putting the cover back on most of the time values will change?

 

Junior Stockers had none of that electrical stuff.

 

Not so much in cl*** but running for stock eliminator lines got long and to keep the car as cool as possible required pushing the car or several restarts.

 

Yep, been there done that won't go back to it.
Now days guys have remote coolers and generators on the back of their golf carts so no drain on the battery and running the water through an ice cooler you can get the motor a lot colder.

 

It was a fun truck.





Its for sale again. No motor or ****** but the truck is for sale again. LOL

 

IF you are not running a charging system and powering a fuel pump,water pump,and electrictronic ignition and starting the car twice you are down to less then 12 V. At 6,000+ it starts to be a bit of a strain on the ignition system. Coil out put is dependent on coil input. So even with a little fork lift alternator will keep you up around 14 Vs. Yes heat and metal cover have an effect on reg. settings.

 

Truck 64 mentioned old battery chargers dropping amperage as the voltage comes up. You can't have high amperage flow and high voltage at same time. Whenever you charge a battery always hook up volt meter and as the voltage gets close to 15 drop charge rate back to the next lower setting.

 

I will clarify my comments from yesterday. To round off the numbers
i will use 2 volts. Battery 12.5 charging system 14.5. If you must use stock factory ignition coil saturation time is very short at 6000 rpm. The extra 2 volts will help coil output .Coil output is dependent on coil input. If the battery is at full charge the only drag on the charging system would be 1 amp for field currant and gauges and 2 5/8 amps for ignition. A 4 amp drag on the charging system should not offset the advantage of hotter ignition system.

 

my h.s. buddy had a '55 chevy with a cammed-up 265 that he wound to 7 grand on many occasions...

 

The charging output has nothing to do with the fact that the internals are still going to be spinning the same rpm, it will come apart once it hits it's rpm limit. The car may be faster not charging, but thats not what was asked.

There are three choices to make, slow down the generator rpm with a pulley change at the crank or generator, lower the motor redline, or take the chance it comes apart! I left out the alternator swap, ***uming the owner wants to keep it period correct.

 

"...Lucas itself". LOL. Joseph Lucas-ifer, the Prince of Darkness!

 

All kinds of "theory" doesn't negate real world results. In the real world with a fully charged battery, opening the fields ONLY, no other changes, same day, same time, same temperature, same atmospheric pressure, same car, resulted in the idle RPM jumping from 800 to 1000 that is real world DRAG from the charging system. Someone good with math should be able to calculate exactly how much of HP does it take to reduce a 200 HP engines idle 200 rpm.

In the same scenario, no other changes, resulted in a constant 0.20 reduction in ET. For free as I had a toggle switch and spare wire.

If the NHRA agreed with your theory there would be no need for this rule Alternator or generator must be engine-driven and functioning. Belt must be tight ... because they know a non functioning charging system gains an advantage.

 

I used to see slung solder was that just because of RPM?

 

Interesting info here. Help with three cars that I wired that run at the drags. They run 7.60, 8.60 and 9.60 cl***es. All are without charging systems and run elec fans fuel pumps and water pumps. They usually charge between rounds and drive to the staging lanes from the pits-they are consistent cl*** winners and no issues thus far but big batteries in the trunks. The 8.60 car is my friends and will run 8.10-I would think that a small alternator would work fine on this one. They seem to work fine for the past few years with no charging systems. I know a car with only points ignition and nothing else on will run a long time on a fully charged battery-been there done that when generator quit.

 

Loudbang I do not doubt your personal experance,but why do people spend money on trick ignition systems? With higher coil out put you can run wider plug gaps which exposes more and hotter spark to the fuel mixture.

 

THe solder comes from starting out with a low battery and other electrical load such as lights heater and radio. The car is driving down the highway for some length of time and generator is at full capacity witch makes a lot of heat,and there goes the solder.

 

I quess I' m not that much of a purest I use Alternators.

 

A generator is a starter also if wired that way.
So a little creative wiring through a switch at WOT the generator will now be turning the belt.