Voltage drop

[farmerdick]

Hey Guys, I noticed that the amp meter dropped from a + 6v to a negitave 4 to 6 volts when I turned on any of the lights. This happened while going 45mph. Any adjustments or ideas. Thank you.

Richard/Maine

[Patrick L.]

I'll assume you meant amps. What does the meter read when sitting still ? Then turn the lights on and see what it says. What does it read while running before turning on the lights ? At a fast idle the ammeter should show about a 3-4 amp charge and when the lights are turned it'll discharge about 5 amps or so depending on the light bulbs. Adjusting the third brush to charge about 10 amps at fast idle will keep from discharging as much when the lights are on, but, will boil off water in the battery faster. If its not charging then polarizing may help, if not, then something needs to be fixed. We'll help with that when we have more info.

[farmerdick]

I checked the "amps"/ 0 at idle, + 8 at fast idle, and -8 with light on. If I make no adjustments will these readings have any adverse on discharging the battery? And one more quick question. What is the engine oil weight. I never asked the guy who rebuilt it? Thank you.

Richard

[Mike V. Florida]

yep working good.

[Patrick L.]

The charging seems OK with those numbers. I'm concerned about the high discharge when the lights are on. What is the discharge when the lights are on without the engine running ? I'm wondering if there is a light wire grounding itself.

[farmerdick]

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It is -10amps with engine off and headlights on.

Richard

[Tom Wesenberg]

Everything sound like it's working as designed, which isn't the best way to keep the battery at the proper charge level. 8 amps will boil out the water from the overcharging, then when driving at night the -8 will drain the battery and leavi it in a state of discharge. You can set the adjustable brush down to about 2 or 3 amp charge, which is easier on the battery, then when you turn on the lights you reset the adjustable brush to an output that will carry the lights plus about 2 more amps to keep the battery charged.

I don't know of anyone that keeps resetting the adjustable brush, and a far better solution is to use an electronic voltage regulator. Your car will still look stock, but the battery will last longer since it is getting the correct charge, and not being overcharged and undercharged.

BTW, from your readings, it would seem the lights are drawing about 16 amps (+8 to -8), which is about twice the original light draw. You must be using halogen bulbs, or very high draw regualr bulbs. My car has regular bulbs and lights the road well.

[Patrick L.]

One of Tom's regulators is a good investment.

[H. L. Chauvin]

Hi Richard,

The other advantages in having a voltage regulator, especially if your battery is not 100% charged appear to be:

1. The voltage regulator allows the generator to continue to charge when the engine is at idle as opposed to stop charging at idle with a cut out..

2. Also, when one stops at night at a stop sign or at a red light while the cut out is not producing current at idle, with a voltage regulator & a slightly weak battery, your headlights will not look like (2) birthday candles shining in (2) dull mirrors.

3. Then, at the red light, at night, with your engine at idle & the generator not charging, & a slightly weak battery, if you blow your horn with your lights on to make the guy up front see that the light is green, with a voltage regulator, your lights will not get so dim that you could survive a midnight air raid on a desert during an enemy airplane attack.

4, The generator will probably last longer also by supplying only what the battery needs as opposed to constantly providing high voltage to boil the water out of the battery.

Others may notice other advantages for Model A voltage regulators -- I like mine.

[farmerdick]

Where can I purchase one of these electronic voltage regulators?

Richard

[Patrick L.]

Originally Posted by farmerdick

Where can I purchase one of these electronic voltage regulators?

Richard

Just ask Tom Wesenberg

[Mike V. Florida]

Originally Posted by farmerdick

Where can I purchase one of these electronic voltage regulators?

Richard

There are three available;

Tom's
fun projects
James Peterson 541-389-0438 info at http://www.fordgarage.com/pages/generator.htm

[BILL WILLIAMSON]

Folks, please don't "JUMP ON MY CASE" cuz I don't feel good, BUT on my other car, I solved all the above problems by installing a 6 Volt positive ground, single wire alternator. Bill W.

[Napa Skip]

Nothing against voltage regulators, however an alternative would be to adjust the generator to produce an output of +2 to 3 amps at normal engine operating speeds with the headlights on and then always drive with the headlights on.

Upside: simple solution.

Downside: marginally decreased fuel mileage and headlamp bulb life. As to generator life, until I shifted to an alternator a couple of years ago, I routinely drove with my headlights on all the time (including several years as a daily driver) and noticed no degradation in the generator commutator film or increased brush wear.

And, yes I did leave my headlights on one or two times, which had the unintended consequence (besides deep-cycling the battery, which - if not done too frequently - is good for the battery) of honing my "ok dummy, start it with the hand crank" 'skills' (you can still start a Model A with a battery lacks sufficient capacity to crank the engine over). I finally started turning on the dash light to remind me that the headlights were on.

Now - as I get ready to enter my 8th decade here on planet Earth - if I can just remember why I turned my dash light on during the day, everything seems to work well...