700 RPM's ??

[John Dayhuff]

I want to check the charging of my generator with a meter and was told that it should be at a "high idle" of 700+ RPM's. Without a timing light how else would I know if I'm up to speed or not?


John

[Patrick L.]

Does your ammeter show a charge when the engine speed is up ? What charge does it show ?

Is this a stock factory system ?

2-3 amps is fine for daytime driving while it could be bumped up to 5-6 amps if driven at night fairly often. I wouldn't be concerned about the exact engine speed, as long as you raise the engine speed and it then shows a charge it should be fine.

[Railcarmover]

get a cheapie tach dwell meter,it uses the point impulse to measure engine speed

[John Dayhuff]

Yes the car is pretty much stock ,including the six volt battery/generator system. At a fast idle I'm getting 7.8 volts at the generator and 6.8 volts at the terminal box, is this normal? The third brush is turned all the back. My amp meter on the dash says minus 4 amps at a slow idle and plus 4 amps at the faster idle speed. Could this lower amperage mean my battery is being drained? Why does it go so low at times? The amp meter is a reproduction 20/20 meter however.


Thanks or the tach advice, I'll look into that.


John

[30 Closed Cab PU]

Here is what I use, inexpensive. Only one lead wrapped around the coil/plug wire about 2-3 wraps, programmed for 4 pulses. Has internal battery. The lead is long enough to mount inside, a lot of inexpensive battery tachs have short leads, not long enough to mount it inside the A. There is a backlit version available. Updates every 1/2 second or so.


https://www.amazon.com/Trail-Tech-74...s%2C225&sr=8-1

[30 Closed Cab PU]

Sponsored Links (Register now to hide all advertisements)

At very low idle approx. 400- 650/700 rpm, the generator is basically not working, this is normal.


The 3-4 amp discharge you see is mostly for what the A needs to run the ignition. Typically you do not sit at this rpm very long, and when the generator starts charging at higher rpms the generator charges/refreshes the battery for the current/power supplied by the battery during that time of low rpms.


Same Is true of using the starter which presents a huge temporary load on the battery when starting. You do not see this load since the starter does not go through the ammeter. But since the starter is a temporary load, the generator refreshes the battery at a lower current to charge the battery back to full charge.


I am rusty on electrical, but believe the battery, generator and terminal block should always match voltages. You possibly have poor connection(s). Check/Clean the: battery post connections, battery to frame connection, starter/start switch (large and smaller wires) connections, generator/cutout relay connections, Terminal block connections, remove the instrument panel and check the ammeter connections.
Make sure to clean to bare metal, and check that crimps are tight.

[ryanheacox]

Yes, you should have the same voltage at the terminal box and cutout terminal as they are directly wired together. The ideal charging voltage on a 6V system is around 7.2V, 7.8 isn't bad. I believe in some Ford literature the headlights are referred to as 6-8V so you'll be good to go once you figure out why your terminal box voltage reading is low. Like 30CCPU said, check the wire end crimps. There have been multiple posts about how they can work loose and cause all sorts of weird problems.

[John Dayhuff]

Thanks guys for all the great info. I'll work on that and report back on it when I can.

[Tom Wesenberg]

All wire harness terminals should be soldered, and not just crimped.
At 500 engine RPM the generator is running 750 RPM and my battery is being charged.

[John Dayhuff]

So I go out to start the car yesterday and it can't hardly even turn over like the battery is dead again. UGH!! I'm heading out for a new battery ASAP.


John

[ryanheacox]

Check those grounds. Do you have a separate ground to the transmission?

[John Dayhuff]

Not that I know of.

[30 Closed Cab PU]

Originally Posted by Tom Wesenberg

All wire harness terminals should be soldered, and not just crimped.
At 500 engine RPM the generator is running 750 RPM and my battery is being charged.

Went out and checked my truck, -2 amps at 500 motor RPM. At 700 rpm amp meter is at 0 amps. When truck is off, at 0 amps. Lights on truck off, -3 amps (have LED head lights).


Generator is a new rebuilt this year from Berts. At 1000 rpm charge rate is 6-8 amps with lights/etc off. Can not get lower charge rate, 3rd brush is adjusted full up.


My generator must somehow act differently than yours. I do not know what is normal. Perhaps mine is abnormal?

[Tom Wesenberg]

As the battery ages, or if it's too small, it is less able to control the generator output. When I first bought my 29 Tudor, the 6 volt battery was shot, so I jump started the car on a 12 volt and drove it around on the worn out 6 volt, but I couldn't get the powerhouse generator to regulate less than 12 to 15 amps. A new battery took care of that.

[Patrick L.]

I would recommend checking for a draw and then check/remove/clean the battery ground connections.

[Ranchero50]

Put a free spectrum analyzer or frequency meter on your phone and set the idle to 23.3hz at the exhaust.

700 revolutions per minute x 2 exhaust pulses per revolution divided by 60 second equals 23.3 pulses per second or 23.3hz.

Science

[eagle]

Better yet, put a voltage regulator in and forget about the generator AND the battery. It'll take good care of them.

[Patrick L.]

A voltage regulator is a good idea and I like the one Tom W makes.

[ryanheacox]

Yep, I use Tom Wesenbergs voltage regulator as well. You can't go wrong. Charges around 1A under most circumstances, even running down the road with the stock 50cp headlights on. Just put it in this year and I think my 8 year old battery gave a sigh of relief.

[John Dayhuff]

Voltage regulator?? Talk to me Tom!!


I checked the battery without the terminals hooked up and I got 5.8 volts. I can't remember what it was at the starter but I want to say about a volt less? I'm taking the battery to Auto Zone where I bought it a year ago to let them test it and go from there I guess.

[John Dayhuff]

Originally Posted by Ranchero50

Put a free spectrum analyzer or frequency meter on your phone and set the idle to 23.3hz at the exhaust.

700 revolutions per minute x 2 exhaust pulses per revolution divided by 60 second equals 23.3 pulses per second or 23.3hz.

Science

HUH?? Are you even speaking English? There's no place to sit a frequency meter on my wall phone. You must be from another planet or something way off in the future.

[Ranchero50]

Originally Posted by John Dayhuff

HUH?? Are you even speaking English? There's no place to sit a frequency meter on my wall phone. You must be from another planet or something way off in the future.

You are me from 4 months ago. Bit the bullet and bought a smart phone. It's come in handy for more than Facebook and talking.

[ETAModel]

When trying to figure out the RPM's of Charlene, my 1956 Farmall 450, I was told to get a photo tachometer. They're on Ebay under $10.00. They come with magnetic tape you put a small piece on the flywheel and then point the Tach at the tape while running and you get your RPM's.
Just a thought.
ET

[John Dayhuff]

Cool, thanks for the tip.

[chap52]

What ETAModel said...
Here is a really handy tach I got on Amazon which works on any rotating surface. Just stick a small piece of reflective tape (lot's of it comes with unit) on the front pulley where you can see it when the engine is running. Point the laser, read the RPM. Not to mention it comes with a nice zipper bag to keep it in.... Chap


https://www.amazon.com/FITNATE-Tacho...s%2C208&sr=8-5

[Patrick L.]

Sponsored Links (Register now to hide all advertisements)

Hmm, I wonder how they did all this stuff back in 1931. [smiley face]

[John Dayhuff]

Exchanged the old battery for a brand new one today. Took a reading on it before I put it in the car and it's measuring 6 volts. Stick it in the car and it fires right up like it's nobody business. I mean you can instantly feel the difference as soon as you push the starter, very strong turn over. Now if it would just stay that way I'd be happy. I gotta take some more measurements but ran out of time today, but "I'll be back".

[ryanheacox]

With any luck that battery should last you about 10 years. Have fun!

[John Dayhuff]

I'd be happy with just a year at this point.....LOL.