THEORY QUESTION

[2fulhund 0]

ALL: 1) In theory, if we have an ammeter, and the bat is fully charged, and there is no load on the gen or bat, the ammeter should show "0" charge? 2)Do I not have a faulty votlage reg: the bat is cooking and I'm frying fuses? 3)VOM over the bat at approx 1/2 throttle = +16 VDC! 4) And again, if the Volt Reg is working properly, it should shut off current from the gen to bat when the bat is fully charged, but if additional current is needed: i.e. lights, we should still see a positive draw across the ammeter for current to the lights? Please if you can answer accordingly: Semper FI GREG

[wminmi 0]

16VDC sounds way high.....i could be totally wrong, and i'm sure someone smarter than me will chime in here, but that just sounds WAY high. My truck pushes out 14.6V MAX

[D-17_Dave 12]

An APM meter shows only the flow or electicity from a supply to a load. What you see on the APM meter depends on how it is wired also. IMO, an AMP meter is almost useless. To truely know the condition of an electrical system you need a VOLT meter to monitor the system. Anything over 14.5 volts is TOO much so it sounds like your regulator is fried. Over voltage and overchargeing the bat. will result in cooking the bat. whitch is what your doing.

[ambler 0]

I assume its a SG.Look at Al's post on SG theory and voltage regulators

[PhanDad 3,766]

This post became longer than I wanted. Sorry, but maybe it'll help some folks. The answer to your 4th queston is no, as explained below. I think you have a bad voltage regulator. The amp meter is usually connected between the battery positive terminal and the wire that runs from the generator to the ignition switch. The amp meter acts as a flowmeter that is directionaly sensitive and measures the current flow (amps) to and from the battery ONLY. The battery is a storage device (it stores "amps", a unit of current flow). When the tractor isn't running (no generator output) and the ignition switch is turned on, the amp meter will show negative flow since amps are flowing from the battery; if you turn on lights, an electric clutch, etc, the negative flow will increase as more power is used from the battery. When the tractor is running (generator working) the power draw (load) is supplied by the generator up to it's maximum capacity. If the load is less than the generator max, then "extra" amps will flow to the battery and a postive reading will show on the amp meter. When the battery is fully charged (usually around 14.5V) the amp flow to the battery will stop and the amp meter will read "0". The generator, however, is still suppling current to the various users (lights, etc). If more electical users are turned on than the generator can supply, then the amp meter will show negative as the extra amps needed are coming from the battery. This is why a battery can be "ran down" even though everything is working properly - the total load is greater than the generator can supply and the battery never gets any "amps to store".

[ambler 0]

From Service Manual Battery Will Not Charge 1. The battery will not charge. a. With the engine running at 1/2 or more throttle, connect a voltmeter from the “A” terminal of the starter generator to ground. See Figure 2, B-3. b. If the starter-generator is operating correctly, a reading of 13-14 volts will be obtained. If a reading of 1-3 volts is obtained, use a “jumper” wire to momentarily ground the field terminal (“F” terminal, see Figure 2, B-3) of the starter-generator. If the voltage reading goes high, the problem is usually the regulator and it should be replaced. If the reading stays at 1-3 volts the starter-generator should be repaired If a reading of “0” volts is recorded, the starter-generator can be assumed to be defective. Battery Overcharges 3. The battery overcharges (loss of water). a. Check to insure all cells of the battery require water. If one or more cells do not take water, the battery is defective. b. Connect a voltmeter from the “A” terminal of the starter-generator to ground. See Figure 2, B-3. With the engine running disconnect the field lead from terminal F on the starter-generator and observe the voltmeter reading. A high voltage indicates a bad starter-generator; a low voltage indicates a ground in the field circuit. Use an ohmmeter to locate the ground. c. After these checks have been made without locating the problem, the regulator will most likely be the problem, and should be corrected.

[Al 6]

Hi, With the unit running at near full throttle, remove the wire from the F terminal of the starter generator. the voltage should drop to battery voltage around 12 volts. Touch the F wire back on and if it jumps to 16 v the regulator is bad. If with the F wire disconnected the voltage stays about 16 v, the field winding is shorted to ground inside the SG. It may be under the terminal, or on the outside of the field winding. If it is one with the soft plastic insulation, the unit has probably been overcharging due to a bad regulator and the SG ran so hot the insulation melted and the varnish on the wire rubbed through and shorted the winding to the SG case. If the fields aren't toasted, if it keeps running at 16 volts they will be toasted. My thoughts, Al Eden

[patrician12 0]

It definitely has a bad regulator if nobody altered the wiring.The reason the gauge may show zero charge is because it might have been replaced.Some ammeters have shunt on the back of them if they are used to charge the battery.If the gauge fails they still charge the battery with a shunt.

[firefoxz1 4]

All juice to and from the battery should flow through the ammeter except the primary start circiut. Without running the charge circuit through it it would be a useless gauge. Some auto systems did use a resistance shunt so if more current was flowing than the gauge wire could handle, or the gauge show, some would bypass like extra water over a dam. This probably has nothing to do with your problem and do what Al said to check it. One other thing would be to remove the surface charge from the battery (crank the engine with plug wire removed for 5 seconds or so) let it sit a little then check voltage if not between 12.3 and 12.6 check for a shorted cell, but I doubt this is your problem because amp gauge shows 0, right?

[2fulhund 0]

UPDATE: Just did the Al test above: At full throttle with "F" wire disconnected I have 2.85 VDC on the "F" Terminal of the S/G. Is This good? The bat is reading 12.6VDC. And at full throttle when I connect the F wire back to terminal the engine tone/sound/rhythm changes.