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Need help with mystery
have 52 200 with an ultramatic
battery light goes on brightly when travelling above 58-60 mph ,below this speed seems to work normally,on at idle goes out with a bit of acceleration
what gives? battery is a dry cell 6v which seems to work fine ,generator is a recant rebuild ,voltage regulator is replaced ,cables are fresh ,belt is new any ideas??will the battery run down driving at 60 at night?
I need to use the car at this speed and conditions to use it for commuting to work

I would take it somewhere with some decent diagnostic equipt and verify the output at various RPM.

Assuming no wiring was changed, the bulb is between the A or gen terminal on regulator and the B or bat terminal. Only way the light can illuminate is when the voltage differential between the normal battery voltage and generator output is enough to light the bulb. When no charging, the battery supplies a voltage which feeds to one side of the bulb and other side goes back thru generator and gets ground thru windings there. When generator starts supplying a voltage then that voltage will match the battery so each side of the bulb is at same potential and it goes out. When idling, the gen voltage is not quite as high as the battery so the light is dim or flickers when the regulator cuts in and out.

It almost sounds as if the regulator/generator is not the proper match or the regulator might need adjusting and is regulating too soon. Either due to current or voltage, it almost sounds as if the regulator is cutting off charging at 60. I guess it is also possible something is amiss with the gen rebuild--but don't think as likely as a mismatch or adjustment. The light could also light if the voltage from gen is much higher than battery but if that were the case, I would think all kinds of other bad things would be happening.

Had that same problem on a 51 20 years ago. Turned out to be a short in the armature of the generator and the voltage would drop at speed. Its easy enough to check: hook a voltmeter to the A terminal of the generator, and the other lead to ground. As you rev the engine, the voltage should come up to at least 7.2 and stay there throughout.

If you decide to remove the generator, you can remove the armature and check each segment of the commutator to ground (the shaft) with an ohmmeter to detect any grounded segments. This should be a standard check each time we service the generator for brush or bearing replacement or for commutator service.

Ross makes a good point. Centrifugal force could easily be at work in the armature causing a short. The test he mentions is easy enough to do and well worth doing as a first step. I am not sure it will be definitive as to the cause though. The regulator, still being in the circuit, could also cause the generator output to lower if either the current section or the voltage section thinks it sensed too much and starts limiting. Would be good to check and see what the actual voltage is though in case it is going high (unlikely, but possible).

Unfortunately, taking the regulator out of the circuit and then running at speed long enough to measure anything without some safeguards could cause real damage and is best left to a proper shop.

O_D's suggestion is also good and hopefully done by the shop that rebuilt generator but unless there is a suspicious area that looks discolored or otherwise different to look at now, don't know how much will be found in a static test since it works well most of the time and only happens at speed.

how does one check the voltage regulator adjustment ? the manuel statwes there eas a exchange program in 1952 so when the thing blinked out one just got a new one installed .
mines a new one from max merrit .I didnt understand how to do the initial de static thing on initial installation in the directions ,I have adry cell 6 v battery ,,i wonder if that is the sourse of the problem ,
it seems to work fine .the concept of overcharging making the light go on is facinating ,I guess first it would be easy enough to go to the mechanic shop on a day off ,put the voltage meter on the generator and rev the engine and see if there is a drop .
what rpm do you suppose is 60 mph?
Ive always wondered if anyone made a 6 volt positive ground tack I could mount in the passenger compartment just to know how fast the old flat head was spinning
oh come to think of it Max merrit guys said it wasnt actually a packard generator ,it was some other kind ,they had their rebuilder fix it anyway and sent it back to me .hmm the mystery continues!!

If you mean the Optima dry batteries, they should not be a problem. Many have them, myself included, and they work fine.

The install step you mention is probably the polarizing of the generator. All that means is taking a short piece of wire about the same size as that used in the car and touching it between the GEN or A terminal and the BAT or B terminal on the regulator for a brief time-maybe half a second or so. There will be a spark and what that does is orient the magnetic field in the generator to whatever polarity is in the car. You can do it again if you want since it won't hurt anything, but since it charges at low speed probably not needed.

The regulator is adjusted in different ways depending on the brand. Some have screws to turn in or out and others have tabs to bend. If your shop has the equipment, then they should be able to do it. At any rate, without the proper equipment and understanding of procedure and what is supposed to happen, not something I would recommend you try right off.

One thing you can do is the voltmeter test Ross mentioned. Just follow his directions and look at the voltage. Should start out low -- maybe 4 volts or so at idle then as you increase engine speed should go up to max of 7.4 or so and no further. It will fluctuate a little as the regulator contacts start doing their job. Keep increasing speed until it either drops off or increases to where the light comes on. If you wanted to, you could get a long wire and connect to the A terminal on regulator along with the generator wire and bring it inside. Connect the other side of meter to ground and you can check the voltmeter as you drive.

6v pos gnd tachs are available. Here is one sitewestach.com/ and Northern Toolnortherntool.com/ has small battery operated things that don't even connect to the car power.

Quote:

They're not actually dry, they're gel cells.

I know but it's a convenient description.

I've used 12v tachs on 6v systems. Not sure how long they will last that way because i only run them for maybe 10 or 15 minute intervals.

eBay search Tiny Tach or digital tachs for motorcycles. Simple one wire conexxion to coil wire only so number of cylinders does not matter.

As for the charging lite situation if u have an ordinary WET cell type 6v battery on hand i'd put it in the car a test for the presence or absence of the problem stated.

Did the problem exist PRIOR to using a Gel Battery????

The gel batteries have presented some problems in 6v M/C applications but i'm not famailiar with the details of those problems.