with a brand new battery just installed, why would the battery be drained? when using a test light, should there be power at the generator cut (battery side) with the key in the off position?
forgot to mention, this is a 1926 Roadster
Larry, I have the same question. I was blaming it on the cheap Walmart 6V battery that probably sat on the shelf for a year before I bought it.
I also have installed the turn signal thing that came without a wiring diagram. The thing does not buzz and the little lights on the switch don't work so I often forget to return it to center position. However, that should not drain the battery once the key is in the off position...
I also need a stronger return spring on my brake pedal to make sure the brake light is off.
I am looking forward to the replies...
The battery wire at the cutout is always hot, regardless of key position. So, if you're running an old fashioned mechanical cutout and it sticks, your battery will go dead and maybe your generator will fry.
"...that should not drain the battery once the key is in the off position..."
It all depends how you've got it wired. It very well could be the cause.
With everything being stock, the key only kills the ignition circuit in the "Off" position. In other words, it's not a kill switch.
Jerry, thanks, wasn't sure because I rewired the terminal block and was thinking the wires got mixed up there. I pulled the cutout off and looked inside and it appears very clean and hasn't arched across the points. I have been starting and stopping this rebuilt engine numerous times and all of a sudden there's no juice to even turn it over. possibly a bad new battery or me miswiring the terminal block!
Maybe I should have said, "... it's not a battery disconnect switch."
With a fresh battery installed and everything presumably turned off, do you show any discharge at the ammeter?
Also, with everything turned off, remove one of the battery cables at the battery. Using a voltmeter, see if you show any voltage reading with one probe on the battery terminal and the other on the battery cable clamp. If so, you've got something "on" and draining the battery.
This may help.
Jerry, remove which battery cable? plus or negative side!
the oldest trick to test for shorts is take off a batt cable and see if you get a spark if you do disconnect things one at a time until you find it.
Larry, it shouldn't matter. Either one. The current flows in a circuit (think circle) from one post, through the car, and back to the other post. An unintended ground anywhere (closed switch, wires touching the wrong thing, stuck cutout) connects the circuit and the current flows.
If you run your car on magneto and start on battery there is no way you can hook up an item that needs battery power to only be on when the key is on since the key switch on a T hooks either battery or magneto to the coil box and any extra battery powered item cannot be hooked to the coil box without frying when you switch your keyswitch to mag position since the battery powered item we be fed magneto voltage rather than battery voltage. There is no accessory position for the keyswitch.
Some of us have traded out our original cut outs with the more Modern "Fun Projects" voltage regulators which are hidden inside a cut out housing and look original. Not only do these solve the problem of stuck closed contact points but they will help save a generator from self destructing with a direct short. Someone more electrically adept explain these better please!
another related question. on the ammeter, is there a plus or minus terminal or doesn't it matter. so far I've traced all the wires to the terminal block and have found some discrepancies. biggest concern now is terminal 4 and 6 aren't making any sense. everything else is correct. that's why I'm asking about the ammeter.
Larry, it is good practice to remove the ground cable first. If a wrench touches a metal part from that terminal there is no spark. If you disconnect connect the hot first, it can arc, and since a battery can produce hydrogen gas, you can get an exploded battery. When you install a battery, connect the hot (non ground terminal first) then the ground cable for the same reason, no sparks that way.
If you have an ohmmeter, remove the positive cable from the battery. Connect the ohmmeter between the positive cable and ground. The meter should read infinity. If you get a reading, start with the generator and disconnect the lead from the wiring loom at the cutout. Now check the ohmmeter. If you still get a reading, put the wire back on the generator and go to the terminal block. Disconnect the yellow wire which comes from the starter switch and repeat. Do this with each circuit until you find one which changes the reading to infinity. Some wire somewhere in the electrical system is grounded. Usually you will find the problem at the generator cutout or the terminal block or the switch. Note when you work around the terminal block or the switch, be sure that you don't accidentally connect battery to the magneto.
Heck pull one battery cable and put a test light clip on terminal you removed and the test light prong on the post. With the key or switch off the light shouldn't light. If it dose pull wires 1at a time till the light goes off. You will then find your drain. Easier to see the light than a volt meter.
Related side note, I installed a Fun Projects volt meter last fall. I planed today to wake it up as I have not started it since before thanksgiving. I have been keeping an eye on it because as its wired in the meter is on ALL the time. In four and a half months the battery voltage has dropped .1 1/2 volts. It's now at 6.2 volts plus almost two witdth's of the needle, and late last year when I laid her to rest the needle rested just left of 6.4 Volts. I feel really good that there is no drain on my battery.
I fitted a new factory style cutout on my Genny and since then it flattens the battery over night. I have a red isolator and as long as I remember to turn this off when parking up the problem is solved ....in the meantime.
Yes, on the ammeter there is a positive/negative terminal, so to speak... Though it's not marked as such, it does matter which way the wires are hooked up. Do this: hook up the wires to the ammeter the way they appear in the wiring diagram. With the battery hooked up and all other wiring complete and in place, turn on the lights. If the ammeter shows a reading on the "charge" side, reverse the wires. Obviously, the load of the lights on the circuit should indicate a "discharge". My idea in performing this little test is due to my understanding that, through the past 97 years of Model T ammeter history, not all ammeters are made the same. Bottom line, a current draw has to reflected as a discharge reading on the ammeter.
Take that "factory style" cutout out off and throw it away. You'll eventually ruin your generator or battery and might even start an electrical fire. Why keep a defective part in place that's so easy to replace?
Larry: make the checks for a possible draw on the battle as suggested (the test light one Richard posted is easiest) but if all checks out you could have a battery with suicidal tendencies. LOL. Check first. Spend later.
I fitted a new factory style cutout on my Genny and since then it flattens the battery over night.
Another instance of a defective new part.
Quote: "I have been starting and stopping this rebuilt engine numerous times and all of a sudden there's no juice to even turn it over."
Maybe you're not running it enough to recharge the battery? Is the generator actually charging?
My generator used to show a significant charge when I first bought it. Then when I added a second tail light the wiring must have got changed around because it only showed 9 amps max charge running. I replaced the cutout, no change.
I replaced the generator with an alternator, no change.
I look at the above drawing and everything looks OK even if the wiring colors are different, I traced every wire from beginning to start.
I added a brake switch and added a dual filament lamp for the brake light, then added a turn signal kit and it sort of works.
When I look at the dashboard switch which position does the switch have to be for the running lights to work at night?
Do I get the power for the turn signal from the #3 or the #1 terminal so it goes through the ammeter?
I had a battery in a 29 model A sedan that always had a dead battery but when i replaced the entire wiring harness with a new one the car never has had battery or cranking issues again. Now i put a new harness in all of the old cars i buy. Especially with the age of these Model A s and Ts! Tim
To power the turn signal, take the power from #1, in the diagram above. This will put its load through the ammeter so, if you leave it on or it malfunctions, your ammeter will show a discharge and you'll know there's trouble.
The switch can be in "ON" or "DIM" to operate the headlights.
By the way, 9 amps is pushing it a bit. Five or 6 amps is usually fine, unless you do a lot of night driving.