I was about fifteen miles from home at sundown. There was plenty of twilight for the first few miles coming home, but my view of the road became dimmer and dimmer, especially where the road was lined with overhanging trees. My magneto lights were useless.

When I got home I did a little test that showed why.


Here is the car running at idle with "magneto bulbs" installed. At least that's how they're listed in the catalogue. The only marking on them is 24 V.


This is at the same idle with #1142 bulbs installed.

I fully understand that the #1142 bulbs are not designed for headlights, and I know that 24 volt bulbs are sold for this application because they're less likely to burn out than the #1142 bulbs rated at 12.8 volts. But the 24 v bulbs' survival is useless because they don't provide enough light to show the road.

I don't intend to do much night driving, but I will run 1142's unless I find something better. I'd rather run the risk of burnout than drive blind. I'll carry plenty of spare bulbs and perhaps be able to see where I'm going. An added advantage of the 1142's is that they cost less than ¼ the price of the 24 V bulbs.

A suggestion would be to use Ford's 1918 solution to the burning out magneto bulb problem - a dimmer coil. You can probably source a used one somewhere. On 1918-22 T's without battery equipment they were mounted on the firewall, later on the backside of a plate where the electrified T's had the ammeter.

The beauty of the dimmer coil is that it takes the top out of the AC voltage at high rpms (revving in low) that kills bulbs on 1915-17 T's while it doesn't take any of the light at normal rpms like a regular resistor would. It can also provide a dim light setting, but then you would need another light contact with a dim position.

http://www.mtfca.com/discus/messages/179374/200361.html

I would expect John Regan to weigh in on possible solutions if he has time. Should be possible to adapt in some sort of voltage regulator.

I think the original Ford magneto headlight globes were something like 9 volts, with both being wired in series for a working 18v.

I've driven a '15 with a pair of 12v globes in series and it was quite acceptable at cruising speed, brilliant in first gear, but you needed to gather speed quickly when you went for top gear...

24v globes in series would be dreadful and if they're in paralell you mighn't have enough energy, current wise, to drive them in any case.

I'm not sure if there's an LED solution that would have a broad operating window, but they mightn't like AC?

Has anyone tried putting a simple bridge rectifier/filter on the light circuit? Just curious because I am about to begin rewiring my headlights where the barn vermin ate the wiring away.

I remember one time when I was a boy trying to get home after a parade that went too late. There were 3 cars with light problems so all 3 ran together. The first had no tail lights, the second no lights, and the third no headlights.

I need to do whatever necessary to make it easier to remove and reinstall the rims on my headlights, with out having the rims loose enough to worry about losing them on the road. If I ever get the thing on the road.
Didn't mean to hijack the thread.

Tommy - Bob's in Illinois makes a tool that helps turning the rim, also sold by other vendors: https://www.modeltford.com/item/1243.aspx

I always carry a really bright flashlight with me on night drives.
Many newer ones are much brighter than the headlights.

I didn't mention what I've been doing before I installed the "magneto bulbs" last week. I leave the lights on all the time. So when the car is running the lights are on. That means those #1142 were working at all speeds, including the day I did 50 MPH just to see if I could. There's no dimmer, but I've never burned out a bulb. Apparently the combined 25.6 volts of the two bulbs is sufficient to make them survive even with occasional high speeds. Maybe if I were running original 9 V bulbs there would be a burnout problem.

I can't give details because it happened over two weeks ago and my pea-brain can't remember exactly, but....

I once used a Model T coil primary winding as regulator for mag lights. I hooked two fairly low current, low voltage bulbs in series and also in series with the coil primary that I had extracted from a coil with a bad secondary. I then unwound several turns from the winding until I got the brightness that I desired. The winding as an inductor based ballast did a remarkable job of stabilizing the brightness over a wide range of engine speeds.

Say what you will about those old mag lights, they sure give your car a fine set of "dimmers".

Well,Steve since you are using the Mag to charge a battery,can't you hook the lights up to the battery ??

Here's the thread with the details that I couldn't remember.

http://www.mtfca.com/discus/messages/179374/248579.html?1322449173

George, the bulbs are 12 volt and the battery is only 6 volts.

It would be possible to make a small power supply that you could hide somewhere that ran off mag voltage, or 6 or 12 volt battery voltage, and gave you a nice steady 12 volts for lights.