1914 White 18 volt headlight bulbs

[fleajr]

Are there any 18 volt headlight bulbs available for my 1914 White automobile? I heard that the stater/generator was originally 18 volt and needs to be 18 volt for the generator to work properly and to start working when driving in 4 TH gear above 12 mph. Any help is appreciated. 

[edinmass]

Having spoke to at least five owners of White’s with 18 volt cars……..the answer is not that anyone is aware of for the last 80 years.

[ply33]

This may be totally off the wall, but there are voltage converters made for golf carts that can take anything from 12v up 48v on the input and give you regulated 12v out. They are used to provide 12v power for lights and other things on the cart that use regular automotive voltages. A quick search turns up this one: https://www.amazon.com/Cllena-Automatic-Converter-Regulator-Waterproof/dp/B08KZS81Y1 (I have no opinion on how good this one is or if there are better ones available). If you can find 12v bulbs that will work in your headlights then maybe one of these converters could then be used to power them.

[ABear]

If you can find them Model T headlight magneto bulbs were rated 9V at 1.7A and were wired in series would be as close as you will get provided the filament is in the right place for the reflector and the bulb has the correct base. The downside though is T magneto bulbs are pretty scarce now days and are out of stock in the T suppliers websites..

 

Ply33 does have a viable solution, there are electronic converters called "buck/boost" that can take a wide DC voltage range and convert that higher or lower than the input voltage.

 

Here is one that takes 8-36V DC and converts to 12V DC at 10A..

 

https://www.amazon.com/Valefod-Efficiency-Converter-Buck-Boost-Transformer/dp/B082GD23W3/ref=sr_1_11?dib=eyJ2IjoiMSJ9.VLAMp0bGeiQt5fEvkiHyTVxOzXszikOJlF2dNpAb6QSuD1vNWTPm2ozpGAGhMT_-2Wnpc6onJcQ5yimoYWOu-X0BgqIo8Rh4Liuj-fMEgcnPuMwq_dr9vMI6j01HZuF4OgdR3SDQe7GhhUFK_zoS8kopWYRH3EfJWLf1Y4jR8DPiIiAnUi4GRvg8ofx9cZfxgrkKHJvCXGKJ6W-VUPGOKDZruwQS0Lc9rfDMRtwTg2s.0J1mLHuJp1Netw8LZdbfeN2nszF_HvMJhgxTmUTwocs&dib_tag=se&keywords=buck%2Bboost%2Bdc%2Bpower%2Bsupply&qid=1713534961&sr=8-11&th=1

 

Just be aware of the amount of current your bulbs will draw and make sure you get a converter that can handle all the lighting loads you have.

[LI_BENTLEY]

The White used 6 volt headlight bulbs.  They tapped the battery at 6 volts you can use 3  -  6 volt batteries for 18 Volts and wire the first one to light sw.

[edinmass]

1 hour ago, LI_BENTLEY said:

The White used 6 volt headlight bulbs.  They tapped the battery at 6 volts you can use 3  -  6 volt batteries for 18 Volts and wire the first one to light sw.

 

I have the wiring diagram showing the bulbs and battery as all 18 volts. Using three modern batteries and switching to 6 volt bulbs is a modern adaption that could have been done back before WWI. It's a good solution to a difficult problem. 

 

After looking over several different diagrams, it seems the 18 volt battery actually has a special tap for 6 volts.....if you wanted to use it. The White diagram shows 18 volts to the lights. 

Edited May 2 by edinmass (see edit history)

[jdome]

Have you measured the actual voltage supplied at the socket ? What is the bulb number specified ? Sometimes an old box of nos obsolete bulbs show up on ebay or at swap meets.  What sort of socket base do the bulbs have? If it is a typical bayonet or pre focus base, there are some LEDs with those bases that take a wide range voltage. Another possibility would be to use 12v bulb and calculate the proper.droping resister. 

[ABear]

Electrical system voltage, doesn't matter where you measure it, can be at battery, magneto, generator or at the bulb.

 

Some early autos used what we would consider now days as non standard voltages which are not your typical 6V or 12V battery systems..

 

I the case of the vehicle in this post, obviously their system calls for 18V and 18V incandescent bulbs now days are as rare as hen's teeth..

 

LEDs might be a possible solution, however, they are not without their own challenges and depending on the glass will not look period correct. For LEDs to work voltage wise, one must look for the electronic regulated versions which have a wide working voltage, something like 10V-30V, using LEDs that depend on a internal dropping resistor that were designed for 12V WILL burn out at 18V.

 

While one could use a dropping resistor with a 12V incadescent bulb, it is highly inefficient to do so and will require a healthy high wattage resistor to pull it off as you have to drop 5V across that resistor at at least 2A for each bulb (minimum 10W resistor, 20W would give some wiggle room but that is a lot of heat).

 

Model Ts which used the magneto to power the bulbs used 9V bulbs, in the case of the OPs car one could wire two 9V bulbs in series but that requires making sure the lights are not grounded through the fixtures and some series wiring.. Not to mention, right now even those are scarce..

 

For best efficiency, using a DC to DC switching power supply can be employed and output can be adjusted down (Buck) to 12V so one can use off the shelf incadescent bulbs. The DC to DC power supplies are 95%-98% efficient so very little energy is wasted unlike a resistor.

[Frank DuVal]

9 hours ago, ABear said:

using LEDs that depend on a internal dropping resistor that were designed for 12V WILL burn out at 18V.

Or just add another external dropping resistor....😉🛠️🚋

 

DC to DC converters I have used were way less efficient than 95%. They required a heat sink to get rid of their waste energy. Still, they got the job done!👍

[ABear]

11 hours ago, Frank DuVal said:

Or just add another external dropping resistor....😉🛠️🚋

 

Wasted energy, 10W-20W depending on the bulb you use worth of wasted energy. Sure, to a vehicle engine 20W is peanuts, however, consider this, often in old vintage vehicles you have extremely limited amount of power the gen or magneto can develop. I would rather use something that only wastes 5% or 1.5W from a 26W load! And that ISN'T a resistor.

11 hours ago, Frank DuVal said:

DC to DC converters I have used were way less efficient than 95%. They required a heat sink to get rid of their waste energy. Still, they got the job done!👍

Many of the new modern switching DC-DC converters are very efficient, they are based on the exact same switching power supply technology used in pretty much every modern device.. TVs, computers, USB chargers for example.

 

You can find one example of the main IC chip employed in modern DC-DC switching converters..

 

HERE

 

Which states "3A Output, 96% Efficient Buck-Boost DC/DC Converter Sets the Standard for Power Density"

 

Additionally the technical document states..

 

The LTC3113 single inductor buck-boost converter offers a compact, highly efficient alternative. Internal low resistance switches allow the converter to support an impressive 3A of load current in a tiny 4mm × 5mm package. The LTC3113 offers an extended input and output operating voltage range from 1.8V to 5.5V, with peak efficiencies reaching 96%. The internal PWM controller is designed for low noise performance and offers a seamless transition between buck and boost modes. The combination of these features allows the LTC3113 to easily meet challenging high density power requirements.

 

Now granted, that example is only 3A and operating voltage maxes out at 5.5V, the reality is, switching supply technology HAS most likely advanced  a lot from what you have used..

 

For very large heavy loads, yeah they can get warm, may require a heatsink, but keep in mind that a resistor with 20W of wasted heat, you CAN melt solder with it.. Old school pencil irons for soldering used a 15W-20W heating element..

 

95% is pretty typical for efficiency now days with switching DC-DC buck/boost converters.

 

Modern switchers employ high frequency switching, very efficient compared to old school method of low frequency switching.

[jdome]

20 hours ago, ABear said:

Electrical system voltage, doesn't matter where you measure it, can be at battery, magneto, generator or at the bulb.

 

That is true except when it isn't.  I would think Ed knows his stuff when he said that the White uses 18 V bulbs, but then he seemed to be confused about a 6 V battery tap, which is possible. There may also be series resistance voltage drop already designed into the system for the lights. Then again, the OP's car may have also been modified sometime in its life for lower voltage bulbs.  That's why I say, if there is any doubt about what should or shouldn't be, and there is in my mind; just measure the dam voltage at the socket and see which battery or what voltage  you got. I tried to search for  a wiring diagram for the 14 White but couldn't find one. I would like to see a diagram if someone has one they can post.

 

The more I think about it, perhaps the White has a battery system similar to the 1912 Cadillac Delco 24/6 v. system.  The first electric starter in a production car. That system has four 6v batteries with a relay box that switches the 4 batteries in series for the 24v starter motor and then switches them in parallel for 6v running mode and 6v lighting.  Its been a couple decades since I fooled with a 1912 but if I remember correctly, the Cadillac had a 6v tap off the low battery (the grounded battery) so 6v would always be available for the lights, even when switched in the 24v starting mode.  Cadillac/DElco developed a 6V starter/gen the following year.  There were other early electric start systems that were dual voltage. 

[ABear]

1 hour ago, jdome said:

That is true except when it isn't.  I would think Ed knows his stuff when he said that the White uses 18 V bulbs, but then he seemed to be confused about a 6 V battery tap, which is possible. There may also be series resistance voltage drop already designed into the system for the lights. Then again, the OP's car may have also been modified sometime in its life for lower voltage bulbs.  That's why I say, if there is any doubt about what should or shouldn't be, and there is in my mind; just measure the dam voltage at the socket and see which battery or what voltage  you got. I tried to search for  a wiring diagram for the 14 White but couldn't find one. I would like to see a diagram if someone has one they can post.

picking "nits".

 

There was no real "standards' to go from back in 1914, odds are the OP may actually HAVE a 18V bulb in their hand.

 

Additionally, 18V could have been derived from nine 2V cells (which were popular back in the early days) in series, could have been derived by three six volt batteries in series, could have been derived by two 8V batteries in series, could have been derived by one six volt and one 12V battery in series.. I would lean towards two 8V batteries in series.. But it is anyone's guess at this time..

 

As long as the OP only has TWO wires connecting the batteries to the auto then one MUST come to the conclusion that the bulbs should also indeed be 18V.. Only the OP knows for sure.

 

The ONLY way any other voltage back then would have been derived would have been to add a THIRD WIRE to tap at one of the batteries.. That tap would have only gone to the headlight switch.  My guess on that is no..

 

18V bulbs were a thing as was many other odd voltages, my car originally used 80V bulbs (try finding those)..

[edinmass]

I edited my post......as after I responded I looked up some information. Below is the battery set up with the 6 volt lug to pull power. It is NOT used on a White. The information I have is they used 18v bulbs. Of the three 18 volt White cars I have driven, all were converted or altered in some way, so I have not clear indication of what was stock factory. I would guess by 1920 any 18 volt cars still driving were partially converted to 6 volts. Just pure conjecture. Anyway, you can see the battery was a single 18 volt unit. The entire system is strange with the crazy starter/generator that actually moves on a hinge to engage the flywheel. The car uses the "two wire system" common to the era. Thought the photo would be of some interest. Ed

 

 

Edited May 3 by edinmass (see edit history)

[ABear]

36 minutes ago, edinmass said:

I edited my post......as after I responded I looked up some information. Below is the battery set up with the 6 volt lug to pull power. It is NOT used on a White. The information I have is they used 18v bulbs. Of the three 18 volt White cars I have driven, all were converted or altered in some way, so I have not clear indication of what was stock factory. I would guess by 1920 any 18 volt cars still driving were partially converted to 6 volts. Just pure conjecture. Anyway, you can see the battery was a single 18 volt unit. The entire system is strange with the crazy starter/generator that actually moves on a hinge to engage the flywheel. The car uses the "two wire system" common to the era. Thought the photo would be of some interest. Ed

Sort of what I expected that the OEM did indeed use 18V bulbs and it did use only two wires to the battery. OPs car may or may not have been altered over time but if it had been altered to use 6V bulbs, then I would expect a third wire to be present for the 6V tap on the battery..

 

For others nitpicking my responses, the OP did ask where they could get 18V bulbs or how to make other voltage bulbs work. OP didn't ask specifically ask how to troubleshoot or determine if they needed 18V bulbs, I just gave them a answer how to substitute and use more common modern day 12V bulbs efficiently in a 18V system..

[edinmass]

ABear....I think your response was fine and spot on....no need to qualify it. I would install three 6 volt optima batteries, and pull 12 volts off the set up so I could install better bulbs than 6 volt. My 17 White is 12 volt from the factory, so I converted to 12 volt halogen bulbs in the front and led bulbs in the rear........BUT my conversion left the factory lights alone......I made a quick attachment light bar in the front and tail lights in the rear so they come on and off with only one bolt. The lights plug into a custom harness that hooks to the battery and completely eliminates any alterations to my 100 percent original car.  Only drawback to my system is the light switch is under the car next to the battery shut off......no big deal as I only drive at night with the added lights here in Florida at night when its too hot in the summers. Best, Ed

 

Photo shows the quick attach headlights.......of a 1920 Chevy. 

 

 

Edited May 3 by edinmass (see edit history)

[human-potato_hybrid]

I would just use an inline resistor with a 12v bulb. Resistor ohms is just 4 divided by the rated bulb amps (since 12V bulbs are actually designed for 14V). Resistor watts 4 TIMES the rated bulb amps.

 

e.g. if they are "12 volt" 5 amp bulbs then you need a 1¼ ohm resistor at 20 watts (per bulb). Or you could use four 5 ohm, 5 watt resistors in parallel (per bulb).

Edited May 3 by human-potato_hybrid (see edit history)

[jdome]

Yea you're screwed . Sorry if I came off as nit picking but I don't recall an 18v only system. Several  dual voltage because the industry settled on 6v lights by 14, or so I thought. 

 

Ed, by 2-wire system I assume it uses + and - wires instead of chassis ground. If so it should be easy to rewire for 2 6v bulbs in series.  Using modern electronics on an antique car is against my religion.  Below is how I  would solve the problem. I would pick a  pair of common, available  6v headlight bulbs and wire them in series with a dropping resister.  You would have to measure the resistance of one of the bulbs and find a 20watt sandblock resister with the same olms.  If the sockets are grounded you only need to replace the left socket  with a 2-lead, insulated socket.  The resister can easily be hidden inside one of the headlight buckets. Quick, simple and no complicated wiring and modern electronics to hide.

[Bloo]

What are you guys planning to do with all the heat made by these resistors? You understand that in both of those last two proposed scenarios 1/3 of the energy used is going to be dissipated as heat, right? And that the car's electrical system will have to generate about half again the current to keep up? There is no fooling mother nature, and if you try Mr. Ohm, Mr. Kirchoff, and Mr. Watt are going to want a word.

 

I see no good solution The best things I have heard in this thread so far are the 9v magneto bulbs connected in series, or using 3 optima and tapping at either 6 or 12 volts. Neither are perfect. The magneto bulbs sound the best. Given the shortage of magneto bulbs, and the fact that we don't know whether they will fit or focus in White reflectors, 3 Optimas and a tap sounds like a best, though somewhat flawed solution. Some brass era cars had 6v/12v arrangements with a tap, as shown for 18v above. It gets the battery's charge levels out of balance. There is a good reason systems like this weren't sold for very long.

 

DC-DC buck boost converters, in theory are the only reasonable solution, because they don't have to waste all that energy as heat. In practice, I doubt they will hold up long at all in an antique electrical system. I expect a lot of failures. The voltage spikes on antique car electrical systems are huge. Auto designers did not make any attempt to control back EMF from motors, relays, ignition coils, etc. until they were trying to put digital electronics in the cars themselves. That would be the late 1970s at the very earliest.

 

[edinmass]

Bloo- I agree that I don’t like all that resistance and heat in the circuit on a car this early. Ultimately using three Optima 6 V batteries is really no different than the original set up and just grabbing a tap off of it to run six or 12 V really isn’t a big deal. Keeping everything hidden as well as done in a safe and workmen and like manner is the biggest issue. For my particular car I did what I thought was best with 11,000 miles and it being totally original except for the tires and hoses I didn’t really wanna make any changes to the car. It has the original 1917 valve gaskets on it. The definition of original. Ed

Edited May 4 by edinmass (see edit history)

[prewarnut]

7 hours ago, Bloo said:

What are you guys planning to do with all the heat made by these resistors? You understand that in both of those last two proposed scenarios 1/3 of the energy used is going to be dissipated as heat, right? And that the car's electrical system will have to generate about half again the current to keep up? There is no fooling mother nature, and if you try Mr. Ohm, Mr. Kirchoff, and Mr. Watt are going to want a word.

 

I see no good solution The best things I have heard in this thread so far are the 9v magneto bulbs connected in series, or using 3 optima and tapping at either 6 or 12 volts. Neither are perfect. The magneto bulbs sound the best. Given the shortage of magneto bulbs, and the fact that we don't know whether they will fit or focus in White reflectors, 3 Optimas and a tap sounds like a best, though somewhat flawed solution. Some brass era cars had 6v/12v arrangements with a tap, as shown for 18v above. It gets the battery's charge levels out of balance. There is a good reason systems like this weren't sold for very long.

 

DC-DC buck boost converters, in theory are the only reasonable solution, because they don't have to waste all that energy as heat. In practice, I doubt they will hold up long at all in an antique electrical system. I expect a lot of failures. The voltage spikes on antique car electrical systems are huge. Auto designers did not make any attempt to control back EMF from motors, relays, ignition coils, etc. until they were trying to put digital electronics in the cars themselves. That would be the late 1970s at the very earliest.

 

 I agree, there's a reason these things have heat sinks....I like Ed's proposition better.

 

[human-potato_hybrid]

8 hours ago, Bloo said:

What are you guys planning to do with all the heat made by these resistors?

If you buy the correct ones they will dissipate through the air. I know that it would make the lighting circuit only about 75% efficient but how much are you using headlights on a 19 teens car anyway?

[Bloo]

I know it sounds crazy, but some of us like to actually drive them. 🤪

 

[jdome]

On 5/4/2024 at 9:19 AM, human-potato_hybrid said:

If you buy the correct ones they will dissipate through the air. I know that it would make the lighting circuit only about 75% efficient but how much are you using headlights on a 19 teens car anyway?

No use, HPH. I usually leave these discussions up to the experts who haven't actually done anything like this but repeat misinformation and old wives tails.  Mr. Ohms says that if you add resistance in series with a bulb, that it will actually reduce the current demand on the battery.   AMPS = Volts/Ohms  or   18amps = 18 volts/1 ohm  vs   9 amps = 18 volts/2 ohms.  In reality, though, the combined resistance of the 12v bulb plus dropping resister will be about the same as the 18v bulb they replace. it will have little effect on the battery load.  In the case of the White, you need a series resister half the resistance of the 12V bulb you want to use., to create the necessary 6v drop.

 

Resisters DO NOT make heat.  Current passes through resistance and that produces power in watts:  P(watts) = Amps X Volts.  This production of power (watts) occurs in all devices including, motors, LEDs, filament bulbs, and resistors.  All of these may have the same wattage rating yet differ in heat byproduct.  Power (watts) is NOT DIRECTLY RELATED TO HEAT.  A bulb has a filament that glows and the filament creates heat. A resister does not have a filament, it does not glow.  The resister's sole purpose in life is to reduce voltage for other devices and absorb and dissipate POWER. Resisters, like any other device, are not 100% efficient. It can get warm to the touch but no hot.  Must be properly sized for circuit specifications. A 20 watt resister does not make 20 watts of power or heat, but it will dissipate 8 watts more effectively than a 10 watt resister.  For those of you who may have been frightened by the enlarged photograph posted earlier, of the menacing, high power resister,  I have included the photo below of some common resisters. I thought I should show them in prospective.

 

The 10 watt resister above, at about $1 ea. should be satisfactory for a single bulb, Proper calculation will determine actual value.   You would simply connect the resister between the socket and power line, inside each bucket that needs to be converted to 12v. No other modification or changes in battery connections or charging. There is no harm maintaining a mix 18v bulbs and 12v bulbs + resister on the original battery/electrical system.  The high power 50 wat resister is used by some people to connect more than one device to one resister.  I don't recommend doing that but then I don't convert my cars from 6 to 12. I'm content and capable of maintaining my cars on 6v. In the case of the White, in this application, the only way to go is with the resisters in series with 12 volt bulbs that you want to replace. 

 

 What are you guys planning to do with all the heat made by the third battery in the 12v tap off scenario? 

You picked the worst of the options.  These sort of battery taps can even be dangerous.  Nothing wrong with using 3 identical 6v batteries in series but the tap will discharge the first 2 batteries more than the third. This will cause the first 2 batteries to under charge, and the third to overcharge. Undercharging has its own issues but overcharging can can produce dangerous heat that will deform the case, And the battery is not designed to dissipate excessive heat. What the third battery will dissipate is battery acid in the form of sulfation, hydration, hydrogen  and oxygen gasses,  Non of which you want to accumulate on top of the battery or its posts or the batteries next to it. You certainly don't  want any of this gas-off to collect under the hood or in an enclosed battery box.  Overcharging is the major cause of battery explosions, and it even occurs with Optima batteries, particularly the yellow top version. But of course, all this depends on how much you use the lights. I hope the viewers at home are not getting the idea that they can do a half-arce 6/12 tap-off on a vehicle they drive more often or long drives.

 

It appears to me that the White electrical system in question is similar to model T.  The batteries are normally only used for the starting motor. The lighting is power by a separate set of gen windings that produce 10-20 amps necessary for the lights. It appears that a second set of windings are used for the starter motor that revert to recharging the batteries when the engine is running.  Since there doesn't appear to be any charging regulation, it is probably a low trickle charge rate of maybe 2 amps which is enough to replenish the battery between starts.  If that is the case, with the 12v tap, when the lights are on the first 2 batteries will drain 10 amps faster than they charge.  That cant be good on long nighttime drives.

 

I'm trying to be helpful. Please don't anyone take this as a personal offense.

 

 

Edited May 7 by jdome (see edit history)

[human-potato_hybrid]

2 hours ago, jdome said:

 

Resisters DO NOT make heat.  Current passes through resistance and that produces power in watts:  P(watts) = Amps X Volts.  This production of power (watts) occurs in all devices including, motors, LEDs, filament bulbs, and resistors.  All of these may have the same wattage rating yet differ in heat byproduct.  Power (watts) is NOT DIRECTLY RELATED TO HEAT.  A bulb has a filament that glows and the filament creates heat. A resister does not have a filament, it does not glow.  The resister's sole purpose in life is to reduce voltage for other devices and absorb and dissipate POWER. Resisters, like any other device, are not 100% efficient.

You make some good points but there are errors in this section. You are correct that power = V×A (or what is often more useful, power = V²÷R), and that the wattage rating of the resistor is the maximum continuous power output of the resistor without damage to it.

 

However, the one thing a resistor does is make heat. That's generally not why we use them, but strictly speaking that's all it does. Likewise, a resistor is 100% efficient... at turning the power lost across a voltage differential into heat. If you want to be REALLY pedantic you could say that there are EMF emissions and things but for all intents and purposes it's 100% efficient.

 

It's worth also noting that efficiency depends on the goal. For example, an incandescent bulb is 98% efficient... at being a space heater. The energy in the light is only 2% of the energy it consumes.

 

For this reason my comment about the lighting system being "75% efficient" was technically incorrect. It's already only 2% efficient and my suggestion would drop the efficiency to 1½% overall.

[edinmass]

I enjoy the technical answers provided by the people above. And have no issues or complaints about the friendly and informative opinions of all the people who opine. While I have a decent formal education , it certainly was not an electrical engineering degree. While I’m confident on almost any electrical system in a car, home, and a fair amount of electronics……….my understanding is from the working standpoint of repair and diagnostics……..certainly not the minutia of designing circuits with solid-state components. That’s the great thing about pre-war cars that are stock……. no electronics! Yes……I can and do keep up with modern cars, and my ASI certifications. I just don’t like fixing anything newer than 1942. Thanks to all who contributed to this tome. 
 

 

Edited May 8 by edinmass (see edit history)

[nsbrassnut]

Another off the wall option.

 

Some may know that Ford Ts in the '15-'18ish era used the magneto to power the headlights. The magneto voltage can vary from as low as 6 to 18 or more volts. The magneto bulbs were rated around 9 volts or so and operated with two in series to absorb the magneto voltage and if one burned out then the lights went out. This much has nothing to do with Whites.

 

Anyway, one of the T parts vendors offered "modern replacement magneto bulbs" for a while and I bought two for my '15. When you look close at them they were actually modern 32 volt bulbs. The fit the sockets and they don't burn out when turned on. They also turned out to be nearly useless at actually putting out any light. They barely glow at idle and don't do much more than that when driving. But they do fit the socket and don't burn out if you turn them on. Eventually they are getting replaced with something that provides more light.

 

The point being for this application. If you are just looking for a bulb for mostly cosmetic purposes and that shouldn't burn out if 18V was applied, then these modern 32v bulbs might be an option. They still likely would not provide much actual light in use, but also wouldn't burn out when turned on.

 

https://www.mcmaster.com/products/32v-light-bulbs/?s=32v-light-bulbs

 

[edinmass]

Interesting……I have a 15 T, all original with an electric horn. Didn’t know it used the mag to run the lights………

[nsbrassnut]

Some additional information that I ran across this morning that might be of interest.

 

From the Dykes book, c1920. Here is a table of light bulb information for the 1918 cars. White is included in the list along with many others. In this table they list Mazda lamps with a rating of 12-16 volts. And a few other makes that use the same 12-16 volt bulbs.

 

Perhaps this will provide some additional options, and a Mazda light bulb reference.

 

 

[human-potato_hybrid]

Here's another option. First, I'm assuming that an 18V system is three 6V batteries in series, meaning it's actually 21V when the electrical system is charging.

 

In that case, if you can find a 24V bulb anywhere that will fit, just buy a bit higher wattage than you actually want, and it will basically work fine.