They don't make bulbs like they used to.

wunderwerks

wunderwerks

Member
Converted my '49 to an 8 volt battery. Cranked up the regulatory to 9.2 volts output from the generator. Was told my many the 6 volts bulbs would be fine, they would just shine brighter. Two hundred miles later all four turn signal filaments are burned out which also means the brake lights are gone. Don't think they make 8 volt bulbs. Suggestion was made to put an in line resistor on each wire to reduce the voltage to 6 or just run all lights through a separate voltage regulator. Don't know what would be best?
 
I don't want to sound like a smart alec, but you will be much better served to find/repair the problem with you 6V system, probably with less time and expense than with getting the 8V to work. I rarely hear of anyone who gets acceptable service from the 8V battery. Usually it is a band-aid to get a car to start until they can sell it.
 
In the big picture, maybe not worth converting to 8 volt ? Try 12 volt bulbs. They'll accept 8 volts and just be dimmer than if they were at 12 volts. Never had to contend with this simple approach but should work. Would save all that work installing resistors or having two voltage regulators and extra wiring.
 
Last edited:
not trying to discourage you from trying to use an 8 volt syst. But, this is usually a band aid that is hiding what ever your real problem is. 6 volt bulbs rarely last long on 8 volts, especially the stop lamps and headlamps. 6 volt bulbs are getting hard to find and are expensive. you need to find the cause of whatever your 6 volt problem is. ( usually bad grounds, wrong size Battery cables, generator not charging enough, or bad regulator or regulator adjustment. ) If you do not want to keep the 6 volt system, your best bet is to switch to 12 volts. you may find that using the 8 volt system over a long period may damage your gauges, as they are designed for 6 volts. I personally have no problems with the original 6 volt system on my 51 Merc. . I have owned this car since 1994 and have not had any problems with the 6 volt system. keep the connections clean and tight, and use good quality, properly sized battery cables. ground the Battery to the engine then the engine to the frame . then from body to frame and then from one of the starter mount bolts to the frame this has worked for me for many years. just my opinion and advise.------Jim
 
"They don't make bulbs like they used to."

Yes they do.
6 volt bulbs with 30% more power running through them should burn out quickly.
It isn't the bulb's fault you've run too much power through it.
 
wunderwerks said:
Converted my '49 to an 8 volt battery. Cranked up the regulatory to 9.2 volts output from the generator. Was told my many the 6 volts bulbs would be fine, they would just shine brighter. Two hundred miles later all four turn signal filaments are burned out which also means the brake lights are gone. Don't think they make 8 volt bulbs. Suggestion was made to put an in line resistor on each wire to reduce the voltage to 6 or just run all lights through a separate voltage regulator. Don't know what would be best?
Click to expand...
What was behind the idea of going to 8 volts in the first place?
 
P Poor picture but these are my brake lights on the roadster. Plenty bright.;)
 

Attachments

  • brake lights.JPG
    brake lights.JPG
    62.9 KB · Views: 24
Didn't know they made 8 volt car batteries. Any time you up the voltage you decrease the amps thru the wire, with lower amps some components will not even turn on especially bulbs which have a filament! Stay with original voltage..that way everything that is already set up to run with it will woik!
 
FrankWest said:
Didn't know they made 8 volt car batteries. Any time you up the voltage you decrease the amps thru the wire, with lower amps some components will not even turn on especially bulbs which have a filament! Stay with original voltage..that way everything that is already set up to run with it will woik!
Click to expand...

FrankWest-- amps (current) draw is dictated by the appliance's (component, fixture, etc.) resistance. You can't add or subtract amps to a system. You can only add or subtract voltage or resistance.

In a 12 volt system, half the amps (compared to 6V system) are required to perform the same work--- let's say brightness measured in candlepower. For instance, a 12 volt bulb has twice the resistance of a 6 volt bulb and will require half the amps (current) to produce the same brightness.

If you supply 12 volts (or 8 volts) to a 6 volt system, the 6 volt bulbs (built with half the resistance of 12 volt bulbs) will burn twice as bright (until they melt), but still use the same amps as the 12 volt bulbs burning half as bright.

Think of it this way, you can buy 12 volt batteries in various amp ratings. Some have 400 amp capacity, some have 800 amps. Swapping these batteries has no effect on the electrical system because amps are the carrying capacity, not the force. Force is from voltage.
 
The following was true back when Henry built his cars and is still true today.

E=IR where E= voltage, I= current(amps), R= resistance (6v bulb filament)

If you increase the voltage(E) to the bulb from 6v to 8v (33% increase)and the bulb stays the same(resistance) then the current (I) has to increase by 33%

While the increased current and increased voltage in the circuit causes a much brighter bulb, the77% increase in heat generated inside the bulb results in extremely short bulb(filament) life.
 
I bought the car in Sep. in Michigan. It had a Willard 6/12 battery in it. Used 12 volts for starting by means of a separate button to depress at the same time I stepped on the starter pedal. Battery was cracked. New one was $450. During my farming days an 8 volt replaced the 6s in our tractors and worked great including the lights. Should not have remembered those days as it definitely did not work on the '49. It has an overdrive so with everyone consensus I'm going back to a straight 6 volt. Thanks to everyone for chipping in and getting me straightened out. Any recommendation on a good 6 volt brand?
 
Now to insure your 6v system works correctly for you make sure you have the proper gauge wire on the battery (heavier than 12v) and ALL of the grounds are clean!
 
I am using 2 optima batteries wired together where they are still only delivering 6 volts to the system. I have plenty of reserve cranking power. I could drive the car down the road on the started if I had to. LOL. I made up my own cables before I retired. I used the shop tools to crimp my own battery cables. make sure that your cables are the correct size. you only really need one optima Battery, I just like over kill.
 
When I lived in Eastern Idaho during the early '50's it was very common to use 8v batteries in 6v systems.. I used a 8v battery in my '36 Ford for several years, never had a problem with any of the lights and/or accessories, heater, radio, etc..
I would suspect that possibly the wiring in the vehicle has some issues, and/or the for bulbs are of poor quality.
 
blucar said:
When I lived in Eastern Idaho during the early '50's it was very common to use 8v batteries in 6v systems.. I used a 8v battery in my '36 Ford for several years, never had a problem with any of the lights and/or accessories, heater, radio, etc..
I would suspect that possibly the wiring in the vehicle has some issues, and/or the for bulbs are of poor quality.
Click to expand...

Were you just using the 8v battery? Believe this setup modified the generator to match the 8v battery so it is running somewhere in the 9v+ range. That would not be the same as just installing an 8v battery which most likely was only charged to ~7.2v or so by the stock generator. This is really no different than a stock setup with a little more cranking voltage, the voltage that the bulbs see would be the same as stock. That is a completely different situation than this one.

Edit: Just checked post #1 and yes, he adjusted the regulator to put out 9.2v That is around 2v more than a stock generator/regulator. Comes out to ~28% increase in voltage to the bulbs.
 
Last edited:
You must log in or register to reply here.
Back
Top