Higher candlepower bulbs an issue with stock wiring?

[cjshaker]

I've tried to find a formula for converting candlepower to watts so that I could figure out how much extra strain on the stock type wiring it would be to use the newer, higher candlepower bulbs, but unless I'm a physics master, I can't find out how.


I think the stock bulbs were around 22cp, correct me if I'm wrong. So the easy question...will the newer 52cp bulbs overtax the stock (but new) wiring and sockets on my '37? Do they cause any other issues?

[tubman]

Not so easy. What kind of bulbs are the 52 CP? If they are LED's not a problem. LED's covert the majority of the electrical energy to light; incandesents convert it to heat.

I believe Halogens are like incandesents, but I think they are passe'.

[cjshaker]

They are incandescent, styled just like the originals. That's why I wondered. Apparently, it gets real complicated trying to convert candlepower to watts, and the only rating on the bulbs, at least in the pictures I see of them, is candlepower....just like the originals. Even 'candlepower' is listed as an obsolete term now, replaced with 'candela'. There is an equation to convert between those two.
Has anyone done a current draw check on the newer bulbs?

[Pete]

For what it is worth, I have been running 32 x 50 cp bulbs in my tail lights for about 40 years with original wiring.

[cadillac512]

For more info, give this older thread a look:


https://fordbarn.com/forum/showthread.php?t=76669


Terry

[terry]

Sponsored Links (Register now to hide all advertisements)

This doesn't answer your question, but I have used "brite bulbs" from Ron Francis wiring for over 10 years now with no pbms. The headlights are rated at 125-75 candlepower. I am using newer wiring made for a 36 Ford ( my vehicle). I have sweitched to 12v but believe they have these bulbs for 6v as well. terry

[Bob C]

My GE catalog shows 32/32 = 4.66/4.49 design amps, 50/32 = 7.2/4.66 amps.

[BlueSpark]

The key would be how many candlepowers do you get per watt. This all depends on the bulb so there is no generic equation. An LED will give a much higher value than an incandescent. Your current will be watts divided by voltage so a 50W bulb will draw 4.2A on 12V but 8.3A on 6V. I dont know if there is any information given on power consumption by car light manufacturers but it can be easily measured with a meter. I dont know the gauge of the wire in your harness but if its #12 you should be good for 15 amps or so, maybe they used #14 which is lower but this number is conservative because you can stand a bit of heating since the wire is not enclosed or bundled with many other high current wires. A #14 is good for at least 10 amps which will deliver 120 watts at 12V, 60W at 6V. Again these numbers are quite conservative so the wire can carry more than that as long as all connections are good. Cars used to use thermal breakers for wire protection instead of fuses, probably because they are slow to trip and reset automatically after a fault but make sure you have either one of those or a fuse close to the current source to prevent a fire in case something goes terribly wrong like a connection coming loose and touching ground.

[cjshaker]

Originally Posted by Bob C

My GE catalog shows 32/32 = 4.66/4.49 design amps, 50/32 = 7.2/4.66 amps.

Thanks for all the great info, including that old post, Terry.
And Bob, if that info is accurate, it's very helpful. Thank you.
I'm going to have to look at the early charging systems more. I'm not familiar with the 'cut-out' style of controlling the generator. If the generator can't keep up with higher draw lights, I'm going to have to figure out something. I don't want to go the 12 volt route and change the whole system, but I admit dropping the current draw by using a higher voltage is tempting. But that leads to a domino effect with the radio, clock etc.
I've got to think this over a bit more.

[BlueSpark]

I looked up the power consumption of a headlight and found this. "A normal 55W 12V car headlight draws a current of 4.5 Amps." I guess they are talking about a standard incandescent. So it looks like with your 6V system you are looking at 9 amps.If both headlights share a wire you are looking at 18 amps for modern brightness lights. The ratings for a certain wire size I gave you is based on federal codes for industrial equipment and therefore are very conservative, you would have to have much higher current to cause the wire to get hot enough to cause a problem (except for some loss over the length of the wire if you really push it). I think you are in good shape. Make sure you have it fused and run the lights for a while. Feel the wire, I doubt you will feel any heating. My original (rebuilt) generator on the '36 cranks out more than 20A. (I have a 20A fuse on that and its blowing, thats how I know.) If you measure more than 6V on the battery when engine is running and lights are on you know the generator is keeping up.

[Flathead Fever]

I would just put a digital ammeter on one of them and find out how much amperage its actually drawing and make sure the size of wiring can handle it. It would only take a few minutes to check it if you have a meter. Remember it's not just the wiring but the contacts in the switch that also need to be rated for the amperage. If the amperage is too much then you use the switch to control a seperate relay that directs the power from the battery to the lights.

Watts is just amperage multiplied by voltage. If you put your ammeter on one of the bulbs and multiply that reading by the voltage you will have the wattage of the bulb. I'm not sure there is a formula for candlepower converted to Watts.

I'm pretty sure you will be fine using them. Those 6V Fords had large wiring to handle the 6V amperage which is double that of 12V systems.

[38 coupe]

I have run the correct type 6V halogen bulbs with a reproduction 37 Ford wiring with no issues. Good wires and connectors can handle the load, corroded wires and connectors need to be replaced regardless of bulbs being used.

[cjshaker]

Originally Posted by 38 coupe

I have run the correct type 6V halogen bulbs with a reproduction 37 Ford wiring with no issues. Good wires and connectors can handle the load, corroded wires and connectors need to be replaced regardless of bulbs being used.

Thanks for the input. I'm assuming the halogens put out more light than the higher candela incandescents, but I'll look into it more. Either would be a good upgrade, I would think.

[Brian]

Thanks for the input. I'm assuming the halogens put out more light than the higher candela incandescents, but I'll look into it more. Either would be a good upgrade, I would think.

Whilst the halogen bulbs put out more light than the regular bulbs, the important thing is to ensure the filaments are located in exactly the same place. Having the filaments located correctly within the parabolic reflector will produce a focused parallel beam, if the 'new' filaments are not in exactly the same location, sure, you'll have brighter light, but it will be 'scattered'. easiest way to check this out is to install a particular bulb into the reflector, and on a dark night, turn the lights on without the lens. The beam should be a nice, parallel beam.
I know this, because years ago, on a dark night, I was driving my 35 and went over a large pothole in the road. One of the headlight lenses and its surround fell off onto the road, and although the bulb and reflector remained in place, there was a focussed, parallel 'spot' illuminating the road ahead for the rest of that drive.