Lightbulbs - Question

jimainiac · Feb 1, 2009

I wonder if there is a chart anywhere that lists the different brightness of 12V automotive bulbs, either in candlepower or wattage. I've wondered about this before, but what brought it to mind again was when replacing a bulb in one of the revolving amber emergency lights that I use. I have one mounted on the Kubota for when I have to go out in the road, and I stick them on the roof of the pickups when snowplowing. They're economical and handy rigs, but I noticed that the bulb was rather small, so I did some experimenting with a bunch of spare bulbs. I ended up putting in an "1156" bulb that is normally used for backup lights. The glass was bigger but the socket was the same, and what a difference in the brightness!You'd think they'd put the watts or candlepower on the packages at the store at least, or have a chart somewhere. Maybe on a website?

CCWKen · Feb 2, 2009

Most online catalogs have the specifications for individual bulbs. I've assembled my own into an Excel table that I use a lot in auto restorations. Some dealers have old catalogs that will have the specs too.

I can tell you that the 1156 is a 32cp bulb. It's about the brightest you can get in a BA-15 single contact bulb. Many bulbs will be listed in Candle Power (CP) OR Watts (W). You can't compare CP to W as there is no direct correlation or conversion. One is a measure of brightness and the other is current draw.

Your 1156 should be as bright as any auto stop light bulb. To go brighter, you'd have to convert to halogen and probably upgrade the wiring.

DieselPower · Feb 2, 2009

Ahhhh, light bulbs. Which one, what Cp and what is it. I know the feeling all to well. I have collected quite a collection of catalogs over the years working on trucks. I think I have something like 250 different bulbs for automotive and industrial in stock. There's just to many bulbs.

Probably the easiest thing for you to do is replace the standard 1156 bulb with a 50 watt 795X halogen bulb. It's a T6 shape, BA15 base single contact bayonet base bulb just like the 1156 but much brighter with a smaller lens. #795X HALOGEN MINIATURE BULB BA15S BASE, HALOGEN BULB SC BAY 12V 50W, 795X, #795X, #795X BULB, #795X HALOGEN MINIATURE, #795X LAMP, #795X MINIATURE, #795X INDICATOR, EIKO# 44021 Like CCWKen said, you might need to upgrade the wiring to handle the extra load.

Some sell them as 50 watt 1156 bulbs. Automotive Light Bulbs and Light Bulb Sockets Scroll down to 12 volt halogen bulbs, their part number is 39093.

Here's a excellent online bulb reference. CEC Industries Product Line Just click on the type of bulb (halogen, minature, etc...) and it takes you to a full listing with all the juicy details about that bulb type like your looking for.

jimainiac · Feb 2, 2009

Thanks, guys, for the information. I guess I'll stick with the 1156 bulb. It's much brighter than the bulb that came in the light, and I don't think it'll cause trouble with the extra current draw. It would be interesting to see what it looked like with a 50 watt halogen bulb in it, but that might be too much for the unit, both extra heat and extra load.
Thanks for the link to CEC Industries' website, it's very informative. That's the kind of information I was looking for. It's interesting to see how many different bulbs are available, too.

DieselPower · Feb 2, 2009

If the 795 is to much you could go with a 796 bulb, just a lower power version of a 795. It's a 35 watt / 60Cp halogen bulb. The 1156 is rated at about 27 watts so stepping up to the 796 wouldn't require that much more power. In other words, for a little more power you get about 2 times the light output. The other advantage of using the halogen bulb is they tend to burn with a much whiter light when compared to a conventional bulb which tends to be a yellowish light.

ray66v · Feb 2, 2009

jimainiac said:
Thanks, guys, for the information. I guess I'll stick with the 1156 bulb. It's much brighter than the bulb that came in the light, and I don't think it'll cause trouble with the extra current draw. It would be interesting to see what it looked like with a 50 watt halogen bulb in it, but that might be too much for the unit, both extra heat and extra load.
Thanks for the link to CEC Industries' website, it's very informative. That's the kind of information I was looking for. It's interesting to see how many different bulbs are available, too.

If it doesn't melt first, a halogen bulb in a sealed plastic light fixture is potentially going to heat up the air enough to pressurize it, and break the seal somewhere. This is why plastic headlights have an air vent. It was common to see early plastic headlights with water in them, because of this.

Even an 1156, if it is on long enough, can melt a lens. Watch the light closely after moving up to a brighter bulb, especially in warm weather, until your confident with it.

jimainiac · Feb 5, 2009

Thanks for the heads-up on the heat problem. I hope I'm not making trouble for myself by using a brighter bulb. That would be par for the course for me. "No good deed goes unpunished", as they say. I don't think I dare go any brighter/hotter. The 1156's shouldn't be a problem in the revolving lights on the snowplows - there's a lot of natural cooling going on on the roof while plowing. I'll find out, next snowstorm.

AndyMA · Feb 5, 2009

Here's a link to one catalog page that provides some info. There are many out there. Just Google something like cp automotive lamps

http://www.prosperitylamps.com/kandolitecatalog/P91L_NA-Automobile.pdf

When I designed for Bose we had many catalogs from lamp manufactures that had all the information you need, I suspect they are all online now. Believe it or not Bose uses automotive lamps in series with some of there speakers to protect them from too much power. As you over drive them the lamp warms up and the resistance increases. At normal levels the lamp is almost a short circuit. I know just another useless piece of trivia.

Andy

RalphVa · Feb 5, 2009

A far more efficient light bulb than an incandescent or halogen and probably as birght as a halogen is an LED one. This site has the 1156 ones: www.autolumination.com Tail Light Brake Light Turn Signal LED Bulbs They're not cheap, $29+ each.

Don't buy the red ones if your car has a rear antenna or have a radio on your tractor. The red ones transmit FM interference. The white ones don't. Can't say about the amber ones. Haven't tried them, because if you put LED ones in for your signal lights, the signal flasher may think there's no bulb there because of the extremely low current draw. Actually, I tried one on the old Benz, its flasher did just that: flashed fast as though the bulb was burned out.

Ralph

DieselPower · Feb 5, 2009

Installed thousands of LED's on road tractors over the years and your dead on about the flasher Ralph. In heavy trucks once you replace the last incandescent bulb with a LED one the flasher usually stops working, just not enough current draw to make the flasher function. However, it's very easy to fix. They make LED flasher relays, non electromechanical type's that are solid state. If you go to the CEC website I listed above and look at their flashers section you will find some that have their minimum operating current in the low milliamps, these are the ones for all LED systems. They work like a charm. I had been using the Grote brand LED relays up until I found the CEC ones. Theirs are about 2 times less expensive and I have yet had one go bad.

If you check the CEC website you will find they also have a full line of LED replacement bulbs like your talking about. The one thing you have to be watch when buying these is the veiwing angle. Some are designed for use as tail lights and emit no or little light to the side while others cover a good 180 degree's.

At last count I think we had gotten something like 280 LED lights on this tow truck. Even with 12 turn signal lights per side I still had to install a LED flasher, it just didn't draw enough to make the factory electromechanical one operate.