Question about candle power

polk county

Petty Officer 2nd Class
Joined
Jan 22, 2008
Messages
128
The submersible fishing light in this link is no longer in production. I am building one with a Pyrex glass test tube and some waterproofing rubber gaskets. It uses a 12V bulb and produces 250,000 candle power. How many watts is that? Im having trouble finding the right bulb. My other question is what gauge wire should I use for this? The cord will be 10ft long.

Thanks for the help.
http://www.brinkmann.net/Shop/Detail.aspx?category=Flashlights+%26+Spotlights&subcategory=Fishing+Lights&sku=800-1515-0&id=409
 

boat1010

Senior Chief Petty Officer
Joined
Mar 10, 2009
Messages
781
Re: Question about candle power

The short answer is, you cannot. Unless the manufacturer already has calculated both candlepower and watts, you're pretty much out of luck. You could try searching review sites in addition to the manufactures site, in hopes of finding the information already calculated.

Different light sources could have the same power requirements, but vastly different light output. They are just not directly related enough.

For example, searching Amazon.com I found descriptions of two different 12,000 candlepower flashlights. One was listed as 3 watt and another listed as 1 watt.

Not sure this will help but is what I got when I googled it..
 

polk county

Petty Officer 2nd Class
Joined
Jan 22, 2008
Messages
128
Re: Question about candle power

So if I buy a replacement bulb for a 250k cp light will that get me in the ball park? The submersible light boast low amp draw. Is that the nature of this bulb or did they do something to limit the amount of amps drawn?

thanks again
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: Question about candle power

CP doesn't relate directly to wattage, light output is somewhat dependent on efficiency. LED's are far more efficent than incandescent and so on.

However, by comparison, a typical hi power 12v hand held light rated at 1 million CP using an H4 lamp, consumes 50 watts. So theoretically, your 250k CP should be in the ball park of 12? watts.
 

EricKit

Petty Officer 3rd Class
Joined
Aug 31, 2009
Messages
81
Re: Question about candle power

A CP is a measure of light at a particular frequency in a particular direction. Specifically it is the Wattage of the light per Steradian (Which is a base angle like radians in 3D Space). So, it is measureing how much power (in the form of light) is being emitted in a given direction. Like many said before me, you cannot figure out how many watts the actual original bulb used to produce this effect.

Here is what I suggest:

Here is a site which will show you the maximum current for each wire. Going too big won't hurt you, but this table will show you how small you can go.

http://www.powerstream.com/Wire_Size.htm

Just pick out a 250,000 CP bulb, look at it's current draw (If it's DC you may need to calculate it with P=IV.). Then compare I, the current draw, to the guage of the wire. Also, make sure that your battery won't drain too fast with the current draw.
 
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