Can you recommend a fuse for my homemade flounder light?

[scrampbell]

I've got a theoretically water tight flounder light that I made. Although the plans I used don't include one, I'm thinking that putting in a simple fuse would be the prudent thing to do.

Can anybody tell me what kind of fuse I need? The light is 55 watts I believe and it's running off of a single marine battery (12V DC). If anybody knows of a good basic primer on how to calculate what size fuse I need, that would be great too!

I am also running a trolling motor off of the same battery, is it necessary to put a fuse on the trolling motor circuit too?

Thanks!

 

[Silvertip]

Re: Can you recommend a fuse for my homemade flounder light?

Determining fuse value is not a complex problem.
The formula P (watts) = E (volts) x I (current/amps).
Therefore 55watts divided by 12.6 volts = 4.36 amps.
Since the light will probably draw slightly more current than 4.36 amps when initially turned on, I would suggest you use a 7.5 amp fuse.

 

[Chris1956]

Re: Can you recommend a fuse for my homemade flounder light?

A 5amp fuse at 12Volts fuse will handle 60 watts (12VDC * 5A=60W). real simple stuff...one you know the formula

 

[Silvertip]

Re: Can you recommend a fuse for my homemade flounder light?

Guess we were typing at the same time. Forgot to comment on the trolling motor though. Yes - you need a circuit breaker or fuse on the trolling motor. Same principle applies but you need to know the maximum current draw of your trolling motor. You know the voltage is 12.6 so you need wattage or current (amps) to calculate breaker size. Most end up using a 40 - 50 Amp depending on motor size.