fuses keep blowing why?

[SUNB15]

I originally had two circuits hooked up to the single battery on my 15 ft boat. One was the OB motor and the other accessories such as lights etc. I added a few more things and ran the wires (14g) right from the accessory to the battery (cig lighter, compass, fish finder). These are all on separate circuits running to the + and - of the battery, I didnt want to combine anything on one wire before it reached the batt. They are all fused as recommended. When everything was hooked up (motor, original circuit, and the 4 or so new ones) to the batt first the cig lighter fuse 15A blew so I put in 25A thats fine now. Then I tried and everything worked including the OB for a while so Im sure the wires arent reversed anywhere. But right now neither the motor nor the original accessories circuit will work, I suspect its a fuse in the latter which I think also controls the OB through the ignition. Can anyone make some sense of this and tell me what steps to follow to figure out whats wrong? (I guess the first one would be to disconnect all the new circuits change the fuses and see what happens but then what?)<br /><br />Thanks<br />J

 

[cp]

Re: fuses keep blowing why?

When the cigarette lighter fuse blew, was the lighter in use? 25 amps seems like way too much for a lighter. Have you measured the voltage at your battery since nothing worked? Just my 2¢ but maybe the lighter circuit has a short in it that blew the 15 amp fuse and has now drained your battery. Check battery voltage, if low - disconnect lighter circuit, recharge battery and if everything works again, re-do the lighter circuit very carefully checking for shorts. Good luck, let us know how you make out.

 

[tailfin10]

Re: fuses keep blowing why?

Disconnect all circuits,re-connect each individual circuit one at a time and operate the device on that circuit multiple times. If you installed an in-line fuse in the circuit and its <br />a standard agc glass type , buy a variety of <br /> say 2-5-10-15 and 20 amp. Use a fuse that has<br /> an amp rateing approx. 35% higher then the actual devices usage, this will give you the best protection from fire and help protect the<br />device , fuse electronics as closely as possible.<br /> If each circuit works independently their is<br />no reason why they should not work together if as you say they are on their own circuit.

 

[SUNB15]

Re: fuses keep blowing why?

Thanks for the tip, I tightened the connections on the battery since there are so many loop connectors at that end and everything seems to be ok now. Still not sure why the cig lighter fuse blew, someone told me not to fuse it at all but I did a 25A, blew with a 15A, is 25 ok? It didnt come with any instructions.

 

[cmyers_uk]

Re: fuses keep blowing why?

someone told me not to fuse it at all but I did a 25A

Hes one of the guys you read about in the Darwin Awards!<br /><br />The fuses are there to protect the device and stop excessive current melting your wires and causing a fire. <br /><br />The solution to a blowing fuse is to find out whats causing the problem not put a larger fuse in it. <br /><br />As an example my blower fuse blew, I had a look at the blower and a crisp packet had jamed the fan. Removed the crisp packet no problem. If I had put a bigger fuse in, the motor could have been damaged, the wiring melted etc. <br /><br />You need to find out the correct rating for your cigarette lighter and stick to that fuse.<br /><br />Good luck,

 

[SUNB15]

Re: fuses keep blowing why?

There are no problems with the wiring and its a brand new lighter but Ill try to find out the rating, thanks

 

[cp]

Re: fuses keep blowing why?

When the cigarette lighter fuse blew, was the lighter in use? If the original 15A fuse blew without the lighter being in use, that's an indication of a short somewhere in that circuit. If you're sure you've checked the circuit out after the fuse blew and all is good then maybe, just maybe, you had a momentary short from doing all the work in there. (American Cancer Society trying to keep you from puffing ?) Does the lighter now heat up without blowing fuses?<br /><br />BTW, my vehicles have used an 8A fuse, for just the lighter itself, up to a 20A fuse, for a circuit with the lighter and radio and some relays. If you have a multimeter, measure the resistance of the lighter heating element then divide 14.2 volts by that resistance and that should give you the maximum amps the lighter should draw. Use a fuse about 10% higher and you should be OK. Make sure you've used a gauge wire size that can handle that current.<br /><br />Good job getting the wiring done and finding the bad connection at the battery. Now just have to make sure nothing's been overlooked so you can have a worry-free time on the water . Good luck.