fuse placement

so i continue on my stereo install, and im about to run the power and ground for the wetsounds syn 6 amp. They recommend placing a fuse off of each battery within 18 inches of each battery, i want to however run my power wire off the perko switch to the amp, the perko is however not with in 18 inches. I tried to do some research but cant see any reason other than wetsounds instructions that it has to be so close. can anyone give me some info on this?

thanks alot,

Jeff

I'm assuming they recommend that because the possibility exists for the wire off the battery to turn red hot, melt, and potentially catch fire in a ground fault situation. If you have the fuse close the battery, this danger would only be for that short run between the battery and the fuse. The further away from the battery you get longer piece of wire can potentially melt.

Those inline fuses are pretty easy to install near the battery and still have your other fuses on the distro blocks for each amp etc.

so wetsounds recommends a 150 amp fuse just for the amp, so what size would i use on the power wire from the battery to the perko considering they power the rest of the boat as well?

Don't run it from the switch. Run the power AND ground from the battery, and put a 150A fuse close to the battery.

so i have two batteries, and if i do that, then i cant turn power off to the amp, correct? i was hoping to be able to control the power still.

The remote turn-on wire from the head unit to the amp turns the amp on and off.

You can always run straight from the battery and install a fuse and switch on that run. If you do, make sure the switch you choose is rated for the amps you might draw. I recently did an install and ran straight to the battery with a fuse. I think I'll go back and add a switch so it's easy to cut power to the amps.

Why would you do that? That's what the remote turn on is for!

John,

If you want any easy way to disconnect the 12V supply to the amp(s) replace the in-line fuse with a marine rated manual-reset circuit breaker. It will act as a switch, just like you want.

Jeff, it is my job to hijack your posts not vice versa. Hope the install is going well. I suggest you add wetsounds in the subject line so Tim will respond and give you his opinion. let me know if you have any trouble w/the Stargazer, I can help you out w/that.

Jeff-

If your starter is wired to your battery switch you do not want the fuse between the battery and the battery switch. The starter WILL blow the fuse at some point and it will leave you stranded.

The law for new boat production outline by the Coast Guard in CFR33 183.455 is a little vague, but the starter circuit is specifically exempt from the requirement of a fuse or circuit breaker. As a result, the battery switch can be interpreted as a simple switch in-line with the starter circuit, allowing NO breaker or fuse along that direct circuit path from the battery, through the switch, and to the starter.

So, if you are going to wire your amp power wire to the switch, put the fuse or breaker between the switch and the amp, as close to the switch as possible. Put another way, for the stereo installation, consider the switch as the positive battery terminal. Again, don't put the fuse between the battery switch and the battery or the starter and the rest of the entire boat will pull all its juice through that same fuse or breaker.

When you do your wiring in this manner, just remember that for any battery switch position, the stereo is running from the same battery as the starter. Be careful not to run both batteries out of juice or you will have to try to get a jumper start to get back in!

Hopefully that clears things up a little without me writing too long a book...

I also want to apologize for jumping in on a thread that maybe the Kicker guy is not the best one to answer; Tim from Wetsounds may want to recommend something different or add to my thoughts. I just felt it best to throw out my two cents; as a member of the ABYC and the NMMA I get to spend a lot of time reading and understanding the details of the laws that relate to new boat production; in particular as it relates to wiring and safety.

Hope that helps!

Phil
Kicker

i would re-think your setup imo.

you can still keep your battery switch.

run your syn6, HU and EQ if you have one directly off of of your second battery and put a 150A self testing circuit breaker close to the 2nd battery between it and your amp. problem solved. when you turn your manual switch to off (or trip your breaker) your HU and amp are OFF until you reset the breaker or change the switch although as mentioned, no need because that's what your remote wire is for. also if you run directly off your battery you bypass the ignition and you don't have to mess with turning to ACC on the key. this would give you the ability to use both batteries to crank should you need it in an emergency.

as Phil mentioned, not necessarily best practice to have your starting battery in the mix for your stereo. a battery seperator/combiner would be ideal. something like the surepower 1314 or the blue sea 7610.

oh and remember to NEVER switch pas "OFF" on the manual switch when the boat is running. it could damage your alternator.

thanks for all the info Phil and Bruce, Here's what i'm thinking now... im going to run the power and ground directly off the batteries to a distro block with fuses in each power wire- so basically "T" the two power wires off the batteries and bypass the Perko switch. My question is, since my perko switch is set up to run all systems off of either battery or both, when i select for instance battery 1, will it truly only being drawing from batt 1? or will the amp still take from both batteries is what I am assuming? So if i stop and listen to the stereo itll drain both batteries not one correct? Then i'm stuck with not being able to start the boat because im draining from both if they died right? Ill be isolating one battery from the perko, but since the power wire runs from both batteries the switch is basically useless. Now im thinking maybe i should tap the common post on the Perko again. gees this is making me nuts! Thanks again everyone.

Jeff

Jeff-

If you tie both batteries together the way you describe for the stereo, you are tying them together for the rest of the boat. If I read you correctly, you do not want to do this; in effect you are taking the battery switch out of the circuit, as both batteries are going to be always wired together in parallel. No matter what the battery switch position, anything drawing power will be drawing from both batteries, regardless of the switch position.

If you want to connect the amp to a battery, and not the switch, pick one battery, but do not "T" both batteries together.

Hopefully this makes sense???

Phil
Kicker

yes Phil, this makes sense, i really wanted to just run the power from the common post on the perko which would allow me to run the amp along with the rest of the boat by selecting bat 1, 2, or both, but i was discouraged from doing this in an earlier post, but dont know why. So i bought a distribution block to T both batteries, but if i do this, as u said the switch is now useless. So do you see a problem with running the power wire off the perko instead of the battery? The power wire for the rest of the boat going to the perko is at least 4 guage maybe 1/0. If you dont think i should do this, and i select one of the batteries, should i rewire stuff on the perko to separate because right now i can run everything on either battery. Thanks again.

Jeff

i'm confused. post up a crewd drawing.

here's what i want to do using power from the perko...

here's what I think ill do if I don't include the perko in the amp wiring...

Jeff-

My first post earlier with regards to your question was a little long-winded... Sorry..

It will be okay to pull your primary amp power wiring from the common post of the Perko switch. This is a common thing to do.

Just know there are proper procedures with regard to the Perko switch to make sure you do not blow voltage regulator diodes when switching between batteries while the engine is running. Short and sweet, you never want to click past OFF or at any other time lose contact with at least one battery while the motor is running. Take the time to find the Perko switch instructions and read them carefully.

For your second pic right above this, say you run the BAT2 totally dead with the stereo. You will have to switch to BAT1 to start the boat, then either switch to BOTH or to BAT2 to re-charge BAT2... You will have to make sure you do not flip the switch past OFF when doing this or you will cause damage. Most new battery switches are designed to MAKE-MAKE; i.e. when switching between BAT1 and BAT2, it briefly is connected to both. Some older switches do not have this feature, so you need to be careful. This is maybe the only downside to switches; the potential to do damage when you are unfamiliar with how they are supposed to be used...

Hopefully that clears up your question, and provides some additional information that is helpful?

Let us know...

Phil
Kicker

Thanks Phil, I appreciate your time to explain these things to me so i can understand them! I decided im going to run the power off the perko switch, allowing me to power everything including the stereo off either battery or both. I was at the marina today and im getting somewhere anyway! got the eq wired in, new headunit in, just gotta run this power wire for the amp and mount the tower speakers! Thanks again for the help everyone.

Jeff