Fuse sizing for amps.

[Paxdad]

I am in the process of upgrading my power supply wire from the Perko switch to my amps and want to make sure the fuse I use is adequately sized for the amps I have. They are:
Tower= Arc Audio 600.2
In boat= Arc Audio XDi805
I was going to use a 60 amp AWG fuse and holder and locate it about 8 inches away from the Perko switch and then run 1 gauge to the distribution block under the observer seat. I currently have a 30 amp Maxi fuse which has been fine. Is the 60 amp AWG fuse too much?

I think I just answered my own question.... The 600.2 has a max amp draw of 130 amps and the 805 draws a max of 90 so it looks like I will need a fuse somewhere in the 225 amp range of the ANL type. Let me know if this is incorrect.

[core-rider]

I personally look at the on-board fuses to the amp and size based off that. If the amp has 3 - 30 amp fuses I will try to use as close to that as possible, say 100 amp fuse for example.

The other item I noticed in your post was you plan on mounting the fuses 8" from the Perko switch. How close is that to your battery bank? The fuses need to be within 18" of the power source. If the Perko is 24" from the batteries and you mount another 8" past it, this puts it 32" away from your power source.

I personally have a fuse that is properly sized for the load of all my stereo capacity near the battery bank that runs through a 1/0 cable to a fused distribution block that is fused for each load on those 4 different circuits (3 amps - 1 lower load distribution block for random stuff). Each of those amp circuit I sized the fuse by looking at the amp fuses.

You can see the fused distribution block in this pic at the top left. The 1/0 cables come from the left but weren't installed at the time of this pic. These fuses protect the wiring from the distribution block to the amps.


My main fuse you can see in this pic after a shut off switch for safety IF something goes bad. This fuse protects the 1/0 cable from the battery bank to the distribution block

[MLA]

So theres a 30A fuse currently carrying the load of these two amps? That says alot about their efficiency. I see no need to step up to a 225 range, but, I would want a little more headroom then 30A. Given the amps, distance and 1/0 cable, I would likely use a 150A as my main trunk line protection. Having this main circuit protection right off the main battery switch is perfectly acceptable. The fuse's job is to protect the line between the fuse and the amps.

[Paxdad]

Core,
Thanks for the photos. Mine will be wired much like yours but my supply will originate off the Perko switch. You are correct and thanks for catching that fuse location in relation to the battery. I will have the fuse somewhere very near the battery supply.

[core-rider]

Core,
Thanks for the photos. Mine will be wired much like yours but my supply will originate off the Perko switch. You are correct and thanks for catching that fuse location in relation to the battery. I will have the fuse somewhere very near the battery supply.

No problem... I actually have a Perko on the other side of the boat next to the 3rd battery (starting battery). It switches between 1 (starting battery), 2 (house bateries), and All (all 3 batteries combined). I only run the boat on the starting battery while the house batteries stay isolated to power just stereo. If I ever lost the starting battery I could switch over to the house side to get back home. This way the alternator doesn't have to deal with heavily depleted house batteries after a long day. They all 3 get charged/maintained at home via on-board charger.

[Paxdad]

MLA,
Thanks for the input and recommendation.

[MLA]

Unless you are going to have a complete stand-alone battery bank or something like a diode isolator, I recommend wiring the amp's trunk line to the common output of the main switch, rather then battery direct. In this manor, the audio will draw from which ever battery you have the switch set to, and that same bank will also receive a charge from the alternator while the engine is running. In this case, the main circuit protection would be post switch.

I would not go battery direct, unless there is an isolator as part of the system. In that case, yes, the circuit protection would be post battery.

[Paxdad]

MLA,
That is exactly how I intend to wire it and expect/ recall it is wired that way now. I am really only upgrading the main trunk line from the Perko switch to the amps and adding a distribution block at the trunk line + amp end. I will then run 4 ga wire from the distribution block to each amp +. I am also upgrading ground - wire in similar fashion but it will be connected to the port side battery negative post. Again this is the way I have it wired at present and works out great, allowing me to shut the entire system off at the Perko switch when in storage. The only problem I ran into was when I was bench fitting the fuse holder it was not sized to allow for 1 AWG wire I am using. Therefore, I need to find a fuse holder that will accommodate the 1 AWG wire. If you have any recommendations please let me know as I was just searching around on eBay and Amazon. If I understand you correctly it is ok to place the 150+ amp fuse/ holder on the trunk line just past the Perko switch leading to the distribution block I am installing?

[Paxdad]

I was thinking this may be the best approach instead of the fuse holder. Thoughts?

[MLA]

Yes, trunk line to the common post of the switch with circuit protection just after switch. Im all for breakers, but that one looks a little on the cheap side.

[Tallredrider]

Unless you are going to have a complete stand-alone battery bank or something like a diode isolator, I recommend wiring the amp's trunk line to the common output of the main switch, rather then battery direct. In this manor, the audio will draw from which ever battery you have the switch set to, and that same bank will also receive a charge from the alternator while the engine is running. In this case, the main circuit protection would be post switch.

I would not go battery direct, unless there is an isolator as part of the system. In that case, yes, the circuit protection would be post battery.

Mike,
I am in the process of getting my G up to snuff. I was going to go direct to the battery with a circuit breaker like was mentioned above. And an onboard charger to be able to keep the batteries fully charged.

When would you recommend going straight to the battery? I am not sure what the Perko switch on my boat is rated for, but I see the bigger ones rated to 250-300 amps continuous draw. Anyone know what the rated amp draw for my Perko switch is? I am planning on about 3200 Watts total....so in theory that could be about 230-250 amps when playing full tilt.

[MLA]

TRR,

IIRC its the Blue Sea 6007 mini. Its rated at 300A continuous. Should not be an issue issue for the switch, but check the cable gauge based on the added current of the system. The switch is about 10ft from the batteries and IIRC, its 2ga.

Have you got the amps and their perspective loads worked out yet?