fuse size for running two digital mono amps

How big of a fuse do I need if I plan on running two mono block amps
with a fuse of 150amps each and a single four channel amp with a 60
amp fuse? Will I need to get a 360amp fuse or can I go with just a
300 amp fuse? Need to know quickly.

Also, I wanna run an extra battery in my car, how can I do that?  Do I need to run 0 guage wire from my main battery to the extra battery or is it more complicated than that ?

Thanks
Pervy

First, the fuse near the battery is protecting the wire, not your amps. The amps have internal fuses for that. That said, you can't just add up the fuses on the amps. What we need to know is how much power they will be drawing (how big the amps are, rated wattage). Assuming you're running three big amps (150 amp fuses better be on big amps) I would guess you'll need 1 or 0 gauge power wire or bigger. I would suggest a 0 myself. With a 0 gauge wire, a 325 amp fuse should be fine. With 1 gauge, 250 amps is good. Assuming you're running 2 800 watt mono amps and a 500 watt 4 ch (2100 watts), you could run on 1 gauge with a 250 amp fuse probably. If you get over about 2100 watts, I'd run 0 gauge with a 325 amp fuse or smaller. (It is always safe to use a smaller amperage fuse - it just might blow more often). Remeber to use a fused distro block or fuse each wire right after the block when you split to each amp.

As to another battery...If you wanted to just use it so you would have a greater power reserve while the car was running, you could just wire it in parallel with the current battery. But if you want to use it to power your system when the car is off, you need to isolate it from your starting battery so both aren't drained. There are two ways to do this: Diode and solonoid. A Diode isolator is very simple and reasonably easy to install. They usually come with good instructions for installing them, and are always working (you can't forget to hit a switch and kill both batteries) Solonoid isolators are a bit more complicated and less trustworthy, and are usually actuated by switch. A diode isolator would be the best way to add a second battery in your situation most likely. You can find them at many car parts stores (schucks) and RV stores and audio sales places. All you have to do is make sure you use a diode rated high enough to handle all the power you'll pull through it.

Hope I helped some - come back for any more questions.

/NyxBass

Thanks for the information. Just to let ya know, I'll be running two MTX Thunder1000D to two 15L7s at 2ohms per sub, so that alone is about 3000 watts. And I'll also be running a MTX Thunder4244 4 channel amp, so all in all I'll be running anywhere from 1500( that's if I run the sub at 4ohms instead of 2) or 3500 watts of continious power. So knowing that, do you think I should go with the 325 amp fuse at the battery or do you think that a 250  will do? Also for the battery part do I run 0 gauge from my main battery to the Diode isolator then from the isolator to the second battery? Also, just to be sure, will I need to ground the second battery? Hey it doesn't hurt to ask these question. Better to ask now, rather than pay for it later.

Thanks

Pervy

Sounds like you're going to have a kicking system! Here's what I'd suggest: Min. 0 Ga. wire from battery with a 325 amp fuse. That way, if you do kick it into high output (2 ohm) setup, you'll have the power you need. Better to spend a little bit more on the good stuff now than ripping all of it out and replacing it when you want to upgrade. For the battery side: Consider why you want an extra battery. An extra battery is good for running the system with the car off, so you can still drain a battery and start it later. It's god for competing, or running your system at the park or whatever. It isn't going to give you a whole lot of extra reserve while the car is running. If you find that you are experiencing dimming headlights or a draining battery while driving, it is your alternator that needs upgrading.

Also - with a system this big, I would definitely consider 1 or more stiffening caps. They are like small batteries that can release their power exceptionally fast - like as in microseconds. They are only really needed on subs and low end, and they let the subs have all the power they need for that split second to make it kick.

If you do think the extra battery is for you, you would want O Ga. from the alternator to the Isolator, and from the isolator to the main battery + and to the Secondary batt. + . The second battery should get a well connected, short ground (w/ oGa. ) to frame or body. The isolator may also be grounded and or have a fourth terminal for current flow control. It should have good instructions on how to install it.

Hope that helps. As always, come back here for more questions.

/NyxBass