Fusing The Input On The Orion 2500d

using Ohms law we see that 300amp @ 14.4 volts is 4,320 wattws of potental electical power

so the amp need to total of 300amp protection

Since Electrons flow equaly through 2 wires connected to the same source and terminated at the same point, you will need 150amp protection on each power cable

However make sure your using 3 fuses

I would runs a Single 1/0 ga wire back with a 300amp fuse close to the batter, then in the trunk use a distribution block to run 2 4awg power wires each with their own 150amp fuse AS CLOSE TO the amp as possible. then I would reverse the process to ground.

 

Exactly... I posted this over there too...

You will want something on the order of a 300a fuse up front (bear in mind that's just to protect the wiring itself, but if you go lower than that, this fuse potentially can pop before your amp's fuses during normal operation).

And if you are feeding that 1/0 into a distribution block, where you are going to have two short (as short as possible) 4 gauge wires coming off and feeding the amp's two power terminals...
Then you can install two 150a fuses - one per power wire - that's what is appropriate.
Installing two 300a fuses would be bad... effectively fusing the amp at 600a. Might as well not fuse it in that case. :lol:

On Michael's side note...
If Ohms Law shows that 300amps of current draw @ 14.4 volts is 4,320 watts of potental electical power...
And the amp is rated for 2500 watts of potential electrical output...
That would show the amp to be just under 60% efficient, if you trust those numbers.

I think I'd trust the 270a rating to be more accurate...
270a @ 14.4v = 3,888 watts of potential electrical power.
Which works out to a more flattering 65% efficient.

And that's interesting to take note of the amp's efficiency, but bear in mind the fusing consideration is a bit different...
They aren't concerned with the amp's current draw at 14.4v as much as they are the amp's current draw at 12v, or even 11.5v, because the amp would need to draw more current to make the same power.

Anyway...
Yes, two 150a fuses. One per wire.
I'm actually really surprised that the owners manual wouldn't clearly spell that out for you.. given the amp was obviously designed to take two 4 gauge inputs.

 

I am not at all surpirsed, DEI like most manufactuers want you to have their "professionals" Screw up errr install their products, not the consumer

as far as my Ohms law caculations, I was not getting in to effeciancy, the poster stated they recommened 300amps, I was merely showing him that it is easy to fiqure out what they ment by using ohms law, if they ment 600amps total (300 for each power supply) then that would be over 8500watts of potental power, so 300amps total is the logical awnser here

weather or not 300amps is excessive is not my call, I am not the manufactuer

and like you said, I am sure they increased the rating from 270 to 300 because of the voltage drop that can be expected with that much power on a stock system