I am wanting to install a high output (300 amp) alternator in my 94 2.3l Mazda B2300. From the pics it looks pretty similar to the stock one. Its on ebay, the guy had 29,000 reviews with 100% positive feedback so I thought I would give it a chance. I currently have a 1k amp hooked up but have plans to get something in the 3k-5k range in the coming months and would like to start getting my electrical set up.

My issue is, it has that small positive post on the back. I am wanting to run 2/0 from it to my batter and assume the wire lug wont fit and I don't want to short out on the case. I saw an old tutorial or two on here but the pics were gone. Is there a typical way people install these or do the 'big 3' on this alternator? I didn't know if trimming the lug is a viable option or is there is some sort of extension, 90 degree attachment, or distribution block that could attach or maybe run something smaller on the short run to my fuse? How small would be safe for 300a assuming it was just 6 inches or so?

Maybe I'm overthinking it but would like to have my ducks in a row before ordering the alt. Also, would I need any kind of separate voltage regulator or any other issues with adding an h.o. alternator. I'm pretty sure I will need a smaller serpentine belt but nothing else comes to mind other than running the 2/0 power line and grounds.

 

To this terminal ?

Most major cities have "Battery Stores" that sell nothing but batteries, wiring and connectors, they should have a ring terminal that will fit your 2/0 wire and that stud.


Also, don't forget you will also need to run the same size ground wire from the engine block to the battery.

at 300 amps, 2/0 wire is good for 10 feet, any longer you'll need heavier wire.

 

That is good to know. Time to break out the yellow pages (well more like Bing or Google) and track some ring terminals down. This is my first time doing a big wiring/alt overhaul and I usually enjoy not being on fire so have been trying to get my ducks in a row before starting. Thanks for the reply

 

300amp alternator, gotta ask WHY??

And you know it will only have 150amp, maybe, at idle, engine needs to be at 1,800+ RPMs to get full amps
And its not good for instant amps, like for music systems, or winches, lights are OK
Second batteries are best for instant power, they have the amps "on hand", alternators have to create the amps "on demand", so they have a delay as they try to ramp up amp output

 

My current alternator has been a bit weak even before I put the 1k amplifier in so it is going to need to be replaced soon. The stock is 95a. The amplifier has 120a in fuses by itself and voltage drop is already an issue. I was going to get a 200a alternator for the time being but can get the 300a for $50 more. I am going to set up a second battery and probably replace the current one at the same time. I have been looking at AGM batteries but haven't decided what route I'm going yet.

I plan on either doing a speaker wall with the extended cab area or setting up a blowthrough. I'm working on box designs now to see. Either way I am looking at a 3k or 5k(possibly bigger but I doubt it) amp plus a small one for the components in the front. If I am rewiring the whole thing I figured I may as well get a solid electrical setup so I don't have to redo it later. 300a is overkill at the moment but I plan to have the new speakers setup within the next 6-8 months so I guess it's just prep work.

 

1000watt amp at full output should run 120amps, so 300amp alternator at idle RPMs should be just enough, so not overkill
As said alternator ratings are 50% at idle, so 300amp is 150amp at idle, most vehicles will use 40amps with all lights on, which is why stock alternators are 80-100amps, so they have enough amps at idle, 40-50amps
So with 1,000watt amp and vehicle load you are at 160amps needed at idle, so not overkill

You are probably running or wanting bass or subwoofer speakers, you will need capacitors for those, if self powered, or for the amplifier running them
Larger diameter speakers need more amps to move the cone when those "big" bass frequencies "hit", if engine is running so system voltage is at 13.5-14.0 volts a battery can not make up those amps, because a battery is at 12.8volt max
The voltage regulator in the alternator can not respond fast enough to the amp spike from the bass speaker(s) so there is an overall voltage drop across the whole system

Capacitors are like "temp batteries", if voltage is at 14volts then they store amps at 14v, if there is a high amp draw(spike) the voltage will drop instantly to 13.8v and capacitor will release some amps to keep it at 14v, so there is never a voltage drop, its all instant
The size and number of capacitors you use depends on the needed "stored amps" to keep your system at a steady voltage

A capacitor is like an automatic voltage regulator, but in real time, no delay