i had to replace the factory engine-chasis. that thing was toast. I ran a new battery-chasis and left the factory one too. I still need to do the power but I have to get more wire first. I figured it would be best to do the grounds first.

 

agreed, i always do grounds first. power is a bit more tricky because you also want to fuse that wire, at the battery. getting good strain relief is also tricky.

 

if i am running the factory alternator, a 150 amp fuse should be god, huh?

 

size fuse for the wire. if you run 4awg, 100A-125A

recognize that there are parallel paths for current with the big 3, you have the factory wire and the new wire. the benefit is a reduction in resistance which yields a reduction in voltage drop - which is our goal.

 

alright. the only thing i was thinking if the alt is 130A I guess I wouldnt blow it using a 100A because of the stock run plus my new one?

 

right, a 130A alt will split current between the two wires (not equally since resistance won't be equal). probably 60/40. so the new wire and fuse will see something like 80A at peak alt output.

I can tell you that my 100A alt positive fuse has never blown.

 

I am looking to upgrade the factory sound system and since this is my first time ever, i have been looking through tons of forums and this one seems to have the most educated people that aren't bickering back and forth as to whether an alt is better than a cap. anyways, i am looking to put in a JL Audio HD900/5 5 way amp that is 100WX4 + 500Wx1 at 4ohm. i will be adding a JL audio stealthbox with a 600W rms 10" sub and Alpine SDR-60C front component speakers 110w rms and SDR-60 100W rms speakers. As of now everything in the car is stock, however i don't want to upgrade the entire sound system just to have it not work. Will upgrading the electrical wiring to a 4AWG for the big 3 be enough to handle the system or should i look to budget in a new H.O. alternator and new battery. If i will be replacing those i have seen ones that are in the 140A range for H.O. factory alt is 80A, will that be enough. any suggestions or guidance will be greatly appreciated, and i will have everything professionally installed just need to get an idea of what all im in for. Thanks for the help.

 

i had the same concerns as the poster above me. i know the big 3 is supposed to help with how much resistance there is and that you should always do the big 3 before a HO alt switch. i have 2 12" L7's and a kicker zx1500.1 mono amp ( already looking to buy a new amp) and the amp booklets says you should have an alt of at least 140 ampere. what i was wondering was even if i did the wiring for the big 3, would it matter since my stock 2002 accords alt doesnt measure up? also i was wondering hows the McGowan alt you bought?

 

sorry for the delay.

the big 3 should be looked at the same as running power and wire amp ground wire. when you add load to the factory system, you need to upgrade all wiring associated with current draw - including the big 3.

do it first, every time you install an amp.

how much current you actually draw varies based on music choice, volume level, amp gain setting, impedance load, etc. you may have a 1500W amp but only use 300W 98% of the time.

you need a voltmeter that is visible from the drivers seat in order to determine if you need an H.O. alt. of course, the ELD is also working against you and that sticky is equally important for us Honda owners.

My McGowan alt is doing great. no complaints. The output at idle is sometimes less than my draw at full tilt with accessories on. i can increase RPM or turn it down. spending 2x on an Irragi or Ohio Generator alternator would have given me more output at idle. i do not recommend using a smaller pulley. I have my stock alt also, and a local shop can rewind it for me. I'll have that done at a future date so I have a H.O. backup ready.

 

so how would i determine what size wire i would need for the big 3? i just hope its not above 4 gauge lol. and could you also elaborate on my amp maybe only using 300w most of the time, i remember coming across that on another site but no one really discussed why.

i did read the sticky about the ELD problem and did get the gist of it but some of the technicalities made my head spin haha. if i dont do something about the ELD will it be bad in anyway or is it more an annoyance of having to turn on the A/C to get my voltage back up?

do you mind if i get some info on the other alts you were looking at like maybe the irragi one? i want to compare to the DC alt i was considering on buying since their in the same price range. i saw something on another site about getting the stock alt re-spun and strengthened instead of a HO alt. switch, any thoughts on that?

thanks for the feedback btw!