Aternator Wiring Question

BigDeal · Soul Rider Joined: 18 Oct 2003 Posts: 477 City: Orlando

I replaced my OEM alternator (52 amp) with an aftermarket alternator (110 amp) to aide in powering my sound system and other boat toys. I also replaced the main engine breaker (back of motor) with a new 135 amp Blue Sea breaker as well. Here's my question(s) to you guys that have doen this upgrade to your boat.

What re-wiring did you do to accomodate the larger amperage output of your new alternator? I was thinking about re-wiring from the output leg of my alternator to one side of my new main breaker, and then from the other side of the breaker on to the starter, with 4awg wire. I have 0/1awg wire running from my battery (+) to the starter and 2 awg wire on the gorund (-) side of the battery. Currently I have 10awg wire running in the locations I'm thinking about re-wiring. Although the 4 awg re-wire seems like a good idea, I'm concerned about the effect on the other wires (and electrical components) also wired onto the main breaker.

Any feedback on this issue would be greatly appreciated since I'm a little concerned that I am inadequately wired right now.

-Mike-

boarditup · Addict Joined: 01 Dec 2003 Posts: 731 City: Allendale, MI

Wire size is based upon demand, not supply in most cases. It think you are fine with the as long as the battery and main breaker wiring is sized for the demand. I usually size for 150% of max demand for most applications. Based upon what you said, I think you are fine unless you put on some tower lights or a big amp.

tryan · Soul Rider Joined: 06 Feb 2003 Posts: 257

if it is possible for your alt and breaker to carry a higher load, i would base the wire size on the breaker size, only.

if something shorts with the proper size wire, the breaker will trip and all is fine after the derfective circuit is removed.

if something shorts and the wire is not capable of handling the load before the breaker trips, you've burnt your wires and possibly the harness if you run your wires together.

IMHO.

BigDeal · Soul Rider Joined: 18 Oct 2003 Posts: 477 City: Orlando

Sound Illusions · Posted: Mar 15, 2004 8:33 am Post subject:

Hey Big Deal, Have you seeen my alternator page?http://svtsupercharged.com/gallery/alternator. If not check it out I think it answers your questions. Read the text below each photo it taks about your question's

I ran a 4 gage wire from the output of the new 165 amp HO Alternator to a 150 amp breaker and then another 4 gauge wire from the 150 breaker to the battery realy.

The fat red wire you see in the photo near the alternator is the New 4 gauge wire I ran from the alternator all the way up to the batterys in the front,

Styk33 · Posted: Mar 15, 2004 12:56 pm Post subject:

You need to remember that the wire size is dictated by the breaker/fuse size. Your breaker size is going to be based on the demand of your equipment.

Why run a 1/0 wire when your ground is only 2awg? Unless your run is extra long (like wrapping around your boat) for your power wire, you should have saved money and just put in the 2awg. The ground needs to be equally sized to the power for DC (as opposed to AC).

Sound Illusions · Posted: Mar 15, 2004 3:34 pm Post subject:

The alternator I have is a Self grounding unit so it grounds it self threw the motor, No need to run a ground wire. I agree with STYX33, the size of the wire is going to depend of the output of the Alternator The breaker and the Load you put on it. Example You might have a 300 Amp Alternator and a 300 Amp breaker but if you only have a 50 amp draw that does it really matter???

BigDeal · Soul Rider Joined: 18 Oct 2003 Posts: 477 City: Orlando

BigDeal · Soul Rider Joined: 18 Oct 2003 Posts: 477 City: Orlando