|
05-18-2012, 08:15 AM | #11 |
VIP Member
Join Date: Mar 2007
Posts: 2,329
Likes: 547
Liked 1,656 Times in 507 Posts
|
Re: gauge of wire for Alternator to battery?
If you put an ammeter on the wire you could tell what the alternator is actually putting out to the battery. I would say its no where near 140 amps. Size the wire on the actual load. Thats probably why the small wire has been working for you. Just remember the lower the voltage the higher the amperage is. Thats why the starter has such a large cable going to it.
__________________
Mike Pearson 2485 SS |
05-18-2012, 10:46 AM | #12 | |
Veteran Member
|
Re: gauge of wire for Alternator to battery?
Quote:
.
__________________
Jim Wahl....NHRA #2239 S/SS - IHRA # 8 Stock, D2 Stock Champion (forever I guess) 2019 Baby Gators Stock Champion 2009 D2 National Open Stock Champion 1981 D2 West Palm Beach LDRS SS Runner Up Past President, Southern Stock / Super Stock Association. |
|
05-18-2012, 01:12 PM | #13 |
Member
Join Date: Feb 2009
Posts: 244
Likes: 1
Liked 8 Times in 7 Posts
|
Re: gauge of wire for Alternator to battery?
I embarrassed to say this, but I've run 12 ga for years with no problems. I do intend to beef it up though. I run a fan, fuel pump, water pump, tail lights, Racepak, digital 6A and headlights.
|
05-18-2012, 01:46 PM | #14 |
Senior Member
Join Date: Mar 2006
Posts: 960
Likes: 631
Liked 167 Times in 61 Posts
|
Re: gauge of wire for Alternator to battery?
The battery capacity has a lot to do with the load induced on the alternator. Think of it as the battery being a bucket, the bigger the bucket the more capacity it has, and does not ask the alternator for any more amperage than is being used to maintain the battery charge. The voltage from the alternator is also higher than the load from the battery. The higher the voltage the smaller the wire needed. Look at the overhead power lines coming from your local power plant they are extremely small diameter due to the voltage they are carrying.
Sean
__________________
Sean Marconette 84 Mustang 5060 SS/N |
05-18-2012, 01:48 PM | #15 |
Senior Member
Join Date: Mar 2002
Location: usa
Posts: 751
Likes: 204
Liked 133 Times in 49 Posts
|
Re: gauge of wire for Alternator to battery?
I do harnessing for a construction equipment manufaturer. We run 6GA for all our alternator charge wires. And they are a much shorter run that to the back of a race car. And as some one already mentioned run an inline high amp fuse for protection.
|
05-18-2012, 03:14 PM | #16 |
Member
Join Date: Aug 2007
Posts: 152
Likes: 110
Liked 61 Times in 22 Posts
|
Re: gauge of wire for Alternator to battery?
If battery is fully charged(12.65 volts) then alt. will only put out amps to run all the race cars accy. requirements. Ign. system 10A, water pump 5A, fan 15A, lights 15A etc. These are approx. figures. An alt. is not intended to be a battery charger, just a device to maintain the elect. system during load. Therefore #10 Guage should be fine, most all autos from the 60's thru 80's had #10 off the alt stud. Just my thoughts on the subject,Tony.
|
05-18-2012, 04:09 PM | #17 |
Junior Member
Join Date: Aug 2008
Location: columbia TN
Posts: 88
Likes: 0
Liked 0 Times in 0 Posts
|
Re: gauge of wire for Alternator to battery?
You have to consider the lenght of the wire you are running when the battery (and kill switch) is in the trunk. Ask the guys at powermaster or East Coast.
|
05-18-2012, 07:08 PM | #18 |
Junior Member
Join Date: Dec 2009
Location: Winnipeg, MB
Posts: 88
Likes: 199
Liked 18 Times in 11 Posts
|
Re: gauge of wire for Alternator to battery?
Also keep in mind one wire alternators charge at full capacity (based on RPM) with no load sensing.
|
05-20-2012, 03:50 PM | #19 |
Member
Join Date: Feb 2009
Posts: 244
Likes: 1
Liked 8 Times in 7 Posts
|
Re: gauge of wire for Alternator to battery?
I'm confused. If a 100 amp one wire charges at full capacity based on rpm, does that mean it's putting 100 amps through the charging wire @ 7,000?
|
05-20-2012, 08:47 PM | #20 |
Senior Member
Join Date: Sep 2007
Posts: 574
Likes: 6
Liked 44 Times in 22 Posts
|
Re: gauge of wire for Alternator to battery?
The 100 amp alternators in some stock Mopars about 30 years ago used 6 gauge wire and it wasn't real long--between 3' and 6' I guess. If you will only be using 30 amps, why have a 140 amp alternator? The point of using heavy enough wire is that the alternator can run up to its capacity when needed.
|
|
|