Helping a buddy w/ his ride today. He's in a wheelchair right now so I'm trying to be helpful as possible. It's a glass 32- kinda streetroddy, but very cool anyway. Plus- he' cool as shit & has helped me in past. Installed a 100 amp 1 wire & I can't find my chart on computer for wire size to alternator. Wire runs from starter batt terminal to back of alternator. Probably 5 ft long. I have 10 ga & 8 ga in my garage. I need to pick up terminals in AM & fire up the car tomorrow night. Any help?
I always go "up " in wire size--so I'd go with the 8 gauge over the 10 gauge.The 1 wire alternator tend to "excite " better with less resistance--so bigger wire means less of a work-out nfor the alternator.
according to a google search a general rule is 70-75 amps for 8 gauge wire, 100 amps for 6 gauge. but those are likely pretty conservative ratings
Thanks guys. Well- I gotta buy ends anyway so I'll pick up the 6 gauge. I doub't he will be even close to 100 amps. No a/c, no power windows, small stereo. But..... maybe someday.
100 amp? How big is the RV? Do your friend another favor. Read this site before you go one step farther with that tractor alternator: http://www.madelectrical.com/index.shtml Thanks again madelectrical !!
Here's a handy chart for wire gauge size to current handling capability. Better too big than too small! http://omentrance.com/resources/wirechart.html
i been using #10 for awhile,wire never got warm and no problems.but i'm talking no ac,or alot of accessories.
From an electrician's point of view and from the National Electrical Code,#10 wire is rated for a continious 30 amps at around 180 degrees depending on the type of wire insulation.Short lengths will handle a lot more amps for brief periods.However, building codes to not apply to vehicles. Most later GM vehicles use a #10 wire for the alternators in the 75 amp range.Car engineers always try to save a penny so they are gambling the alternator will only put out high cirrent for short periods of time. A number 8 wire is more than adequate.And don't be afraid to fuse that alternator wire to protect the equipment and wiring in case of a short circuit.The fuse should be in excess of the alternator draw to prevent nuisance fuse blowing,like an 80 amp fuse for a 60 amp generator or alternator.
One thing to keep in mind is that the bigger alternator will deliver more fault current. Which can add up to excessive component damage in some cases. Is the car a typical thin fender/highboy without many accessories? A 65 amp alternator will be more than enough.
I ran a 10-ga wire from the alternator to the MaxiFuse; but then ran an 8-ga from there to the starter. It works well.
I've read it before. Most of that (IMO mind ya)- relates to muscle cars & stock wiring w/ long runs & running a gen or idiot light & installing a 1 wire bigger alternator on too small wiring. This is not a long run. Battery is in trunk w/ a 2/0 weld cable from battery to starter (w/ remote solonoid) I will run probably less than 5 foot of 6 ga from start solonoid to alternator. His car is newly wired w/ a Ron Francis kit (by me). Mark at Mad Electrical sells alternator wiring kits. He also sells Gen light kits. Despite what his article says- even though he doesn't sell alternators- it's skewed towards the 3 wire & poo poos 1 wires (except Powerhouse ). So what if it doesn't excite at idle? I don't start cars & drive- keeping the RPM under 1000 rpm anyway. Who does? 1st time you raise RPM- it excites & charges. All mine do. My 55 has a 1 wire & Ron Francis wiring. My 32 has the same thing. Never an issue- ever. Now my friend has a 1 wire & wants my help, so I'm going to help out. BTW- even if it was a 100 amp 3 wire- it still would need a 6 gauge wire to batt terminal- wouldn't it? Not trying to start an arguement on 1 wire vs 3 wire but read the article again & pretend you don't have 50 year old wiring, or are swapping out a 3 wire 40 amp to a 100 amp 1 wire & making no wire changes, or aren't installing it on a muscle car w/ long runs or aren't swapping from a gen to a 100 amp alternator w/ no other changes. It' not my car anyway so if he wants to run a 1 wire- all I'm interested in is the power supply big enough so I don't burn down his car.
Yes, a 3 wire alternator would need just as big a battery cable as a single wire. 6 AWG will be plenty for as short a run as you're talking about (and it sounds like you got things pretty under control, considering you ran 00 back to the battery) I'm with you on the 1 wire excitation... Not exactly a big deal... Hell, my Galaxie doesn't have a choke, it has to go over 1000 RPM every time I start it. IMO the biggest benefit of a 3-wire simply boils down to cost. You don't have to replace the whole damn thing if the voltage regulator gives up the goat, or vice versa. Sounds like, even though they don't SELL alternators, they are friends with someone that DOES. Because my ignition system needs max power at idle, and what 3rd world country are they livin' in where you can't find a replacement single wire one at any parts store ... As far as not being able to run a idiot light? 50 cents worth parts can take care of that... Although I do use a 3-wire, but I also have a mountain of 'em in the basement with a mountain of VR's to match.
IMO, a #1 gage wire is best for in the trunk batteries. Having said that, my pal just put his 46 Ford sedan battery in the trunk and hooked it up with #6 fine stranded cable. It spins over ok and the engine lights right off (mildly cammed, 600 cfm Edelbrock carb, 302 Ford) but someday his battery is gonna be a little low and it won't start. My big ol Buick engine fires on a touch of the key most times. Attributable to #1 battery cable and a well-grounded system - to frame in three places and engine with a dedicated ground cable. Battery is under the body and just in front of the rear axle in my 32.
depends on the distance between the alt, and the battery, voltage, and amperage. 12 volt, 100 amp under 10 ft 6 GA stranded wire 20 ft 4 GA stranded wire over 20 ft 2 GA stranded wire if it's a trunk mount battery you can run a 6 GA wire to the starter solenoid battery side, and a 2 GA wire from the solenoid back to the trunk with no problems.
Guys, He mentioned he had the battery in the trunk wired with double aught... That's about the size of a garden hose, if it ain't enough, there are PROBLEMS, that's serious overkill! (Don't get me wrong AT ALL. When it comes to wire size, overkill is great! And I'm not bein' a wiseass, it IS about the size of a garden hose) Some serious stuff for sure, he just needed to make the short jump from the solenoid to the alternator. For what it's worth, I have all 4 AWG cables and the damn starter cranks so hard it'll rock the car back and forth, but I have a stock mounted battery.
I used 4 gauge cable on my 1 wire, i went to the stereo shop, cost about $10 and they crimped it for me. L
Yeah, it takes quite a crimper to do big gauges.... Startin' to look like bolt cutters. Another way, if you don't have access to a crimper (or feel like going to the effort of getting in a car and driving there) is that on these big cables, you can actually sweat the lugs on, essentially just like sweating copper pipe fittings. I am one of those that falls in the "too lazy to go get it crimped" club, I've used the solder method several times.
I bought 2 rolls of 2-0 weld cable years ago from a shop going out of business. That's alot of cable! So- every car I touch gets overkill cables. It has more strands & more flexible than your auto parts variety. I'd rather have to much cable than not enough. A friend of mine w/ a 55 had me wire his car & trunk mount the battery years ago. He bought some kit for the battery that included the cable. Fine for the time but over the years w/ upgrades (a/c, power everything, big stereo)- we wound up upgrading the cable. I'd rather do it once & be done with it. Just got back- finished wiring the alternator- 12.2v at idle, 1200 RPM & we had 14v+ Drove it down, gassed it up & all is good in street rod land.
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