1 wire or 3 wire alternator

[Jgard]

What are you guys running out there on your T buckets for an alternator and why would you recommend it? What amps would you recommend just running normal electric items electric tranny cooler fan, electric radiator fan etc.

[Bill Cleveland]

I'm using a 1 wire rated at 100 amps, with a horn, electric fan and electric fuel pump. No problems.



PS - Using Rick's chart below, I come up with 51.5 amps at maximum possible demand.

[Orville Duncan]

I agree a 100 amp one wire is plenty. Not many power hungry electrical things on a bucket.

[Indycars]

The Long Way To A Solution

First you need to add up all your loads and add them up to see what your total will be. To help
I have included a table with many of the loads included. Now these are only approximate and
especially the radiator fan seems low. I know mine is supposed to draw 30 amps at full speed,
it’s a 16 inch and has a rating of 2500 CFM.

The problem you might encounter is the alternator puts out the lowest amount of current (Amps)
when the loads are at their highest. Picture this ……Your radiator is barely keeping up, it’s at 210°F
and your thermostat is a 180°F, it’s night time and your light are on, your turning so your signal
are flashing and the brake lights are also on while you wait for the light to turn green. Besides that
you also have an electric fuel pump and the fan is running at full speed, full speed for 12v and not
full speed for 14.4v. Therefore the fan is running at a reduced speed and now the engine is starting
to overheat at 220°F and traffic won’t get out of your way. It’s 230°F now and climbing, what will
you do in this situation. If I had just put the bigger alternator on so my fan could run at its designed
full speed, maybe I wouldn’t be in this situation. Also my headlight wouldn’t get brighter every time
the engine RPM picked up either.

To keep from getting in the above situation, know your load and the output of your alternator at idle.
Use the graphs below and determine alternator output at idle. Note that the graphs are at the
alternator RPM, not the engine. The alternator turns 2.5-3.0 times faster than your engine. To know
exactly, measure the diameter or circumference of the crank pulley and divide that by the alternator
pulley. Multiply that number by the idle RPM.

This way is of course the long complicated way of doing this, or you can just buy good size alternator
and be done with it and hope for the best.

Below are some typical loads:

Delco_10SI_PerformanceCurve.png (76.46 KiB) Viewed 232 times

Delco_12SI_PerformanceCurve.png (81.94 KiB) Viewed 232 times

Delco_CS130D_PerformanceCurve.png (66.84 KiB) Viewed 232 times

Electrical_Loads.JPG (81.86 KiB) Viewed 232 times

Delco_CS144_PerformanceCurve.png (59.04 KiB) Viewed 232 times

Three wire alternators are a little better in my opinion, but if you don't have time they can be wired to
function just like a one wire alternator.

http://www.madelectrical.com/electrical ... wire.shtml

[isaltz]

very opinionated type ? but the facts are facts, depends on how many amps you need, i have a small chrome 50 amp alt and so far it works fine, i have heard the elect fan will take 30-40 amps. i have a manual fuel pump, manual water pump, no fuel injection, i have led gauges, so far so good, good luck, mine is working fine