Why should you get amped up? Because there's a good chance you have more accessories drawing current from your truck's electrical system at idle than your stock alternator can keep up with. It seems as time continues to fly by that people are incorporating more power-hungry modern features into their old trucks than its stock electrical system was designed for and soon the alternator is taxed way beyond its output at idle, which for most stock alternators is around 40 amperes or amps. Running an aftermarket stereo with an external power amp at idle can leave the alternator in a 30-40 amp deficit alone, not to mention running air conditioning which can suck up another 20-23 amps. As a rule of thumb, an electric cooling fan zaps another amp per inch of fan diameter (double that at start up) and many systems use two fans, which could add up to another 30-40 amps!
On top of these items, does your truck have an air-ride, EFI, CDI ignition, electric fuel pump, fancy lighting, electric brake booster, power locks, power windows, door solenoids, electric wipers, or any number of other things needing power, as well? Many of you have nodded more than once to yourself while reading this, but may be thinking that you don't idle in your truck much-wrong!
Most of us that live in any sort of metropolitan area these days spend time sitting in heavy traffic, much to our chagrin. Those that live elsewhere are more than likely to travel where there is traffic- say, for a big show. And what do people like to do at most big shows besides park their trucks? Cruise the fairgrounds at idle! Regardless of whether we sit on the freeway or do parade laps at a show, a decent amount of idling will be happening while running the A/C, stereo, cooling fan(s), and more, because we don't want to be hot or bored in any traffic situation, right?
As we just learned, the current draw alone for these things will max out a stock alternator's amp output at idle and soon you'd be relying on your truck's battery to power the remainder until it dies. So what's the fix? Three words: high-amp alternator. A high-amp alternator will put out about the same max amps at speed as a stock unit, which is usually around 105 amps, but it will crank out 70 amps at idle. How do I know all this? I sure wasn't born with this knowledge or a very good grasp on all things electrical despite being the son of an electrician-sorry dad. I got a good lesson in alternator basics by calling the knowledgeable folks at Painless Performance and finding out firsthand.
See, it turns out that a stock alternator can be the weak link in the charging system, unless you have a bone stock truck with none of the aforementioned amenities, but as soon as you start adding them you'll be in murky water. There's nothing wrong with a stock alternator; it simply wasn't designed for the amount of current draw today's accessories require. An added bonus of upgrading to one of Painless Performance's Powerstar alternators is that it's a one-wire, internally regulated unit. This means there is literally one wire (the current output wire) to connect, which is already connected to the back of the stock three-wire alternator. You eliminate the external voltage regulator, simplifying wiring and under-hood clutter that much more.
No brainer, right? Right, and if I can get a grasp on this so can you. Nothing scares me more than cutting into a vehicle's stock wiring for fear of opening a can of worms, but installing the Painless Powerstar alternator couldn't be any easier-unless you had someone do it for you.
Here are all your high-amp...
Here are all your high-amp needs all wrapped up in one little package. Painless sells the Powerstar alternator in natural (shown), chrome, and black powdercoat in both V-belt and serpentine configurations.
The basic view here is common...
The basic view here is common for many of you: a stock, externally-regulated three-wire GM alternator. They work, there's no doubt about it, but they just can't keep up with the times. As soon as I put air conditioning and a stereo in my '72 C-10, the stock alternator could be easily pushed past its anemic 40 amps at idle output.