Do I Need a High Amperage Alternator?
Alternators
How to size an alternator for a modern build, with a component-by-component current draw reference.
How Many Amps Do I Need?
One of the most common questions we get asked is "how large (amps) of an alternator do I need?" All stock vehicles will typically get by with small alternators in the range of 60 to 100 amps. As our industry has evolved over the years, very few vehicles can still be considered "stock". We have come a long way from needing to run a few lights and a radio. Air suspension, sound systems, air conditioning, electric fans, aftermarket ignitions and electric water pumps are just a handful of the upgrades common in today's builds.
Here at CVF Racing we provide a wide variety of alternator sizes that allow you to accommodate just what you are running in your vehicle. Standard on CVF alternators is 140 amp, and we now offer some at 160 amp. All of our Wraptor™ All Inclusive Serpentine Systems include one by default, so you have that much capacity before you have upgraded anything. If that is not enough for your build, a 300 amp alternator is available as an upgrade with all CVF Wraptors.
Component Current Draw Reference
To get a better idea of how many amps your vehicle and its components require, check the chart below for estimates on what each component can draw.
Note
These are estimates only. Always check with the manufacturer of each component.
| Component | Low End Draw | High End Draw |
|---|---|---|
| Air Conditioning | 20 | 21 |
| Air Suspension | 20 | 50 |
| Amplifiers (70 is average) | 10 | 250 |
| Back-Up Lights | 3 | 4 |
| Cigarette Lighter | 10 | 12 |
| CD/Radio with AMP | 7 | 14 |
| CD/Radio without AMP | 2.5 | 5 |
| Clock | - | .3 |
| Dash Panel Gauges | 1.5 | 3.5 |
| Defroster | 6 | 15 |
| Dome Light | 1 | 2 |
| Electric Fans | 6 | 15 |
| Electric Fuel Pump | 3 | 8 |
| Electric Water Pump | 5 | 15 |
| Headlight Dimmer | - | 2 |
| Low Beams | 8 | 10 |
| High Beams | 13 | 15 |
| Horn | 10 | 20 |
| Ignition | 1.5 | 36 |
| License Plate Light | 1.5 | 2 |
| Nitrous Solenoid | 5 | 8 |
| Parking Light | 1.5 | 2 |
| Power Antenna | 6 | 10 |
| Power Seats | 25 | 50 |
| Power Windows | 20 | 30 |
| Side Marker Light | 1.3 | 3 |
| Tail Light | 5 | 7 |
Watch it on video
How to size an alternator to what you are actually running.
What Alternator Do I Need? — CVF Racing on YouTube
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