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How To Fix Your Power Drain

Know the Hows and Whys

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Buy a Meter

You'll need an amp meter that can measure at least 0-10A DC to performthese tests. Most multimeters can do this, and you can spend as much oras little as you want to get one. We checked Harbor Freight and found anAC/DC meter made by Cen Tec that can measure up to 20 A of DC currentwith overload protection for $19.99. We also found a Wavetek for $169.95and a Fluke meter for $209 that does the same thing but has a lifetimewarranty. If we had to buy a new one, we'd go with as much meter as wecould afford--the new models have temperature probes and other goodies.The Fluke we used in this story was purchased in 1989 for $85 and itstill works great, so you get what you pay for.

Amp Hour vs. Reserve Capacity

Even though Amp-Hour (A.H) and Reserve Capacity (RC) are very similar inmathematics and general theory, they have subtle differences. For thepurpose of this article, we used A.H rating to show the rate a batterywill discharge with a small amp draw for a fixed period of time, likewhen your street machine is in storage. The RC rating is the number ofminutes a battery will last if your charging system fails while you'redriving your car. Temperature is a factor, but generally, the RC ratingassumes a 25-amp draw to run essential accessories and the A.H ratinggives you a formula to illustrate what would happen with a smaller ampdraw over a longer time period. Since RC is a more practicalapplication, it is more commonly seen as part of the battery rating.

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