Tutorial Measuring Current
In this tutorial we will show you how to properly test for current. Current is important to know how smoothly or bind free your car is running. Binding is the number one enemy of performance. If your car is binding you will lose power, your batteries will discharge faster, your motor will overheat sooner and FETs will fry quicker. Current load is the most important measurement you can make when building a car to be sure it runs as smooth as possible.

This tutorial is based on our Mini Meter Pro, which comes with Micro Plugs on the wires and the series harness needed to test amperage. This can be done with any MultiMeter with the ability to test amperage. However, if you don't have the Mini-Meter Pro, you will need to make your own series harness as shown here. This tutorial also assumes that your are using our Micro Plugs on everything.

Required Items


Mini Meter Pro
Any Battery or Power Source

Dial Setting and Lead Position


Turn the dial on the meter to the Current position. This is clockwise 7 clicks from the off position to where it reads "10A"

Plug the series harness in as shown and connect the series harness. You cannot plug it in wrong as it has no polarity.

Connecting the Series Harness


Now connect it to the car as shown. Again you do not need to worry about polarity, you cannot plug it in wrong.

Running the Test


Now pick the car up off the work surface and give it some throttle. You should get a reading on your current tester.

This is a very smooth car at a 2.04A draw.

Results Table


At this point you may find yourself wondering what your numbers should be. Below is a chart with AtomicBuilt cars and represent the best numbers you can get with these cars. A variation of .1-.2 should not alarm you as this could be merely the difference between one motor and the next. If your car is running at these numbers, you have a smooth running machine, but if not you are losing valuable power somewhere.

Atomic Built Car Serial Motor Pinion/Spur Drive Voltage Current(A)
Cosmo CS050 Stage 2 10/23 AWD 8.4 1.6
Cosmo CS052 Stage 2 8/25 AWD 8.4 1.1
Fission FS0151 Stage 2 8/25 2wd 8.4 1.0
Fission FS0154 Stage 2 8/24 2wd 8.4 0.9
Gamma GM0150 Stage 2 10/23 2wd 8.4 1.0
Gamma GM0152 Stage 2 8/25 2wd 8.4 0.7
Gamma GM0153 Stage 2 8/25 2wd 8.4 0.9
Modified AWD Team 008 T2 19/29 AWD 6 1.3
Modified AWD Team 010 Macho 19/29 AWD 6 1.0

Current - Important Warning!


Important!
Do not plug your meter directly into the battery pack while in the current position as this will short the battery pack.

Do not leave your meter in the amperage testing configuration because if you forget and plug it directly into a battery pack it will short the battery pack.

Notes:


We load test each and every car we work on as it is very telling. If the car is well assembled and running smooth, you will have good numbers. If something is too tight, binding, rubbing or assembled wrong, the numbers will be too high. This is the fastest way to determine the integrity and quality of a cars build and you should perform this test anytime you make a change to ensure you didn't degrade your performance.

Written & Edited by Robert Byrd