This nifty Y harness invented and available exclusively at Radical RC is handy to use for loaded voltage and current testing of your radio system. Here is what it can help you do: 1. Use in conjunction with an amp meter to test current to any one servo or between the battery pack and the entire system. 2. Use a combo of your amp meter and ESV to see how far your battery voltage is depressing at a given load. 3. Use in combination with our ESV to see what your voltage is while your system switch is on. A jumper plug is used to complete the connection when your doing volt only and no amp tests. Regular hobby battery test and charge cords (you probably already own) can be used to interact with this Y harness.
Here is how is how to use me:
To measure current. First set your meter to measure amps and set it one setting higher than you expect to measure so as not to damage your meter. For a typical aircraft you might start at 5 or 10 amps range to be safe. You can reduce the range later (if that is an option) once you know your not going to over drive it. For many digital meters you'll have only two settings, one low like 300mah or less and one for over 300mah up to 10 amps. Use the higher of these two settings for most applications. Unplug the jumper plug. The jumper plug is shown unplugged above at the top of the photo. Plug your JR or Futaba RX charge cord in where the jumper was (notice all black wires here) plug the banana ends of your charge cord into your meter (most meters use standard 4mm banana inputs) correctly. Your meter completes the ground wire connection between your battery and your RX or Servo (or whatever load your checking). Run your device and take your reading.
To measure voltage, Set meter for DC, if it has a set of ranges, choose a lower range like up to 10V (this setting should be above what you expect to measure). Plug the jumper back in and plug your charge cord into the other arm of the Y. Plug the banana plugs from your charge cord into your meters volt check inputs. Take reading.
If you have 2 meters, you can test voltage and amps load at the same instant. Also, with 2 Test Y Harnesses, you can take readings between the battery and also at a distant servo. Maybe you want to know how much voltage drop there is at the end of the line in your tail servos for example. In this case you need to know the loaded voltage at the battery and also at the distant servo to see what the actual drop in your wiring harness's really is. If you only measure at the servo your total voltage drop will be the total of the wiring and the battery and not just the wiring.
Not reccomended for any in-flight applications.