RC-Monster Forums - View Single Post - Home-brew battery measuring station

J57ltr · 05:10 PM

Flukes are only rated for 10A for most of them and 20 on a few models. You could use a shunt and measure higher loads, but then you have to convert milivolts to amps via a chart from the specs of the shunt

Using the Datalogger he is using will give recordable shots of exactly what's happening.

To build an non-adjustable drive for a brushless motor.

Simple version:
Use a servo tester an ESC, motor, power supply/battery. Connect them together and set the motor RPM you want. Remove the tester and measure (in Ohms) the pot for adjusting the "servo" between the middle terminal and one of the outer terminals, then the same for the middle and other terminal.

Write down those numbers and find resistors that match those 2 numbers. Remove the pot. There will be 3 holes where the leads of the pot were connected. Solder the 2 resistors into the 3 holes left by the pot and use the numbers written down earlier to determine which resistor goes on which side. You will have a lead from each resistor in the middle hole and the other lead goes into the outer hole. You will also need to have a Dual Pole Dual Toggle (DBDT) switch to be able to switch in 2 resistors of the same value half the resistance of the pot. (if the pot is a 5K you will need 2 2.5K resistors.) That way you have a neutral position and a place so the ESC can arm.

More complicated version should be handled in another thread:

Jeff

	(#5)
J57ltr RC-Monster Aluminum Offline Posts: 610 Join Date: Feb 2009 Location: Tomball/ Houston Tx.	07.19.2009, 05:07 PM Flukes are only rated for 10A for most of them and 20 on a few models. You could use a shunt and measure higher loads, but then you have to convert milivolts to amps via a chart from the specs of the shunt Using the Datalogger he is using will give recordable shots of exactly what's happening. To build an non-adjustable drive for a brushless motor. Simple version: Use a servo tester an ESC, motor, power supply/battery. Connect them together and set the motor RPM you want. Remove the tester and measure (in Ohms) the pot for adjusting the "servo" between the middle terminal and one of the outer terminals, then the same for the middle and other terminal. Write down those numbers and find resistors that match those 2 numbers. Remove the pot. There will be 3 holes where the leads of the pot were connected. Solder the 2 resistors into the 3 holes left by the pot and use the numbers written down earlier to determine which resistor goes on which side. You will have a lead from each resistor in the middle hole and the other lead goes into the outer hole. You will also need to have a Dual Pole Dual Toggle (DBDT) switch to be able to switch in 2 resistors of the same value half the resistance of the pot. (if the pot is a 5K you will need 2 2.5K resistors.) That way you have a neutral position and a place so the ESC can arm. More complicated version should be handled in another thread: Jeff The Warnings & Cautions discussed in this manual cant cover all possible conditions/situations. It must be understood that common sense and caution are factors which cant be built into this product. Last edited by J57ltr; 07.19.2009 at 05:10 PM.