FAQ
Q: How will my driving effect the range of my electric vehicle?
A: When you accelerate hard an electric vehicle uses more amps than if you were cruising at the same speed. Unfortunately, more throttle(amps) = less range. The good news is you (hopefully) have a meter like the Cycle Analyst that so you can easily determine exactly how your inputs effect your range, and how far you can go at any given time.
Q: Do I need anything special to run a lithium battery?
A: You should run a Battery Management System(BMS) for both charging and discharging to insure that all cells are balanced, that way you get maximum battery life.
Q: Why do I need a low voltage cut off ?
A: Batteries are damaged from fully draining all power from the battery, and the end life performance is not much. Most lithium batteries must have each three volt cell managed individually by a BMS to make sure none of the cells get below or above a set voltage.
Q: Why do you need a pre-charge resistor across the main contactor terminals?
A: A pre-charge resistor is an inrush current limiter, and additionally, slowly discharges current at shut down. The pre-charge resistor will cause a very small amount of current to flow at all times. If you want to avoid this discharge you could wire a (momentary) switch in series with the resistor. Flip/hold the switch (down) for some seconds before you power on and equalize the voltages. Then you have to do this before every time you turn the bike on or you run the risk of blowing your controller with an arc of inrush current . NOTE: The LogiSystems controllers sold on our products page are designed to be used without a pre charge resistor!
A: When you accelerate hard an electric vehicle uses more amps than if you were cruising at the same speed. Unfortunately, more throttle(amps) = less range. The good news is you (hopefully) have a meter like the Cycle Analyst that so you can easily determine exactly how your inputs effect your range, and how far you can go at any given time.
Q: Do I need anything special to run a lithium battery?
A: You should run a Battery Management System(BMS) for both charging and discharging to insure that all cells are balanced, that way you get maximum battery life.
Q: Why do I need a low voltage cut off ?
A: Batteries are damaged from fully draining all power from the battery, and the end life performance is not much. Most lithium batteries must have each three volt cell managed individually by a BMS to make sure none of the cells get below or above a set voltage.
Q: Why do you need a pre-charge resistor across the main contactor terminals?
A: A pre-charge resistor is an inrush current limiter, and additionally, slowly discharges current at shut down. The pre-charge resistor will cause a very small amount of current to flow at all times. If you want to avoid this discharge you could wire a (momentary) switch in series with the resistor. Flip/hold the switch (down) for some seconds before you power on and equalize the voltages. Then you have to do this before every time you turn the bike on or you run the risk of blowing your controller with an arc of inrush current . NOTE: The LogiSystems controllers sold on our products page are designed to be used without a pre charge resistor!
Q: What if my vehicle is too heavy for a given motor?
A: If the motor is overloaded and not able to accelerate at a quick pace, the life of the motor will be shortened. Overloading causes much higher currents to flow through the motor and its brushes. This causes both motor windings and brushes to heat more quickly. As a result, the life of the brushes and the windings insulation is shortened. In addition, the controller is faced with this exceptionally high current level. The controller must handle a higher current over longer periods of time. This causes the controller to heat up more quickly and to a higher temperature. At some point, the controller might fail because the internal MOSFETs or IGBTs can't handle as much current at higher temperatures. This can occur even if the controller has over-temperature cut out, or if the controller does not have excellent peak current limiting. Peak motor currents can destroy the controller. Peak motor current can be very high during initial acceleration.
Q: Is an Agni Motor suitable for use on my vehicle?
A: Agni motors are suitable for use with a fixed transmission ratio on a road vehicle whose total loaded weight in Kg multiplied by its intended top speed in Km/h come to a figure of 30000 or less, if run on 60V (or 72V, which is safe if the motor is not overdriven above the speed at which it runs without a load). If the weight multiplied by speed come to more than 30,000 it will be necessary to use a gearbox (and accept a large reduction of speed when climbing hills) or to use more than one motor. With a fixed transmission ratio it will be possible to maintain near full speed when climbing hills, provided that the battery can supply the necessary power.
Example: A motorcycle weighs 200 Kg loaded and is to have a top speed of 120 Km/h; multiplying these figures gives 24000 and there should be no problems. The reduction ratio needed will be about 2.75:1 with typical size motorcycle wheels (3.00x17, 23 inches overall diameter including tyre) or 2:1 with typical scooter wheels (3.50x10, 17 inches diameter including tyre). These ratios can easily be obtained in a single stage with various types of chain or toothed belt.
Q: How large of a controller should I run?
A: That will be limited mostly by motor and battery limits. First off your batteries need to be able to pull the desired amperage without cooking themselves, it can be fairly hard to find a battery that will pull a 10-20C rate (C rate is the number of times the amp hour rating of the battery is multiplied. ex. a 50ah @ 5C = 250a, or 50ah @ 10C = 500a). Make sure you know the controller and battery ratings for "continuous amps" and something like "Max amps 30 sec" or "peak amps". The motor must be kept cool enough and must not exceed it's max speed. If heat is a problem you can route cooling ducts and/or add a fan.
Q: What is horsepower?
A: A measure of power.
One electric horsepower is equal to 746 watts.
One mechanical horsepower is equal of 550 foot-pounds per second.
Q: How is total electrical power measured?
A: Electricity is kind of like water pipes, the pressure difference(voltage) determines how quickly the electrons will travel through the circuit. Current(in amperes) in the same analogy, is a measure of the volume of water that flows past a given point per unit time(volumetric flow rate). The flow rate is determined by the width of the pipe(analogous to electrical resistance), the pressure difference between the front end of the pipe and the exit is analogous to voltage. The analogy extends to power dissipation: the power given up by the water flow is equal to flow rate times pressure, just as the power dissipated in a resistor is equal to current times the voltage drop across the resistor(amperes x volts = watts).The relationship between voltage and current(in ohmic devices) is defined by Ohm's Law.
