gas beating electric race kart
What can make it better?
It can be said that the weakest link is the noisy engine, which requires regular and expensive reconstruction to remain competitive.
Why not keep the fine-tuned frame, wheels and steering and replace the motor with something modern.
To improve the experience and excitement of the original racing car, the electric kart takes at least 20 minutes of riding time between a 20 hp, light weight battery pack and charging.
How did we do it? . . .
Kart was released via video of its pacesA rotax 21 KW cc gas-powered kart engine (29hp)
At 11,500 rpm and 8750 rpm, the weight is 24 kg (60lb)
Rrp costs about $3,500.
To keep the gas kart honest, we need a not too heavy motor and battery pack to keep the Operation Sharp and at least 15 KW power output.
With a higher torque output and a wider torque band, the motor with a slightly lower power output will beat the gas in almost all cases except the highest speed.
Motenergy is a popular high-output, small motor (Mars before
We think they are equivalent to the best power for Rotax, so we chose ME1114, which will provide more than 20 KW of the power (27hp)
At 78 V, the peak torque at 0 rpm is 98 nm and the weight is 16 kg (22lb)
The cheaper option is ME1117, with a peak of 20 KW and a weight of 10 kg and a price of about $600.
You can get a high power RC model motor with lighter weight, cheaper, moderate power rating, but the Motenergy motor will run reliably all day on small electric vehicles, due to the fact that the motor of the RC model needs to slow down for the use of gokart, and it is easier to overheat and fail.
You need a controller and a battery pack in addition to the motor.
We use brushless (
Permanent magnet communication)
This means that you need an electronic controller to turn on and off the coil in the motor, not the brush.
These offer higher efficiency, power, control and reliability in a very compact package, but they do require a more expensive motor controller, which may be at least as expensive as the motor.
In this case, we are using the Sevcon size 2 controller, which is a reliable European brand, fully programmable and retails for about $700.
Therefore, the price of the new Rotax motor is about half of its price ,($1600)
We can buy a new motor and top level controller similar to Rotax\'s power output.
The battery pack of Kart includes 24 batteries, weighing 12 kg (26lb)
, The nominal voltage is 78 V, the peak current output of the battery pack is 300, need to match the motor to make sure we can get the maximum output from the motor, we will not damage the battery because the current is too high, and provide a reasonable range.
To keep the performance consistent with the gasoline kart, lead battery, although cheaper will not reduce the performance.
In addition to affecting the handling of the weight, they also weaken the power output of the motor.
This is because the storage capacity of lead-acid batteries is not only much heavier compared to lithium, but also the peak current output is much lower, which means that we need to adjust the larger battery pack size, so that it can handle peak current bursts.
Let\'s face it. we don\'t have lead acid batteries in our phones.
Lithium batteries are the obvious choice.
If you would like to know more about the battery type, I will go to other sites or structures.
There are several different lithium battery formats, including bag batteries (
Common in RC models)
Large format prism (
Usually used for car modification), 18650\'s (
This is AA for lithium batteries, in 18 v Makita Li-
On batteries and other cordless tools or batteries.
The bag cells are OK, but it is easier to damage and the quality is more difficult to determine.
They may be the cheapest option, but they may be the most dangerous one.
Large cells don\'t fit unless you\'re racing enduros because they don\'t have that high peak discharge, so you end up with a larger range of packages (or kWh)
Peak current capacity required.
The power density of 18650 and head way is similar, both are suitable, but the headway battery is much larger, so you need a lot less battery, which makes the battery pack simpler.
There are several progression cells of different sizes.
We chose 3 15Ah 40152 cells.
2 v, 15 Ah capacity, 300A pulse can be provided.
The 72 V battery pack costs $30 each (
In order to adapt to the motor)
It costs $720 for 24 batteries.
Battery packs also require battery management and Chargers, so the total packaging cost is about $1000.
The weight of the battery pack is 12 kg or 26 (480g per cell)
If you touch it with your fingers, but don\'t connect them to your jewelry, pacemakers, or little brother, 78 v dc from this battery is unlikely to hurt you.
If you short these cells out, they create huge currents, so be very careful not to accidentally short them out.
They melt the tools, cause serious burns, and self-destruct.
There is a system to make sure that you don\'t put down tools or tools on the packaged terminal and isolate your tools in case of an accident.
If you face the above warning, it is not difficult to set up a lithium battery pack, do it systematically, and purchase a suitable battery management system.
Battery Management (BMS)
This can be daunting, but you need it to avoid the risk of damaging your battery pack and preventing it from crashing.
BMS monitors and limits the charging current, the peak current consumption of the battery pack, and can also monitor the temperature of the battery pack, so protect your cells and let you race as hard as you can, instead of worrying about your cells, we suggest that BMS is essential.
To build this package, all you need to do is connect each battery in series, I . E. e.
Use the appropriate connector positive to negative.
Our battery supplier EV Power offers terminals lugs and plastic clips with batteries to connect the batteries together with screw terminals, so, the first step in assembling the package is as simple as cutting and screwing 24 cells together.
There are several decisions to be made, such as what is the best way to package the cells, and the task is reminiscent of using Lego and finding the best way to wrap the power brick together and install it on a kart.
Once the battery is connected together, battery management will need to be connected to each battery.
Instructions for this will be provided along with the battery management board you are using.
The BMS board of EV Power we use needs to connect one wire to each positive battery in the right order, so we start at one end and connect each wire in turn to the next positive terminal, avoid confusion and mistakes in an orderly manner, or eventually lead to a large amount of wire confusion.
The photo shows the BMS battery connector used in this Kart package.
There is also an example wiring diagram of BMS (
For systems with smaller capacity than we use on kart)
Displays the connection to the battery, charger and motor.
We are using a brushless motor, so we need a suitable brushless motor controller.
The controller obtains 78 v power from the battery pack, 5 v input from the throttle, and input from the position sensor in the motor (
Commonly called Hall sensors)
And power directly to the coil in the motor, quickly switch the coil when the motor rotates.
The controller selected for kart is the Sevcon Size 2 controller.
Sevcon manufactures a compact and reliable controller with a highly programmable nature, and the No. 2 controller can be configured to 78 V and can provide up to 80.
We are running the motor in 14 KW capacity of the controller, a little lower than the 20 KW peak that the motor will produce.
The Sevcon controller, together with the battery and the motor, comes from the power supply of the electric vehicle and costs less than $700.
The project is about building an electric train and installing it on a kart.
There are a lot of used gokarts that cost less than $1000, and it\'s cheaper without engines.
We are using sprint kart, which originally ran the 100cc Yamaha J-class engine for this project, but any type of Kart will be used with the electric train.
To assemble it, you only need to install the electric parts on the kart chassis;
The motors, batteries, controllers and lines are all installed.
The electric motor has a surface bracket, and the motor has 1 feet brackets as a standard kart frame.
In order to install the motor, 90 degree angle bracket is made with 8mm aluminum plate.
One side of the motor Bolt, other bolts of the motor bracket on the frame.
Small automatic timing pulley (toothed belt)
Mounted on the motor, a large pulley is installed on the rear axel bolted to the standard gokart sprocket carrier.
Just keep the regular kart rear sprocket and install the chain sprocket on the motor, it is possible, but the chain is more noisy than the belt, we do not want the quiet hum of the motor to be overwhelmed by the clicking sound of the chain.
BatteryThe cells are arranged vertically in two rows and a clear acrylic box is made to hold them.
The battery box is thin enough to accommodate the space between the kart seat and the side pod and is secured on the kart frame using the front and rear aluminum brackets.
It is higher than the side cabin, so it sits higher and is easy to see on the kart.
The controller is bolted to the kart frame in front of the car, and there is an on/off switch in a small box in front of the controller, forwarding and forwarding switch contractor.
The controller has the battery in the power feed, the battery management of the inputBMS)
If the battery is too low, it can turn off the power (
Or any other battery failure detected)
Input of throttle and sensor input of motor.
Three thick gauge power cables directly connected to the motor.
Making a battery pack is probably the most complex part.
It is easy to connect the battery together, but 24 BMC battery connectors must be installed on each battery.
It\'s not hard, but you need to follow the wiring diagram correctly with great care or you will damage your BMS.
The throttle cable usually connected to the gas kart carburetor is connected to the throttle tank or the electronic throttle (see photo).
The electronic throttle has a 5 v input from the controller and outputs 0-
5 V signal back to the controller.
The big red button on the big red button is connected directly to the battery pack and can isolate the battery pack if any problems arise.
A small on/off switch in ContactorThe kart does not directly turn on the power of the controller and the motor.
Small switch for operating contactor (
Large amp relay)
Switch on the power supply.
If you need to protect the battery, the contactor enables the low-voltage switch in the BMS to turn off the power supply.
One of the problems that often arise on instructures is how much it costs, so I summarize the costs below.
Car racing-used car racing
The change is great, but if there is no engine, you should be able to get one for less than $1000.
$800 Motenergy motor $900 Sevcon size 720BMS monthly controller $70024 shift cells $300 contact, switch and wiring $150 in total, the $3,570 racing kart can be expensive to run with frequent engine modifications to stay competitive.
In addition to the apparent lack of fuel and oil, electric kart hardly needs maintenance.
The battery pack installed on this Kart will help the car for about 45 minutes and the lithium battery will help with up to 1000 cycles.
It can be charged within 30 minutes, and if you can never wait for 30 minutes to charge, the second battery (
Worth about $1000)
It can be exchanged easily.
Some controllers, such as Sevcon, have the ability to program or tune the motor, but it is different from the gas kart that requires precise tuning of the carburetor, exhaust, air inlet, and the valve and timing to remain competitive.
Tuning the motor involves inserting the controller into the computer and fine-tuning the torque transfer curve, throttle, and regen mapping so you can spend more time having fun on the electric kart.
Kart, the future is electric.
This Roddilkes Instructure is working with Ganhaar.
The concept and development of running kart Roddilkes.
Ganhal wrote and filmed it.
Electrical system powered by electric vehicle power supply.