Some DIY electric car owners sometime complain about their vehicle not having mileage proportionate to the amount of power available in the battery bank. These people really do not know what causes their EV to consume more power than necessary.
Reducing power consumption from the electric motor and attaining maximum driving mileage from your homemade electric car depend on two very simple things; the overall weight of the vehicle and the friction with the road surface. If both these factors are reduced, the vehicle will give more mileage per charge.
Let us see how the weight of a vehicle can be reduced. Before discussing about the weight reduction, we have to understand the types of weight your EV has. The weight of a vehicle can be divided into two types; the sprung weight and the unsprung weight.
The sprung weight of an electric vehicle is the weight of a vehicle’s electric motor, the deep cycle batteries, body and other accessories supported by the vehicle’s suspension system.
The sad thing is that we cannot do much to reduce the sprung weight of the vehicle since all the necessary parts of the vehicle have to be there and they cannot be removed for safety reasons. What we can do to reduce the sprung weight is to avoid carrying unnecessary cargo and other extra fittings that add weight to the vehicle.
Another weight, which also falls under the unsprung category, is the weight of dirt attached to the underside of the vehicle. People are very keen on cleaning the outside of the vehicle to give it a shiny look but they fail to notice how much mud and other dirt particles are attached to the underside of the electric car.
Cleaning the vehicle thoroughly including the underside using pressure washer will help a lot in reducing the sprung weight of the vehicle. But make sure you do not get the electric motor or the controller wet.
Though sprung weight reduction results in better mileage, it is not as effective as unsprung weight reduction. Unsprung weight reduction is more important than sprung weight reduction in attaining better mileage per charge from your battery bank. Unsprung weight of a vehicle is the weight of axles, wheels and tires.
Regarding the axles, we can’t reduce their weight because they are manufactured according to specifications. But we can do something with the wheels and tires.
Some people like to use very large and wide wheels and tires. They are good for some reasons but the vehicle will have more friction with the road and to overcome the friction, the vehicle will need to use up more electricity in order for the electric motor to propel the car forward.
Lighter wheels and tires will reduce friction with the road and so your DIY electric car will suck up less power from the batteries thus giving you longer drive time before needing a recharge.
Reducing the unsprung weight, the weight of the wheel and tires is the key factor in improving the mileage of pure electric vehicle. Replacing the factory made wheels and tires with custom wheels and tires will be a good idea to reduce the unsprung weight of a vehicle. The tires too must be as narrow as possible. The wider the tires, the more will be the friction and the less will be the mileage.
Thus a reduction in unsprung weight will give the vehicle more mileage. It will also improve the overall performance of your electric car.
DIY Electric Car Conversion Manual
If you are looking for a good Do It Yourself (DIY) electric car conversion book, check out Gavin Shoebridge’s Electric Conversion Made Easy guide.
Gavin is from New Zealand and he has converted his old 1987 Mitsubishi Treadia into a pure electric car in his garage.
Gavin is also well known in the homemade electric car realm. This is because of all the videos he took when he was converting his Tredia to EV.