Electric Cars Reliability
First Published in WDHV Backfire September 2021 Revised 12/2024
This was written as my experience as a white goods repairer and not as an EV owner
Personal transport was originally by horses, camel, donkeys and ox. Then the horseless carriage was was invented.
The steam engine was first invented but it was more suited to large things like factories, ships and trains although some were put into cars. Steam Powered cars have many disadvantages like a slow start-up time for the steam to be generated, the danger of the boiler exploding. Steam engines made little noise and were more reliable than petrol engines.
The internal combustion engine was developed to become the main source of powering cars. They were noisy, unreliable, and difficult to start. They had to be started with a cranking handle which required some effort. The slow development of petrol engines resulted in extensive railway lines throughout the world. The railway lines became redundant with the improvement of the petrol engine and road transport. We now have many “rail trails” because of this.
At the same time, electric battery cars were developed. Electric cars had the advantage that they did not have to be started with a cranking handle. They were regarded as ladies cars. They used lead-acid batteries which made the cars very heavy. Electric cars were quiet but had limited range and were considered city cars. With the improvement in the petrol engine, the electric cars lost out. Electric vehicles were still used in special applications such as forklift trucks and wheelchairs etc.
Step into current times. We are now seeing new developments in electric cars. I would have thought that small urban cars would be developed first but normal-size cars are now available.
A lot is said about the performance of electric cars but I'm going to discuss the reliability.
Electric cars have not been around long enough to judge their reliability and durability.
To judge this I will look at other electrical equipment.
Electric motors are much more reliable than petrol motors. The electric motor driving the compressor in the refrigerator will run for 10 years stopping in starting about every hour. All this without an oil change, new spark plugs, or any other maintenance. When the refrigerator is at the end of its life the motor will still be working. Refrigerators fail when they lose their refrigerant gas, failed thermostats, and wear and tear on the cabinet. Frost-free fridges are more complicated and have more things to go wrong. For more on fridge repairs see my links to 'Information'.
There are many types of electric motors. The electric motor does fail and there is a trade called electrical mechanics to repair them. When electric motors fail, what fails? Bearings fail, but there are only two. Windings can fail when overheated or overloaded or water gets into them. Also, the switchgear controlling the motor can fail. This is the weakest link. Mechanical switches are being replaced by solid-state or transistor switches. They work better but are prone to fail with overload. More on this later. The carbon brushes and commutator wear out but now brushless DC motors are being used in power tools. I have not used these yet or know their reliability as they have not been around long enough. They are in the top-of-the-range battery tools. Brushless motors are used in washing machines such as the Fisher & Paykel and some direct drive front loader washing machines. The motors are reliable but the electronics that power the motor work can fail and the machine is scrapped due to the high cost of replacement. Brushless DC motors will be the type of motors in electric cars. All my garden power tools except the lawn mower have electric motors for reliability and ease of starting. They are 240V with an extension lead as battery one was not available when I purchased them. They are still going! Not sure what I will do when the lawnmower needs to be replaced, but have noticed a large number of batteries power ones in the hardware stores. This decision is still some years away. The electric motor in an electric car should be as reliable as a differential in a conventional car. Also, see my article on electric motor repairs for a workshop in the Backfire March 2016 page 11.
The batteries will be the weakest link. They will need to be replaced like tyres and brakes in petrol cars. This will be an added cost. There are many varieties of lithium (Li) batteries each with its advantages. But the cost is coming down. You can compare the battery life of power tools and mobile telephones. The life of these is getting better. The batteries in the mobile telephone are almost impossible to replace now. See https://www.ifixit.com for DIY repairs and ratings on the difficulty in repairing. My DIY was a failure as the mobile telephone would not come apart and the screen broke! Bad luck, new phone. The mobile telephone I had was extremely difficult to repair (10/10). The manufacturer thinks the batteries will last the life of the telephone. Power tools have easily replaceable batteries. Power tools are replaced when the batteries are at the end of their life due to the high cost. There are companies rebuilding power tool batteries. Battery replacement in electric cars will be a major cost, but so are internal combustion engines (ICE). When petrol or diesel engines fail or wear out they can be repaired or rebuilt, replaced with a used engine from a motor wrecker, or the car is scrapped because it is too expensive. The same can be done for the batteries. Some people recycle electric vehicle batteries for home solar batteries when the life does not give a sufficient driving range.
Brakes in electric cars will last much longer if the car is driven correctly and the way it was designed to be. Most of the braking will be done by regenerative braking. The electric motors will become generators and charge the batteries. The conventional brakes will only need to be used in an emergency or when stationary. I remember when automatic cars appeared and the brakes did not last as long as manuals. Some savings will be with the brake replacement with electric and hybrid cars.
The control electronics for the car are of two types. The logic controls (computer/brains) and the power controls to the motors (speed and braking control). Cars have many microcomputer control systems now They control fuel injection systems, ABS brakes, delay lights, and locking car doors. The logic and control systems should be reliable. Computers, mobile telephones, fuel injection computers, and all the other ones in cars are now fairly reliable. The sensors and the control mechanism are more likely to fail than the computers. Some will display error codes or special tools and laptop computers may be needed to find faults. However, the cost of replacing the computer controls in all cars is high and there will be no difference between petrol and electric cars. Will manufacturers release service information or keep it secret, to keep out independent repairers? John Deere in the USA does not release it but claims it contains company secrets. (itfixit.com and supports the right to repair)
The electric power to the motor needs to be controlled by power electronic circuits for speed and braking. These circuits will contain transistors that carry large currents and will generate heat. The transistors are mounted on aluminum heat sinks to try to keep them cool. The unit will fail when it overheats. In the hot Australian environment this will be more of a problem. Looking at other power electronics to see the reliability. My inverter for my solar household electricity has failed twice, the first one under warranty. The inverter is not in the coolest place at home. I have put compurer fans on the inverter controlled by electronic fridge temperature controllers. This is for a 2kW system, electric cars are about 100kW, so the system will have to handle much more heat. A washing machine with electronic controls will only be powering 0.5kW motors. What are the problems with electronic controllers in washing machines? Sometimes the PCB can fail for no apparent reason. Sometimes the power mains may have a surge causing it to fail. Ants and mice coming into contact with the high-voltage components can cause failures. Sometimes the other components fail and it takes out the controller PCB. An Asian washing PCB fails when the water valve fails, not a good design. Fisher & Paykel washing machine replaced an inefficient drain pump with a highly efficient inverter pump, but the problem was when the pump blocked it took out the main PCB. They quickly brought out a new model with a different type of pump.
Li Battery fires: When Li batteries are charging a thermal runaway can occur and the batteries can catch fire. To prevent this very complex control of the charge by electronics is used. Samsung had a recall on one of its models of mobile phones due to Li battery fires. Electric car manufacturers had a recall on their batteries. Some power tools batteries have caught on fire, charge these in an open space away from inflammable materials to reduce the risk of the fire spreading. Most Li battery fires are in eScooters and eBikes with cheap batteries and chargers. Also, rubbish trucks have had a fire when the batteries have been damaged in the truck. They should not be put into rubbish bins but taken to a battery recycling program. Big batteries are used to store electricity from wind and solar and feedback into the grid to meet demand when solar and wind are not producing. There has been 43 of these fires overseas and one at Moorabool (near Geelong) on 30/7/21. Li batteries are used in house solar systems and 'house', batteries in caravans. Caravans are now using Li batteries instead of deep cycle Pb Acid batteries to save on weight. If changing the caravan battery you need to change the charger as the different charging voltages. Electric cars do have a fire risk but so do petrol cars. Jeep had a recall on their cars catching fire. World statistics show that Petrol or diesel cars are 20 times more likely to catch fire than Electric cars.
Motor mechanics will have to learn new skills, but this is not new.
Motor Vehicles Accidents: (MVA). Electric and hybrid cars have a green diamond (now blue) on the number plate to warn emergency responders of the dangers of high-voltage electricity. Training is being undertaken. This is no different from the red diamond on LPG powered cars and associated risk.
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