EV Newbie FAQ
Q: What is an EV?
A: EV stands for Electric Vehicle. This can be any vehicle which uses electricity for propulsion, including hybrids, fuel cell powered, solar powered, battery powered, floating trains, electric subways, ect.
Q: What is a BEV?
A: BEV stands for Battery Electric Vehicle. These store most or all of the electrical energy needed chemically in batteries on the vehicle.
Q: What type of battery do most BEVs use?
A: Almost all BEVs use lead-acid deep cycle batteries.
Q: What are some advantages of BEVs?
A: They are clean and quiet. They don't emit any odors or toxic gases. They can be powered from any source of electricity making them independent on oil or any other fossil fuel. The drive system is simple. They are easier than ICE vehicles to maintain.
Q: What makes an EV go?
A: Electrical energy is converted to motion by an electric motor. Most EVs use a low-voltage DC motor.
Q: What controls the speed?
A: The motor power is almost always controlled by PWM (pulse width modulation) done by semiconductors in a controller unit.
Q: How do you "fuel up"?
A: Recharging the batteries requires a charger that usually plugs into a 120v wall socket. Most EVs take several hours to charge.
Q: Do the batteries ever need to be replaced?
A: Yes, about every 2-4 years.
Q: Does it matter if I leave the batteries discharged?
A: Yes. It is best to keep lead-acid batteries completely charged, but they will be okay if they sit for short periods discharged.
Q: Do I need to drain the batteries completely dead to prevent a memory effect?
A: No. Lead-acid batteries do not have any memory effect, and draining them down completely dead can damage them.
Q: My battery has died. Can I drain and refill the electrolyte to restore it?
A: No, because the active material inside the battery is depleted. Sometimes adding water will help if the electrolyte level is low.
Q: Why did the SLI batteries for my golf cart/other EV die so quickly?
A: SLI (starter lighting ignition) lead-acid batteries are not designed for deep cycle use, and should never be considered for a BEV unless you have old batteries for testing.
Q: Can I use a generator to generate the electricity needed that is driven from a wheel?
A: No, because some energy will be lost in the process. Perpetual motion is not possible.
Q: Can I use a windmill on the vehicle to generate the electricity needed while driving?
A: No, see above. You can however use a windmill to charge the vehicle while it is parked.
Q: Can I cover my EV with solar panels and drive forever in the sun, like solar cars do?
A: Not really because the energy generated from the panels will not be nearly enough. Solar cars are extremely light, aerodynamic, and efficient.
Q: Can I cover my EV with solar panels to charge it?
A: You can, but the energy generated from the panels will most likely not be enough.
Q: Why is the rated hp of my EV motor so low?
A: Motors are rated at their continuous output power, and can peak 2-4 times that. They also produce full torque at startup. Additionally, with a direct drive setup, they suffer no losses from a clutch or torque converter.
Q: I noticed that capacitors have a very high cycle life. Can I use them instead of batteries?
A: Not really. Ultracapacitors have a very low specific energy compared to lead-acid batteries. They are also very expensive for the amount of energy storage.
Q: Can I use a starter motor to power a small EV.
A: Starter motors are not recommended because they are not designed to run continuously. They are also not very efficient. Although they can work.
Q: Can I use a car alternator for an EV?
A: It would be difficult to do because an alternator does not have a commutator and will not run on DC.
Q: I heard x battery technology can offer a 200 mile range, be charged in 5 min, and last for a million cycles! Where can I get it?
A: It is much easier to make claims than deliver results. Don't trust them.
[this list is in progress]
[Updated Feb. 20, 2008. Please add any Q/A additions below and I will link them in here]