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Made in India: Reva, the Electric Car

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How far (mileage) will Reva go?

Most EVs today have a maximum range between 60 and 100 miles. This includes conversions and new cars from the manufacturer. Some vehicles may do less if they have small battery packs, lots of heavy-draw accessories like air conditioning, or if they are heavy, or using obsolete components. Some cars that have been maximized for range may get a little more.
From time to time you will hear about records of several hundred miles on a single charge. This kind of performance is not yet available for the average person. These records are generally set in vehicles using hand-built experimental batteries. Sometimes these batteries will only last for a dozen charges before they need to be replaced. Sometimes the battery packs costs many thousands of dollars. And sometimes the batteries are not in production and commercially available.

Battery capacity for range is usually measured in amp/hours. The more amps you draw as you drive, the less range you have. A higher voltage car will have better range because amp draw decreases as voltage increases. The more volts you have, the less amps you use. Range can be improved dramatically by quality, low-rolling resistance tires with good air pressure, a good alignment, and good driving habits.

How long does it take Reva to recharge?

Charging time can vary between 5-6 hours up to 10-12 hours. It depends on the voltage of the battery pack, and the voltage of the power outlet servicing the charger. A 96-volt car charging on a 110-volt outlet will take 10-12 hours. (Note: this is only if it has been driven to the end of its range and completely discharged. Since most people only use a fraction of a car’s range in a day, their charging time will be much less.) The same 96-volt car will charge about twice as fast from a 220-volt outlet. A 120-volt or 144 volt car will take longer to fully recharge.
Most people can drive their cars for their daily needs, and get a full recharge at home overnight. Some people also plug their cars in during the day at work to “top off”. As electric cars become more common, more charging facilities will be available.

The most common charging arrangement on a conversion uses an onboard charger with an ordinary 110-volt household outlet, because this type of outlet is most commonly available. It is best to have the outlet on a separate circuit, with at least 20 amp service.

You will sometimes read about fast charges done in a few minutes. There is much work being done to develop this technique, but it is not commercially available yet. This kind of charge requires a very high voltage source, often 440 volts, or more. It must be carefully regulated to prevent damage to the batteries. This usually means that the pack can only be fast-charged to 80% of capacity; more than that would cause damage.

How many batteries does Reva use?
A roadworthy, freeway-capable conversion will typically use between 16 and 24 batteries. These are 6-volt batteries that are specially designed to power electric vehicles, and they are wired together in series to produce between 96 and 144 volts.
Some race cars use more batteries and higher voltages, because they are looking for exceptional performance for a racing application. Many EVs from manufacturers use more batteries and higher voltage systems. Most conversions use more affordable DC systems, and retain the transmission to step up the motor rpm to higher speeds.

How long do the batteries last?

The lead acid batteries used in most conversions will last about four years before needing replacement. An entire pack typically costs $1,000-$1,200.
These are deep discharge traction batteries that are designed to power a vehicle. Their internal construction is different from the starting battery in a gas car, or from an RV battery.

How long the pack lasts depends on how it is treated. Batteries that are left sitting unused for long periods, or left sitting partially discharged, will have a shorter lifespan. The best thing you can do for your battery pack is to drive it every day and charge it every night.

Everything about batteries involves trade-offs. One trade-off is capacity for lifespan. Some batteries are designed to give higher than normal range on a single charge. These generally suffer from a reduced lifespan. Some may last only a year or two, others only a few charges.

Where can I buy one?

Reva is India’s first commercially produced electric car. Reva is a joint venture between the Bangalore-based Maini group and AEVT Inc of California in the US. The car can travel 80 km on a single charge of nine units. The running cost is about 40 paise per km. The Maini group plans to launch the car across in India in a phased manner.
(c) http://www.indiacar.com/infobank/ele_cars1.htm

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