Range Confidence: Charge Fast, Drive Far, with your Electric Car

By David Herron

Last Update: 2021-01-03T23:53:32.513Z

  1. Range Confidence: Charge Fast, Drive Far, on Electricity
    1. The false 'Range Anxiety' story would keep us from driving electric
    2. A brief history of Range Anxiety in electric cars and gasoline cars
  2. Learning Range Confidence
    1. Step 1 - Map your trips to know how far you need to drive
    2. Step 2 - Know your local EV charging terrain
    3. Step 3 - Getting around town with your electric vehicle
    4. Step 4 - Set up charging at home, at work, or nearby
    5. Step 5 - Prefer electric cars with fast charging
    6. Step 6 - Charging station network memberships and smart phone apps
  3. Solving range anxiety in daily driving - putting range confidence into practice
    1. Typical daily driving needs, on electricity
    2. Electric vehicle charging scenarios
    3. How and where to charge electric cars in public
    4. Example longer trips with electric cars - putting range confidence into practice
  4. Autonomy and electric driving freedom
  5. Charging station etiquette - effectively sharing limited electric car charging resources
    1. Electric vehicle drivers Bill of Rights
  6. Electric vehicle range and charging infrastructure
    1. Energy storage, energy consumption, weather and electric car driving range
    2. Total driving range in electric cars: plug-in hybrid versus fast charging
    3. What happens if an electric vehicle runs out of power in a city with no charging stations?
    4. Why doesn't the dashboard show accurate range?
    5. Battery pack age, and capacity loss
    6. How does EPA estimate electric car driving range?
    7. Understanding the EPA ratings label for electric cars
  7. Charging electric cars in public
    1. Electric car charging speed and effective trip speed on road trips
    2. What electric car charging rate do we need at home, at the office, on road trips, at airports, or elsewhere?
    3. Can you drive an electric car away from charging network coverage areas?
    4. What charging networks exist? ChargePoint? Plugshare?
    5. Types of electric car charging connectors, and compatibility: A Field Guide to electric vehicle service equipment
    6. Is it bad to charge an electric car with an extension cord?
    7. Best portable electric car charging stations for home or on trips
    8. How do I pay for energy consumed in charging my electric vehicle?
    9. How do electric car charging station networks make money?
    10. Electric car fast charging held back by standards battle between CHAdeMO, Combo Charging System and Tesla Supercharger
    11. Electric car fast charging required for widespread EV adoption
    12. Smart-phone apps for finding electric car charging station networks
    13. Known electric car charging networks around the world
    14. What to do if the charging cord is stuck, cannot be removed
  8. Getting and installing at home electric car charging equipment
    1. Installing cheap/inexpensive electric car charging at home
    2. How to plan for and install 240 volt circuit to charge an electric car/vehicle?
    3. Fast charging your electric car at home
    4. Apartment/Condo dwellers - what to do if you cannot charge at home
    5. How-to: 240 volts when all you have is 120 volt outlets
  9. The best electric car charging stations for home charging or on trips
  10. A brief study of EV Ownership Economics
    1. Fuel cost per mile
    2. Tipping the economic balance in favor of electricity
    3. Charging cost at home versus in public
    4. The high cost of free charging
  11. Electric car charging technology
    1. Charging levels - Level 1, Level 2, DC Fast Charging, etc
    2. EV DC Fast Charging standards – CHAdeMO, CCS, SAE Combo, Tesla Supercharger, etc
    3. EV AC Fast Charging Systems – Renault ZOE, Smart ED
    4. Fast charge adapters are possible, but how many really need CHAdeMO-CCS adapters?
    5. Why does charging a battery take so long? Hint: reversible electrochemical reactions cannot be rushed
    6. Wouldn't battery swapping be preferable over waiting to recharge?
    7. Can an electric car be charged while driving? Such as a battery pack in a trailer?
    8. When will electric cars charge as fast as a gasoline car? (5 minutes to recharge)
    9. What is the technical limitations on maximum electric car charging rate, why is the Tesla Supercharger limited to 120 kW?
    10. Safely use Extension Cords when charging an electric car or electric motorcycle
    11. Informal electric car charging at any power outlet, versus a regular charging station
    12. When are electric car extension cords required?
    13. Electric car charging within electrical code and power outlet limits
    14. Is it safe to charge an electric car in the rain?
    15. Why do all-electric cars not have a small (efficient) generator for a limp home to ease range anxiety?
    16. Why is there a 12 volt lead-acid battery, and how is it charged in an electric car?
  12. About the Author - David Herron
  13. Copyright

You might be thinking the lithium-based traction battery is the only battery pack in modern electric cars. And, you would be wrong. Look under the hood and you'll find a 12 volt lead-acid battery just like you'd find in a gasoline car. Let's talk about why that battery is there, and how it is kept charged.

The 12 volt system

All the accessories in an electric car run on the 12 volt system, just as they do in a gasoline car. That's the interior lights, external lights, the horn, the heating/cooling, the infotainment system, seat accessories, automatic windows, and everything else.

That 12 volt system comes from somewhere -- namely the 12 volt lead-acid battery.

There is an effort by some car makers to shift to a 48 volt system rather than 12 volt system. If this were chosen for an electric car, the lead-acid battery would then be 48 volts rather than 12 volts.

The need is the same - to have a battery pack meant to maintain voltage, whether 12 volt or 48 volt, for the on-board car systems just named.

Why is the 12 volt battery a lead-acid battery?

There may be a legal requirement that the 12 (or 48) volt system be powered by a lead-acid battery. But there are a couple technical reasons that could lead a manufacturer to choose a lead-acid battery.

Cost The cost for the lead-acid battery is much less than the lithium-ion battery.

Off the shelf The manufacturer can certainly throw a few cells in a box, add a small BMS, and design a 12 volt lithium-ion battery pack. But why go through that trouble when suitable 12 volt batteries are available off-the-shelf and are very easy to integrate into a vehicle?

Easy to replace It's easy to find replacements for 12 volt lead-acid batteries, just go to any automotive parts store.

Small gains in weight reduction The lithium-ion battery would be lighter weight than the lead-acid battery, but the weight difference is not all that great for such a small battery.

How is the 12 volt lead-acid battery kept charged?

The 12 volt system is constantly draining the 12 volt battery while driving. Therefore the state of charge must be maintained. In a gasoline car this is taken care of by the alternator and a voltage regulator that keeps the 12 volt battery topped up. In an electric car an alternator simply makes no sense.

Instead a DC-DC converter is used. These gizmos take a range of DC voltages on one side, and produces a stable voltage on the output side.

You can find DC-DC converters for a wide range of possible input voltages, output voltages, and amp capacities. The car manufacturer is responsible for sourcing the DC-DC converter.

Some mistakenly use the phrase "DC-DC inverter" which is incorrect. An inverter takes a DC input voltage and produces an AC output voltage. In this case the box needs to convert DC voltage from the traction battery (typically 400 volts) to the DC 14.2 volts required to charge the 12 volt battery.

The DC-DC converter in this case must also function as a charge controller. This means that it must shut off charging current if the 12 volt battery is fully charged.

Range Confidence is Copyright © 2016-17 by David Herron

About the Author(s)

David Herron : David Herron is a writer and software engineer focusing on the wise use of technology. He is especially interested in clean energy technologies like solar power, wind power, and electric cars. David worked for nearly 30 years in Silicon Valley on software ranging from electronic mail systems, to video streaming, to the Java programming language, and has published several books on Node.js programming and electric vehicles.
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