FAQs - Batteries
The answers here are based on Battery EV drivers' experiences and also
culled from extensive battery information provided on sites such as
http://www.uuhome.de/william.darden.
and
http://www.pacificpowerbatteries.com/aboutbatts/Car%20Battery%20FAQ/carfaq7.html
Sulfation and storing of batteries is discussed here.
Q: How do I determine how much battery pack to build into my EV?
A: It's all about how much energy your vehicle uses.
Major factors affecting vehicles of all fuel types are:
- Vehicle Characteristics
- Vehicle weight affects energy to accelerate to speed, rolling resistance.
Generally, energy used is a linear function of vehicle weight
- Vehicle cross-sectional area and coefficient of drag affects energy used at cruise
- Tire rolling resistance affects energy usage
- Power transmission efficiency optimizations help by a few percent
- Vehicle Usage Dynamics
- Stop and go driving decreases system efficiency
- Hill climbing decreases system efficiency
- Unnecessarily hard acceleration decreases system efficiency
For lead-acid technology use the following table as a guideline:
|
Percent of Vehicle Weight
|
25%
|
33%
|
50%
|
|
Practical Range (km)
|
50
|
70
|
100
|
For all battery chemistries use the following guideline to estimate
all-electric range for a typical small battery electric car or
stock hybrid to plug-hybrid conversion.
Count on getting 5 to 8 km per kWh depending on traffic conditions,
speed and driving style.
|
Range per Charge (km)
|
25
|
50
|
100
|
150
|
|
Required kWh
|
5
|
10
|
20
|
30
|