Most electric vehicles come with a battery pack that only holds the energy equivalent of from one quart to a couple of gallons of gasoline. Luckily, electric motors are 2-3 times more efficient than the ICE. To effectively use that limited energy, you will need to start thinking about your driving style now, as well as after you convert your car to electric.
Here are the basic EV performance questions to ask before you convert your car to electric:
1. How far do I need to go before turning around?
2. How much does my car weigh with no motor?
3. What top speed do I need to go?
4. Do I still want to burn rubber? (You can - it just takes power)
5. Are there a lot of stops and starts that use up power?
6. Is it really cold where I will drive the EV?
7. Is it really hot where I will drive the EV?
8. Are there steep hills to go up where I will drive my EV?
9. Is it windy where I drive?
10. Am I going to haul passengers in my EV?
11. Do I want heat, AC, power assisted brakes, and power steering?
12. Do I want or need regenerative braking?
13. Is there a place to plug in at the other end of my commute/drive?
14. Where will I charge my car at night?
15. Do I want an onboard charger or a home charger….or both?
Before answering all of these questions, you might want to take a look at the
three basic battery configurations below used to convert your car to electric.
This is because the batteries at this point in time will form the heart of your conversion, unless you are building a drag car, in which case you don't need this write up.
Let’s look at good old flooded lead-acid batteries to begin with. Assume that
the EV motor is a 9” DC pulling 144 volts; let’s use a 144V pack with discharge at the standard 20AH rate:
Best Range: 24 - 12 volt Trojan @ $100/ea = $2,400 US
Pack weight = 24 x 62lbs = 1,488lbs; Storage = 24 x 225AH = 5,400 AH
Pack Storage = 225 AH x 144 volts = 32,256 Watts = 32.26 kWh
This is close to 1 gallon of gasoline energy equivalent
Range/Performance mix: 18 - 8volt Trojan
Pack weight = 18 x 69 lbs = 1242 lbs; Cost@$100/ea = $1,800 US
Pack Storage = 190 AH x 144 volts = 27,360 Watts = 27.36 kWh
This is close to 3/4 gallon of gasoline energy equivalent
Performance: 12 - 12 volt Trojan @$100/ea = $1,200 US
Pack weight = 12 x 82 lbs = 984 lbs
Pack Storage = 150 AH x 144 volts = 21,600 Watts = 21.60 kWh
This is just over 1/2 gallon of gasoline energy equivalent
Note on prices: Prices above are only estimates for comparison to help you
convert your car to electric.
Note on battery types: The cost of LifeP04 (lithium-ion) battery packs is quite a bit higher than for lead-acid. Here are a few quotes.
1. 144V150Ah packs = 720 cells + BMS + assemble fee= $23,000 US (BMS - Battery charger) 144V x 150 AH = 21.60 kWh. That’s $1.07 per Watt/hour.
2. Another source lists costs at about $0.5 per Watt/hour. That’s $10,800 US for the pack with NO Charger; therefore the most expensive option to convert your car to electric.
However, the LifeP04 batteries do have a few big advantages. They are only about 1/3 the weight and list 2,000 recharge cycles compared to about 400 recharge cycles for lead acid.
Now that you have some knowledge about energy storage, you can start answering the questions above. A sample is on the next page.
If you want to convert your car to electric, you will want to start by understanding what your EV needs are, what your conversion is capable of and planning from there. If you do not do this, chances are you will end up with a car that will not do what you want it to do, and you will just end up selling the rig at a discount.
Performance is everything for the electric car. The electric car is still not “perfected” with respect to the performance from the average internal combustion engine car.
This is because most cars come with a gas tank that holds from say 10-25 gallons or so of fuel. This automatically gives just about anybody hundreds of miles of range under acceleration, hills, wind, passengers, and cold weather. Ironically, gasoline gets denser in the cold, so you get a bit more energy.