Homebuilt electric car Battery conundrum.

In summary, the speaker is planning to build an electric car at home despite having no prior experience with electric vehicles. They have been inspired by videos of homebuilt electric cars and have a background in physics and knowledge about cars. They plan to convert an old sedan or hatchback to electric power using a DC, 96v, 21Kw forklift motor and a battery pack containing 300Ah @ 96v. They have also calculated that they will need to purchase 2600 3Ah 3.7v Li-ion cells and will assemble them into 100 battery packs in parallel. However, they have concerns about the current output of the cells and have heard that cells with lower current output may be more efficient.
  • #1
conaman551
1
0
Hi all.

I planning to build an electric car at home. I have no expierence with electric vehicles but I studied physics at high school and know a fair amount about cars. After seeing homebuilt electric cars on you tube and elswhere I've been inspired to try bulid one also. I am going to try convert an old sedan or hatchback to electric power while still using the existing transmission.

The motor will be getting is a DC, 96v, 21Kw forklift motor. So far Iv'e established that if i use a battery pack supplying 300Ah @ 96v this should allow for about 1-2 hours drive at highway speed or approx 150Km range.

I definitely want to use Li-ion cells and I established that It would be cheapest for me to buy 2600 3Ah 3.7v cells @ $1.50 each on ebay. By having 100 battery packs in parallel each containing 26 3.7v cells in series, this gives me the 300Ah 96v battery i need.

After some quick math Iv'e also established that when the motor is at full power (21Kw) each cell is putting out 2.2A or 8.1 Watts. Is this current too high for the 18650 cells? I've heard that at low current <1 amp a cell is more efficient and is more likely to supply the rated capacity of the cell.
 
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  • #2
conaman551 said:
I definitely want to use Li-ion cells and I established that It would be cheapest for me to buy 2600 3Ah 3.7v cells @ $1.50 each on ebay. By having 100 battery packs in parallel each containing 26 3.7v cells in series, this gives me the 300Ah 96v battery i need.

I've seen some really poor cells on ebay. They're mass produced from China and break easily. I'd advise to steer clear.

I think you should build a prototype model and scale up from that.
 

1. What is the best type of battery to use for a homebuilt electric car?

The best type of battery for a homebuilt electric car depends on a variety of factors, including cost, energy density, and lifespan. Some popular options include lithium-ion, lead-acid, and nickel-metal hydride batteries. It is important to do thorough research and consider your specific needs before choosing a battery for your electric car.

2. Can I use recycled batteries for my homebuilt electric car?

While using recycled batteries may seem like a cost-effective and environmentally friendly option, it is not recommended for a homebuilt electric car. These batteries may not provide the necessary power and can pose safety risks. It is best to use new, high-quality batteries specifically designed for electric vehicles.

3. How do I determine the battery size and capacity needed for my electric car?

The battery size and capacity needed for your electric car will depend on factors such as the weight of the vehicle, desired range, and power requirements. It is important to consult with an expert or use online calculators to determine the appropriate battery size and capacity for your specific electric car model.

4. What is the expected lifespan of an electric car battery?

The lifespan of an electric car battery can vary greatly depending on usage, maintenance, and type of battery. On average, lithium-ion batteries used in electric cars can last anywhere from 8-10 years or 100,000-200,000 miles. It is important to properly maintain and monitor your battery to ensure its longevity.

5. How do I safely dispose of old electric car batteries?

Electric car batteries should not be disposed of in the regular trash as they can be hazardous to the environment. It is recommended to contact your local recycling center or an electric car dealership for proper disposal methods. Another option is to repurpose old electric car batteries for home energy storage systems.

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