Archive for the ‘Kit Car Electric Heater’ Category
Question by Grassman: Tesla Motors Roadster – are the claims realistic?
I am fascinated by the Tesla roadster car. But some of the specifications don’t seem consistent.
Tesla claims 140 miles of range with “aggressive driving” and 220 miles using EPA city/highway estimates.
Their battery holds 53kWh of charge.
They claim 80% efficiency at peak power, and 90% average efficiency.
They claim maximum power of 185kW of power, or roughly 250 horsepower.
They claim $ 0.02 per mile for energy usage.
OK, so 53kWh of available energy times 80% worst case efficiency, I get a total of about 42.4kWh available to power the wheels. At 185kW of peak output, isn’t this only 13 minutes of driving before the battery is empty? This is a lot less than 140 miles of range. Am I calculating this correctly? Also, can a Lithium Ion battery really run at this rate (5C!)? I thought that the power tool industry did not like lithium batteries for precisely this reason: they could not provide high levels of discharge current.
Using the 90% efficiency figure, I have 47.7kWh of energy available to power the wheels. So if I drive 55 miles per hour, I should be able to drive 4 hours according to Tesla’s claim. This is an average of about 12 kW of continuous output, or 16 horsepower. I understand that the car is one of the more aerodynamic on the market, and I know that 16 horsepower may be enough to maintain speed. But what happens if I play my music loud or run my A/C or heater while on the freeway? Do I really get 220 miles? Is my calculation correct, will I only get about 16 horsepower of output before I wear out the battery assuming 55 miles per hour constant speed for 4 hours? Assuming that I will accelarate and decelerate routinely during the 4 hours (i.e., pass cars, etc),is 16 horsepower average output enough to drive with real-world creature comforts being powered inside the car? I am assuming zero charge from regenerative braking, since I am assuming that energy transfered will be very low relative to 53kWh battery.
As far as price, 2 cents per mile times 220 miles (?) is $ 4.40. So this means that a 53kWh recharge should cost me $ 4.40 according to Tesla. This is 8 cents a kWh. They say these calculations assume time of use meter and night time charging. If I drive 2200 miles per month at 55 miles per hour, using assumptions above I will need 530kWh of charge. Where I live, I get 240kWh of off-peak usage at 8 cents each before I go over my baseline in the Summer. Charging my car, alone would push me into the 4th tier at $ 0.27/kWh for night charging (weighted average of about $ 0.20). My day usage would also be billed partially at tier 4, so I’d end up spending about $ 150/month extra on my day electric bill in Summer, and I’d spend roughly $ 125 for the 2200 miles at night. This totals an extra $ 275 to charge my car for 2200 miles, or around $ 0.13/mile. My current car gets 27 miles to the gallon, or $ 0.15/mile. If gas goes to $ 3.50 a gallon, I end up paying $ 0.13/mile.
Lastly, the Telsa has a 70A charging kit. How do I get 70A through my 30A circuit breakers? Do I need to upgrade (and if so, where do I find 75A circuit breakers)? Is it safe to run 70A? At 70A, they say it needs 3.5 hours to fully charge. Assuming I use 25% of the battery’s charge, I should need under an hour to charge. The problem is that I don’t think I have 70A capability into any of my outlets, I believe I have 15A/30A breakers universally. This would mean that I would need over 2 hours to recoup the energy used to fuel my daily commute. This adds up to a lot of time spent “refueling” each week. I refuel my gas car every two weeks and it takes me under 10 minutes. I understand that the car charges at night just like my cell phone, but I REALLY don’t like the lack of ease towards getting my car refueled. Am I calculating these charge times correctly?
Best answer:
Answer by tamperfinder
The claims are usually based on experiments and Experience.
Give your answer to this question below!
Power Hunt High Performance 2250 BTU 12 Volt Heater Kit for First Time Buyer
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Heater Specifications:
Voltage: 12 Volt DC
Power Rating: 45 Amps/650 Watts
Dimensions: 213 x 211 x 117mm 8.39″ x 8.31″ x 4.61″)
Weight: 1.15kgs (2.53lbs)
Price: $ 136.07
