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Very true James, but how much of your range in a Nissan Leaf will you loose in the same climb.
5000 feet in a 3300 pound car is 6 HP seconds per foot of elevation, or 42 HP per second per 100 feet traveled on a 7% grade.
5000/7=714 seconds of 42 HP above what it takes for you to travel the same speed on level ground.
3600/714=12 minutes at 42 HP above the level ground demand.
Level ground sustained demand at that speed is probably 7 HP give or take.
Say 37 kilowatts sustained for 12 minutes, or 6.6 kwh of battery capacity just to make the grade in your example, assuming it is 7% consistently for 5000 vertical feet.
You would have travelled 71400 feet distance or 13.5 miles.
Now double your example, or even triple it.
How much battery do you need with a 30% usable reserve capacity, and how long will it last being subjected to that kind of discharge stress on a daily basis?
The example of sustained grade climbing applies to both vehicles. If I need only a 75 HP gas engine to make the same grade, that engine is running at its peak efficiency. In fact you can size the engine to make it operate at peak efficiency on that grade and it won't change the overall mileage of the vehicle. The larger the engine the less time it needs to maintain accumulator reserves, so the only penalty for a larger engine is the weight of the engine itself.
The UPS trucks gross weight is 26000 pounds based on its class size. We are talking about a car that weighs 2000-2200 pounds. The INNAS (linked in my first post) thread clearly states "no weight penalty".
The in-wheel drives weight the same as the brake components they replace (weight neutral).
The cross members that support the suspension could do double duty as the accumulators, so their additional weight would be negligible if any.
On the other hand you need a 400 pound battery pack, a fairly heavy motor, some form of transmission and power train and you still need brakes for when your speed is so low regeneration can not be effectively accomplished.
How bad is the wear on your brakes when you are going down the same grade beyond your regenerative capacity?
Please correct me if my math is seriously flawed.
regards
Mech
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