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Thread: WRC main class in 2025
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5th February 2022, 11:02 #11Senior Member
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You keep repeating empty theoretical phrases.
Every battery has its limitations for charging and discharging which is linearily dependent on its own capacity. You can not charge a smaller battery with the same maximum current as a twice larger one and say that you will charge it twice faster. It doesn't work like that.
Let's say we need to charge those 48 kWh in 10 minutes because that's the energy we need to get to another charging station in our example. What could be the average C value? With the Tesla S or Taycan it is around 1,5-1,6 average when charging 20-80%. Let's say we can have an average C=2 which is more than in the stock systems. That means that if we want to charge 48kWh at C=2 in 10 minutes we need to have the total battery capacity 144 kWh. Such battery weight is around 600 kg.
Let's see the Kreisel car because that is an example of something which works in the real world not only in phantasies. It has a battery of 52,25 kWh with a said average consumption of 1,2 kWh per 1 stage km. That means the car's average output is 120 kW, not 150 kW as I counted but its battery is a bit larger than I counted, i.e. it can run theoretically somewhat farther (or not if it used in the range 20-80%). The car has 1330 kg. This car is clearly slower than Rally2.
The voltage of the Kreisel is 860V to allow hi-speed charging with maximum charging power 280 kW. Sadly this is the maximum value not an average value and simply dividing 52/280 does not give the time to fully charge. I have found that the maximum and average C values (for 20-80% charging cycle) at Tesla or Taycan are around 1/2-1/3 of the maximum C value (maximum being around C=3). It means that you can not simply devide required energy by the maximum charger power (52kWh/280kW=11,5 minutes) but you need to multiply the vallue by 2-3 to get to the real numbers, i.e. it will be probably around 20-30 minutes.
In a system you suggest where 10 minutes of charging would need to cover 20 km of a stage + 30 km of a road section the cars would need to bring a lot more extra dead weight (unused battery capacity) to allow such fast charging. Simply you can not charge a battery from 0 to 100% at 10 minutes because that requires 6C charging level which would be possible only for the cost of permanent damage to the battery.
That's without the discussion about the cost of having charging trucks on every stage and an infrastructure allowing recharging of those trucks in the service park overnight.Stupid is as stupid does. Forrest Gump
- Likes: becher (5th February 2022),cali (5th February 2022),pantealex (6th February 2022)



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