Quote:
Originally Posted by dpeilow OK so I had a bit of a think about this cable requirement and came up with the following. Maybe someone can check the maths.
Based on a typical 13A cable having cores of 1mm diameter, I recon you would need three cores of ~27mm diameter for a 3 phase system (I'm assuming UK 415v three phase here). Not including insulation, that means a 77mm diameter overall cable.
Taking the density of copper as 8950kg/m3, that leads to a cable mass of 15.5kg per metre, plus insulation.
Not out-of-the-question heavy, but certainly very unwieldy. Think of an F1 refuelling hose.
No idea how much difference braided cable makes to this, and this assumes 100% efficiency in the charging for the assumed supply current. |
Someone can gladly check my math but I did some calculations on the first post on autobloggreen on the Lightening, I'll quote:
"OK lets do the math then.
The battery pack is 36kWh, and it can get to 80% they say in 10 minutes. So assuming you've completely drained it and you want to recharge it. You then need to supply 36 x 0.8 = 28.8kWh. Lets say there is a 10% lost to inefficiencies in the charger. You then to draw 28.8kWh x 1.1 = 31.68kWh from the grid. That is over a hour to full the battery but we only have 10 minutes so we are talking 6 times as much power. 31.68 x 6 = 190.08kW continously over a 10 minute period.
I must admit I'm no expert on 3-phase power but it seems our normal industrial 3-phase and 3-pins or 4 pins, IEC 60309-type connectors has a maximum of 690V and 250A, which gives you a max for the plug (and probably the wire as well) of: 690 x 250 = 172kW.
So you are talking special extra thick industrial type plug. And that is just the plug, the power needed is so much you probably need a dedicated feed from a powerstation. All this means for someone to be able to do this they will be paying a LOT more than the basic rate for the kW you pay at your meter. Hence the economics of the quick-charge means it will hardly ever be available."
Sounds to me as 10 min charging is not effectively possible. And the range is NOT 200 miles, probably 200km. Tesla's choices are looking better and better every minute :) I'm actually pretty sure for the Roadster they hit the exact right choice. For the model S it might be different with the shortish shelf life of standard Li-ion but we'll see I guess.
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