# 48V or 72V? Watt/hr + Peukert, etc.



## Jan (Oct 5, 2009)

If you use lets say 5kW to maintain speed. This means you draw a 104 amps from the 55Ah pack, which is almost 2C. And you will draw 70 amps from the 38Ah pack, also aproximaly 2C. So the peukert effect stays the same.


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## mechman600 (Oct 16, 2010)

Wow. It's amazing how simple these calculations are that I am overlooking! Thanks.


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## ElectriCar (Jun 15, 2008)

Generally speaking the higher the voltage the better. Voltage is what forces current to flow into a given load. More of it means more current flow = more power. 

Consider a 9V battery. People test it with their tongues. As the battery gets weaker the current it can force to flow decreases thus a weaker shock to the tongue. If you place it on your dry skin you won't feel a shock, even with a new battery. However if you get on 120V from your home power, it will shock you MUCH MORE even with dry skin because of the MUCH HIGHER VOLTAGE. 

Another issue is the size of the wire. Higher voltage allows smaller wire for a given KW because less current is needed to produce a given speed. Smaller wire cost less and weighs less too!

Just had some time to kill... Hope this helps.


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## frodus (Apr 12, 2008)

higher voltage = higher RPM as well, so your top speed will be about 1/3 less at 48V than at 72V.


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