Sam Shepherd wrote:
In the same auto what would be the difference in range between 6 volt and
12 volt lead acid? Like 24 6 volt next to 12 12 volt?
Your range is directly proportional to pounds of batteries. It doesn't
matter if they are 6v or 12v, or what pack voltage they are all wired
for. A rough analogy is that the shape of your ICE's gas tank doesn't
make any difference in your range. All that matters is gallons (weight)
of fuel. In an EV, the batteries are the "fuel", so the weight of
batteries is what that matters.
Now, there will be differences. The *type* of battery affects its energy
storage per pound. In round numbers, lead-acid stores about 20
watthours/pound, nimh about 40 watthours/pound, and lithium about 60
watthours/pound.
The quality and construction of the particular battery also makes a
difference. Within lead-acids for example, you find el-cheapo ones that
only deliver 16 wh/lb, and premium high performance ones that deliver 22
wh/lb. A battery can also be optimized for peak power at the expense of
range, or for range at the expense of peak power.
For the *special case* of 6v golf cart batteries vs. 12v marine "dual
purpose" batteries (the two options that people commonly use):
- Golf cart batteries are specifically designed for EV use, and so
perform well for this purpose. They are true deep-cycle batteries,
so their range, life, and cost tend to be good. But they tend to
be optimized for range, and not peak current.
- Marine "dual purpose" batteries are actually a compromise between
normal car engine starting and deep cycle types. They accept reduced
life and range to get higher peak currents. People who have tried
them have better acceleration, but shorter life.
--
Humanity is acquiring all the right technology for all the wrong
reasons. -- R. Buckminster Fuller
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
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