# Consider a lead-acid battery with 500 Ah capacity and a rated voltage of 12 V.

a)What is the total capacity of energy in watt-hours that can be stored in the battery?

b)Assume that the battery is completely empty. The battery is now charging at a C-rate of 0.20C. What is the charging current in amps that is going into the battery?

c)How much time in minutes will it take for the battery to go from 0% SOC to 100% SOC, assuming a constant C-rate of 2C? You may assume a linear rate of charging.

d)If the battery is charged at an average constant voltage of 13 V, and discharged at an average constant voltage of 11.7 V, what is the voltaic efficiency of the battery in %?

e)If the coulombic efficiency of the battery is 95%, what is the roundtrip efficiency of storage in % for the battery? Assume the same voltaic efficiency as you calculated above.

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1. a)_6000
B)_100
C)_30
D_90
E)-85.5

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2. a. Power in watt hrs = volts x ampere hours

b. coulombs = amperes x seconds

c. See b above.

d.e. This should get you started. You can google this stuff.

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3. 6000

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