Below is the formula for determining the cost per charge of our products. 4 easy steps:
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Determine how many watts a charger will consume per hour. The back of the charger has a sticker with the “Output”. Our example will use a 24v1.8a charger. Power consumption over an 8 hour charge cycle will be higher at the beginning and lower at the end so for this example we will use an overall average determined by the rated output.
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Volts * Amps = Watts
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24v * 1.8a = 43.2w (average power consumption)
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Power companies charge for power in units of 1 kilowatt per hour (1kWh or 1000 watts per hour) so we need to convert watts into kWh
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watts / 1000 = power consumed per hour in terms of kWh
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43.2w / 1 kWh = 0.0432 kWh (this is the amount of power consumer per hour)
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Determine how much your power company charges for 1 kWh of power. LADWP (Los Angeles Department of Water and Power) Residential Rate A (as of 11/20/08) is $0.07288 per kWh
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kWh consumed per hour * rate per kWh = cost to charge per hour
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0.0432 kWh * $0.07288 = $0.003148416 (this is the cost to charge per hour)
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Determine how many hours you will be charging the battery pack. Our example will use an 8 hour charge which is typical of our 24v bicycles and scooters.
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cost to charger per hour * amount of hours charging batteries = total cost to charge batteries
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$0.003148416 * 8 = 2-1/2 cents (cost to charge a 24v battery pack with a 1.8a charge for 8 hours)
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