Typically, Segway batteries have a capacity of around 36 volts and 10 amp-hours (Ah). This means the battery stores 360 watt-hours (Wh) of energy. To fully recharge the battery, you'll need to supply this amount of energy.
The cost of electricity varies widely depending on your location. In the United States, the average electricity rate is around 13 cents per kilowatt-hour (kWh). In Europe, the average electricity rate is around 20 cents per kWh.
Assuming you're in the United States and your electricity rate is 13 cents per kWh, it will cost around 4.68 cents to fully recharge a Segway battery. This assumes that the charger is 100% efficient, which is not always the case. In reality, the charger may be only 80% efficient, which means it will consume 5.85 cents of electricity to recharge the battery.
Over a month, the cost of recharging a Segway battery every day would be around $1.40, assuming a 100% efficient charger. If the charger is only 80% efficient, the cost would be around $1.75.
It's important to note that these calculations are just estimates and the actual cost may vary depending on specific circumstances.