Cost efficacy of electric scooters and bikes: doing the maths
Summary
Chances are that you will not save money by using an electric scooter. So, your motivation for using an e-bike should be non-financial (e.g. wanting to use an eco-friendly fuel in a city, thus contributing to cleaner air; being different from others; not having to frequently visit petrol stations; any other reason). However, even if you lose money, chances are that it will only be a small amount per annum; but if you are careless with battery charging, your losses would be high.
Assumptions
Assume that petrol, with or without added oil, costs Rs.75 per liter.
Assume that you have a petrol bike that gives you 50 km per liter.
Assumptions and calculations
Assume that your e-bike batteries cost Rs.12,000 [Prices are Rs.13,000 to 19,000 as of May 2015].
Given that you are paying this money up front, at 10% simple interest per annum you have lost Rs.1200 at the end of the first year; that is, you have paid Rs.13,200 for the batteries.
Therefore, in order to break even relative to a petrol bike, you have to get (13,200/1.5) km; that is, 8,800 km out of your batteries.
In my 7-year experience, batteries usually don't last beyond one to one and a half years, and they do not given more than 5000-6000 km (often less). Therefore, when one accounts for other factors such as electricity costs (see below), e-bikes can actually be far more expensive to run than petrol bikes. However, do take into account all the factors involved and do your own calculations based on your individual situation. Also take into account that all the mileage that you get out of your first set of batteries is transport for free, so you are way ahead of the reckoning at the outset (see Point 6 below).
Further considerations and adjustments
1. You will need to add a little to the above number in order to make up for what you are paying for the electricity (e.g. if your electricity bill goes up by Rs.750 a year because of your e-bike, you will need to run an additional 500 km to break even).
2. You will need to add a little to the above number in case you do not run this distance during the first year. This is because you must include the interest on the cost of your batteries for the additional months of the second year that it takes you to run the necessary distance.
3. You will need to adjust the above calculations for the actual mileage that your present petrol bike gives; and for the actual sum that you are paying for your petrol, with or without the added oil.
4. You will need to adjust the above calculations for the sum that you are paying for the servicing and maintenance of your present petrol bike as against what the maintenance of your e-bike costs you.
5. If you run your e-bike for a greater distance than what you need to break even, every extra kilometer that you run is like transport nearly for free (because the electricity costs are negligible).
6. If the cost of your e-bike is not much different from the cost of the petrol bike that you planned to buy, then you do not need to break even for the cost of your initial set of batteries. The distance that you run on these batteries is like transport for free because the electricity costs are negligible.
7. Make sure that you also factor in the cost of the accessories. You may be charged extra for the side stand (a necessity, given the weight of the bike), the seat cover, the helmet lock, the crash guard, and others.
Final notes:
1. Lead acid batteries are stated to have a life of about 300 cycles. If your e-bike is stated to have a range of 40 km per cycle, you can expect only about 25-30 km per cycle in city traffic (less, as the battery ages). Thus, if you do not lose your battery early due to overcharging and if your battery runs a normal life, you can expect a maximum of about 300 x 25 km; that is, 7500 km from it. If you divide the cost of the battery by 7500, you will get an idea of how much you're going to pay per kilometer. Use this logic to calculate your expected costs based on the stated range of the bike you propose to buy, the real life range (60-70% of the stated range, and less as the batteries age), the cost of the batteries, and the interest lost because of the upfront capital expenditure at the time of purchase of the batteries.
Chances are that you will not save money by using an electric scooter. So, your motivation for using an e-bike should be non-financial (e.g. wanting to use an eco-friendly fuel in a city, thus contributing to cleaner air; being different from others; not having to frequently visit petrol stations; any other reason). However, even if you lose money, chances are that it will only be a small amount per annum; but if you are careless with battery charging, your losses would be high.
Assumptions
Assume that petrol, with or without added oil, costs Rs.75 per liter.
Assume that you have a petrol bike that gives you 50 km per liter.
- Then, you are paying Rs.1.50 per km when you use a petrol bike.
Assumptions and calculations
Assume that your e-bike batteries cost Rs.12,000 [Prices are Rs.13,000 to 19,000 as of May 2015].
Given that you are paying this money up front, at 10% simple interest per annum you have lost Rs.1200 at the end of the first year; that is, you have paid Rs.13,200 for the batteries.
Therefore, in order to break even relative to a petrol bike, you have to get (13,200/1.5) km; that is, 8,800 km out of your batteries.
In my 7-year experience, batteries usually don't last beyond one to one and a half years, and they do not given more than 5000-6000 km (often less). Therefore, when one accounts for other factors such as electricity costs (see below), e-bikes can actually be far more expensive to run than petrol bikes. However, do take into account all the factors involved and do your own calculations based on your individual situation. Also take into account that all the mileage that you get out of your first set of batteries is transport for free, so you are way ahead of the reckoning at the outset (see Point 6 below).
Further considerations and adjustments
1. You will need to add a little to the above number in order to make up for what you are paying for the electricity (e.g. if your electricity bill goes up by Rs.750 a year because of your e-bike, you will need to run an additional 500 km to break even).
2. You will need to add a little to the above number in case you do not run this distance during the first year. This is because you must include the interest on the cost of your batteries for the additional months of the second year that it takes you to run the necessary distance.
3. You will need to adjust the above calculations for the actual mileage that your present petrol bike gives; and for the actual sum that you are paying for your petrol, with or without the added oil.
4. You will need to adjust the above calculations for the sum that you are paying for the servicing and maintenance of your present petrol bike as against what the maintenance of your e-bike costs you.
5. If you run your e-bike for a greater distance than what you need to break even, every extra kilometer that you run is like transport nearly for free (because the electricity costs are negligible).
6. If the cost of your e-bike is not much different from the cost of the petrol bike that you planned to buy, then you do not need to break even for the cost of your initial set of batteries. The distance that you run on these batteries is like transport for free because the electricity costs are negligible.
7. Make sure that you also factor in the cost of the accessories. You may be charged extra for the side stand (a necessity, given the weight of the bike), the seat cover, the helmet lock, the crash guard, and others.
Final notes:
1. Lead acid batteries are stated to have a life of about 300 cycles. If your e-bike is stated to have a range of 40 km per cycle, you can expect only about 25-30 km per cycle in city traffic (less, as the battery ages). Thus, if you do not lose your battery early due to overcharging and if your battery runs a normal life, you can expect a maximum of about 300 x 25 km; that is, 7500 km from it. If you divide the cost of the battery by 7500, you will get an idea of how much you're going to pay per kilometer. Use this logic to calculate your expected costs based on the stated range of the bike you propose to buy, the real life range (60-70% of the stated range, and less as the batteries age), the cost of the batteries, and the interest lost because of the upfront capital expenditure at the time of purchase of the batteries.
- The maximum distance that I have obtained from any set of batteries was about 5000-6000 km.
- The batteries seldom last for longer than 12-18 months, regardless of distance run.