Recently my mind has been wandering and thinking about an ideal electric bike for long distance cycle touring, and these are my thoughts, i would really appreciate any input here.
Assuming that Crank drive systems like the Panasonic seem to use about 8wh and hub drives about 12wh per mile. The biggest consideration for distance is a combination of the drive efficiency and how many watt hours you are carrying. So a 26v Panasonic 10ah battery has 260w/hours and a 36v Hub motor 10ah battery has 360w/hours.
Assuming cut off at 10% of the full capacity, so that we actually get to use 90% of the batteries capacity
Crank Drive 260 X 90% = 234w/hours divided by 8Wh = 29.25 Miles
Hub Drive 360 X 90% = 324w/hours divided by 12wh = 27 Miles
So both bikes are going to run out of steam at a similar distance lets call it 28 miles, So if you left the campsite/Hotel in the morning and you are averaging say 12 mph you have about 2 hours 20 minutes until you are out of battery power.
This is not very long so what are the solutions? as you will not even make the lunch break.
Increase battery capacity lets use 18ah which is now available for the Panasonic System, we were using a 10ah battery before so we just multiply our distances by 1.8
Crank Drive 29.25 X 1.8 = 52.65 Miles
Hub Drive 27 X 1.8 = 48.6 Miles
Lets call it an average of 50 miles, That is better and gives at an average of 12mph just over 4 hours. So 2 batteries of this size would get you through a full day.
But then it got me thinking that a very important issue is also how fast you can recharge. For example I was looking at Kudos website today and they state that with there charger they can recharge there 10ah LiFePo battery from 50% capacity to full in 1 hour, so it must be a quite powerful 5amp charger. So assuming that you had a French style 2 hour lunch and you can blag an electric point for this lunch, on your travels you could completely charge a 10ah battery over the 2 hour lunch break. which would give you about 28 miles and then another 28 miles.
Now what if we had a 10amp charger this time would come down to 1 hour, or what about a 20amp charger, that would recharge in only 30 minutes or charge an 18amp battery in under 1 hour !!!!!!!. The point i am trying to make is we talk a lot about efficiencies of crank or hub systems, but for long distance use surely this is not actually as important as the ability to recharge A BIG BATTERY PACK AT A FAST RATE. Or am i completely missing something here?
Assuming that Crank drive systems like the Panasonic seem to use about 8wh and hub drives about 12wh per mile. The biggest consideration for distance is a combination of the drive efficiency and how many watt hours you are carrying. So a 26v Panasonic 10ah battery has 260w/hours and a 36v Hub motor 10ah battery has 360w/hours.
Assuming cut off at 10% of the full capacity, so that we actually get to use 90% of the batteries capacity
Crank Drive 260 X 90% = 234w/hours divided by 8Wh = 29.25 Miles
Hub Drive 360 X 90% = 324w/hours divided by 12wh = 27 Miles
So both bikes are going to run out of steam at a similar distance lets call it 28 miles, So if you left the campsite/Hotel in the morning and you are averaging say 12 mph you have about 2 hours 20 minutes until you are out of battery power.
This is not very long so what are the solutions? as you will not even make the lunch break.
Increase battery capacity lets use 18ah which is now available for the Panasonic System, we were using a 10ah battery before so we just multiply our distances by 1.8
Crank Drive 29.25 X 1.8 = 52.65 Miles
Hub Drive 27 X 1.8 = 48.6 Miles
Lets call it an average of 50 miles, That is better and gives at an average of 12mph just over 4 hours. So 2 batteries of this size would get you through a full day.
But then it got me thinking that a very important issue is also how fast you can recharge. For example I was looking at Kudos website today and they state that with there charger they can recharge there 10ah LiFePo battery from 50% capacity to full in 1 hour, so it must be a quite powerful 5amp charger. So assuming that you had a French style 2 hour lunch and you can blag an electric point for this lunch, on your travels you could completely charge a 10ah battery over the 2 hour lunch break. which would give you about 28 miles and then another 28 miles.
Now what if we had a 10amp charger this time would come down to 1 hour, or what about a 20amp charger, that would recharge in only 30 minutes or charge an 18amp battery in under 1 hour !!!!!!!. The point i am trying to make is we talk a lot about efficiencies of crank or hub systems, but for long distance use surely this is not actually as important as the ability to recharge A BIG BATTERY PACK AT A FAST RATE. Or am i completely missing something here?