Electric bike range extender
Discussion
Good evening! Not posted for a while. Over the last year I've been using an electric bike for commuting to work. Quite a revelation to be honest. The trouble is the issue of range for a long ride. The battery is good for maybe 45 miles and that's it. What is the legal standing if you had a small petrol generator to extend the range? Bike conforms to the current legislation re assist, max speed, motor power etc. thr generator only supplies electrical power, would never directly drive the wheels.
Edited by bryan35 on Friday 3rd November 22:49
I did in fact buy another battery. Well, a summer ride out to the coast - 120 miles - is quite feasibly, apart from the lack of range. The range would be pretty much limitless with a petrol generator. Just curious. I can't see how it can be illegal, and wouldn't be surprised if they begin to appear. Now there's a dragons den moment!
Generators are not normally designed to run while moving, cheap ones would no doubt shake themselves to bits within a couple of minutes, and even decent ones i suspect would not last much longer, and even if they did running anywhere near peak power the quality of the power would be too poor to actually charge from without damaging the batteries while stationary, let alone while moving. Then there is the issue of does the bike even allow charging while powering the motor at the same time? It won't have been designed to do that.
Then you have the extra weight even the smallest generators are about 20kg, how much of a dent in the 45 mile range is adding that going to make?
The fuel tank probably won't be safe in a accident.
In theory from a 2kw generator you could get 2kwh over an hour, and that could maybe get you another 20 miles.
In practice the 2kw generator will only be able to sustain about half that, and 1kwh of extra charge will only just about be about enough to offset the energy used to carry the extra weight. Then in 2 weeks time you'll have a broken generator, a broken bike and a burnt ass.
Then you have the extra weight even the smallest generators are about 20kg, how much of a dent in the 45 mile range is adding that going to make?
The fuel tank probably won't be safe in a accident.
In theory from a 2kw generator you could get 2kwh over an hour, and that could maybe get you another 20 miles.
In practice the 2kw generator will only be able to sustain about half that, and 1kwh of extra charge will only just about be about enough to offset the energy used to carry the extra weight. Then in 2 weeks time you'll have a broken generator, a broken bike and a burnt ass.
I'd guess the best range extender going would be the nut holding the handle bars!!! ging84 said:
Generators are not normally designed to run while moving, cheap ones would no doubt shake themselves to bits within a couple of minutes, and even decent ones i suspect would not last much longer, and even if they did running anywhere near peak power the quality of the power would be too poor to actually charge from without damaging the batteries while stationary, let alone while moving. Then there is the issue of does the bike even allow charging while powering the motor at the same time? It won't have been designed to do that.
Then you have the extra weight even the smallest generators are about 20kg, how much of a dent in the 45 mile range is adding that going to make?
The fuel tank probably won't be safe in a accident.
In theory from a 2kw generator you could get 2kwh over an hour, and that could maybe get you another 20 miles.
In practice the 2kw generator will only be able to sustain about half that, and 1kwh of extra charge will only just about be about enough to offset the energy used to carry the extra weight. Then in 2 weeks time you'll have a broken generator, a broken bike and a burnt ass.
well, you don't need anything like 2kw. A typical battery pack is in the area of 400wh of capacity giving about 40 miles of comfortable range. Roughly 10wh per mile. At 15MPH that's an average of 150 watts, so the generator only needs to be maybe 200 watts. With a switch mode charger, quality of supply is pretty much irrelevant. So basically a little 27cc strimmer engine would easily supply enough energy for a small alternator and only weights a few kilos. Then you have the extra weight even the smallest generators are about 20kg, how much of a dent in the 45 mile range is adding that going to make?
The fuel tank probably won't be safe in a accident.
In theory from a 2kw generator you could get 2kwh over an hour, and that could maybe get you another 20 miles.
In practice the 2kw generator will only be able to sustain about half that, and 1kwh of extra charge will only just about be about enough to offset the energy used to carry the extra weight. Then in 2 weeks time you'll have a broken generator, a broken bike and a burnt ass.
That said, a spare 400wh battery is only 2.5kg !!
bryan35 said:
well, you don't need anything like 2kw. A typical battery pack is in the area of 400wh of capacity giving about 40 miles of comfortable range. Roughly 10wh per mile. At 15MPH that's an average of 150 watts, so the generator only needs to be maybe 200 watts. With a switch mode charger, quality of supply is pretty much irrelevant. So basically a little 27cc strimmer engine would easily supply enough energy for a small alternator and only weights a few kilos.
That said, a spare 400wh battery is only 2.5kg !!
A little engine would make it a motorbike - of one sort or another - with all the complications that involves.That said, a spare 400wh battery is only 2.5kg !!
Possibly a spare battery? Or take the charging cable with you and persuade someone to let you plug in. Good luck with that in Yorkshire!
The coast must be nearer than 60 miles away?
The Mad Monk said:
A little engine would make it a motorbike - of one sort or another - with all the complications that involves.
Possibly a spare battery? Or take the charging cable with you and persuade someone to let you plug in. Good luck with that in Yorkshire!
The coast must be nearer than 60 miles away?
which brings us back to the original question. If the bicycle satisfies all the requirements of an electric bike, but has a petrol engine to re-charge the battery/supply the electric system, is that legal?Possibly a spare battery? Or take the charging cable with you and persuade someone to let you plug in. Good luck with that in Yorkshire!
The coast must be nearer than 60 miles away?
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