and how I make it.
I know some of you, probably most, think I am quite mad. I encourage you to do so. However I thought a short look into how a diseased mind works might be in order.
I have a hub motor that is 24volts 250 watts. It works pretty well and since I want to get some exercise when I ride, I don't want another hop on and ride bike. I also do not want a bike that requires me to pedal my guts out on a slightly steep hill. I want one that will let me pedal like it is on the flats even when it is a monster.
Now the bike I have runs like a 25cc friction drive for those of you who have ridden one of those. 70% of the time if I pedal at all it's to keep the speed up. 25% it's actually to help the bike up a hill it might have difficulty with, and 5% it serious pedal power to keep the bike from stalling. And that's about how a 25cc weed eater is.
Now a 31cc is different in that the numbers change significantly but only slightly. 80% of the pedal is to adjust the speed. 28% is to help the bike up the hill but it would make it without any help but at a crawl.. 2% is to keep it from stalling out. All numbers are estimates. Now every area and rider is different but my experience is the only one I really care about.
So what are my choices.
1. dump this bike and get a bigger one. A pretty expensive and wasteful choice.
2. Take the chance that I could screw up this one and try to modify it.
3. Do nothing and just live with it.
Now I bet you can guess which one I choose.
Step one... weigh the options.
option one...Replace the whole kit.... not a chance
two...increase the input voltage.
...(A) So to do that find out how much tolerance there is in the motor. I asked around on an ebike forum. The hub motors come in two types. Gear and direct drive. Mine is direct drive. They say those will take a little extra hit of juice. So the motor isn't a great concern to me.
...(b) What effect would it have on the controller. Again from the other forum I learned that the limit is on the capacitors in the controller. I can take the controller apart and see what the rating on the capacitors are. A fully charged battery pack for a 24volt battery pack is up to 28volts 27 more likely. So the capacitor would have to be at least thirty volts. I would need 40 volts if I were to add a 6volt boost to the power circuit. 50 volt to jump it to 36volts.
worst case I burn up the motor and controller. that is a really, really bad case and not the most likely. Most likely I would burn up the controller. I can buy a replacement controller. I'm not sure how much it would cost but I could get one. In which case I could get one capable of 36volts.
best case, I would have a slightly more powerful bike. Maybe enough to be a little more comfortable but not a great improvement. 6volts seems to the safest power jump for me to go with. I can't image the capacitors not being at least that strong. If I'm wrong I will need to buy a new controller. That is not a pleasant thought but I could get a stronger one.
The downside even to the best case, the cut off on the power which saves the batteries is about 24.5 volts. By the time the battery pack got down to that the batteries would be in pretty bad shape. Deep cycle charge needed which is not good for them.
I should add that I used a six volt boost to my scooter motor friction drive and there was a slight but noticeable power increase.
In my case there is two more days of good weather. I am going to ride the bike both days, then when the rain sets in I will make the decision.
So what decision would you make. I'm leaning to the 6volt boost. If it provides a slight boost with little risk, it seems like a good first step.
I know some of you, probably most, think I am quite mad. I encourage you to do so. However I thought a short look into how a diseased mind works might be in order.
I have a hub motor that is 24volts 250 watts. It works pretty well and since I want to get some exercise when I ride, I don't want another hop on and ride bike. I also do not want a bike that requires me to pedal my guts out on a slightly steep hill. I want one that will let me pedal like it is on the flats even when it is a monster.
Now the bike I have runs like a 25cc friction drive for those of you who have ridden one of those. 70% of the time if I pedal at all it's to keep the speed up. 25% it's actually to help the bike up a hill it might have difficulty with, and 5% it serious pedal power to keep the bike from stalling. And that's about how a 25cc weed eater is.
Now a 31cc is different in that the numbers change significantly but only slightly. 80% of the pedal is to adjust the speed. 28% is to help the bike up the hill but it would make it without any help but at a crawl.. 2% is to keep it from stalling out. All numbers are estimates. Now every area and rider is different but my experience is the only one I really care about.
So what are my choices.
1. dump this bike and get a bigger one. A pretty expensive and wasteful choice.
2. Take the chance that I could screw up this one and try to modify it.
3. Do nothing and just live with it.
Now I bet you can guess which one I choose.
Step one... weigh the options.
option one...Replace the whole kit.... not a chance
two...increase the input voltage.
...(A) So to do that find out how much tolerance there is in the motor. I asked around on an ebike forum. The hub motors come in two types. Gear and direct drive. Mine is direct drive. They say those will take a little extra hit of juice. So the motor isn't a great concern to me.
...(b) What effect would it have on the controller. Again from the other forum I learned that the limit is on the capacitors in the controller. I can take the controller apart and see what the rating on the capacitors are. A fully charged battery pack for a 24volt battery pack is up to 28volts 27 more likely. So the capacitor would have to be at least thirty volts. I would need 40 volts if I were to add a 6volt boost to the power circuit. 50 volt to jump it to 36volts.
worst case I burn up the motor and controller. that is a really, really bad case and not the most likely. Most likely I would burn up the controller. I can buy a replacement controller. I'm not sure how much it would cost but I could get one. In which case I could get one capable of 36volts.
best case, I would have a slightly more powerful bike. Maybe enough to be a little more comfortable but not a great improvement. 6volts seems to the safest power jump for me to go with. I can't image the capacitors not being at least that strong. If I'm wrong I will need to buy a new controller. That is not a pleasant thought but I could get a stronger one.
The downside even to the best case, the cut off on the power which saves the batteries is about 24.5 volts. By the time the battery pack got down to that the batteries would be in pretty bad shape. Deep cycle charge needed which is not good for them.
I should add that I used a six volt boost to my scooter motor friction drive and there was a slight but noticeable power increase.
In my case there is two more days of good weather. I am going to ride the bike both days, then when the rain sets in I will make the decision.
So what decision would you make. I'm leaning to the 6volt boost. If it provides a slight boost with little risk, it seems like a good first step.
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