Ebiker33
Well-Known Member
Hi All
I wanted to talk about batteries. I have a slightly different perspective on these because I am coming over from a very extensive background in cordless power tools.
My career path has had me dealing with these for decades. Recently I began to look for an Ebike. I haven't purchased one yet but, but I have visited some bike shops to pick up some idea's.
One of the things that some of the sales people have told me is don't worry about Amp hours on a battery, that I can tell you is just wrong, straight out. So I want to go over I few things from my industry and how that transfers over to the Ebike industry and batteries. The power tool industry has long used 18V as the standard for decades now, the early nineties is when they first arrived en mass. But they where Nicad, after a brief stint they went to NiMh and then Lithium mostly using the 18650 cell. They kept upping the game 1.5/2/3/4/5/6/8/12 amp hours they also have recently transitioned to the better cells the 21700. So either tandem 2 X 6amp for Makita or a single for Milwaukee can now power some really big tools, full size hammer drills, chainsaws, tables saws, miter saws even lawnmowers. But here is the interesting point many customers report great run time on the lower amp batteries 6-9amp/hrs the tool works fine with those batteries. But we now know that the motors prefers and makes use of the higher amp hours not just for run time alone but for actual power use, and it's actually easier on the motor. For example the Milwaukee table saw works fine with the lower 5/amp hour battery, but you can hear the motor really straining when using it, whereas it purrs along with the bigger recommend 12amp/hr battery. Another customer using an outdoor tool said the 9amp battery worked fine he was very happy with it, but when the 12amp/hr was released he just had to have it, he reported it was liking finding a whole new gear on the tool, he didn't care about run time. So this is the point it's not just run time we are looking at.
Also is an under power supplied motor an issue, it is in hardwired examples, lets say you have a hardware voltage supply system that is 208V 1ph 15amps = 3120W but your motor is 240V 15amp 1 ph =3600w, it's never getting enough power, the motor wants more power and it's over the 10% variance, which will be hard on the motor, perhaps causing it to heat up. My point is these Chinese bikes that have true 500W motors that are supplying low volts and amps could be harming the motor long term, this is not an instant burn out issue but more like premature motor failures after many months.
Now it is possible that none of this will matter if you have a controller that is bottle necking the entire system, let's hope for the sake of argument it isn't.
So first the formula V X A = W
Volts X Amps equal Watts
So let's plug in a few
36 X 10 = 360W
48 X 15 = 720W
52 X 19 =988W
48 X 21 = 1008W
Also larger voltage is not always better as this shows for actual wattage
So if they are using that newer M620 Bafang mid-drive and don't put a big enough battery, it's being totally wasted
If you are considering an Ebike or already own one, don't ever discard the amp hours, it's much more important than distance you can ride, it also effects the torque/power to climb that hill you need to when it's on a full charge.
If the Ebike industry follows the tool industry the newer 21700 cells will make there way into the 48V and 52V sooner or later giving more power output and run time.
For me I won't be buying one under 48V/16amp/hrs as this gets you to your full supply to a peak 750w motor at 768W.
A final thought, it amazes me that only 216 watts can now power all major power tools that have brushless motors, that truly is a great leap in technology when many of these corded brushed tools were using up to 1500W hard wired.
Some customers report their cordless tools now outperforms there corded machines.
It is so revolutionary many power tool companies no longer spend any R & D on corded product it's all going toward cordless now, 100% of it. This means battery technology is only going to get better for both industries.
Companies like Bosch are doing both, so their R & D helps both sides.
In 10 years almost everybody will own an Ebike powered by new and exciting battery technology, the baby boomers are going to love it.
I wanted to talk about batteries. I have a slightly different perspective on these because I am coming over from a very extensive background in cordless power tools.
My career path has had me dealing with these for decades. Recently I began to look for an Ebike. I haven't purchased one yet but, but I have visited some bike shops to pick up some idea's.
One of the things that some of the sales people have told me is don't worry about Amp hours on a battery, that I can tell you is just wrong, straight out. So I want to go over I few things from my industry and how that transfers over to the Ebike industry and batteries. The power tool industry has long used 18V as the standard for decades now, the early nineties is when they first arrived en mass. But they where Nicad, after a brief stint they went to NiMh and then Lithium mostly using the 18650 cell. They kept upping the game 1.5/2/3/4/5/6/8/12 amp hours they also have recently transitioned to the better cells the 21700. So either tandem 2 X 6amp for Makita or a single for Milwaukee can now power some really big tools, full size hammer drills, chainsaws, tables saws, miter saws even lawnmowers. But here is the interesting point many customers report great run time on the lower amp batteries 6-9amp/hrs the tool works fine with those batteries. But we now know that the motors prefers and makes use of the higher amp hours not just for run time alone but for actual power use, and it's actually easier on the motor. For example the Milwaukee table saw works fine with the lower 5/amp hour battery, but you can hear the motor really straining when using it, whereas it purrs along with the bigger recommend 12amp/hr battery. Another customer using an outdoor tool said the 9amp battery worked fine he was very happy with it, but when the 12amp/hr was released he just had to have it, he reported it was liking finding a whole new gear on the tool, he didn't care about run time. So this is the point it's not just run time we are looking at.
Also is an under power supplied motor an issue, it is in hardwired examples, lets say you have a hardware voltage supply system that is 208V 1ph 15amps = 3120W but your motor is 240V 15amp 1 ph =3600w, it's never getting enough power, the motor wants more power and it's over the 10% variance, which will be hard on the motor, perhaps causing it to heat up. My point is these Chinese bikes that have true 500W motors that are supplying low volts and amps could be harming the motor long term, this is not an instant burn out issue but more like premature motor failures after many months.
Now it is possible that none of this will matter if you have a controller that is bottle necking the entire system, let's hope for the sake of argument it isn't.
So first the formula V X A = W
Volts X Amps equal Watts
So let's plug in a few
36 X 10 = 360W
48 X 15 = 720W
52 X 19 =988W
48 X 21 = 1008W
Also larger voltage is not always better as this shows for actual wattage
So if they are using that newer M620 Bafang mid-drive and don't put a big enough battery, it's being totally wasted
If you are considering an Ebike or already own one, don't ever discard the amp hours, it's much more important than distance you can ride, it also effects the torque/power to climb that hill you need to when it's on a full charge.
If the Ebike industry follows the tool industry the newer 21700 cells will make there way into the 48V and 52V sooner or later giving more power output and run time.
For me I won't be buying one under 48V/16amp/hrs as this gets you to your full supply to a peak 750w motor at 768W.
A final thought, it amazes me that only 216 watts can now power all major power tools that have brushless motors, that truly is a great leap in technology when many of these corded brushed tools were using up to 1500W hard wired.
Some customers report their cordless tools now outperforms there corded machines.
It is so revolutionary many power tool companies no longer spend any R & D on corded product it's all going toward cordless now, 100% of it. This means battery technology is only going to get better for both industries.
Companies like Bosch are doing both, so their R & D helps both sides.
In 10 years almost everybody will own an Ebike powered by new and exciting battery technology, the baby boomers are going to love it.
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