Battery Technical Discussion

Ebiker33

New 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.
 
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BBassett

Active Member
I average 50 miles on 15 Ah with a fully loaded bike and can get over 90 miles on 60% of a 30 Ah pack when stripped down. This is both using a BBS02 for the 1st 9000 miles and now with a BBSHD. The advantage of having a pair of big batteries is that I don't have to stress them. I don't charge past 80% and don't deplete past 20%. This will hopefully extend the number of charge cycles to over 1800. Use a Satiator to charge them in a proper manner and try to wear a pack out and you should have all your answers.

https://imgur.com/a/3w6izz7 - Bike and Trailer
https://imgur.com/a/DKpcF0a
https://imgur.com/a/zXXlyuv

Check out 70 miles w/front panniers & trailer on Relive! https://www.relive.cc/view/g37290970278
https://photos.google.com/share/AF1QipN67sUw0ykU-Mg5gLsOw9vF8kBMEM5cGCgCNmLT_j72h9iu5fKYFFVbLJ2Z415Umw?key=LUZqdEl1d3RjNV9id0ZvTEFickhITnBwWFZrU3hR
 

Mike's E-Bikes

Well-Known Member
You are mixing up the terminology of amphours and amps. Your misunderstanding of terms used and lack of electrical fluency is not helping with your attempt at articulating some sort of use of battery technology. I can assure you that plopping a 17 Ah capacity, 48 volt battery will not help the same motor on the same ebike operate any differently than a 13 Ah capacity, 48 volt battery, other than achievable range. sure you might be able to run at higher assist levels for longer periods, but again that relates to range.
 

BBassett

Active Member
You are mixing up the terminology of amphours and amps. Your misunderstanding of terms used and lack of electrical fluency is not helping with your attempt at articulating some sort of use of battery technology. I can assure you that plopping a 17 Ah capacity, 48 volt battery will not help the same motor on the same ebike operate any differently than a 13 Ah capacity, 48 volt battery, other than achievable range. sure you might be able to run at higher assist levels for longer periods, but again that relates to range.
No, I'm really not mixing anything up, and I never implied that a battery with a larger capacity would make the bike go faster, just farther. I am telling you what data I get back from the GPS(s), Eggrider, and most importantly the Satiator once the battery is recharged... "I assure you".

 

FlatSix911

Active 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.

Thanks for posting... well done! How long do you think it will take to see the 21700 cells in new eBikes?
 

Ebiker33

New Member
You are mixing up the terminology of amphours and amps. Your misunderstanding of terms used and lack of electrical fluency is not helping with your attempt at articulating some sort of use of battery technology. I can assure you that plopping a 17 Ah capacity, 48 volt battery will not help the same motor on the same ebike operate any differently than a 13 Ah capacity, 48 volt battery, other than achievable range. sure you might be able to run at higher assist levels for longer periods, but again that relates to range.
My definitions might be wrong on the cross over from hard wire to cordless due to "electrical fluency" but what is in the cordless industry on power tools is the same technology, I know for a fact higher amp/hrs is helping motors run better, I have heard them running the two different batteries under load. But with further research I have found that the controller better be at 20/25 amps not 10 like one bike manufacturer told me, you are bottle necking the whole system. And it won't matter what battery or motor you have. The owner of Bolton bikes sells 35 amp controllers for Rad bikes, and those that have installed them report huge increases.
Really three components are critical voltage, amp/hrs and the controller amp hours if you have all three of those jacked up your motor is going to be jacked too, but the question is, will it last...maybe somebody can answer that question who has done that.

It could also be that due to government regulations manufactures are using the controller in suppressing the output to allow the bike to stay in its allowed classification code for speed and watts, the upside is longer run time, the downside is I won't have the full torque availability to me when I want to zip up that 18% grade hill. I really think the classification should not be in watts but speed restrictions only, 20 MPH for city is safe, but maybe we need that full 1000W to move a 70 pound bike with 15 pounds of gear, with a 250 lb rider up that hill with a throttle. If he can do it at 20 mph that is great.
 
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BBassett

Active Member
I'm more interested in a capacitance pack at about 1 ounce of weight to each Amp-hour of storage that would take 10 minutes to charge. I guess we can all dream.