Does"over volting" a brushless direct drive motor result in

[ebikedelight]

Its interesting to see so many different opinions on this subject.

From my limited knowledge , it doesnt make sense to me that just increasing volts , would result in a noticeable increase in power , ecpsecially at low rpms or from a standstill.

For example :

lets say you have a ebike that is using a 1000 watt direct drive hub motor with a 48 volt battery and 48 volt controller and you try and travel up a incline that is 20 degree grade , from a dead stop at the bottom of the incline using 1/3rd throttle .

then we use the same example but use a 60 volt battery / controller at 1/3rd throttle . Would we see a significant increase in the ability of the bike to go farther up the hill and if so , is that due to a increase of power / torque at low rpms..or due to the bike going a bit faster, from a standstill, at the same throttle setting due to voltage increase to the motor at that setting, compared to the 48 volt setup.

Also , lets say im happy with my 48 volt - 1000 watt direct drive hub motor as far as its top speed of 35 mph . Id like to keep that top speed at 35 mph for legality reasons, but increase just the power/ torque , ecpsecially at low/ mid rpms . Is this possible with just changing a controller / battery setup ?

 

[wesnewell]

Watts is power. VA=W, so increase either V or A = more power.. It's that simple. The only thing that will increase power at the same voltage is increasing the max amperage. Now you can get better acceleration using a smaller wheel, but the power will still be the same.

 

[markz]

I am amused at the different statements made.

 

[ebikedelight]

I am amused at the different statements made.

and we are amused at the beneficial content of your above post pertaining to the subject at hand.

 

[d8veh]

Its interesting to see so many different opinions on this subject.

From my limited knowledge , it doesnt make sense to me that just increasing volts , would result in a noticeable increase in power , ecpsecially at low rpms or from a standstill.

For example :

lets say you have a ebike that is using a 1000 watt direct drive hub motor with a 48 volt battery and 48 volt controller and you try and travel up a incline that is 20 degree grade , from a dead stop at the bottom of the incline using 1/3rd throttle .

then we use the same example but use a 60 volt battery / controller at 1/3rd throttle . Would we see a significant increase in the ability of the bike to go farther up the hill and if so , is that due to a increase of power / torque at low rpms..or due to the bike going a bit faster, from a standstill, at the same throttle setting due to voltage increase to the motor at that setting, compared to the 48 volt setup.

Also , lets say im happy with my 48 volt - 1000 watt direct drive hub motor as far as its top speed of 35 mph . Id like to keep that top speed at 35 mph for legality reasons, but increase just the power/ torque , ecpsecially at low/ mid rpms . Is this possible with just changing a controller / battery setup ?

I've done exactly that test on two different bikes. On the first, I tried 24v, 36v and 44v. On the second, 36v and 44v. It's always the same. The higher the voltage, the further up the hill you go until the motor stalls. In the above cases with 44v, they both made it to the top of the hill.

You can immediately feel the difference in torque when you increase the battery voltage.

 

[ebikedelight]

Its interesting to see so many different opinions on this subject.

From my limited knowledge , it doesnt make sense to me that just increasing volts , would result in a noticeable increase in power , ecpsecially at low rpms or from a standstill.

For example :

lets say you have a ebike that is using a 1000 watt direct drive hub motor with a 48 volt battery and 48 volt controller and you try and travel up a incline that is 20 degree grade , from a dead stop at the bottom of the incline using 1/3rd throttle .

then we use the same example but use a 60 volt battery / controller at 1/3rd throttle . Would we see a significant increase in the ability of the bike to go farther up the hill and if so , is that due to a increase of power / torque at low rpms..or due to the bike going a bit faster, from a standstill, at the same throttle setting due to voltage increase to the motor at that setting, compared to the 48 volt setup.

Also , lets say im happy with my 48 volt - 1000 watt direct drive hub motor as far as its top speed of 35 mph . Id like to keep that top speed at 35 mph for legality reasons, but increase just the power/ torque , ecpsecially at low/ mid rpms . Is this possible with just changing a controller / battery setup ?

I've done exactly that test on two different bikes. On the first, I tried 24v, 36v and 44v. On the second, 36v and 44v. It's always the same. The higher the voltage, the further up the hill you go until the motor stalls. In the above cases with 44v, they both made it to the top of the hill.

You can immediately feel the difference in torque when you increase the battery voltage.

Then your experiment helps to prove the facts. More voltage does result in more power and torque at low rpms or from from a dead stop , up a incline.... along with a higher top speed.

Thanks.

 

[Punx0r]

No, because you are also changing the phase current, which is different to battery current.

Torque is unrelated to power (you can have infinite torque but zero power). Torque is the result by magnetic flux generated by the motor coils, which is entirely dependent on amp-turns in the coils. The motor is wound with a fixed number of turns, so the only thing that can be changed is the current, ergo: current = torque.

 

[DrkAngel]

Did a ebike.ca ebike simulator of my 25.9V and 33.3V batteries on a reasonable equivalent of my motor and ...
It clearly demonstrates a torque and speed increase from an identical amp controller.

Efficiency is reasonably similar.
Reducing throttle for same acceleration rate as lower voltage battery, should actually improve overall efficiency. = less heat from same performance + higher performance (acceleration and top speed) when desired.
Within reason!
Bumping up the voltage somewhat is reasonable ..
Doubling voltage might be pushing reasonability-suviveability a bit ... ! (dependent on the motor)

 

[ebikedelight]

Its interesting to read the opinions on this subject and how so many people disagree .

I have a generic 1000 watt - 48 volt D.D. , rear ehub motor off ebay from the seller known as " xcessories" . Running it at 48 volt lifepo4 - 20 a/h , it will do a top speed of
36 mph on flat land , but the power is lacking . I was curious if I increased voltage by 50% and went to a 72 volt battery/ controller, would the increase in power be 50% better ? I have no need to increase the top speed ...so I would be increasing the voltage to only try to gain more power from dead stops, travelling inclines and riding thru dirt trails.....and would this voltage increase result in more overall efficiency ? I dont need huge power to pop wheelies from a dead stop.

 

[DrkAngel]

so I would be increasing the voltage to only try to gain more power from dead stops, travelling inclines and riding thru dirt trails.....and would this voltage increase result in more overall efficiency ? I dont need huge power to pop wheelies from a dead stop.

Higher voltage, or higher Amp controller, would likely give you better off the line acceleration.
However ...
The typical hub motor is not designed for low end performance.
Throwing in more watts will, mostly be wasted as damaging heat.

Best Solution?
Put it in low gear and pedal assist to get started ... ?
0 - 5+ MPH, you might have 400% the torque of the motor!

 

[teslanv]

Its interesting to read the opinions on this subject and how so many people disagree .

I have a generic 1000 watt - 48 volt D.D. , rear ehub motor off ebay from the seller known as " xcessories" . Running it at 48 volt lifepo4 - 20 a/h , it will do a top speed of
36 mph on flat land , but the power is lacking . I was curious if I increased voltage by 50% and went to a 72 volt battery/ controller, would the increase in power be 50% better ? I have no need to increase the top speed ...so I would be increasing the voltage to only try to gain more power from dead stops, travelling inclines and riding thru dirt trails.....and would this voltage increase result in more overall efficiency ? I dont need huge power to pop wheelies from a dead stop.

I have the exact same kit from xcessories. It is a 2807 DD hub motor with a Kv of around 8 RPM per volt. If you increase the voltage to 72V, you will need to replace the controller, since the stock kit's controller has 63V Caps. If you are going to do this, I recommend a 9FET or 12FET IRFB4110 Xie Chang/infineon controller, which is capable of up to 100V and 30A-40A of current. This will give you a noticeable increase in total power, but be sure that your battery can handle the additional current requirements. Low-C rate Lithium cells (18650-based packs) and LiFePO4 packs can typically only output 1C of power continuously. (i.e. a 72V - 15AH pack at 1C is 15 Amps continuous) Many guys will use RC LiPo because it has high C-rates. (10C and higher)

You WILL increase the top speed at 72V, unless you program the new (Infineon) controller specifically to limit speed to say 75%

 

[r3volved]

Increasing the voltage without changing controller should (obviously?) increase both speed and torque - you are keeping the same amps at higher volts, so increasing power.

Could someone please explain the relationships between these following changes, in respect to:
a. Increased/decreased torque?
b. Increased/decreased top speed?
c. Does the sweet spot change for efficiency?
d. Will there be a difference in wh/km (wh/m)?

--------
Original Spec:
36V + 10A controller providing 360W
(for simplicity sake let's just say batteries are capable of continuous >=20A so sag, C rate, *battery* is not affecting results)

Case #1:
Upgrade to 48V with same 10A controller = 480W (133% original power)

Case #2:
Upgrade to 48V and downgrade to 7.5A controller = 360W (100% original power)

Case #3:
Maintain 36V and upgrade to 13.3A controller = 480W (133% original power)
--------

At 133% original 'power', what are the performance differences between case 1 and 3? Is this where phase amps come into play? (I don't think I have a clear understanding of phase amps vs battery amps)

Despite the differences in opinion here, this is still all very helpful

 

[MadRhino]

No matter how you increase the power, extra power will result in shorter range, unless you can keep yourself from using it.

Higher voltage does result in higher top speed. If you don't use the extra speed and this is making you ride out of your motor ideal efficiency zone for a longer part of the time, it will result in lower efficiency.

Controller settings, like battery current to phase current ratio, can decrease or increase efficiency; for this can feed your motor more or less power, and may also cause current losses in heat when the ratio is too high.

Usually, when we want better power, we care little about efficiency. I mean: You want power or range, you can't have both.

 

[ebikedelight]

Its interesting to read the opinions on this subject and how so many people disagree .

I have a generic 1000 watt - 48 volt D.D. , rear ehub motor off ebay from the seller known as " xcessories" . Running it at 48 volt lifepo4 - 20 a/h , it will do a top speed of
36 mph on flat land , but the power is lacking . I was curious if I increased voltage by 50% and went to a 72 volt battery/ controller, would the increase in power be 50% better ? I have no need to increase the top speed ...so I would be increasing the voltage to only try to gain more power from dead stops, travelling inclines and riding thru dirt trails.....and would this voltage increase result in more overall efficiency ? I dont need huge power to pop wheelies from a dead stop.

I have the exact same kit from xcessories. It is a 2807 DD hub motor with a Kv of around 8 RPM per volt. If you increase the voltage to 72V, you will need to replace the controller, since the stock kit's controller has 63V Caps. If you are going to do this, I recommend a 9FET or 12FET IRFB4110 Xie Chang/infineon controller, which is capable of up to 100V and 30A-40A of current. This will give you a noticeable increase in total power, but be sure that your battery can handle the additional current requirements. Low-C rate Lithium cells (18650-based packs) and LiFePO4 packs can typically only output 1C of power continuously. (i.e. a 72V - 15AH pack at 1C is 15 Amps continuous) Many guys will use RC LiPo because it has high C-rates. (10C and higher)

You WILL increase the top speed at 72V, unless you program the new (Infineon) controller specifically to limit speed to say 75%

I have the LYEN EC- 124110LD- 1012L178 controller...and the programming cable , so thats not a problem { of course Ive never re- programmed it from the stock 48 volt setup and dont know the easiest procedure to do it } .

Ive only used 48 volt- 20 ah lifepo4 for my ebikes....so if I wanted to push the xcessories motor harder to gain more power , would a 72 volt lipo setup be best overall option and what settings on the lyen controller would I need to re-program ? I also assume that I would need to upgrade the phase wires/ sensor wires....what gauge is best for that , and do I need to dissasemble the electric hub and change the wires, or can I just snip the wires where they come out of the axle and solder thicker wires from that point, to the controller ?

 

[ebikedelight]

.

Usually, when we want better power, we care little about efficiency. I mean: You want power or range, you can't have both.

Very true...

For my needs, I only need to have that extra power, about 25% of my riding time...the other 75% of the riding time, the power would not be called upon .

 

[teslanv]

I have the LYEN EC- 124110LD- 1012L178 controller...and the programming cable , so thats not a problem { of course Ive never re- programmed it from the stock 48 volt setup and dont know the easiest procedure to do it } .

Ive only used 48 volt- 20 ah lifepo4 for my ebikes....so if I wanted to push the xcessories motor harder to gain more power , would a 72 volt lipo setup be best overall option and what settings on the lyen controller would I need to re-program ? I also assume that I would need to upgrade the phase wires/ sensor wires....what gauge is best for that , and do I need to dissasemble the electric hub and change the wires, or can I just snip the wires where they come out of the axle and solder thicker wires from that point, to the controller ?

With the xcessories (YescomUSA) DD Hub motor, you will probably NOT need to upgrade the phase wires, as long as you stay under 40A Battery, and 60-80A Phase Current. If you notice the phase wires getting excessively hot, you could always just upgrade the phase wires from where they exit the motor's axle to the controller, and this would help quite a bit.

A 72V LiPo Set-Up (18S to 20S) would be a great solution for a lot of power. You could easily run 3000W+ of power which is enough to make that motor beg for mercy...

http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=58858

 

[MadRhino]

Ive only used 48 volt- 20 ah lifepo4 for my ebikes....so if I wanted to push the xcessories motor harder to gain more power , would a 72 volt lipo setup be best overall option and what settings on the lyen controller would I need to re-program ? I also assume that I would need to upgrade the phase wires/ sensor wires....what gauge is best for that , and do I need to dissasemble the electric hub and change the wires, or can I just snip the wires where they come out of the axle and solder thicker wires from that point, to the controller ?

You will have to reproram the controller. It is not very complicated. For the current that you plan to feed, 10ga silicon wire is enough. I find 8ga is the best wire to use between battery and controller, and between controller and motor. Phase wires inside the motor are very good on some motors, but too small on others. Usually, cutting them short off the motor and splicing heavier ga to the controller is enough.

 

[ebikedelight]

I have the LYEN EC- 124110LD- 1012L178 controller...and the programming cable , so thats not a problem { of course Ive never re- programmed it from the stock 48 volt setup and dont know the easiest procedure to do it } .

Ive only used 48 volt- 20 ah lifepo4 for my ebikes....so if I wanted to push the xcessories motor harder to gain more power , would a 72 volt lipo setup be best overall option and what settings on the lyen controller would I need to re-program ? I also assume that I would need to upgrade the phase wires/ sensor wires....what gauge is best for that , and do I need to dissasemble the electric hub and change the wires, or can I just snip the wires where they come out of the axle and solder thicker wires from that point, to the controller ?

With the xcessories (YescomUSA) DD Hub motor, you will probably NOT need to upgrade the phase wires, as long as you stay under 40A Battery, and 60-80A Phase Current. If you notice the phase wires getting excessively hot, you could always just upgrade the phase wires from where they exit the motor's axle to the controller, and this would help quite a bit.

A 72V LiPo Set-Up (18S to 20S) would be a great solution for a lot of power. You could easily run 3000W+ of power which is enough to make that motor beg for mercy...

http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=58858

Thanks for the info....I would probably just go ahead and upgrade those phase wires , at the axle exit, just to be safe...they look so thin and fragile anyways. Whats a good gauge wire to go with, that isnt overkill on thickness/ bulk ? I wouldnt need to upgrade the 3 sensor wires ?

 

[wesnewell]

ebikedelight.
" xcessories" is the ebay seller for Yescomusa. They sell 2 different kits. One is a ringed motor and the other is solid black. The ringed motor comes/came with a 30A controller while the black one comes/came with a 26A controller, so you get a little more power with the old version ringed motor, but top speed should be the same on the same voltage. 36mph sounds a little high to me, but I'm probably a lot heavier than you at 270lbs. Typically on 12s lipo they do ~28mph, and on 16s lifepo4 ~32mph, so you might want to check your speedo settings. Now if you just want faster acceleration, a shunt mod will give you that. I did a 50% shunt mod increase on one of their controllers up to ~45A and there is a noticeable increase in power and acceleration. 50V x 30A = 1500W and 50V x 45A = 2250W. It will also increase top speed a little on the flats, but more so going up hill. If your battery pack is not capable of 45A, then don't increase amps beyond its capability. As far raising voltage, the stock controllers are limited to 63V max (not 63V nominal).
http://endless-sphere.com/forums/viewtopic.php?f=2&t=31643

 

[teslanv]

+1 for the shunt Mod.

 

[ebikedelight]

Thanks for all the info guys,.


For upgrading the 5 phase wires and 3 sensor wires , coming directly out of the AXLE , to take 72 volts - 40 amps wouldnt 14 gauge wire be thick enough ? The wires they use now, is very thin...

 

[ebikedelight]

+1 for the shunt Mod.

for my LYEN controller...I shouldnt have to do the shunt mod at all..right ? Just reprogram the controller settings to 72 volt - 40 amp ?

 

[ebikedelight]

ebikedelight.
" xcessories" is the ebay seller for Yescomusa. They sell 2 different kits. One is a ringed motor and the other is solid black. The ringed motor comes/came with a 30A controller while the black one comes/came with a 26A controller, so you get a little more power with the old version ringed motor, but top speed should be the same on the same voltage. 36mph sounds a little high to me, but I'm probably a lot heavier than you at 270lbs. Typically on 12s lipo they do ~28mph, and on 16s lifepo4 ~32mph, so you might want to check your speedo settings. Now if you just want faster acceleration, a shunt mod will give you that. I did a 50% shunt mod increase on one of their controllers up to ~45A and there is a noticeable increase in power and acceleration. 50V x 30A = 1500W and 50V x 45A = 2250W. It will also increase top speed a little on the flats, but more so going up hill. If your battery pack is not capable of 45A, then don't increase amps beyond its capability. As far raising voltage, the stock controllers are limited to 63V max (not 63V nominal).
http://endless-sphere.com/forums/viewtopic.php?f=2&t=31643

Yeah..I wiegh around 230 lbs...so maybe thats why I get a few mile per hour faster on top end.

My wifes bike uses the stock controller set at 63 volts....

My controller is the Lyen , so I can change its settings as needed for a 72 volt setup.

 

[teslanv]

Thanks for all the info guys,.


For upgrading the 5 phase wires and 3 sensor wires , coming directly out of the AXLE , to take 72 volts - 40 amps wouldnt 14 gauge wire be thick enough ? The wires they use now, is very thin...

Use 12AWG Silicone or PTFE for better "Punch". On my MXUS 3000W Hub Phase wire upgrade I am actually using 8AWG, and the performance boost is nice.

 

[John in CR]

Increasing voltage with no other changes doesn't increase max torque at 0 rpm, but at all rpms greater than zero it does increase torque for the same throttle position and controller settings. The reason is because increasing voltage moves the torque curve (mostly a straightish line) from the same starting point at 0 rpm out to a higher rpm. As part of that process it forces the controller to deliver higher phase current at rpms above 0, and the increased torque at the higher end of the rpm range and increase rpm range will always result in higher top speed. Because wind resistance increased geometrically, the increase in speed will not be proportional to the increase in voltage. How stressed the system is will also impact how much your top speed increases.

These statements are fact, not opinion.