36v Vs 48v
- Thread starter anon4
- Start date
Yes & Yes.
48v battery will have more wh if the ah is the same, so significant range will be greater. 33% more range.
As an example battery range.
36v x 14.5 ah = 522wh.
48v x 14.5 ah = 696wh.
A 48v 11ah battery would be as near as a damn the same as a 36v x 14.5ah.
Torque will increase by 33%.
As an example torque.
36v x 17a controller = 612w max output or about 489w at the wheel, allowing for efficacy loss.
48v x 17a controller = 816w max output or about 650w at the wheel, allowing for efficacy loss.
In both cases if you do the math, difference is about 33%.
The max torque is most noticeable in pas5 on inclines, though you will most definitely feel the extra speed from the torque when tonking along on the flat.
Speed is also increased but the trade off is range will be less, you will only see the extra range if you keep to the same speed which you rode along with the 36v set up.
Another consequence is the hub speed, rpm will increase by 33%.
201rpm becomes a 265rpm hub.
260rpm becomes a 345rpmhub.
328rpm becomes a 436rpm hub.
48v battery will have more wh if the ah is the same, so significant range will be greater. 33% more range.
As an example battery range.
36v x 14.5 ah = 522wh.
48v x 14.5 ah = 696wh.
A 48v 11ah battery would be as near as a damn the same as a 36v x 14.5ah.
Torque will increase by 33%.
As an example torque.
36v x 17a controller = 612w max output or about 489w at the wheel, allowing for efficacy loss.
48v x 17a controller = 816w max output or about 650w at the wheel, allowing for efficacy loss.
In both cases if you do the math, difference is about 33%.
The max torque is most noticeable in pas5 on inclines, though you will most definitely feel the extra speed from the torque when tonking along on the flat.
Speed is also increased but the trade off is range will be less, you will only see the extra range if you keep to the same speed which you rode along with the 36v set up.
Another consequence is the hub speed, rpm will increase by 33%.
201rpm becomes a 265rpm hub.
260rpm becomes a 345rpmhub.
328rpm becomes a 436rpm hub.
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48v gives you 33% extra of every thing, you can keep it in reserve and use it occasionally to gain range or on hilly terrain use the extra torque and speed for less range. Keeping the gearing the same you should see 33% more mph if your cadence is fast enough and can be maintained.
It is when you have experienced both.
On my town/errand /commute Norco 700c, I am still plodding along with my 36v 29E's. They still provide the range I need locally but I can certainly feel the voltage sag and hesitant power supply if asking for too much amp draw.
Probably sometime next year I will call it a day with them and finish my 13s2p drinks bottle battery with 20a cells.
The extra 33% is noticeable on my touring 700c Boardman and the Yose responds well to 48v.
To go in this direction you will need new electronics and a new motor.
Motors are built to work correctly, without overheating and burning out, for a specific voltage. If you simply increase the voltage, the motor will soon be damaged, in practice you may not get one mile up the road, then a walk back with a destroyed electronics and motor!!
Some after market electronics can be switched to a different voltage, but not all!
That is the difference between theory and practice!
You would be better off selling the complete bike and buying new in most cases.
Depending upon where you live, there are legal limits to motor power, For example, in the EU only a 250 watt motor is allowed.
Regards
Andy
PS. I almost forgot, in the EU and some other countries,there is a maximum speed limit for e-bikes, 25 KPH or 15 MPH!
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Interesting, I wasn't aware there is a risk of damage. I was thinking recently of pairing my yosepower 36v rear hub with a 48v battery and contoller for a bit more speed and torque for off road use, but don't want to risk damaging it, so will stick to the stock 36v battery
Motors are "wound" for a particular voltage. They are also "wound" for a particular current, that the controller must "control" the motor within prescribed limits....or it will simply overheat.
E-bike motors have no active internal cooling, only cooling of the exterior case by the air passing by....
regards
Andy
I disagree with half of what you are saying:
- increasing the voltage of a typical 36v geared motor to 48v will do no harm on 99% of motors (maybe some of the tiny motors will be at risk of overheating)
- you have to be very careful increasing the current
I must beg to differ. Motor windings are configured to give a particular rpm, that's what the winding code signifies. The insulation involved is more than capable of standing up to the increase in voltage. It's true that you have to be careful with any current increase, but a 36v 17A contriller replaced by a 48v 17A controller should present no problems. Motors run most efficiently at 50-80% of their design speed. At these speeds running with minimum waste heat production, the efficiency curve is merely moved up a little.
As to speed, the system can still be restricted to legal cut off via the controller. So you get the benefit of greater torque with less speed loss when hill climbing.
Overvolting is something many on this forum have done without motor damge. Of course, as with anything, if you go overboard there will be consequences. But the 36-48v increase has been done many times, just select a new controller with the same maximum current draw.
Crossed with AK's post.
As to speed, the system can still be restricted to legal cut off via the controller. So you get the benefit of greater torque with less speed loss when hill climbing.
Overvolting is something many on this forum have done without motor damge. Of course, as with anything, if you go overboard there will be consequences. But the 36-48v increase has been done many times, just select a new controller with the same maximum current draw.
Crossed with AK's post.
It's been tried and tested many times and over volting doesn't damage a hub unless you go banana's. Deciding to over volt you need to take in the current winding speed (rpm) as this will increase by 33% to give a faster wound motor and not labour the motor too much, the only component to upgrade is the controller if you are running a stock 36v model to a 48v one with similar amp output to give the extra torque and battery celled to cope better with the extra demand. Any decent 10a 5p celled battery would be good with PF being best bang for your money.
The Q100/Aikema's are ok up to 20a @48v but are very near their operating limit, the key to over volting is not to use the extra power constantly but to be selective in it's use. That said the 120mm Yose is 350w nominal and quite happily takes 17 or 20a @48v, my one has now been in for 11 months and working perfectly the only thong that gets warm hot is the 48v controller, the hub stays nice and cool to the touch so no over heating issues there.
The Q100/Aikema's are ok up to 20a @48v but are very near their operating limit, the key to over volting is not to use the extra power constantly but to be selective in it's use. That said the 120mm Yose is 350w nominal and quite happily takes 17 or 20a @48v, my one has now been in for 11 months and working perfectly the only thong that gets warm hot is the 48v controller, the hub stays nice and cool to the touch so no over heating issues there.
Any one stupid enough to connect a 48v battery to a 36v controller without checking the caps rating is likely to fry the controller straight away as mostly they only have 48v rated capacitors which won't handle 13s/54.6v.
48v capable controllers will have 63v rated caps inside.
48v capable controllers will have 63v rated caps inside.
Then you do not understand how power is calculated if you really believe that.
Let me show you:-
What is the formula for power P is in watts, voltage V is in volts and current I is in amperes (DC).
V x I = P(ower)
36 volts at 15 amps = 540 Watts.
48 volts at 15 amps = 720 Watts. Quite an increase in POWER and heating effect. 33% more heating effect in fact!!
15 amps I picked as it is the maximum current my e-bike controller allows my motor, a 36 volts one!
Power is a product of voltage and current, so if you want to use a higher voltage, on the same motor, (as we are discussing here) you must use a lower current, to keep the power dissipation the same as that the motor is rated for, then the heating effect is the same.
But the end effect is a lot of work and costs for no visible improvement!!!
Why would anyone want to do that?
No increase in power = no increase in speed or acceleration!
Simple physics.....
To go faster, you must have more power!!
If you still have questions, just ask.
Andy
Yes, of course there is an increase in power by overvolting, that's kinda the point of doing it.
The insulation in the motor will be flash tested to a much higher voltage than it's rated 35v. No problem there.
So, yes, the heating effect will be 33% higher than at 36v, but if the heating, at normal speeds, is negligable anyway, then 33% of not very much is...... well even less. As said before, a motor operating at between 50 and 80% of it's rated rpm is operating as efficiently as it can, and that equals very little heating.
I have an Ezee 36v kit on my bike. The controller is a max 20A. The motor is a large diameter bpm type. I live in West Wales where there are stupid hills. Not once in 4 years has the motor been even mildly warm, even after a brutal climb at only 6mph. I know, I've checked. The controller, however, has on occassion been too hot to touch. Yet it's within it's design parameters?
So, to the OP. If you've got to change your battery anyway, it's worth a shot for the cost of a new controller. Be sensible on it's max current and the motor will be fine. They all handle far more power than their nominative ratings.
The insulation in the motor will be flash tested to a much higher voltage than it's rated 35v. No problem there.
So, yes, the heating effect will be 33% higher than at 36v, but if the heating, at normal speeds, is negligable anyway, then 33% of not very much is...... well even less. As said before, a motor operating at between 50 and 80% of it's rated rpm is operating as efficiently as it can, and that equals very little heating.
I have an Ezee 36v kit on my bike. The controller is a max 20A. The motor is a large diameter bpm type. I live in West Wales where there are stupid hills. Not once in 4 years has the motor been even mildly warm, even after a brutal climb at only 6mph. I know, I've checked. The controller, however, has on occassion been too hot to touch. Yet it's within it's design parameters?
So, to the OP. If you've got to change your battery anyway, it's worth a shot for the cost of a new controller. Be sensible on it's max current and the motor will be fine. They all handle far more power than their nominative ratings.
If the power is actually transformed into heat. Usually with a 36v motor run at 48v and the same current there is little to no extra heat generated, the power goes straight to the wheel.
To go faster with an e-bike you need more RPM rarely more power, remember that air becomes a wall at around 45 km/h on a bike, then you need either better aerodynamics or more power.
I was first in class in high school physics too
Most of the heating loss is through current losses (I^2*R) through the windings, which stays the same at same currents.
As for worrying about the extra heat, it's practically winter so if your motor handles 36V at full beans in the summer (certainly the one just gone as it's been well above average) you will be absolutely fine due to lower ambient temps now. Just don't be ridiculous. Chances are you'll burn out the nylon gears before the windings.
Many 36V only controllers will operate on 48V, but may have filter capacitors only rated for 48V. These will fail early if run on a 48V battery. One has to look inside for a 63V rating. Another caution is that the low voltage alarm on these controllers is hard wired for 30V, and you don't want to run a 48V battery that low. Actually, the batteries own low voltage circuit will shut off before that happens, but it's not good for battery life. If your controller can handle it, and you're not crazy about speed, 48V is an option.
I have one 36V 22A controller that works on 48V, and a couple of bikes with dual voltage 36/48V controllers. This allows me to use my various batteries on different e-bikes. My wife and I run average speeds under 15 mph, so we can run a Q100 or a Bafang SWXH on 52V and not worry about burning it up.
I have one 36V 22A controller that works on 48V, and a couple of bikes with dual voltage 36/48V controllers. This allows me to use my various batteries on different e-bikes. My wife and I run average speeds under 15 mph, so we can run a Q100 or a Bafang SWXH on 52V and not worry about burning it up.
that depends on your current configuration and what you want to achieve.
As NealH has already pointed out, don't just connect a 48V battery to a 36V system without checking.
Provided that your system can support dual voltage, then the 48V will give 30% more power and also can achieve higher derestricted speed. However, there is no free lunch, even if you only occasionally need the higher performance. Typically, motors can tolerate higher current but higher current produces higher magnetic flux, when the flux reaches the limit that the rotor can take (magnetic saturation), the extra voltage does not produce extra power, just more heat.
I sell both SWX02 in 36V and in 48V. They are built differently. The 36V has winding code 13, the 48V has winding code 16. You get much more torque at low speed for climbing with the 48V version.
For anyone still considering or wondering if a 36v hub will work at 48v then the answer is yes, if you don't go banana's.
Fit a new same make 48v controller, don't go mad on amps 17a is plenty.
Don't expect a high rpm hub like a 328 36v rated one to be great on hilly stuff better with sub 270rpm 36v hubs.
As mentioned the nylon gears will be the first to melt.
Fit a new same make 48v controller, don't go mad on amps 17a is plenty.
Don't expect a high rpm hub like a 328 36v rated one to be great on hilly stuff better with sub 270rpm 36v hubs.
As mentioned the nylon gears will be the first to melt.
Gears have been known to hold out up to about 72v and 30 Amps... With cooling fluid in the motor.
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