How can i increase the speed of my Wisper 905

[GordonABZ]

Hi folks.

New to this forum so i hope i am posting this in the right place.

I have a Wisper 905 SE Sport which is about 1 year old now.
Its the 36Volt 14Ah Lithium version with the 200/250W motor with the green off-road switch fitted.

I am in the UK and i am well aware of the rules regarding the 15 mph max speed rating etc but i have a long section of my journey to work which is off road (pretty flat too) and i would like to get my assisted speed up on the off-road part of my journey to work.
The system with the off-road button takes me up to about 19mph.

I am not worried about the range being reduced; I would just like to get the speed up to the mid to late 20’s on battery power.

Is there a way to do this by adjusting the controller on the bike?

Failing that is there a possibility to fit a different motor and keep the battery and controller?

Any thoughts to speed the bike up under battery power greatly appreciated.

Cheers

Gordon

 

[TylerDurden]

30mph requires ~700W

I rekon it will take a new motor and controller.

 

[Russell]

Two Words...........More Voltage

Put a 48V battery on the thing or wire in a booster battery. Most 36V controllers can handle 48V but not all so you might have to swap it out.

You can also swap the motor for a 24V motor or any motor wound for a higher RPM/V (though generally low-end torque will suffer).



-R

 

[morph999]

faster tires can also help by a couple mph if you choose the fastest ones. Depends on what you have on it now, though.

 

[cell_man]

I saw your post on Pedelecs too

How much extra speed do you want? If it's just a little you might get away with just changing the motor to a higher speed unit, but that would generally be at the expense of torque so reduced acceleration and hill climbing ability. Without increasing the power you are not going to gain much if anything and you may find that the higher speed motor just feels gutless. So you will probably also have to either modify your original controller to increase the current limit and bypass any speed restriction or change the controller. The higher powered geared hub motors can do about 37-39kph on a 36V battery and from my experience that will take about 600 or 700W to maintain that kind of speed if there's no headwinds and with a 25A controller will pull around 900W under acceleration. If you do a reasonable amount of pedalling you could still maintain a good speed without using many watts.

Higher voltage will also achieve the same thing but you will have to find a way to patch in an additional pack and your controller might have a High Voltage Cut or still maintain the same speed restriction.

 

[dogman dan]

Googling the bike, I see its a rear hub gearmotor. Chances are, it can tolerate some increase in wattage by changing the controller. If a 20 amp controller burns up the motor, then you replace the motor with one that can handle 700 watts. Up to 700 watts or so, the battery should be adequate. A different controller may be all you need, since many euro bikes have a controller that limits speed to very slow. A controller sold in north america may get up to 20 mph out of your motor.

But first, have a look, and see if there are any little wires coming out of the controller, that connect and go back in. On some controllers I have, a single wire and connector that goes back into the box is a speed suppressor loop. Disconnect it and you may go faster. Not real likely, but have a look.

 

[Lock]

Add a booster pack in series w/the existing battery, plus a switch to kick in the booster plus bypass the controller... You'll end up w/the motor directly connected to the pack plus booster pack to up the volts (and take the voltage-sensitive controller electronics out of the equation...)
Higher volts would be fine for the motor for short distances/time.
Lock

 

[Drunkskunk]

I've been reading about your bike. It does have a speed suppressor, but the off road button defeats the suppressor. That means 19.5mph is as fast as that motor can go with that battery.

48 volts of battery should get you up to 25mph (with the off road button) but it runs the risk of blowing up the controller or damaging the motor.

 

[GordonABZ]

Hi folks

Ok, what I had hoped to be able to do was to modify the 905SE Sport and get an extra few mph out of it for my long flat off road section.

Don’t get me wrong, the bike is great for going up hills etc its just that for them main part of my journey I am cycling along the flat, off road section at about 19-21 mph so I am carrying the battery and motor rather than it helping me.

I have been looking on the web to try to source a larger motor or controller for the Wisper 905SE Sport but first problem that I am coming across is the UK legislation.

I am sure I saw a 500W Wisper about a year ago….could well have been in the states but I can’t find any details of it now or where I could get a 500W Wisper compatible controller.

Perhaps some of you guys from the USA could point me in the right direction of a supplier?

I don’t know how the controller knows to stop supplying power at 19 mph when in de-restricted mode (can someone explain this please?) but possibly a circuit diagram would help if anyone has one?

The motor on my bike is stamped with BFY809B12983-28KM 36V 200W and the bike is the last of the kettle plug type battery connectors with the cable connection box mounted in front of the handle bars.

Can anyone help me with either suppliers of alternative parts for the bike to gain a bit more speed or suggest a way of modifying the existing bike.


Thanks for any help, its very much appreciated

 

[dogman dan]

I'm not really expert at the electronic details but the simple version is this.

A controller has various components in it that are rated for a certain voltage and amperage of current. The motor on the other hand, would gobble all the power it can get it's hands on. So a current limiter is part of the controller that keeps the amps limited to a certain amount. There can be also software current limiting, but I am refering to a part called the shunt. This part can sometimes be modified with a blob of solder, increasing the amps. This may get you a mile per hour more or so, but really, soldering the shunt is a way to get better hill climbing and acelleration.

Increasing the voltage to 48v will be the most likely way to get more speed. Look inside the controller to see if it can take 48v. Inside the capacitors will have voltage markings. To run 48v, they need to be at least 60 or 63v caps.

It should be possible to buy a controller in North America, or direct from china, that will run higher voltage. Ebikes.ca in canada is a great vendor that ships internationally. tell them what kind of motor your have and they can suggest a controller. Something 48v 20 amps should get you some more speed. You will need to rewire the connectors, so some anderson connectors would be a good thing to add to the order.