48v bike only putting 26v to the motor?

[(Ronin)]

Hey there,I recently purchased one of those asian scooter-like ebikes and am looking to improve the performance.
The controller on the bike says its a 48v 17A one,but when i checked the voltage going to the motor it maxes out at 26.3?
The battery reads as having 52 volts? i'm confused,whats going on here?
This is a dual battery smart bike,and it runs off dual 48v batteries (one big,one reserve)not 2 24v's.
Would an after market controller allow me to put the power to the motor i need?

[The7]

The controller on the bike says its a 48v 17A one,but when i checked the voltage going to the motor it maxes out at 26.3?
The battery reads as having 52 volts?

Tell us how you measure this 26.3V.
DC or AC range?
Between what wire and what wire?

I think it is an BLDC (brushless DC) motor with 3 motor winding wires.
An full-charged 48V SLA battery would have 52.8V.

Let us base on this 52.8V and at FULL throttle.
Using DC range:
The DC voltage between any one of motor wires and the battery negative = 26 V (approx).
(I think it was what you measured)

Using AC range:
The AC voltage between any two motor wires = 37 V (approx).

[(Ronin)]

Yeah thats right..theres 3 wires going to the motor and they all read 26v at WOT on DC using the battery ground.
I'm curious if the controller is holding back or this was normal..and can i get any more top speed by switching to an after market controller?
the motor is a 350 watt(500 max) brushless hub motor

[The7]

Yeah thats right..theres 3 wires going to the motor and they all read 26v at WOT on DC using the battery ground.
I'm curious if the controller is holding back or this was normal..and can i get any more top speed by switching to an after market controller?
the motor is a 350 watt(500 max) brushless hub motor

This 26V is the max and is normal and there is no holding back for top-speed.

The top-speed is dictated by the battery volt.

The acceleration and hill-climbing is dictated by the battery current limit of the controller (at 17A).
If you use an 35A controller, this will be greatly improved (but not the top-speed).

See also my post for an upgraded 20A controller from stock 15A controller:
http://www.bikeforums.net/showthread.php?t=323269

[(Ronin)]

So a 48v 14a battery and a 500 watt motor is incapable of propelling this bike at more than 30 kmh?
That doesn't seem right
does that mean that 48v hub motors are actually 26v?
i'm confused again :S
How do i get more voltage to flow to that hub motor?

[Leisesturm]

So a 48v 14a battery and a 500 watt motor is incapable of propelling this bike at more than 30 kmh?That doesn't seem right

Why not? Most traffic on today's freeways flows between 60mph and 80 mph, this is regardless of whether you have a 90hp Toyota Prius hybrid or a 500hp Italian exotic supercar. The 500hp exotic accelerates to it's top speed much faster than the econo-box but at some point either a rev limiter set by the factory or the flashing lights of the state police in the rear view mirror limit the top speed to something approaching similarity. Your electric bike is limited to 30km/hr by a governer in the circuitry. This is for legal reasons. It doen't matter whether you have 350W, 500W or 1KW you cannot legally exceed 20mph using motor power so the motor manufacturers limit the top speed of the motor electronically. Usually this can be bypassed but that is beyond the scope of this discussion.



does that mean that 48v hub motors are actually 26v? i'm confused again :S
How do i get more voltage to flow to that hub motor?

The previous poster was telling you that your motor is behaving normally for its design. You are measuring the voltage flow INSIDE the motor after it has been split between pairs of windings that are each carrying half of the total.

H

[(Ronin)]

Well i'm still curious why a 48 volt battery can't push this bike past 30kmh..i've seen other bikes running 48 volts and they are up over 40kmh easily.My question is,will an aftermarket controller allow me to do that?

[Leisesturm]

My question is,will an aftermarket controller allow me to do that? There are some amazingly knowledgeable techs reading these posts. Why not try asking your question like this: "I have _______________ brand motor system and the controller says __________ on it. Can I defeat the governor in this controller or do I need to go to an aftermarket controller, if so, which controller(s) do you recommend?"

H