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Roboteq control system and joystick Info
 

EARLIER VERSIONS: 

BM1 powerchair

BM2 powerchair

Please watch the ROBOTEQ Video opposite to get an overview  >>>

Sadly this is as good as it gets with "conventional" industry powerchair control system. And I cannot use either of these two hi-end systems for the following reasons:
 

• My latest chair uses a LITHIUM battery. With ENORMOUS benefits!  Voltage differences though, mean MOBILITY CONTROLLERS ARE NOT COMPATIBLE. They are all living in yesteryear. The rest of the world has moved on but not the mobility industry. For increased efficiency, less heat problems, and greater speed I also use 45 Volts! This has huge advantages over 24v systems and means HUGE compatibility issues.
   

  Torque. All mobility controllers lack the AMP capability. That is, their BIGGEST controllers are just 120 Amps, and only for a few seconds...   To give adequate torque with higher geared motors needed for sensible speed, (such as the 8.5 MPH motors as I wish to use) we need more Amps than this. As demonstrated well by the lack of torque the faster mobility products have now. But the "Mobility Controller" manufacturers are again stuck in yesteryear here too!  No lithium compatibility, no higher voltage compatibility and inadequate Amp (power) capability.
  
  So doing some basic maths tells me that to EQUAL the torque of a GOOD 6 MPH powerchair, with 8.5 MPH version will require about 1/3rd MORE Amps than the best mobility controllers can supply.
  
  The ROBOTEQ controller is not INTENDED for powerchair use.  BUT it can give 150 amps per motor, 250 Amps per motor peak! That's a HUGE improvement!
  
  MUCH better than any mobility controller as far as power/torque is concerned.  And just in case the motor impedance isn't high enough to actually draw that huge current, the available voltage on my BM3 lithium powerchair is almost doubled at 45 Volts!  So torque levels will be quite astounding and will need to be limited to sensible levels in programming to protect motors and make it controllable. But it will not be lacking power!
  
   

• Power (maximum watts). Existing 24v lead (Gel) batteries cannot supply more power than the current crop of powerchair motors and controllers demand anyway. 2x 120 amps is a step too far for gel powerchair batteries as it is. The voltage drops off really fast under that kind of load.
  
  So more power wouldn't really help much. But with a big lithium battery with 3000 Watt Hours of stored power, with ultra low internal resistance, more power is a great idea!  BM3's huge lithium battery not only stores 3x the energy, it can give out its power MUCH FASTER when required to do so.
  
  So that's 45v & 150 Amp per channel = 13,500 Watts of available power for hills, sand, snow, etc. (Compared to just 5760 watts or 120 amps and 24v from the BEST mobility controllers).  So the RoboteQ & Lithium battery system is around 2.5x as powerful as the BEST POSSIBLE mobility systems. It means cruising along at 15 mph will barely tax it, no heat issues, or power issues on hills etc.
  
   
• Lower resistance (32 Mosfet power output devices!) This means greater efficiency and half the heat problems under severe conditions.
  
   
• DISADVANTAGE (There's always a downside!) is that the RoboteQ was never intended to be used in a mobility device. It has masses of features, data logging capability, PC connectivity & programmability, and full Radio Control capability built in. But it lacks the super safe error checking etc of "safe" mobility controllers. If you use one of these in a powerchair you better understand what this means! And its NOT plug and play. You need to build your own joystick and control interface etc. See below. Any errors, or problems could have this drive you under a train, or into a road... I intend to fit a "red button" to kill all power in the event of any issues.

Top first, then left to right...  My home built joystick pod, using an APEM hall effect joystick and 4 push buttons for RC mode,
off/on, speed reduction to "normal" levels. 45V in 12v out inverter for 12v power for motor brakes, lights etc.
The Roboteq controller. The RC receiver in a waterproof plastic box. Note the huge cables, and Anderson connectors used!

300 Amps total output

That's over 13,500 watts, or approx 18 Horsepower electrical output. Less "at the wheels" obviously as motors are not 100 percent efficient.  That's about 2.5x MORE POWER than any other powerchair! 

And its needed. Most mobility products do not have enough power for safe control or steering in "difficult" situations even at the slow speeds they are capable of.

This RoboteQ controller was never originally designed as a powerchair controller. It lacks some of the fine tuning (programming) capability and the continual safety checking of a "real" super safe powerchair controller such as those supplied by PG Controls, Dynamic etc as used in the powerchair industry.  Full Details PDF  and  Manufacturer site here.

But for those of us who are mighty sick of the safety Nazi attitude of the "industry", lack of power or torque in existing slow products, or lack of different voltage capability, then Roboteq Controllers offer a real high power solution. They are not however a simple plug and play option. Don't just buy one expecting to plug in and use it! Its complex, involved, requires electrical and programming understanding.

And some risk from unknown failure modes will remain.  For e.g. if a connection or input signal fails or an output transistor (Mosfet) fails in the "on" (shorted) condition the powerchair will simply go!   Back, left or right, forwards and it would not stop without some intervention. That is a worry if you are near traffic, or in a busy public bar or a railway station for e.g.

But many simple steps can be made to minimise this risk. And an emergency "kill" button can be added just in case things go wrong. As I will be doing.

What we really need of course is a 150 Amp per side, 50v real powerchair controller, made by a big manufacturer that is Lithium battery compatible. And they are so slow in developing anything in the mobility industry that I don't expect to see this happen in the next 5 to 10 years. So if you want a decent powerchair today then you have to use this DIY approach. Its still safe, controllable, as long as you have a very great understanding of what is happening under you! If you need to get "others" to do any of this stuff for you, then you had better look at a different system...

Because its about CONTROL and POWER! 

I build and modify my own powerchairs since if you want any real speed, and who doesn't? Control, or indoor/outdoor capability there simply isn't any choice. See the BM1, BM2, and the other BM3 pages for design details.

By increasing the VOLTAGE to around 45 volts it means any given powerchair or motor motor is capable of almost double the speed than it would do on the usual 24v. 

So by using conventional HI-END 4 pole powerchair motor speeds can be hugely increased. Since the least stressful time on any motor is while "free running" this isn't particularly stressful! A motor draws the least power while free running, or while going fast in straight lines in a powerchair.

A typical 6 MPH powerchair motor will do 12 mph on 48v Buy we have around 45v (Actually 42.something nominal, and about 43v for most of the batteries useful charge.) So a 6 MPH motor will do about 10.5 mph.  And an 8.5 Mph motor from a "Groove" powerchair will do 15 MPH. This is what I am using. 

And importantly the Roboteq offers a true 150 Amps per channel with a short term peak of 250 Amps per side or 300 (500 peak) Amps total...   That's approx 2.5x the power of any mobility device. It is very low resistance and uses huge power cables for greater efficiency too. That 150 Amps peer channel @ 45v means much more torque available on any given motor.

In addition it allows 3 different inputs to be directly used. I had to build a special interface for a "mobility controller" to allow me to use Radio Control to drive my spare powerchairs about. The Roboteq allows you to plug a RC receiver in directly. It also allows you to program, reprogram, and store your settings directly on a PC.  It also allows you to connect a laptop and log, graph, store everything from battery voltages and amps, to controller temperatures, input values etc as you drive. Very very flexible indeed! I can graph and log the performance of my lithium batteries as I drive.

But it does mean making your own joystick "pod" using either an inductive, hall effect, or other joystick.

This can have a frequency, or DC voltage swing,  digital duty cycle output. All are catered for the choice is yours!  I will use a simple voltage swing device as used on almost every conventional powerchair. The joystick I ordered is an APEM hall effect APEM - 3140RQ0124 - 2 AXES From RS Components, or Farnells online.
                                             PDF - Full Joystick Data  Opposite >>>

Blue Roboteq and my 8.5 mph motors (that will soon be running on 42v to 47v all have the new Anderson connectors fitted and ready! Note the huge and doubled up battery cables on the RoboteQ!

These are needed for the possible 500 Amp peak current! The motors run great on 36v and 48v. They just spin at double the speed! Quietly. So I don't expect any motor problems.

Close up, motor and brake connectors. Added to the Groove 8.5 mph motors.

On the groove motors this is 12v Don't use 24, or 36 as smoke will appear. Each brake takes 0.7 Amp (1.4A total) at 12v measured.

BM3 INFO: BM3 Home | BM3 Lithium battery | BM3 15 MPH | Charging Lithium | Construction detailil | Roboteq controller