Controllers for lightweight chairs

[Burgerman]

No. Power = watts.

Why limit it at all? You present a motor a voltage (pulsewidth) and IT determines the current. Because of its impedance/resistance. And it will be way too low at small stick movements so it wont turn etc. Even at FULL turn signal. Why? Because full turn may be only 2 volts. Or it would run each motor at full speed in opposite directions... So motor compensation ramps up voltage (and so current) behind the scenes in order that it does does begin to move and then removes it before you spin in place... It is one of the reasons that you cant have too much power module current capability. If its not required than it wont be used.

[emilevirus]

Battery BMS will trip over X Amps so everything will just shutdown?
I'll test and see. They use XT30 as motor connector.

[shirley_hkg]

. Mine doesn't have electromagnetic brakes so I'll need to disable that.

Some ignorant grannies here bought themselves those cheap, light weight foldable wheelchairs, on Aliexpress. Chairs have no mechanical brakes, but use electromagnetic force to hold chair stationary. Shut it down and it is in free wheel.

Tested to shut it off on an incline , and it just rolled down slope and gain speed instantly. The AP barely saved himself out.

Power could be cutoff by accident or error of the system. What on earth one would ride a chair that would get himself killed.

[Burgerman]

Exitement?

If the torque is limited by motor current (becase torque = Amps proportionally) then it will not steer correctly or will stall and not follow joystick.
If that happens the controller Amp output is too small for the job, or the gearing is too tall for the amount of current you have available depending how you look at it.

If the correct controller cant be used because of battery capability (or BMS capability - the reason they NEED a current limit in a BMS) then the battery is too small or too low C rate...


But it wont happen. It will not trip. Why? Because motor Amps (and max current capability of the controller) is MUCH higher than the battery current. Or it SHOULD be if the motors have a low enough impedance.

Look at it like this.

Easy numbers.
24V into controller from batt.
Motors pull the MAX STALL current the controller allows at around 6 volts (depending on motor impedance).
And your controller is say set to 50A.
Motors (both) stalled is now pulling say 100A total at 6V (because 2 motors stalled) and its limited to this by the controller max output.
Thats 600 watts.
Battery current is 600 watts div by 24V = 25A...
Thats ignoring say 10% losses etc. So in this exmple battery current is 1/4 of motor current.

Can you follow that?
Gives most people a headache to think that battery current is less than motor current...

[shirley_hkg]

Exitement?
...

Probably.

[JohnnyUK]

WoodyGB made me a connector that worked on the nVSI of my Vienna.

I thought the Q50R had a VSI?

I think nVSI is the cheap and nasty Chinese knock-off version. I'm not sure where the 'Q50R' is manufactured but my 'Q50R Carbon' is all Chineseaum as you call it. Surprisingly the chair looks well made considering it's nearly all carbon fibre components and quite rigid to use on the level, I bought it for its lightweight properties but at 16+kg it's still too heavy for me and skinny wimmin

[hank]

I am baffled by that.
What are you asking or saying?

Sorry John was asking if the quickie q50 R is the best chair lightweight indoor chair to convert to use R net joystick and PM if so best bet module amp wise suitable

[Burgerman]

Well I dont think any are.
Not enough space for a big full power module. And they are heavy. And many - me included find them completely unsable from a seating, ride, and transfering perspective. And they are not stable enough. Wheels too small outdoors to make any sense.

But different people have different needs. I cant really understand why or how one would be better than a properly set up non folding powerchair. They do not have a smaller footprint. They have no suspension. Slow, and unsuitable outdoors, and little range.

IF you can transfer to and from it and a car seat, then the only advantage is its ability to load into a car.

[hank]

I Get everything your saying it's just to replace my manual indoor chair as getting weaker to push around nothing else
got others for outdoor

[Burgerman]

Since its a folding chair intended to travel, what do you see as its advantages in your house over a decent rear drive conventional powerchair? Such as what you already own? Your choice obviously but I honestly dont see any. Just interested to know!

[hank]

Having wooden flooring throughout the 1930s built bungalow worried about weight on joists

[Burgerman]

Really?

[hank]

Really?

not a problem with concrete floors just cold

[emilevirus]

. Mine doesn't have electromagnetic brakes so I'll need to disable that.

Some ignorant grannies here bought themselves those cheap, light weight foldable wheelchairs, on Aliexpress. Chairs have no mechanical brakes, but use electromagnetic force to hold chair stationary. Shut it down and it is in free wheel.

Tested to shut it off on an incline , and it just rolled down slope and gain speed instantly. The AP barely saved himself out.

Power could be cutoff by accident or error of the system. What on earth one would ride a chair that would get himself killed.

Already tested - I was going uphill and LVC kicked in. But It's just to travel and there's always someone walking with me.

[Burgerman]

So you are saying that when the bms kicks in and chops the battery off for any one of a dozen reasons, you can go down a slope onto a road (under a truck?) or off a keyside, under a train? How marvelous! That cant be legal can it?

[emilevirus]

So you are saying that when the bms kicks in and chops the battery off for any one of a dozen reasons, you can go down a slope onto a road (under a truck?) or off a keyside, under a train? How marvelous! That cant be legal can it?

Yes, whoever designed this chair had no idea what he was doing.

[Burgerman]

Does this apply to the sunrise Q50 chinese made chair?

Just checked. It uses VSI (nVSI just refers to new vsi) so is programable and has normal DC motors and electromagnetic brakes, same as other chairs. No runaways... They are a bit weedy, and all in one, no power module so have to be.

[JohnnyUK]

Does this apply to the sunrise Q50 chinese made chair?

Just checked. It uses VSI (nVSI just refers to new vsi) so is programable and has normal DC motors and electromagnetic brakes, same as other chairs. No runaways... They are a bit weedy, and all in one, no power module so have to be.

I didn't know nVSI meant 'new' VSI, thought you said it couldn't be programmed? The Chinese Q50R is twice the price of the standard Q50R but half the weight, I don't know which steers the worst. I don't see the point in a 40kg electric travel chair many would be better off with self propelled for travel and a proper powerchair for home if that's where users spend most of their time.

[Burgerman]

I said if its got a weird chinese controller it cant be programmed like most of the chinese ones and brushless ones. If you get a cable, (woodyGB?) then you SHOULD I think be able to program it. How successful that will be I dont know. I never looked at a vsi joystick as they are basically toys.

40kg is too heavy? Well a lighter chair will be worse.

If you need a powerchair, and many cant manage or walk at all, or cant cope with the seating or lack of stability of a manual chair and portable ones are too heavy to lift then as I mentioned a long while back you need to plan things a bit better!

You need a powerchair?
Then get the best most comfortable, best ride, seating options etc with proper batteries and big enough wheels and motors to do that.
Too heavy? Too big? Well folding ones or lightweight ones meke crap powerchairs.
Best to start as you mean to go on and make a plan. Move somewhere accessible open plan wide doors, no stairs, close to a town with everything you need easily accessible without a car.
Make sure its got enough driveway to easily get in and out of a drive from side entry mobility van. And get a big us type drive from van. Instead of wasting money trying to put out fires with things that dont work properly. At least that way you do it all once. Its not like any of us will likely get any better or younger. We discussed all this by email but you decided it was better to struggle!

[Burgerman]

The Chinese Q50R is twice the price of the standard Q50R

Dont understand this sentence. Q50R is a recent sunrise branded chinese clone.
They are all chinese. Theres dozens of brands all using same or similar chassis. All with different names. Different motors, controllers, wheel sizes, different batteries etc.

[emilevirus]

Does this apply to the sunrise Q50 chinese made chair?

Just checked. It uses VSI (nVSI just refers to new vsi) so is programable and has normal DC motors and electromagnetic brakes, same as other chairs. No runaways... They are a bit weedy, and all in one, no power module so have to be.

There's no way Sunrise would sell a chair without brakes. They'd get sued.

[Raro]

I use a Chinese chair, each one will be different, I suppose the one I have, the brake works the same as a normal chair except for one thing, if you unlock the motors and the chair is on, they remain locked, if you turn it off, they unlock. I know that they are barely adjustable chairs but they have their advantages and disadvantages if you use a good cushion the backrest is as good as the best of a good chair

[emilevirus]

Here's mine: https://efoldi.com/shop/scooter/efoldi-power-chair/
Apparently they sell that in UK with no legal issues

[LROBBINS]

I notice that this one uses manual brakes as on a push chair for holding on a slope.

[Raro]

I notice that this one uses manual brakes as on a push chair for holding on a slope.

yes it's true! It doesn't look anything like my chair.

[emilevirus]

Controller fitted. Had to 3d print a bracket to mount the joystick. Now waiting cables to arrive. Should arrive tomorrow. Soldering 10awg with 18awg will be fun....

[Burgerman]

Why and where would you do that?
I usually dont join wires, but add new full length to connectors.

If you must do it, then I would use flux, (essential) and be sure everything is clean, tin both (use an iron on the thinner wire and a small turbo butane lighter on the heavy one). Then heat, with butane, and they will be easy to join.

[emilevirus]

The motors use 18awg with xt30 connector and I need to connect them to the controller. I cannot solder 10awg on xt30. Unless I can desolder the r-net connector and solder 18awg wire on there?

[Burgerman]

18awg is a microscopic cable. 1.22mm diameter and 1 sq mm cross section.

That CANNOT be the wires to the motor? Because 10A will be about the most you can cope with...

Surely that isnt adequate to move you about? If they were silicone, you could do about 20A and the insulation wont melt. Just about...
I have 3 (as its brushless) 2.5sqmm cables to the motor in my heli. And those are silicone. They get really hot! It weighs 9 lb...

[emilevirus]

Don't know. All I know is that it works. I go uphills just fine. Wires are smaller than my 1/14 rc buggy.