How to unlock brakes on bounder with no battery?

[Jay_x]

your bounder doesn't move in the snow at all?

I added wider, agressive tires as well so all that combined. It barely moves.

how much snow are we talking? Are you just on sidewalks or streets?

[emilevirus]

Plug your charger, you'll have power to remove the brakes.

[Burgerman]

Most chargers will not fire up unless they see 18 volts or similar. So it depends how dead it is. If theres no battery fitted the charger wont turn on.

You need a power supply. If you set that to 26V a MAX 12A so that knocking the joystick will fail to burn up the joystck wires then that will allow the system to turn on, and the brakes to operate. Trying to drive the chair will cause it to try and pull more than 12A and then the power supply with drop the voltage when 12A is exceeded.

Best bet connect straight to battery. 26v and 30A and it will drive.

[emilevirus]

I use my iCharger in PSU mode usually. The battery pole came loose and I needed seat lift to access the batteries. I powered thru the joystick and was able to up the seat.

[shirley_hkg]

I think Jay-X has a ZXD.

Plug into chair's XLR charge connector and you'll get power. If possible, disconnect the dead battery first.

[Burgerman]

So you are saying that if it stops in the street or in the middle of a road junction of something due to a motor wire, brush failure, fuse or breaker failure, batt failure etc that there no way for someone to push it out of danger? Or just home?

That cant be right can it?

If it IS then I suggest you retrofit the parts that do allow this ASAP anyway. Or even ask bounder to supply free or discounted too. Its a danger issue. They wouldnt want to get sued right?

[shirley_hkg]

I am puzzled too.

Free wheel feature is primitive since day 1. How did they get passed FDA?

[Burgerman]

Imagine stopping on a railway crossing...

[emilevirus]

Indeed that can't be right...

[emilevirus]

Wait and see. You will find that even 1 tooth makes a huge difference. 2 will be much more than you expect. I have much motorcycle chain experience! Your chain will be too long, tensioner will not cope. In any case you shouldnt really run old chain on new sprockets.

Not sure if yours is 1/4 or 3/16th, 3/8ths pitch?

Looked it up. This. 3/8ths. I think. 5 meters or 6 yards. 17 feet! Enough to do both sides twice. £27.
https://www.thebearingcompany.co.uk/pro ... 3-8-pitch/
They do SINGLE link joiners, and double (normal) link joiners too.

But if you know what you are doing you can shorten a chain easily too. But now is the perfect time to replace with new anyway as industrial chain is really cheap like the sprockets.

Tell me what reasuringly expensive price do bounder charge for their sprockets and a chain?

I just went from 23t to 19t. Didn't need to touch the chain. Tensioner has actually A LOT of play.

[Burgerman]

Two things.
100% DEAD batteries are also open circut. So they will not charge.
So if you apply 12A not more, set to 26V, then one of two things will happen.

Thing 1... If the battery isnt 100% dead, they will begin to charge. After a short time they might even start to charge at 12A. Within maybe 5 mins to an hour they will have enough power to run the chair. Which solves the problem.

Thing 2... If they are truly totalled, then the POWER SUPPLY will present the 26V to the complete chair system and the dead battery will take no current. The chair will draw almost no current. Maybe a few mA. And now you can turn it on. And all the lights will show a full battery. Because it sees 26V. And now the seat lift etc will work directly from the power supply.

[Burgerman]

I just went from 23t to 19t. Didn't need to touch the chain. Tensioner has actually A LOT of play.

Not sure what you mean by play.
A chain should run between sprockets as straight as possible, without getting excessively re routed by a tensioner. Because that just loads up the tensioner hard when that run of chair is pulled tight. Causes friction and less efficiency and possibly moves it if the spring tension isnt adequate.

The less it deflects the chain the better.

[Burgerman]

I just looked at a parts list.
Bounders do not have a chain tensioner. Those are designed to take the slack out of a chain run and are spring tensioned. Used on bikes, inside engines etc on motocrossers drive chairs etc so as the chain wears the tensioner takes up the slack to keep the chair from making noise, thrashing around etc. It keeps it "tight" automatically.

The bounder has a chain adjuster like a motorcycle or bicycle chain and a quick release cam. When the motor or brake is square with the frame, with the chairn tensioned so that theres about 5 to 10mm of movement in it, then the chain is correctly tensioned. Since no oil pressure or spring tensioner you will need to adjust it manually as it wears. Since you already took up 3 or 4 full links of tension adjustment then its likely that the motor is no longer parallel with the frame and you will run out of adjustment as the chair wears.

[emilevirus]

Must I change the motor compensation after changing the gearing?

[shirley_hkg]

It relates to the IR. You didn't change the motors, so I think NO.

[emilevirus]

I don't get what's going on. Indoors it's fine but when I go outdoors and try to go full speed it just wants to go left.

[shirley_hkg]

Issue is at indoors too, only that it is insignificant due to low speed.
May need to adjust motor balance.

[Burgerman]

Compensation isnt different, unless you changed motors.
3 possibilities.

Did you happen to find a square key on the ground after fitting smaller drive sprocket?

You did reconnect both brakes electrically? because that sounds likely.

Maybe the too long chain is binding up somewhere possibly?

[emilevirus]

ACTUALLY it did the same before changing gearing. It's like LinX doesn't know what to do when one motor is pegged. It spins the other wheel rather than slowing it. Is that possible?

[LROBBINS]

Motor speed depends on load and voltage, it has no "awareness" of RPM and normal controllers do hot have encoders for RPM either. If load is high on one motor, and low on the other, the unloaded one will turn faster. Does the chair go straight if on a flat, smooth surface? If not, you may have to change motor balance as Shirley suggested or re-calibrate the joystick if it is actually sending "go left" when the stick is centered.

[Burgerman]

Motor speed depends on load and voltage, it has no "awareness" of RPM and normal controllers do hot have encoders for RPM either. If load is high on one motor, and low on the other, the unloaded one will turn faster.

Well it WOULD do that. The unloaded motor spins freer, so it draws less current. The load compensation is set correctly reduces the power to that free running motor, and it increases power to the loaded one. And so keeps the chair running straight automatically. From experience on most chairs the manufacturer sets that a little of the "safe" side and it works only partly.

Does the chair go straight if on a flat, smooth surface? If not, you may have to change motor balance as Shirley suggested or re-calibrate the joystick if it is actually sending "go left" when the stick is centered.

Theoretically. Joystick itself could be miscalibrated too. But I cant imagine two motors being different enough for that to happen to any significance you would notice by seat of pants.
Easy to find out.
Lift chair on a couple of books (remember those?) Put a bit of white/coloured tape on both rear tyres. Set joystick to a max speed that allows you to COUNT the wheels rotating against a stopwatch. Put joystick full forwards and be sure its central. Count each wheel revolutions per minute. Or 30 secs will be enough. If both are withing 5% of each other then thats fine.

Could be a motor brush worn or stuck not making contact. How to tell? Take them out and have a look. Or unplug from PM and measure internal reistance. This should be withing 5% each motor. Will be VERY low, hard to measure. You will need a meter capable of reading mOhms. Expect around 60. Its ot important what the figure is but that both are similar. 230 is about 8mph.

[emilevirus]

I doubt motor is worn... It's brand new. I can tell it's really the compensation not working properly. I'll record a video today.

[Burgerman]

Just because new doesent mean a brush cannot be stuck, armature not defective, connection to a brush not good,etc. I suspect the brake is on or you fgot to replace the square key. Or the chain is too long and dragging on something.

[emilevirus]

The key is there I double checked. The chain is tight enough. How could the brake be on? It'd error out if brake is unplugged. I hear it click. If I disengage brakes and push the chair it's easy to push, nothing is dragging.

[Burgerman]

Beats me.

Whats left to check? Motors. And programming. Could it be in your head, by which I mean you think you are pushing the stick forwards but really its at say 1 oclock?

Do the free running check, and count RPM of each wheel.

[LROBBINS]

Yes, it's unlikely that the two motors are different enough, in the absence of a fault, to cause the joystick to be out of calibration. But the joystick may have gone out of calibration for reasons having nothing to do with the replacement of the motors. It's simple enough to recalibrate.

[Burgerman]

This might sound like a silly question. You did do both sdes right? With the same no of teeth on the new sprockets both sides? Theres all the information here that you ned to find and diagnose the fault. So we wait in anticipation.

[emilevirus]

Ok, someone drove the chair for me so I could see what's going on. It's nothing technical. Tires are just crap! Traction is non existant. I was on flat surface with no one in the wheelchair. Wheels would just spin freely like the chair was glued in place.

[Burgerman]

Let me guess. ITS WAY TOO NOSE HEAVY. Because even with NO tyres it should drive properly is all 4 wheels are on the deck.

What happens is that the front tyres follow the terrain, and the user has most of his weight on them. And so a rear wheel has either no weight or even is airborn on uneven surfaces.

ALL my chairs are the opposite. 70% or more of the total chairs mass sits on the drive wheels. If I drive a caster wheel over a hole or a curb edge it just floats in mid air. But drive wheels are in solid ground contact.