Hi from Canada

You dont have to, but its interesting!

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Hi from Canada

Postby eugenech » 09 Oct 2017, 23:04

Hi,

I am Eugene Cherny and 3 years ago I decided to use my experience and knowledge to help people. I created company called Cheelcare ( www.cheelcare.com) and with the help of very talented people we created new design of wheelchair. We are trying to address major issues with existing models and hopefully soon will be able to manufacture them and get it certified in US and Europe. Any feedback is welcome.

Cheers,
Eugene
eugenech
 
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Location: Richmond Hill, Ontario

Re: Hi from Canada

Postby Burgerman » 09 Oct 2017, 23:35

Hello!
Are you sure you want my /our opinions?
Because you probably wont like it! I know what I want, so am very opinionated. So dont think I am being over negative!
I am all for anything new as long as its better. And if "features" doesent add any additional bulk, size, or does all the daily important stuff better or at least as well. Added tricks (like stair climbing) are OK as long as it doesent detract in any way from whats actually important for 90% of daily use. Can I ask, why not ask here BEFORE you made something?

I could write a book on that chair, I just took a 5 min look. But first and foremost theres nowhere near enough tech info. Or real usage vids. It looks like its not going to have adequate strength or rigidity in its odd suspension system for the kind of use my chairs get.

First thoughts, wheels much too small, too skinny, too fragile, and will sink on soft ground in winter or wont work on sand/mud/snow as we all encounter in winter dog walking or getting to the pub. Do you think we all live in a hospital room? Many of us work in workshops, or wherever, and get out and about!
Those slab thingies things on the sides make the chair more bulky and wider. And look odd. That space would be better filled with batteries if you must have them... But they would be in my way a lot. I need/want my seat cushion touching the bed for easy reaching of things I am working on, or to get close to my pillar drill, or to get close enough to lift awquard heavy things. etc. It means pulling up tight to my bed at an angle. And they would hit my door in the van so couldnt be used to drive from. So they gotta go on day 1! Jus too big, and in the way.

Those lift up arms will likely not be strong enough to allow a 20 stone guy to pressure lift on, or stable enough (wobbles side to side) to drive the chair properly once I reprogram it so it goes and steers correctly! They must be rigid like in a vice. I never saw any lift up hinged ones that came close.

Which brings me to the next issue. Range. That chair uses 48V which is commendable for various reasons. But 20Ah? Thats about 1/3 of what is actually required. My own 26 kmh capable chair has 45V lithium ion phosphate (safe) lithium battery of 3.5x that capacity. Its about enough for a good days use at 45V and 72Ah. Or 3.24kwh. Compared to yours at just 20Ah x 48V = 0.96kwh. So 3.4x greater capacity. And then theres the stability issues. With such a small battery the CofG must be very high. So the chair must be either lacking stability or extra long and wide. Theser no option.


Weight with batteries
290 Lbs / 130kg

Too heavy. And top heavy. Did you get it through all the regulations yet? Esp as it includes a small lightweight lithium battery causing a higher CofG.


Rear Tires
3.00-8 (pneumatic or foam filled)
Front Tires
8“ (pneumatic or foam filled)

Tubes? Fragile and not aceptable. Tubeless offers better puncture resistance and less likelyhood of deflation even if punctured, and foam filled is both power wasting and uncomfortable. This iswhy you should ask here first!
BOTH front and rear are too narrow, too small and borderline overloaded anyway for the weight of a heavy chair and heavy user.
This chair has wider 3.00 x 4 (10 inch) casters, and 12 inch x 4 tubeless rims with much stronger radial tubeless 130/60 - 10 tyres. download/file.php?id=3838 TOTAL chair width still under 25.0 inches with a battery that is 3.4x bigger than yours..
And download/file.php?id=4508&mode=view
And download/file.php?id=4455&mode=view
And download/file.php?id=4460&mode=view
And this one uses 6 inch wide tyres, with kevlar reinforcement as well as being tubeless. And is still under 26.5 inches wide. http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

Range
50 km

ISO mileage test? You will get half of that in actual real world use at best. Why? Brushless hub motors have a huge stall current, or when trying to make a lot of torque for turns in place etc compared to geared motors. While having extremely low high speed current draw. So a few minutes indoor use or turning left/right requires a massive amount of battery power compared to the iso test procedure. Which is basically mostly fast running where a brushless hub motor excels. In other words they are at a large advantage on the ISO test procedure compared to geared brushed motor.
My own 26kph chair has 45 to 50 miles REAL WORLD measured range (75 to 80km). Not the unrealistic result from the iso test.

Maximum Speed
15 km/h

Not enough! Thats 9mph. Well it is enough for some maybe, but its far too slow for me!
http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm does 16mph or 26kph.

Speed Settings
10 settings

Why? Mines on max 24/7. If the programming is good, then you only require 1 speed setting or rather 1 profile. If its not and likely it wont be then we also need real full "OEM level" programming access or its basically unusable by me and many on this forum.


Drive System
RWD

Good!


Turning Radius
25“ / 63.5 cm

This is meaningless. Whats total length from anti tips to tip of footplate. THAT determines the space or corridor you can turn in. Mines 37 inches.

Max Obstacle Height
3-4 “ / 7.6-10 cm

Good...


Chair Ground Clearance
3.5-11” / 9-28 cm

Good...


Braking System
Electromagnetic

Thats not a braking system, its a lock that comes on AFTER you stop like a handbrake in a car.


Max Weight Capacity
300lb / 136 kg

Inadequate. For eg I am already on its max limit. Why is it this low? Let me guesss. Inadequate motor stall torque?

Battery
48V 20Ah

Already discussed. 3x too small.

Charger
7A Charger

Too small and its dumb. And you are likely to be using a generic BMS too... See: viewtopic.php?f=2&t=1813 see first couple of posts.
I am using a PC controlled and fully programable charge and discharge graphing, cell balancing 40A 1344 watt charger. And it works in my van too.

Does it have RC? It must do today. I use RC to move my chairs around, daily.

Please dont shoot the messenger, you did ask for feedback. This is before I get close enough for a real look!
Now the question is, can you really stand constructive criticism and feedback? Most manufacturers cannot and they go away in a sulk instead of discussing and addressing or considering the issues.

Send me a chair to test and I can be a lot more useful to you.

We are trying to address major issues with existing models

What do you think those are? I am very interested to know. I doubt that many on here would agree with your list. Had you ask me I could give you a comprehensive list of my issues with production chairs. Its why I build my own.
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Re: Hi from Canada

Postby eugenech » 10 Oct 2017, 03:33

hi Burgerman,

Thank you for your reply and eval of my chair. Love it!

Are you sure you want my /our opinions?
Because you probably wont like it! I know what I want, so am very opinionated. So dont think I am being over negative!
I am all for anything new as long as its better. And if "features" doesent add any additional bulk, size, or does all the daily important stuff better or at least as well. Added tricks (like stair climbing) are OK as long as it doesent detract in any way from whats actually important for 90% of daily use. Can I ask, why not ask here BEFORE you made something?



Valid point and I did ask people and followed your build and this forum.

I could write a book on that chair, I just took a 5 min look. But first and foremost theres nowhere near enough tech info. Or real usage vids. It looks like its not going to have adequate strength or rigidity in its odd suspension system for the kind of use my chairs get.


Valid point again. I will post videos once I get to make them. Hopefully soon. In a mean time feel free to ask for technical info.

First thoughts, wheels much too small, too skinny, too fragile, and will sink on soft ground in winter or wont work on sand/mud/snow as we all encounter in winter dog walking or getting to the pub. Do you think we all live in a hospital room?
Many of us work in workshops, or wherever, and get out and about!


Understandable and that is why we are going to build AWD model with wider tires.

Those slab thingies things on the sides make the chair more bulky and wider. And look odd. That space would be better filled with batteries if you must have them... But they would be in my way a lot. I need/want my seat cushion touching the bed for easy reaching of things I am working on, or to get close to my pillar drill, or to get close enough to lift awquard heavy things. etc. It means pulling up tight to my bed at an angle. And they would hit my door in the van so couldnt be used to drive from. So they gotta go on day 1! Jus too big, and in the way.


This chair is 25" and can be parked flushed to bed. It can be hight adjusted to any table or give you opportunity to order beer at the bar in a pub.BM3 cannot as wheels are wider than cushion and there is no elevation or tilt.

Those lift up arms will likely not be strong enough to allow a 20 stone guy to pressure lift on, or stable enough (wobbles side to side) to drive the chair properly once I reprogram it so it goes and steers correctly! They must be rigid like in a vice. I never saw any lift up hinged ones that came close.


I am a touch lighter than you (only 18 stones or 115kg) and I assure you I can put my weight on them without hesitation. And I already programmed it to steer correctly :) ( Thank you Lenny)

Which brings me to the next issue. Range. That chair uses 48V which is commendable for various reasons. But 20Ah? Thats about 1/3 of what is actually required. My own 26 kmh capable chair has 45V lithium ion phosphate (safe) lithium battery of 3.5x that capacity. Its about enough for a good days use at 45V and 72Ah. Or 3.24kwh. Compared to yours at just 20Ah x 48V = 0.96kwh. So 3.4x greater capacity. And then theres the stability issues. With such a small battery the CofG must be very high. So the chair must be either lacking stability or extra long and wide. Theser no option.


In reality chair is running on 52V. Use of geared brushless motors gives 10-15% advantage in efficiency and weight reduction. I agree that more capacity would be beneficial if you do not like to charge your chair every day. Batteries we use have 3000 cycle lifespan.
So far, I did not witness lack of stability. Doing 90 degree turn at maximum speed is a standard ISO test. Don't forget, the seat of this chair is 14" from the ground in a lowest position. We are testing it half way up.


Weight with batteries
290 Lbs / 130kg
Too heavy. And top heavy. Did you get it through all the regulations yet? Esp as it includes a small lightweight lithium battery causing a higher CofG.


Agreed completely. This is just a prototype. Once we get closer to production it will not exceed 100kg. Please keep in mind this chair has full compliment of power seating. What is the weight of BM3?


Rear Tires
3.00-8 (pneumatic or foam filled)
Front Tires
8“ (pneumatic or foam filled)
Tubes? Fragile and not aceptable. Tubeless offers better puncture resistance and less likelyhood of deflation even if punctured, and foam filled is both power wasting and uncomfortable. This iswhy you should ask here first!
BOTH front and rear are too narrow, too small and borderline overloaded anyway for the weight of a heavy chair and heavy user.
This chair has wider 3.00 x 4 (10 inch) casters, and 12 inch x 4 tubeless rims with much stronger radial tubeless 130/60 - 10 tyres. download/file.php?id=3838 TOTAL chair width still under 25.0 inches with a battery that is 3.4x bigger than yours..
And download/file.php?id=4508&mode=view
And download/file.php?id=4455&mode=view
And download/file.php?id=4460&mode=view
And this one uses 6 inch wide tyres, with kevlar reinforcement as well as being tubeless. And is still under 26.5 inches wide. http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm


Love your tires. Unfortunately, I am currently limited what suppliers can give me in non marking tires. Planning to use similar to yours in future.

Range
50 km
ISO mileage test? You will get half of that in actual real world use at best. Why? Brushless hub motors have a huge stall current, or when trying to make a lot of torque for turns in place etc compared to geared motors. While having extremely low high speed current draw. So a few minutes indoor use or turning left/right requires a massive amount of battery power compared to the iso test procedure. Which is basically mostly fast running where a brushless hub motor excels. In other words they are at a large advantage on the ISO test procedure compared to geared brushed motor.
My own 26kph chair has 45 to 50 miles REAL WORLD measured range (75 to 80km). Not the unrealistic result from the iso test.


Motors we are using are geared. We use chair indoor and outdoor and battery easily lasts though the day.

Maximum Speed
15 km/h
Not enough! Thats 9mph. Well it is enough for some maybe, but its far too slow for me!
http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm does 16mph or 26kph.


I love the speed too.
In Canada we are limited to 15 km/h by law and most people we spoke to do not want to go faster. In some cases we can unlock more speed if desired.

Speed Settings
10 settings
Why? Mines on max 24/7. If the programming is good, then you only require 1 speed setting or rather 1 profile. If its not and likely it wont be then we also need real full "OEM level" programming access or its basically unusable by me and many on this forum.


Some people do not have good driving skills and prefer to limit speed when they are indoors. Some don't. All programming access is done from the same display. No need for external programmer.


Drive System
RWD
Good!


Turning Radius
25“ / 63.5 cm
This is meaningless. Whats total length from anti tips to tip of footplate. THAT determines the space or corridor you can turn in. Mines 37 inches.

Max Obstacle Height
3-4 “ / 7.6-10 cm
Good...


Chair Ground Clearance
3.5-11” / 9-28 cm
Good...


Braking System
Electromagnetic
Thats not a braking system, its a lock that comes on AFTER you stop like a handbrake in a car.


Max Weight Capacity
300lb / 136 kg
Inadequate. For eg I am already on its max limit. Why is it this low? Let me guesss. Inadequate motor stall torque?


This is Canadian standard capacity for non bariatric chair. In real world this chair can lift much more. Each leg can lift 200kg.

Battery
48V 20Ah
Already discussed. 3x too small.

Charger
7A Charger
Too small and its dumb. And you are likely to be using a generic BMS too... See: viewtopic.php?f=2&t=1813 see first couple of posts.
I am using a PC controlled and fully programable charge and discharge graphing, cell balancing 40A 1344 watt charger. And it works in my van too.


I like your setup, you probably can charge you battery in 2 hours. It takes us 3.5 hours. Compared to mass produced chairs this is probably acceptable.

Does it have RC? It must do today. I use RC to move my chairs around, daily.


Absolutely. One can drive it. One can change seat, leg rest, backrest, tilt and etc. You can see picture on a website under Products-> Cheelcare Xceed -> Comfort.

Please dont shoot the messenger, you did ask for feedback. This is before I get close enough for a real look!
Now the question is, can you really stand constructive criticism and feedback? Most manufacturers cannot and they go away in a sulk instead of discussing and addressing or considering the issues.

Send me a chair to test and I can be a lot more useful to you.


I absolutely love your feedback and appreciate it. It allows me to fix what is wrong with it before I get it on a market. I would love to send you this chair and will do it when i build enough of them. For now, I would like us to continue this discussions.



What do you think those are? I am very interested to know. I doubt that many on here would agree with your list. Had you ask me I could give you a comprehensive list of my issues with production chairs. Its why I build my own.


Please share the list with me. I got my list of problems with current models from Occupational Therapists, people who ride those chairs, caregivers and your forum. I understand that I have missed or misinterpreted some. It is never too late to learn new things.

Eugene
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Re: Hi from Canada

Postby Burgerman » 10 Oct 2017, 16:17


First thoughts, wheels much too small, too skinny, too fragile, and will sink on soft ground in winter or wont work on sand/mud/snow as we all encounter in winter dog walking or getting to the pub. Do you think we all live in a hospital room?
Many of us work in workshops, or wherever, and get out and about!

Understandable and that is why we are going to build AWD model with wider tires.

Well I wish you a lot of luck! It takes 5x as many Amps at least to skid steer, or 5x the torque at least to turn in place with 4x4 setups. Requiring a much mre powerful motor/controller setup. And then even my 3x bigger lithium battery that you are not using cant cope, and it tears up tyres and carpets. Been there and tried that!
Unless you mean like a scooter, with power steered casters? There are a couple of chairs like that, but horrid to drive and steer indoors. And heaavy. So not good for an active daily used chair. More outdoor only...

Those slab thingies things on the sides make the chair more bulky and wider. And look odd. That space would be better filled with batteries if you must have them... But they would be in my way a lot. I need/want my seat cushion touching the bed for easy reaching of things I am working on, or to get close to my pillar drill, or to get close enough to lift awquard heavy things. etc. It means pulling up tight to my bed at an angle. And they would hit my door in the van so couldnt be used to drive from. So they gotta go on day 1! JusT too big, and in the way.

This chair is 25" and can be parked flushed to bed. It can be hight adjusted to any table or give you opportunity to order beer at the bar in a pub.BM3 cannot as wheels are wider than cushion and there is no elevation or tilt.


The BM3 with its 6 inch wide tyres is no wider in total than your chair. And in the centre of that is my seat cushion at 18 inches. On my black BM3 chair, or green 24 inch wide BM2 chair, I can get that cushion right next to my bed on either one (and my dressing bench in the shower room, work bench, lath, pillar drill, etc) because the front of the chair and the rear tyres go under the edge. Same with my desk. it if I park at a slight angle to the bed the cushion touches the bed at the front, where I transfer. Cant do any of this with a big plastic thing in the way.

I CHOOSE not to fit a seat lift, tilt, recline, power footrests because a chair is a fine balance. And those things add mass that is too high messing up handling, stability, causing caster shake, and tipping me out on soft ground or on sand, ramps etc. CG is already too high, even with a 3.24kwh lithium battery as it is half the weight of the lead bricks. So it matters. So thats why I ask about your chairs stability. Heavy seating, heavy user, sat above a light base with a tiny light battery means very high CG position. That cannot be safe in extreme angles such as we get crossing rough ground, if a tyre sinks in muddy feild, or up a steep ramp.

Those lift up arms will likely not be strong enough to allow a 20 stone guy to pressure lift on, or stable enough (wobbles side to side) to drive the chair properly once I reprogram it so it goes and steers correctly! They must be rigid like in a vice. I never saw any lift up hinged ones that came close.

I am a touch lighter than you (only 18 stones or 115kg) and I assure you I can put my weight on them without hesitation. And I already programmed it to steer correctly :) ( Thank you Lenny)

I will take your word for it. Can you move the end where the controller sits, side to side more than say 5mm by pushing? If so its no good once programmed to go and steer how I like. E.G. http://www.wheelchairdriver.com/gopro/control.mp4

And its imperative that I can get access to at LEAST the equivelent programming tools as you. At least manufacturing level. When I buy a chair, the very first box to tick is the OEM or factory programmer availability. Not available? Legally or otherwise? Then that chair is automatically removed from my list as a matter of course. Its that important to daily use. I never drove any powerchair yet that I didnt consider gutless, slow to respond, lacking in torque and dangerous because of it. And need to fine tune many things. I doubt any built in programming with a tiny screen can do this OEM level stuff adequately. If it cant then its as pointless as the one built in to the r-net controllers.

Which brings me to the next issue. Range. That chair uses 48V which is commendable for various reasons. But 20Ah? Thats about 1/3 of what is actually required. My own 26 kmh capable chair has 45V lithium ion phosphate (safe) lithium battery of 3.5x that capacity. Its about enough for a good days use at 45V and 72Ah. Or 3.24kwh. Compared to yours at just 20Ah x 48V = 0.96kwh. So 3.4x greater capacity. And then theres the stability issues. With such a small battery the CofG must be very high. So the chair must be either lacking stability or extra long and wide. Theser no option.

In reality chair is running on 52V. Use of geared brushless motors gives 10-15% advantage in efficiency and weight reduction. I agree that more capacity would be beneficial if you do not like to charge your chair every day. Batteries we use have 3000 cycle lifespan.
So far, I did not witness lack of stability. Doing 90 degree turn at maximum speed is a standard ISO test. Don't forget, the seat of this chair is 14" from the ground in a lowest position. We are testing it half way up.


1. you will only get 3000 cycles if you discharge it at low C rates. Typically (well) below 1C. That means max current 20A on your battery... So your battery is way too small for that. It will degrade faster.

2. you will only get max cycles if the battery never sees above 3.600v oper cell or less. Or discharged deeply regularly. I charge at an exact 3.550V per cell plus or minus 0.003v. A typical BMS balances both too soon during the charge and some do it all the time, at too low voltage and with a feeble balance current. And allows too high voltage on charge before repeatedly cutting off charge as it tries to balance with too small current, and so bounces the high cells repeatedly over the ideal voltage limit. So again the battery CELLS charged and used properly may offer 3000 cycles but your BMS and charge setup will limit that to a much lower figure. Or fail. As most BMS setups inevitably do.

3. since the battery offeres only an ISO test 30 miles (50kms) and a real world figure of around half this, is typical. So 15 miles usable in the real world. Thats what you get if you run till its empty. Since we cant do that for fear of getting back home we can go 'away' 6 miles, and back 6 miles leaving a small bit in reserve only. Its called range anxiety, and it limits what we attempt subconciously and affects our lives. . I do more than double that 1kwh most days if I am busy, and going out again in an evening.

The whole point of fitting lithium is so that you can fit typoically 1.6 to 2x the Ah in the same volume as the lead bricks you removed. Failing to do this misses the entyre poiunt of lithium and loses its big advantaages.
Which are RANGE. Which you havent really capitalised on, and fitted a small sub 1kwh pack. (mine are 3.24kwh, over 3x bigger but still lighter than lead.)
And LONGEVITY. By fitting a small pack with a BMS you are running the battery low, daily, and topping up to a too high BMS controlled voltage daaily, and drawing far too many Amps per Ah of battery (high C rate draw). These 3 things mean you will get a far lower number of cycles than you would if you fitted a bigger pack! So losing this advantaage too.


Weight with batteries
290 Lbs / 130kg
Too heavy. And top heavy. Did you get it through all the regulations yet? Esp as it includes a small lightweight lithium battery causing a higher CofG.

Agreed completely. This is just a prototype. Once we get closer to production it will not exceed 100kg. Please keep in mind this chair has full compliment of power seating. What is the weight of BM3?


Its not really about max weight (unless hill climbing) but of the centre of mass. CG position. With a 3.24kwh pack, and a simple frame seat the CG is kept within limits. Even so stability is compronmised compared to a lead battery setup, requiring longer wheelbase, and a slightly wider track. Or we suffer caster shake issues, and tip over the back on steep ramps etc. Longer anti tip bars are a no no because they get hung up on stuff in the real world.


Range
50 km
ISO mileage test? You will get half of that in actual real world use at best. Why? Brushless hub motors have a huge stall current, or when trying to make a lot of torque for turns in place etc compared to geared motors. While having extremely low high speed current draw. So a few minutes indoor use or turning left/right requires a massive amount of battery power compared to the iso test procedure. Which is basically mostly fast running where a brushless hub motor excels. In other words they are at a large advantage on the ISO test procedure compared to geared brushed motor.
My own 26kph chair has 45 to 50 miles REAL WORLD measured range (75 to 80km). Not the unrealistic result from the iso test.

Motors we are using are geared. We use chair indoor and outdoor and battery easily lasts though the day.


Not a chance that a 1kwh battery would last me a day! I use my chairs. 1kwh (yours is 960watt hours) is around the same as you get from a set of group24 lead. Its nowhere near enough for a days use if you are heavy.

Also we suffer from a leaned thing called range anxiety. Its a subconcious thing that stops us getting out there and enjoying life! So even if we know its got an ISO 30 miles as yours has, we can only do half that in reality. The ISO test is not realistic. So you will actually run out of power around half this. That means I cant get through a busy day since its 2pm now, and I already did 14 miles. I am going into town later, to the pub. Thats another 6 miles return, plus all the power used moving around in the pub etc. Would I gt back? I cant know... Indoors shuffling about actually eats more Ah than traveling the streets. So under 1kwh is not adequate. And of course lithium batteries wears out faster with deeper discharges, and recharging daily uses up cycles. And heavy currents per cell mean less cycles. So a bigger battery makes way more sense all around. Thats why my chairs use 3kwh plus packs, with proper charging and balancing, and no BMS I get 45 REAL miles on the fast chair (55 REAL miles on the slower chair) as well as a much greater life expectancy.

Maximum Speed
15 km/h
Not enough! Thats 9mph. Well it is enough for some maybe, but its far too slow for me!
http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm does 16mph or 26kph.

I love the speed too.
In Canada we are limited to 15 km/h by law and most people we spoke to do not want to go faster. In some cases we can unlock more speed if desired.


Great. But remamber that if YOU can unlock the speed via programmiung then I should be able to do this too. This thing where manufacturers lock away the tools must stop! This is why I will not buy any chair that I cannot get FULL programming capability for.

Speed Settings
10 settings
Why? Mines on max 24/7. If the programming is good, then you only require 1 speed setting or rather 1 profile. If its not and likely it wont be then we also need real full "OEM level" programming access or its basically unusable by me and many on this forum.

Some people do not have good driving skills and prefer to limit speed when they are indoors. Some don't. All programming access is done from the same display. No need for external programmer.



See above. this should be the USERS choice! But yes, some cant use proportional linear control.


Max Weight Capacity
300lb / 136 kg
Inadequate. For eg I am already on its max limit. Why is it this low? Let me guess. Inadequate motor stall torque?

This is Canadian standard capacity for non bariatric chair. In real world this chair can lift much more. Each leg can lift 200kg.


Maybe, what does it do for stability, programming, stall torque adequate?

Charger
7A Charger
Too small and its dumb. And you are likely to be using a generic BMS too... See: viewtopic.php?f=2&t=1813 see first couple of posts.
I am using a PC controlled and fully programable charge and discharge graphing, cell balancing 40A 1344 watt charger. And it works in my van too.

I like your setup, you probably can charge you battery in 2 hours. It takes us 3.5 hours. Compared to mass produced chairs this is probably acceptable.



Its not about speed. If you fit a sensible sized lithium battery to take advantage of the extra range, extra reliability, extra longevity that lithium can give us, as you surely must, then a 7A charger will take an age.

E.G. My BM2 chair has a 120Ah pack. I charge this at 7A and it will take almost 20 hours!!!
A 40A charger still takes 3.5 hours because the batterystores a useful amount of power.
More importantly, it charges PROPERLY where a dumb charger and BMS does not. And measures Ah in, and can measure capacity, IR, display cell balance and graph this as you charge etc. And it works as I drive in my van!
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Re: Hi from Canada

Postby LROBBINS » 10 Oct 2017, 21:10

John,

Eugene is using a scripted Roboteq controller, so access to the programming should not be a problem UNLESS he locks users out.
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Re: Hi from Canada

Postby Burgerman » 10 Oct 2017, 21:35

Oh. I see. Interesting. I was wondering! So he has the saame basic script as I am using.
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Re: Hi from Canada

Postby Burgerman » 10 Oct 2017, 23:56

I just did the math. You get approx 50Ah out of a set of grp 24 lead bricks (73Ah @ the 20H rate, but 50 at the rate a powerchair uses them, over approx 3 hours if you keep driving. (MKs used for comparison)

So stored energy in a set of lead MKs is 50Ah x 12v nominal or 1.2kwh.
Now the 20Ah x the 48v nominal is actually 51.2 (16x 3.2v nominal) and so thats an accurate 1.02kwh

So it will give 20% less range than the already inadequate grp24 lead bricks. Theres a gain of approx 10% with brushless. But thats still actually worse than lead.

And theres many on here that cant manage with that.
Its why expresso has 90Ah plus 36Ah addon lithium packs, (3.2kwh) so he can go a real 55 miles around new york.
And why Nandol had 190Ah, x 24 = 4.86kwh pack built before his disapearance.
And why my chairs are 3.2+kwh each, in 24 and 45v forms.
Shirley has about 3kwh too doesent he? Mayber more.
And wills 48V chair is 60Ah, thats also 3x bigger than the eugene one...
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Re: Hi from Canada

Postby eugenech » 11 Oct 2017, 03:50

I heard you loud and clear. I need to increase battery capacity. Just FYI, I use 3.2V 20Ah LiFePO4 pouch cell which offers 3C continuous (60A)/ 6C peak (120A) discharge amperage and can be charge at 20A. 7A was a charger I got for now. I can switch to 40Ah cells to double capacity or switch to cylindrical like you use. This part is easy.
I looked into charger you are using, Hyperion EOS 1420i NET3, and unfortunately it is discontinued. I am also confused, it is rated at 550W. That should give you 11A at 45V?

Your math is great! However you did not account for motor efficiency and weight of the chair. Given that my chair weight half as much as equivalent production monsters it needs less energy to move.
I promise you, I will do real life test of driving it all day inside and outside and let you know the results. So far, during shows we demonstrate and drive it around for 2 days on a single charge. ISO test was done with 75kg dummy on a track.

And yes, I use Roboteq controller with the same script as you are.

Your concern about stability is noted. So far we tried every ISO test for static and dynamic stability and we pass. This is before we enable automatic self-leveling, which helps to keep CG within footprint and make you feel better going on ramps, steep inclines or down the hill. Having 4 legs with suspension, mimics nature and provides very comfortable and stable ride.
Given that some people require power seating and governments position "An option/accessory that is beneficial, primarily in allowing the member to perform leisure or recreational activities, is noncovered."
An electronic interface used to control lights or other electrical devices is noncovered because it is not primarily medical in nature.
Swingaway, retractable, or removable hardware (E1028) is noncovered if the primary indication for its use is to allow the member to move close to desks or other surfaces.
I find it perplexing that people sit on a huge battery and have no means of charging their phone.

We are trying to create wheelchair with this features included at no charge and as part of the design. Technical issues are probably the easiest to fix.
Eugene
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Re: Hi from Canada

Postby Burgerman » 11 Oct 2017, 04:48

I looked into charger you are using, Hyperion EOS 1420i NET3, and unfortunately it is discontinued. I am also confused, it is rated at 550W. That should give you 11A at 45V?


No we are using a 1344 watt 40A charge, 1A balance current PL8v2 which has a modified charge algo after my interfering with them a bit.. And I have custom presets and access to some needed settings and hidden options, better suited to the balance and longevity of the large lithium ion phosphate packs we are using.

That charger will charge 8s. You need 2 of them linked as one, to charge at 40A and at 2,688 Watts... as on my bench. I have another in my van.

Heres a picture. A 40A charge cable, ready to plug in my 8S 24v chairs.
I have 2 chargers as I need to charge a 45V 13S chair as well. And a bunch of hobby stuff.

http://www.wheelchairdriver.com/BM3-con ... DCABLE.jpg

Power supplies, PC, and 2.68kw of charge capabiity...
http://www.wheelchairdriver.com/BM3-con ... arging.jpg

Same but also a couple of old Hyperions. These are now basically unused...
http://www.wheelchairdriver.com/BM3-con ... on/PL8.jpg


I heard you loud and clear. I need to increase battery capacity. Just FYI, I use 3.2V 20Ah LiFePO4 pouch cell which offers 3C continuous (60A)/ 6C peak (120A) discharge amperage and can be charge at 20A. 7A was a charger I got for now. I can switch to 40Ah cells to double capacity or switch to cylindrical like you use. This part is easy.

The roboteq I am using can draw 150A per motor. Thats 300A possible. But unusual. But 200A is quite normal or more. Just by doing a turn in place, with the turn acceleration set to actualy do something as my chairs are.

If you pull more than .5C or 1C max from a lithium cell you really do reduce service life. That quoted cycle life is at a low 1C or less. So taking 200A out of your pack is 10C... And its rated at 3, plus pulse at 6 which means 1 second. So you wont get much in the way of lifespan unless you prevent your users doing ramps, or rapid turn in place. When it comes to lithium, a larger pack extends service life. never going full or empty, never loading the cells hard, means it lives a long time. And the obvious benefit of adequate range which is the problem with most chairs.

Your math is great! However you did not account for motor efficiency and weight of the chair. Given that my chair weight half as much as equivalent production monsters it needs less energy to move.

Yes I did. I was actually comparing to my much lighter chairs. And allowed 10% efficiency gain for brushless geared motors which will be pretty close. And I was using your tennis court test (ISO figures) in my math! My figures will be within 5% and I have a lot of practice and so far never wrong! Pretty good at guestimating this stuff.

Tell me what is the stall current , free running current, at any given voltage of your motors, and impedance, max efficiency after the gearbox?
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Re: Hi from Canada

Postby Twinpanther » 11 Oct 2017, 15:04

Just an FYI. RevoElectric is now selling a dual PL8 (essentially 2 separate PL8's in a single unit) at $260 vs a single PL8 at $240.
USA link but the Singapore store is the same.
Image
http://www.usastore.revolectrix.com/Products_2/Cellpro-Dual-PowerLab_2/Cellpro-Dual-PowerLab_660
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Re: Hi from Canada

Postby eugenech » 11 Oct 2017, 15:21

I attached file for motor performance data.
This motors will consume as much current as you give them until it burns. Currently battery and Roboteq will cut power off at around 60A.
They feel powerful and with acceleration set higher, I can easily lift casters of the ground if desired. Design of the chair allows you to shift CG as desired.
Eugene
Attachments
48V300W700CLishuiLowGear2.jpg
Hub motor performance
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Re: Hi from Canada

Postby Burgerman » 11 Oct 2017, 16:24

If I understand that graph correctly, it shows very little torque, and very low current. 14A?
Biggest torque at 13.8A which will not be enough. And less still at zero RPM...So starting torque very low.

I must be looking at the wrong graph. That cannot be your motors. max amps is normally highest at zero rpms on a brushed motor (say 120A to 180A) Not single digits!

So not sure how those are going to work?
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Re: Hi from Canada

Postby Burgerman » 11 Oct 2017, 16:28

Just an FYI. RevoElectric is now selling a dual PL8 (essentially 2 separate PL8's in a single unit) at $260 vs a single PL8 at $240.
USA link but the Singapore store is the same.


No. You dont want that for 2 reasons.
The biggest of which its linked internally, so you cant charge a 48V pack without seperating each into two isolated 24V packs.

So best to go with 2 PL8s in this instance. They hook together as one regardless, but are isolated electrically but better for your purposes. Also because the firmware on that doesent allow some of the tweaks I can use on the PL8s. And theyu seem to be selling them off. So future firmwares may not be forthcoming. Which may be why they are cheap. If you just want two chargers, no need to charge above 8S then yes.
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Re: Hi from Canada

Postby ex-Gooserider » 17 Oct 2017, 04:02

While supposedly running Lenny's script, I also see on the technology page "Proprietary software algorithms" - sounds to me like a reason to run screaming...

I think the biggest single advantage to Lenny's script and CANBus setup is access to the source.... Better potential for being able to maintain, troubleshoot and support, even if Lenny suffers the hypothetical bus impact...

OTOH, try doing internal fixes on your Pilot + setup....

Far as I'm concerned, no source = no sale.....

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T-5, ASIA-B
Jazzy 1100
Jazzy Select 6
Quickie Q-7
Invacare Mariner
Want to make / get a better chair, ideally one that stands.
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Re: Hi from Canada

Postby Burgerman » 17 Oct 2017, 09:22

What if roboteq go broke or whatever? No alternative developed solution exists.
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Re: Hi from Canada

Postby ex-Gooserider » 24 Oct 2017, 03:03

Burgerman wrote:What if roboteq go broke or whatever? No alternative developed solution exists.


I totally agree, it is the big hole in our electronics. For my money, Lenny has done a fantastic job of work on everything between the user input and the motor controller, with his open-source-hardware CANbus system, but we don't have a solution for the motor controller....

One of our former Asylum members had developed a really potent OSH motor controller for use in combat robots (he was a competitor in the NBC Robot Wars series a couple years back) but it didn't have all the monitoring and failure detection stuff that the Roboteq has...

I know that in the past Lenny has said that he doesn't have the EE chops to do a safe motor controller, which is why he hasn't taken it on. Understandable as high power motor control is a seriously gnarly problem with lots of potential for catastrophic failure. I don't know if there is anyone else in the WCD world that would be up for it either.

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Re: Hi from Canada

Postby LROBBINS » 24 Oct 2017, 08:26

I don't know if there is anyone else in the WCD world that would be up for it either.
Perhaps Irving, but he's hardly been here at all of late.

One advantage of the CANbus system is that it would be easy to re-program to interact with other controllers - as long as it has a CAN interface. So, if something better than the Roboteq comes along, one could switch to that.
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Re: Hi from Canada

Postby eugenech » 24 Oct 2017, 19:49

ex-Gooserider wrote:While supposedly running Lenny's script, I also see on the technology page "Proprietary software algorithms" - sounds to me like a reason to run screaming...

I think the biggest single advantage to Lenny's script and CANBus setup is access to the source.... Better potential for being able to maintain, troubleshoot and support, even if Lenny suffers the hypothetical bus impact...

OTOH, try doing internal fixes on your Pilot + setup....

Far as I'm concerned, no source = no sale.....

ex-Gooserider



There are multiple programs running in this chair, not just Roboteq script. I agree that you should have full access to programmer. For 99% of population that is sufficient. For 1% that is capable of SAFELY changing code we can do special arrangement.
Some of the algorithms we created are proprietary, some will be disclosed.
I see you have a collection of chairs in your signature. Do you have source code for all of them?
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Re: Hi from Canada

Postby eugenech » 24 Oct 2017, 19:55

LROBBINS wrote:
I don't know if there is anyone else in the WCD world that would be up for it either.
Perhaps Irving, but he's hardly been here at all of late.

One advantage of the CANbus system is that it would be easy to re-program to interact with other controllers - as long as it has a CAN interface. So, if something better than the Roboteq comes along, one could switch to that.



I am inspired by Lenny and decided to switch all electronics to CANbus system as well. It offers great advantages and flexibility.
Hopefully, in a month or so I will have it running.
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