We are trying to address major issues with existing models
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.
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?
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.
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.
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! 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 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?
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.
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.
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.
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?
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.
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.
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.
Burgerman wrote:What if roboteq go broke or whatever? No alternative developed solution exists.
Perhaps Irving, but he's hardly been here at all of late.I don't know if there is anyone else in the WCD world that would be up for it either.
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
LROBBINS wrote:Perhaps Irving, but he's hardly been here at all of late.I don't know if there is anyone else in the WCD world that would be up for it either.
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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