Which chair to pick ?

[expresso]

Hi - i am helping my sister pick a new power chair - she just refused the one they gave her - for many reasons - wrong seat height - major one - and left wheel locked up - after 3 days - it was the invacare Tourgu sp -

we are in the states -

any one have experince with a good chair ? we are looking at the invacare TDX - not sure because its invacare - permobil - maybe- but it would be the PS350 i think and its too slow - need to pay for upgrade i believe - not worth it for her -

what other chairs do you guys recommend ? sunrise 636 is one other one - but not sure - thats a little aggressive for her - maybe -

i just need to get her a good reliable working chair - i am hearing too many stories with invacare -

thanks -

[william pitts]

The TDX SI usually comes with group 22 batteries and 2 brush motors. It can be upgraded I assume to group 24 batteries and 4 brush motors. The 636 have those standard. The 636 is RWD and the TDX is mid wheel drive. The TDX SI is a 5 mph chair and the 636 is a 6.5 mph chair. I don't have the specs for the TDX SP at hand.

William

[expresso]

hi - thanks - 5 mph is too slow for anyone - even my sister - so thats not going to happen -

at least 6mph - with any chair - i am more concerned about reliability - i am reading alot of bad reviews for the TDX SP - which is the new model i belieave - the tourge sp she just got broke in 3 days - we gave it back to vendor -

concerned about getting another invacare - but not much choices out there - i would take the 636 if i were her - i am not forcing her to pick what i would get - i think Sunrise is great - solid chair -

i would have to slow down the 636 for her for sure - not really the top speed but the take off speed etc, - shes not comfortable with the front wheels going up etc, -

what chairs is everyone using ? and what experience are you having with them - ? good and bad - ?

[ex-Gooserider]

It would be good if you could go to the User Control Panel (near top of every forum page) and enter your location...

IMHO, of the stock chairs, the 636 seems to be one of the best options...

I wouldn't take a Pride / Quantum as a gift based on my experience with my current chairs.

The Sunrise chairs seem pretty solid in general, and the 6?6 family of chairs seems to be the closest US equivalent to the F-55 that BM uses for his improved chairs...

I'm actually working slowly on making my take on a BM3 starting with an older 626, which is essentially the same chair as the 636, just an earlier model.

ex-Gooserider

[Goibot]

There is a series of videos that the Christopher Reeve foundation produced that compares different chairs. Very well put together, gave me quite a few ideas. I need elevation on a chair so the 626 was not in my choices. I would suggest getting a test drive on a Bounder plus h frame. It surprised me. Speed is there in abundance and it will use group 27 batteries giving it better range, rear wheel drive, elevates 13 inches. It is a heavy chair though. Google 21st century, they link the videos.

[Goibot]

I was also really impressed with the frontier v6. It sat a bit too tall for me though. It was awesome outside.

[Burgerman]

Problem, as reported by many users, and expected by basic physics and my experience is that the fast 11 mph bounder has only 120 amp controller. And its motors are geared for 11.5 mph. So torque is lacking, and even with group 27 baatteries range is pretty dismal. The only solution here is either/or brushless and lithium batteries with much more stored power and a controller that can do more amps, or more volts.

This is the sole reason my BM3 is using a 150 amp per channel, 250 peak, controller and about 45v, and around double the sstored energy of a set of group 27 batteries with the 3000 watt hour 13s lithium battery. Because it NEEDS that to be truly 15 mph capable and still have great range, and as much torque as before...

[expresso]

that chair is not covered by insurance and would non be a good pick for my sister -

i am interested in anyone who has a new invacare tourg Sp model - or TDX SP model - that can comment on them - how they hold up - any break downs etc, -

also anyone with a Quickie 636 model - would like to hear from them - it seems to be coming down to those two models - 636, Tourgu Sp - or maybe the permobil C350Ps -

TDX SP may be too slow in standard setup - so may have to let that one go - i read different speed readings - some say 6 - some say 7 mph and some say 5 mph and 5.8 mph - cant figure it out which one is the correct speed for this model -

may not be a option - she really wants a rear wheel - so thats last on the list

any input on the 636 and Tourgu Sp ?

thanks

[Lord Chatterley]

Lack of torque is a serious issue and a more frequent occurrence than you might imagine.

http://www.youtube.com/watch?v=zl_inKBtiwM&feature=related

LC

[Burgerman]

Interesting link.

I quote: Check out the M300 climbing a gravel path up a steep hill. Notice the user's TDX can not get up the hill...

Well they were both useless! Notice that the GOOD chair was weaving all over due to the fact that once on the hill it had no SPARE torque left for control.

This is a consequence of many things.

a) gearing. Twice as fast literally means that on a slope, or when turning etc that you have half the torque. And draw or would need double the Amps even when going slowly.

b) Controller. A small amp controller may be 50 or 70 amps. Once you try a steep ramp, or have tall gearing, this is a joke and gets maxed out. Result? Lack of torque...

c) Gel batteries, like MK that the industry loves. Add a heavy amp controller, like say a 120 Amp R net one, and the tall gearing, then it writes cheques that gel batteries simply cannot cash. And they get worse with age and the further they are discharged.

A combination of this means 8mph chairs are OK for real lightweight users if set up properly (programming) but dont expect miracles. A 6 mph chair is a better bet for most of us.

My own chair can do about double that ramp, (pub ramp is steeper that I built myself!) but its slower at 6mph, has heavy low impedance 4 pole motors, heavier cables, seriously reprogrammed 100 amp controller, and much lower resistance Odyssey batteries. All of this combined maxes out possible torque.

I use this at least 4x a day, with full steering control, and can stop and start on the ramp. I weight over 20 stone! No stock chair can do this. And no 8mph chair stands a chance. It would need heavier motors and a 130 amp controller at least and nobody makes one.

[ex-Gooserider]

There is a series of videos that the Christopher Reeve foundation produced that compares different chairs. Very well put together, gave me quite a few ideas. I need elevation on a chair so the 626 was not in my choices. I would suggest getting a test drive on a Bounder plus h frame. It surprised me. Speed is there in abundance and it will use group 27 batteries giving it better range, rear wheel drive, elevates 13 inches. It is a heavy chair though. Google 21st century, they link the videos.

I was very underwhelmed by that video series - No real comparison, just a few shots of the different chairs running around various obstacles - with no explanation of that the tests were supposed to be, and especially no comparison of how the different chairs actually did on the tests.... But each one got 2-3 episodes of some sales droid talking about the "features" of the chair - mostly about their colour choices and how the DEALER might be able to do stuff to program the chair (if they felt so inclined and were actually competent...) - little or nothing about how the USER could do something to care for the chair...

However watching it, I didn't see any really serious obstacles like the ones that we find in the real world, and it looked like the testers were getting whiplash trying to go over the small bumps they did feature....

ex-Gooserider

[Burgerman]

With the small footprint powerchairs (must) have its very difficult to not get whiplash both side to side and back and forth though whatever design you use. But I dont think the people involved there actually undertand enough about powerchairs, physics, design to test and compare them in any useful fashion. They just regurgitate the manufacturers blurb.

[malamar]

Casualities of factory distribution provided me with a set of hard cored 12" driving wheels on top of 14" air filled ones; If i mount them, will it be worth torque wise of my ramp or little to no gain at the end? Your expert opinion appreciated, please
Best

[Burgerman]

You will gain the difference in leverage of 6 inches over 7. So I guess about 10 to 12 percent gain. Ad the same loss of speed.

[LROBBINS]

Less, because the air filled would deflect the difference in effective radius is probably more like 6.5 vs. 6. Ciao, Lenny

[malamar]

grazie millle Lenny and BM !
thinking of a chain transmission with a 3 enclosed gears bicycle pinion,...will be great...!

[wheelie207]

I had a invacare chair with brushless gearless motors with recline back and powerlegs.
I now have a permobil C500 Corpus front drive chair with 7.5 mph top speed with R-Net and other cool technology and considered a smart chair.
Well, the great news about this type of chair is the controller and chair will work with lifePO4 cells without changing anything onn the controller.
All I have to do is remove the gel batteries and install lithium batteries. Now I need to figure out which battery setup I would need to use since I have two (2) compartments for batteries. The doors are on each side and have to put them in and hook them up and they become 24 volt.

I'm not sure how the wiring is on my chair that automatically makes two 12volt as 24volt.
I will ask the company for a wiring layout of my chair so I can be sure how it all works.

But, I still would like to know what type of lithium batteries I should go with.

Now if I had kept the invacare chair as described above, the controller would have to be re-configured to work or replaced with a controller that works with the lithium batteries.

wheelie207

[Burgerman]

Some info for you. Almost every powerchair controller will work in a fashion with the CORRECT type of lithium battery. Because that gives you almost the same fully charged voltage as a pair of lead batteries in series.

But its not so simple. The battery meter will definitely read drastically wrong as you use the chair during the day. So another method of seeng battery capacity remaining is needed. And charging can be complex. You need to balance cells as you go.

And as of 2012 there is no suitable dumbed down plug and play lithium battery "swap" that is available or practical. At least none that will give you much benefit.

See here for how to and the best batteries to use:

http://www.wheelchairdriver.com/convert ... ithium.htm This is the the simplest, best, cheapest and most practical way to convert to lithium and get the full benefit and long service life.

Why there are no suitable lead brick dumb replacement batteries:

http://www.wheelchairdriver.com/lithium ... rchair.htm

My lithium pack:

http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

Charging and cell balancing:

http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

[Burgerman]

Added, your invacare brushless controller would have worked fine also with 8 lithium ion phosphate cells and brushless gearless motors. It will actually be more efficient. Other than the battery gauge as usual. Theres a member of this board doing just that as we speak.

This should have been a new thread though and not posted here in "Which chair to pick ?!"...

[malamar]

Would like to know, please:

Given the same power and gear ratio,in what differ 2 and 4 poles motors ??

Thanks indeed

[Burgerman]

Efficiency, reliability. 4 poles are generally the same as 2 poles but have 4 brushes and double the windings number live at one time, and double the magnetic poles. So smoother too. (think more cylinders... Like a 4 or 8 cylinder car)

[malamar]

aha..I see...thanks a lot

[Burgerman]

And think half the amps per carbon brush at any given power level, meaning much less burning away...

[malamar]

Sorry if not technically proficient: my Degree is in Photo-Journalism

[Burgerman]

pHYSICS DEGREES AT HOME:

http://www8.open.ac.uk/science/physical-science/

[malamar]

Too late ! Old dogs don't learn new tricks...prefer rule the seas, actually...



but thanks anyway