Powerchair

[JayWoodhead]

I recently read your article on the BM3 and was wondering what is the fastest legal powerchair that is available to buy and where would you suggest I look for one as I'm looking to upgrade mine in the next few months and am looking for something with good range and quite quick as I do alot of running about day to day any suggestions please ?

[swalker]

Welcome to the forums. There are folks here from all over the world, so it would help if we know the jurisdiction in which you wish for the fast wheelchair to be legal.

Some more information would be helpful.

Are you looking for the absolute fastest? Fast enough, but has other essential functions you need? What about fast, yet still safe. Speeds that are safe for some will not necessarily be safe for others, depending on their ability (or lack thereof).

Are you looking for something that is commercially available, or that is custom built?

Do you want something that insurance will pay for?

Where I live (United States), if I want insurance to fund the wheelchair, I am limited to about 5 miles per hour. I can pay the delta to get a wheelchair that goes 7.5 miles per hour. Bounder makes faster wheelchairs, but getting them funded by insurance can be a struggle (though, some report success in this).

Steve

[Burgerman]

IP Geolocation
City Sheffield
State England
Country United Kingdom
Postal S1
Coordinates 53.3830,-1.4659

Aout 80% likely correct.

Which means that LEGALLY 8mph is the limit. But I never saw a police wheelchair. So speed isnt going to matter as long as you are sensible with it. But you cant buy one. So I made one. As for any normal 8mph chair and thats an option on most full sized high end chairs then be careful what you ask for. Every time you increase the speed on brushed DC PM motors without changing the voltgage then you have to do this by having taller gearing. Or different motor windings. The net result is always the same.

Faster chairs NEED bigger batteries, to do the same range even at the same slower speeds. But they dont have them. So you get ess range and much shortened battery service life. They also have less torque at all speeds. Making them difficult to turn in place on carpets or slopes etc. From experience I can tell you that a 6mph chair with the biggest controller (120A) and the biggest battery (80Ah) and 4 pole motors is generally a better idea. It lasts longer, has better control, has longer motor and battery service life and better range. Unless you weigh very lttle, live where thare are no hills, ramps, heavily cambered road edges etc. And then only if you understand the disadvantages.

I sidestepped these issues because I have experienced them. By runing the BM3 chair at double the voltage, and using a 150A per channel robotics controller. There are no chairs made this way.

[Burgerman]

I might add that I currently own 2 six mph 4 pole chairs. And these have r-net 120A ontrollers, and group 24 sized batteries. Because understanding the above I know that this is the best compromise for reliability, control, range, battery service life, avoiding power rolling back due to heat etc.

[Raro]

I think it is not necessary for you to publish such exact information about its location. Out of curiosity, what is the highest speed that can be configured from the factory on a bounder?

[Raro]

By the way, I remembered that the ten sango chair claims to reach 9 miles, but as they indicate, weigh the windows and disadvantages.

https://www.fplmobility.com/dietz-power/sango-rwd

[Burgerman]

Its not his position details but the ISP. So no problem. Bounders can have any gearing (chains and sprockets) and so any speed really. But all the same stuff applies. Bounder motors are not very powerful, relatively high impedance. So for good control, torque and decent range etc then 6mph is the best compromise. Esp if using lead, and even more so if you are heavy or live near any place with slopes or hills. You can get sprockets and sets that give up to 12 mph. But its not a good idea for most people. Because 6 to 12 mph means DOUBLE the current at every speed. And half the maximum available torque. At every turn. And at every ramp or hill. The limiting factor is the battery and the 120A controller. They cant manage well with taller gearing than 6 to 7 mph (in any chair). And a bounder is heavier than most as well.

If I was desperate for speed, and knew the consequences and didnt expect too much from it then 8mph option would be the highest I would ever choose. But I actually chose 6.2 or 6.5 mph in my own chairs as the best overall compromise.

[JayWoodhead]

I live in the UK and I currently use a quickie 200R which is great if your not travelling very far it's had bigger batteries put in it which gives me a better distance range but when your travelling any distance it just seems to take forever but ideally I'd be looking for something similar to what have with good distance range good battery life and quicker something that would cut my travelling time down a bit especially with the mixed weather we get

[Burgerman]

Well that chair cant have "full sized" grp24 80Ah batteries. It is limited in what battery size can be fitted. And same with speed. So you are torturing its batteries if you go far anyway. They will not last.

What speed is it? Most seem to be 4mph. Which is OK indoors. 6 is ideal. 8 is a step too far usually for the reasons stated above. And below.

You could fit lithium, and get 4 or 5 times the range. But to do that properly you are in for a steep learning curve and a few quid and a little DIY work. There isnt a good drop in lead brick replacement thats worth buying. So it would mean building a pack. But this wont do much for your speed. Also, faster = shorter range...

Motor options...
QJR180014 2-Pole Motor, 4 kph / 2.5 mph, Via Programming £0
QJR180011 2-Pole Motor, 6 kph / 4 mph, Standard £0
QJR180006 2-Pole Motor, 10 kph / 6 mph - an extra cost when ordering £310

But only 2 pole motors are available which lack torque and are a bad idea anyway. You want 4 pole especially if you go long distances.

Batteries:
40Ah (cheapest option so probably stock, 50Ah option, 55Ah is an option (but an extra 5Ah is barely any better anyway)

Control system, can be a miserable 60A unit, o 70Amp unit or extra cost a 90A unit all VR2.
At an extra cost R-Net 90A controller are available. So no gain. The 120A one needed for 6mph isnt listed on the order forms.

So basically you bought the wrong chair. Its a indoor/shopping centre low power and low performance/range cheap option that the NHS like to supply... Without lights.

Your best bet is a "full house" chair. With following specs:
6mph (or 8 if you must) 4 pole motors, 120A R-net controller, and full sized grp 24, 80Ah batteries which just happens to be the easy lithium conversion too should you want 100 miles range. Such as the correct spec Q500R or Dietz or whatever. The make doesent matter. The specs above do.

[Burgerman]

Chair: https://www.sunrisemedical.co.uk/q200r

Order forms and options: https://www.sunrisedice.com/asset-bank/ ... /74763.pdf


For those interested and theres an "order form" which shows the few available options. Its meant as a budget freindly chair. One thats OK for indoors mainly.


For those interested these are the rear drive sunrise options in 24. https://www.sunrisemedical.co.uk/powere ... heelchairs
Q50R (folding) with the firework type lithium battery. Its a toy.
Q100R same as the Q200 but skinnier tyres etc.
Q200R as per this thread.
Q300R Same frame different most of the rest!
Q400R missing...
Q500R different chassis, full rehab full sized 80Ah batteries, more complex seating, and more of a complete chair with a silly rear swinging axle design, and no front suspension, and can be ordered as cheap and cheerful or super expensive with best parts and very high spec. If you do that forget it and go for the 700R as it adds front suspension.
Q600 is non existant so far, watch this space!
Q700 is the same as a fully high spec Q500 with high base price as low spec options not available here. But this adds front suspension too. Basic spec is already high. I have one. Not as good as Dietz or my older Sals with correct spec and mods.

[Raro]

What is wrong with the oscillating axle of the Burgerman rear-wheel drive Quickie chairs?

[Burgerman]

When the chair is stock, meaning that the driver sits about 6 inches too far forwards with all his weight over the front casters then its "needed" in order to keep both the rear drive (and tank steer control) wheels on the deck. The CHAIR and user just follows the front casters. Say you run along and meet a tree root and one front wheel runs over it. The chair tilts slightly as the casters follow the terrain. This lifts a rear DRIVE AND CONTROL wheel off the ground as theres little weight on them compared to the front. So in rediculous nose heavy stock configuration that beam axle at the rear helps the drive tyres stay touching the ground. Although they still have very little traction.

The problem is that ALL stock rear drive chairs for legislative reasons have the seating far too far forwards. This makes the whole chair hard to turn. As the casters have way too much weight over them. And the rear is too far behind your backside and so they are too lightly loaded. What you want is about 80/20 rear front or 70/30. So that YOU sit further back with more of your weight over the drive tyres. And your heels on a centre footplate between the caster wheels. Instead of those godawful swing away ones that both HAVE to sit with your heels ahead of the caster wheels. Those also make the front of the chair wider. What you end up wit on a stock configured rear drive chair is this: Here comes my legs. Here comes me. Here comes the rear of the chair. This makes them feel "heavy" to steer, takes much more power to turn in place, and they frequently wont do so reliably. It also makes the chair longer and it steers from behind your ass.

This is why when I chose a Rear Drive chair, I look carefully at the spec. And design. It MUST have the following parameters to be any good.
1. 120A R-net so can have adequate torque and proper OEM level programming capability. And so I bought 3 full spare sets.
2. Full sized GRP 24 80Ah battery. Because this is the bare minimum that I can manage with and because this gives a perfect battery space for a great lithium conversion.
3. The design MUST be able to be suplied with a centre mount footrest. So that the seat can be moved back - without this the thing will always be an evil handling battery destroying oil tanker that is terrible indoors. Like all stock rear drive chairs.
4. 4 pole 6 to 6.5 mph motors. Best compromise of torque, control range, lifespan, speed, battery longevity.
5. Full sized 10 inch or 9 inch casters. Or front suspension.
6. Full sized "standardised" 3.00 x 8 rear tyres.
7. EVERYTHING ELSE you may want comes last. So colours, branding, looks, lift, tilt, recline, power footrest, coffee maker, TV, guns etc.

Oh yes. I got sidetracked. That stupid swinging hinged rear axle is now a liability as the chair has its main mass on the rear drive wheels once the seat is moved back 5 or 6 inches. At which point it no longer follows the casters on uneven surfaces. It follows the rear drive wheels as those are the ones with the weight on them. And now it flops left and right! So they added this cludge to fix a problem caused by the seating being too far forwards with swing away footrests. And so now it needs bolting solid so the rear suspension can work properly.