Introducing Myself

[tes767]

Hi Folks!

My name is Tim Smith. I'm an Electrical/Electronic/Electromechanical Engineer (Bachelor of Science in Electrical Engineering, and have my Professional Engineering as well). I am a 1989 grad. I work at Howell Ventures Ltd. and our trade name is Sure Grip Hand Controls. Visit our website at http://www.suregrip-hvl.com. We manufacture hand controls for the mobility market. I'm (personally) involved in the design of electronic (secondary) controls. For example, one of our products is called the RF360 Spinner Knob that give the driver access to numerous functions: turn signals, horn, dimmer, wipe/wash, cruise, power windows, etc.

I'm experienced in Autodesk Inventor and SolidWorks 3D design S/W. I do circuit board design, electrical design, electromechanical design, etc. My son is a T2/3 paraplegic from a car accident back in 2002. The president and owner of Howell Ventures (my boss) is a quadriplegic, and he has a passion for the outdoors. He is also really disgusted with the poor performance of powered chairs. Recently, he replaced his lead acid batteries with Lithium batteries on an outdoors machine. I was not involved in the project back then, except to wire in some Li chargers that came with the batteries from an off-shore supplier.

We want to build a really awesome chair, and mass produce it too. We have a factory. We also have about 450 hundred dealers that we work with right now.

Do you have plans, CAD models, or bill of materials for your design? I'm curious as to why you are not mass producing them. You have probably explained this many times...forgive me, I'm a newbie.

Could I Skype you sometime?

Regards,
Tim Smith

Tim Smith, BSc. EE, P. Eng.
Secondary Controls Engineer

Sure Grip-HVL
Tel: 1-506-363-5289 (ext. 111)
Toll Free Tel : 1-888-370-5050
Toll Free Fax: 1-800-506-6666
Howell Ventures Ltd.,
4850, Rte. 102, Upper Kingsclear, New Brunswick, Canada E3E 1P8
tim@suregrip-hvl.com http://www.suregrip-hvl.com

[Burgerman]

The original tubular perimeter frame is a Sunrise one. As are the rear lights. And a few other inconsequential parts. Although even these are modded one way or another.
Parts? Many one off by hand. No drawings etc. And kart, aircraft, industrial parts etc.

Why don't I manufacture them?

I don't have the time, the energy, the interest to build works of art for the typical ignorant end user with all the rules, regulations, responsibilities to make sure they don't drive themselves into a river or whatever. And because I already ran several businesses in the past that were potentially much more profitable. Bigger market, far less competition, bigger ticket etc. But time and circumstances no longer allow this.

And because that chair was designed for me. By me. I wouldn't sell one to someone else as it is. its dimensionally and CG perfect for me. If you sat your boss in it, it would spit him out. Its done that to me a few times too! Its not a normal chair. Its too short, too light (CG too high) and too powerful for most without good joystick skills and reactions. It goes a bit wild! Too much for a quad. And if you were to start adding heavy rehab style seating, (raising seat height, and C of G etc), you would need to make it longer, wider and more nose heavy for stability reasons and ruin the perfect hooligan T4 paraplegic wheelie light steering tool. And make a chair that is much like the ones we already have...

But feel free to build something similar! Everything I do and make, and recycle into newer versions is freely explained and added to the site or this forum somewhere! And there are others building custom versions of this and other chairs on here too.

Related...
I am guessing. But bear with me! The lithium battery you already added presumably is of a lower capacity or the same capacity as the lead you removed instead of much bigger? Of lower C rate than the 10C ones I am using, and using a BMS and a 2 wire dumb charger? That's the way its "done" by battery suppliers. By doing this you missed out on both the longer service life (your BMS / charge system is killing your battery, and the smaller size and C rate means you are working it harder than needed, charging more often etc). And you are missing out on range. But worse, by doubling voltage you could have had either double the speed without loss of range, or by using shorter gearing - same speed and double the range, and double the torque. Or a mix of the above.

This above paragraph is the MAIN KEY to why the BM3 chair is far better than just adding a lithium battery to a 24V chair. At least as far as range, performance etc is concerned. You can more than double your gains for free!

[tes767]

Thanks for your reply!

Yes, the capacity of the Li batteries were approximately the same as the lead-acid ones they replaced, and also, the nominal voltage was the same as well. Like I said before, I was not involved in this retrofit, but it's very possible that I might have done the same thing myself. There is no BMS on this

My boss is a quad but he's no sissy when it comes to driving. He prefers handlebars with a lever type throttle because he's got something to hold onto when going down hills. He wants a seat that goes UP/DN for easier transfers and for making campfires in the woods (sometimes the environment boys give him a hard time). We want to do some testing on his outdoor scooter for starters. Once we determine range and capability it will be time to experiment with other designs--perhaps in-door/outdoor ones like the BM3. But my personal dream is to design something indoor/outdoor that can climb stairs and cross ditches. I toured Europe with my paraplegic son and I had to carry him everywhere. There's not too many wheelchair ramps in old Europe.

I won't promise it, but I'm pretty sure I can add another 50% range with a special circuit of mine.

Thanks again for all the great work you've done! You are an inspiration to me.

PS> Is a Skype a possibility?

[Burgerman]

Special circuit?
Does it make energy?

>>>
Yes, the capacity of the Li batteries were approximately the same as the lead-acid ones they replaced, and also, the nominal voltage was the same as well. Like I said before, I was not involved in this retrofit, but it's very possible that I might have done the same thing myself. There is no BMS on this

If there isn't that's great. But there will be. Somewhere. Because if you are charging with a dumb 2 wire charge without one then its already toast...

[tes767]

This circuit doesn't make energy--it just cleverly reuses it. If I showed it to you your response might be, "Wow, that's neat--why didn't I think of that?" A lot of what we engineers understand about energy was written by some academic who was, "born in the house and never saw the back yard." Warning: engineers are the most skeptical of all. And we seldom ever work with truly closed systems.

To tell you the truth, a 50% increase in range is lacklustre. It should be more like 85%.

When the political will is there to allow it, incredible technologies (which already exist) will completely change the energy landscape. But the "big boys" make a killing through oil, gas, coal, etc. through big energy, control, and political maneuvering. They don't care if your chair runs out of juice before it makes it back from the supermarket. NASA uses it. Spy agencies use it...

The Hyperion 1420i computerised 550 watt charger has been discontinued. Do you have suggestions on another brand/version?

[Burgerman]

Revolectrix PL8v2. But you need 2 to charge a 13S battery like my 45v system.


I will believe this circuit stuff when I see it! Sounds like snake oil right now...

I already get 250 to 300% range compared to the lead batteries removed.