Powerchair Football / Soccer - Make my Chair more powerchair

[dynamicdragon]

Hi all,

I'm looking for some advice on R-net OEM Programming for my sports chair. My settings are pretty much maximum for torque, drive, forward, reverse and turn using 90 deceleration and maximum 100 acceleration.

I noticed the output voltage is 26v ATM which seems to make it more responsive but kills the battery quicker. I have left it at this level. My compensation is 60 which does enough power wise. I also noticed the servos are 2 10 2 10 2 10, should I change these? Finally, I noticed there is rpm in the encoder settings but feel pushing that beyond the default could break the motors.

Are there any other considerations or settings I should be considering? I appreciate changing things like voltage could cause my battery to die faster but I'm looking at fast charging options for that separately.

Thanks!

[emilevirus]

Is Lithium allowed?

[Burgerman]

No they have to fly. We had a guy that used to talk about all this as his wife did powerchair soccer.

[Burgerman]

Hi all,

I'm looking for some advice on R-net OEM Programming for my sports chair. My settings are pretty much maximum for torque, drive, forward, reverse and turn using 90 deceleration and maximum 100 acceleration.

You def need turn acc, turn dec, mon turn acc and min turn dec all set to 100.
Setting torqe wont make any difference to you. It adds a little extra motor compensation at microscopic speeds and when using 1/4 inch of stick movements only.

I noticed the output voltage is 26v ATM which seems to make it more responsive but kills the battery quicker.

Theres is zero point it setting this above 24.5V even with the lowest impedance lead batteries that are fully charged. This is the MAX voltage the system allows to the motors. As you accelerate your battery voltage drops from around 25.0 to 25.5 just rolling 10 feet after charge. It drops to around 18 to 19 volts under load every time you gun it... and then recovers. After 5 mins of driving around on a soccer floor at the sports hall your voltage will never recover past about 25.3 or 4 volts even after a 1 minute rest.

So in reality setting this above even 22 volts will meke absolutely no difference.

I have left it at this level. My compensation is 60 which does enough power wise. I also noticed the servos are 2 10 2 10 2 10, should I change these?

SERVOS???

Finally, I noticed there is rpm in the encoder settings but feel pushing that beyond the default could break the motors.

I never saw a chair with encoders. Unless used with non proportional controls. Sat a tube you blow in. Those are designed to meke motors run straigt across an uneven surface I think. Even if you have them a motor cannot go faster than the BATTERY VOLTAGE no matter what you set anywhere in programming. Which you will see drops like a rock under load.

Watch this very short vid.
The meter shows:
BIG number: Instantanious averaged voltage.
2nd line, peak HIGH voltage.
3rd line, average voltage,
4th and last line, shows peak LOW voltage.

I do ONE tiny hop. 100% acceleration. These are fully charged, ODYSSEY low impedance batteries. And voltage drops to 18.xx volts. Already! What do you think happens during a match?

Gel batteries are worse.

Notice, as soon as I move at all, volts drop from 25V plus to 24. This is because of impedance, and peukert. Not that after a single very short "hop" it droppes to 18.9 volts. Watch a few times. Want more torque? You need better batteries.
https://www.wheelchairdriver.com/gopro/voltdrop.mp4

[Burgerman]

Are there any other considerations or settings I should be considering? I appreciate changing things like voltage could cause my battery to die faster but I'm looking at fast charging options for that separately.

Thanks!

You cant change the voltage, or you can ut its irrelivant Its real purpose is so that under load the battery has enough HEADROOM that the left wheel can speed up, the right one slow down. If you set it above the battery voltage then both motors at full speed you are already using full battery voltgage. So now when you want to turn one motr cannot speed up. Only one can slow down. So you lose some of the steering response. This is why its typically set to 21.5V stock. Turning it up to 100V if it allowed that would not make a blind bit of different to battery discharge speed or chair performance. As long as its set at the same or above battery voltage it does nothing at all.

What battery do you have?
What do you intend to use to fast charge it?

Some batts CAN be fast charged a LOT faster than others. Some batts can have less voltage drop under load, lower impedance etc and so perform better in your heavy usage too.

[dynamicdragon]

They're MK gel batteries 60Ah x2

[Burgerman]

OK...

MK gel can only be charged FULLY in 16 hours to 20 hours. Thats just how long the chemistry takes.
ALL lead batteries take a long time. But gel is about 30% slower than GOOD AGMs like Odyssey.

2 things.
You cannot get good torque or acceleration from a full sized group 24 MK Gel battery as they have too high internal resistance. 60Ah ones are even worse. As you accelerate or turn HARD he voltage colapses in a fraction of a second which gives less power. But worse, it trips the controllers protection system that knows it requires above 18 volts to maintain safe control. Which automatically reduces pulsewidth to limut current (and your torque).

So you need to throw away the gel. Give t to an old lady. Get a set of Odyssey PC1500 group 34/78 batteries in there. Be careful as they are slightly wider at the top. by around 1/2 inch? For several reasons. They are not a miracle cure, lead batteries are generally just crap... But they have just 2.5mOhm (better than HALF the internal resistance of a gel battery). That means half the voltage drop under load. Or more torque...

But you also want to be able to FAST CHARGE between rounds, right? Well MK at 60Ah can only be charged at 20A. And then it will soon slow down and take 16 to 20 hours.
Well with a 50A charger you can get a dead flat Odyssey SAFELY up to 90% charge in 60 mins. Because lower internal resistance, no inrush current limit. All batteries charge fast at first. Then slow down as the charge progresses. The higher the internal resistance (gel!) the faster this current drops away. With a GEL battery and esp a small 60Ah one it will drop to just a few Amps after a couple of minutes. With odyssey which has HALF the internal resistance, and needs a higher charge voltage anyway, it will hold high amps for longer. Try that with gel and the gel gets bubbles and resistance increases permanantly.

Gel charge voltage 14.1V max. Current limit 1/5th of Ah capacity. So about 15 to 20A...
Odyssey 14.7V max - no current Limit. They recommend a 50A charger.

So now you can put back MOST of what you too out rapidly between rounds. And you need a ZXD to correctly do this and an anderson connection to charge from on the battery.

[Burgerman]

Are you learning anything yet, or is your head about to explode? Sorry for the mass of info at once!
Problem is that this is not a simple yes/no subject. If you want to do it right!

Now whilst you can put back 90% OF THE POWER on Odyssey in 1 hour, it still MUST get a full charge too at some point. Maybe 2 or 3 times a week if used daily. That requires a different type of charge. The reason for that ZXD as you can CHOOSE exactly what it does. And around 12 to 16 hours. But preferably longer. That last 10% matters if you value the battery. Without it they will die an early death.

ZXD is supplied already converted by forum member Shirley in HK. I have 2...
Also its super accurate over a very wide range, can be set with a proper termination current, switch to a 2nd float voltage, and has timers etc built in that allow correct configuration. For gel, AGM, etc as well as 3KW of output capability and so great for charging lithium too.

See:

https://www.wheelchairdriver.com/board/ ... 70#p115228

This is both a POWER SUPPLY as well as a very user configurable 3 STAGE CHARGER.
It can do anything from 0 to 50A if powered by 240V as mos of the world. Or 0 to 25A if powered by 110V AC.
And can do 0 to 60V output. Actually it can do up to 70V if configured correctly on 120 or 240V AC.

This is bomb proof, a converted telecoms rack mounted unit. And super flexible. A lot of options!

[dynamicdragon]

My head has exploded already, but it's very interesting technical knowledge, which will come in handy!
So basically, by upgrading to lithium, I'd get more consistent power? I'm also guessing I should drop my voltage to 22v to keep my batteries charged, since it's pretty much overkill at 26v. I'll take a look at those products you mentioned, got to price it all up as I get the feeling it isn't cheap!

[Burgerman]

I went too fast too quickly.

So basically, by upgrading to lithium, I'd get more consistent power?

I didnt think you would be allowed to use lithium. That changes things drastically.
No, Odyssey batteries are LEAD. They are much lower impedance than gel lead like MK and so allow greater torque that you will notice on a soccer chair and allow faster recharge.

I'm also guessing I should drop my voltage to 22v to keep my batteries charged, since it's pretty much overkill at 26v.

Drop it where?
INSIDE programming? It has absolutely nothing to do with keeping battery charged... Its the MAX voltage that the controller allows to go to the battery. Anything above around 22V has no affect as the battery is already less than this once you begin rolling and playing soccer. So its irrelivant where thats set. It will make ZERO difference.
If we are talking CHARGE voltage then it should be 28.2V max for gel, UP TO AROUND 12 to 16 Amps for 8 to 12 hours max.
And 29.4V max @ up to 50A for Odyssey (still lead just better!) for 8 hours.
Then 13.6V float indefinitely for both.

[dynamicdragon]

Inside programming, yes, I have the OEM R-net Programmer.

[Burgerman]

Whatever you set that voltage to will make zero difference to performance, or battery discharge.

What it is really for is to allow a volt or so above the full speed voltage. So that the chairs TURN response still works properly.

[emilevirus]

For it to make a difference you need Lithium. A good quality, properly sized Lithium will make a big difference as voltage barely sags. You get a lot more torque and you get constant torque even if battery is low. If lithium batteries are allowed, of course that'd be the best upgrade you can do.

[Burgerman]

His head is already exploded. Once we get into lithium, what and why etc then that just going to make this all way way worse!

And yes.
A LARGE lithium pack (not a drop in lead brick replacement monoblock) will save you 60lb before we begin. So improve acceleration and turn capability and eat up less current. So less heat into the controller.

Because a lithium battery is not subject to PEUKERT losses and voltage drops in the same way lead is, then we also have a higher voltage under heavy loads too. So now adding say 3 volts to that stock 21.5V makes sense. It will allow a 7 to 8% speed gain to go with your faster accelerating lighter chair...

And now u can charge faster. Because you can charge at 50A from 0 to 99% wihout it slowing doen for 8 to 12 hours at the end.

But you wont need to. Because a fully charged 230 to 244 Ah lithium battery will give you a 500% range (or matches) gain too. Typically 85 to 100 miles on the street.

[shirley_hkg]

Power soccer chairs' speed are limited.

They need fast pickup and swing the front bracket very hard to slam.

Lithium will certainly be better. High C cells are preferred to high capacity in this scenario.

[dynamicdragon]

Power soccer chairs' speed are limited.

They need fast pickup and swing the front bracket very hard to slam.

Lithium will certainly be better. High C cells are preferred to high capacity in this scenario.

Doesn't lithium create a lot of heat? Would having one under my seat next to hot motors be wise?

[shirley_hkg]

You have one in your pocket already, haven't you ?

[dynamicdragon]

Good point. Do you know which model to go for? 70Ah, 60Ah, 50Ah?

[Burgerman]

Basics.

You can fit a huge LOW RATE pack and have enough power stored that you can do many soccer matches. (I have 244Ah, 1C cells that can easily provide all the current in Amps that your chair will require). 1C means battery capacity x 1 in Amp capability. So a 244Ah battery can safely do 244Amps, and double that for an instant. With almost no voltage drop. And give 500% better range than lead. It fits the same space as the MK batts I took out. No they dont get hot! Or even warm.

The SMALLER the battery you fit, in Ah, the higher the C rate has to be. So a 100Ah battery would need to be 3C or higher in order to provide 300A or adequate current. And most are 1C... Because its just smaller. Advantage? Not many. Less range, very hard to find, can still make high currents if C rate is higher, and its lighter.

We dont fit lead drop in replacement lithium bricks here usually. They perform very poorly... And other issues. We fit 8 seperate cells.

See here:
I suggest you read all 10 pages.

I avoided mentioning lithium because as you already said your head has exploded and you obviously dont understand most of what I said already. So I dont think you are ready for this because its 10x more complex and involved than the lead battery stuff and programing that we already mentioned. I would skip this until stage 2 in a few months... Lithium is CHEAP and done properly (typically half the cost of lead batteries for 5x the range and 20 years use) safe and reliable.

But not yet! One thing at a time.

[dynamicdragon]

Sounds good - the see more link hasn't appeared for me though... Will do some light reading and investigate further.

[Burgerman]

https://www.wheelchairdriver.com/board/ ... =2&t=12484

I forgot

[dynamicdragon]

So another question... With these changes come a lot of heat. I've been researching whether a push or pull method works. Apparently, pushing air on would be more efficient and cool the motors better. I do have a couple of 5V running off a powerbank atm on the rear bar of the chair, but they're not good enough. I've since found a CPAP battery which has a 24V DC port. I then found some industrial Noctua fans which seem good from a pressure, efficiency and durability approach. There are also Delta fans, but they're very power hungry, which would kill my supply instantly (though this could be offset by fast charging the power bank between games). Would anyone know which airflow config would work best?

[Burgerman]

So another question... With these changes come a lot of heat.

Are we talking about motors or power module where the heat is measured? The power module is where the thing rolls back power. So a fan blowing here especially on the connections, wiring and that side of the power module will cool best.

I've been researching whether a push or pull method works. Apparently, pushing air on would be more efficient and cool the motors better. I do have a couple of 5V running off a powerbank atm on the rear bar of the chair, but they're not good enough. I've since found a CPAP battery which has a 24V DC port. I then found some industrial Noctua fans which seem good from a pressure, efficiency and durability approach. There are also Delta fans, but they're very power hungry, which would kill my supply instantly (though this could be offset by fast charging the power bank between games). Would anyone know which airflow config would work best?

Fans take little power inc the delta ones. Those sound like vacuum cleaners. Run them from the 24V chair battery... In series so they get 12V each.