Controller/Electronics options

[hotwheels_75]

Not sure if there’s a topic already on what’s available for controller, joystick and electronics options for our custom chairs, but I’m wondering what they are and pros and cons of each?

My project chair is currently using the original 16 year old Pilot + with 100A controller and an old Helix tilt controller, with 8.5mph 4 pole motors. It functions ok, but goes into thermal rollback rather easily & always had/has a problem with uneven inclines, and wanting to spin me in the direction of least resistance... once right into the door of my freshly painted Camaro

My daily driver is an Invacare Arrow with MK6i and 4 pole motors. It seems so much smoother and accurate compared to the old pilot + setup. It has TrueTrack technology that helps keep the chair going straight especially on inclines and uneven terrain. I especially like that feature. I do have the handheld programmer for it. The controller is only 90A from what I can tell. Not sure if that would make a huge difference if installed on the project chair?

At this point I’m just looking for original wheelchair factory options, rather than the full custom controller and joystick like BM did.

I’ve been looking at the R-net controls, and like all the specs and features like 120A per channel and all the features on the new joystick. I would need tilt feature to go with it. But is the proper programmer available for it?
My local supplier says it won’t work because the controller will look for a specific ohm reading from the motors, which will be different if I wire in my own motors. But I assume that could be adjusted with the programming software?

What’s everyone’s opinion, experience etc.?

PS anyone know a source for replacement screws for the pilot + joystick? The heads of mine are stripped.

[Burgerman]

My project chair is currently using the original 16 year old Pilot + with 100A controller and an old Helix tilt controller, with 8.5mph 4 pole motors. It functions ok, but goes into thermal rollback rather easily & always had/has a problem with uneven inclines, and wanting to spin me in the direction of least resistance... once right into the door of my freshly painted Camaro

A sure sign of motor compensation set too low. And the faster the motors the lower the torque, which also causes that same issue.
And setting the temp of rollback from 50 to 70C will mostly cure the rollback issue.

As for which system, the best one is whatever you can get a full oem level programmer for. And the highest Amps.

[Burgerman]

The screws actually go into the bracket. I tapped all of mine M4 and used 2x cap (allen) screws.

[hotwheels_75]

The screws actually go into the bracket. I tapped all of mine M4 and used 2x cap (allen) screws.

So the screws that hold the casing together? You just tapped those?

A sure sign of motor compensation set too low. And the faster the motors the lower the torque, which also causes that same issue.
And setting the temp of rollback from 50 to 70C will mostly cure the rollback issue.

As for which system, the best one is whatever you can get a full oem level programmer for. And the highest Amps.

I knew the faster motors are doing me no favours in the torque department. I have increased the rollback previously after reading your recommendations. But it still seems to rollback easy, mostly in off-road environments.

My motor compensation is currently at 45 milli-Ohms. What should I set it at? Isn’t this the setting that can cause a runaway chair? I was reluctant to mess with it without someone else to test it. Lol

I guess, unless I can get access to the full oem programmer for R-Net, I’ll stick to the Pilot +. No one has one of those yet do they?

[Burgerman]

OEM for rnet? Steve does, I do, obviously rover and a few others on here. You can too but its really not cheap and may involve ordering from the US!

You are lining up all the things that dont go together. Off road, fast motors, lead batteries!

You will struggle with rollback, since Amps cause heat. An 8mph motor takes DOUBLE the amps of a 4mph motor, and 25% extra compared to 6mph... At every single movement, regardless of speed. And that sucks a lot out of the battery leaving a lower voltage under load, requiring yet more Amps! Not to mention the reduced torque. So its hard to know if the vague steering is caused by a lack of available amps, rollback, motor compensation, or battery voltage dropping in response to compensation asking for more amps... You have the full set that hurt each other going on!

Theres a very good reason I choose 6mph / 120A / 4 pole on my new chair...
I like control, range, and torque. Its way more important than an extra 2mph.

[shirley_hkg]

Usually , reprogramme your chair will solve those problems , at least 80% satisfaction .

FYI, true track applies to GB motors only .
4 poles use gyroscope. G-trac .

[hotwheels_75]

OEM for rnet? Steve does, I do, obviously rover and a few others on here. You can too but its really not cheap and may involve ordering from the US!

I don’t mind ordering from the US. But I’ll continue testing and tweaking my current setup before I jump into more upgrades. I was just looking to see what my options are.

You are lining up all the things that dont go together. Off road, fast motors, lead batteries!

I’m actually on the LifePo’s now! Put my first 2.5km on in my yard yesterday, testing things. It’s amazing the difference, and rollback didn’t seem to be an issue, except once when I was really stressing things...doing a burnout on my ramp. but it was only 15°C outside, so assumed that was helping. Last summer while still on lead, during a 30°C day with high humidity, the chair was basically unusable because of rollback.

You will struggle with rollback, since Amps cause heat. An 8mph motor takes DOUBLE the amps of a 4mph motor, and 25% extra compared to 6mph... At every single movement, regardless of speed. And that sucks a lot out of the battery leaving a lower voltage under load, requiring yet more Amps! Not to mention the reduced torque. So its hard to know if the vague steering is caused by a lack of available amps, rollback, motor compensation, or battery voltage dropping in response to compensation asking for more amps... You have the full set that hurt each other going on!

Theres a very good reason I choose 6mph / 120A / 4 pole on my new chair...
I like control, range, and torque. Its way more important than an extra 2mph.

I’m not opposed to slower motors, I’m just using what I had available. And I was looking at R-Net for the 120A. I have tweaked the programming some more and it’s feeling a lot better, but I haven’t been outside to fully test it.

[hotwheels_75]

Usually , reprogramme your chair will solve those problems , at least 80% satisfaction .

FYI, true track applies to GB motors only .
4 poles use gyroscope. G-trac .

I thought True Track was GB, but I couldn’t think of what the 4 pole version was. Thanks for the clarification!

[hotwheels_75]

OEM for rnet? Steve does, I do, obviously rover and a few others on here. You can too but its really not cheap and may involve ordering from the US!

You are lining up all the things that dont go together. Off road, fast motors, lead batteries!

You will struggle with rollback, since Amps cause heat. An 8mph motor takes DOUBLE the amps of a 4mph motor, and 25% extra compared to 6mph... At every single movement, regardless of speed. And that sucks a lot out of the battery leaving a lower voltage under load, requiring yet more Amps! Not to mention the reduced torque. So its hard to know if the vague steering is caused by a lack of available amps, rollback, motor compensation, or battery voltage dropping in response to compensation asking for more amps... You have the full set that hurt each other going on!

Theres a very good reason I choose 6mph / 120A / 4 pole on my new chair...
I like control, range, and torque. Its way more important than an extra 2mph.

The lifepo4 batteries are an amazing upgrade and the chair is so much smoother on and off-road with the wide wheels and tire, but these 8.5mph motors are definitely a huge drain. I’ve been doing some testing. I’ve been using my project chair all week. Rollback only seems to be an issue when going full speed over a distance. Keeping it under 10km, mostly 6-7km and it’s not a problem so far.

I was trying to see what my range is. The GPS on my phone, was not always working, but I think I only got about 10km, although 99.5% was off-road, uneven, dirt and grass and mud. It’s still way better than the Lead batteries ever were. I plan to retest and record every KM as close as I can. I also want to test “on-road” range as well.

Today I lost my first green bar, but shortly after that, the battery meter dive bombed down to one flashing red led. It was just under 22V when I hooked it up the the PL8. I’m at 3:27 hrs as I type, with 34,500 mAh returned and back to 26.688v.

I’m really happy with it overall. But I’d like to make it as good as I can. So have a few questions for anyone

How do I get the R-Net OEM Dongle?

Does it matter which brand of 120A R-Net PM I get? Quickie vs Permobil.

What do I need for the tilt option, controlled via the joystick? I see R-Net seat control modules, but not sure which one I need or wether I can make it work with my actuator.

And What 6mph motors and gearboxes are a good consideration for torque and efficiency? If I were to go that far? That requires a fair bit of fabrication, but it’s a possibility.

[Burgerman]

Today I lost my first green bar, but shortly after that, the battery meter dive bombed down to one flashing red led. It was just under 22V when I hooked it up the the PL8. I’m at 3:27 hrs as I type, with 34,500 mAh returned and back to 26.688v.

22V with lithium is dead. Under load thats way too low. I wouldnt be surprised to see battery or at least the lowest cells to be way below the average at that end point. And possibly damaged.

Also, 34Ah returned means you took out about 31Ah? What is the packs capacity? And what voltage is the lowest cell?

34Ah pack is too small. You will damage it.

[hotwheels_75]

Today I lost my first green bar, but shortly after that, the battery meter dive bombed down to one flashing red led. It was just under 22V when I hooked it up the the PL8. I’m at 3:27 hrs as I type, with 34,500 mAh returned and back to 26.688v.

22V with lithium is dead. Under load thats way too low. I wouldnt be surprised to see battery or at least the lowest cells to be way below the average at that end point. And possibly damaged.

Also, 34Ah returned means you took out about 31Ah? What is the packs capacity? And what voltage is the lowest cell?

34Ah pack is too small. You will damage it.

I realize that. I should have been checking the capacity more often. I thought I had more time. Guess I shouldn’t have trusted the joystick meter. The pack is 96Ah. I’m still charging, 34 is just the point it was at when I posted the message.

Looking at my charging graph, if I’m reading it correctly, the lowest cell was at 2.655v when I started the charge cycle.

[Burgerman]

Guess I shouldn’t have trusted the joystick meter.

You can never trust a joystick meter even with lead. You certainly cant use it with lithium. As soon as 1 light goes out or possibly 2 depending on joystick, you are using. You may well be done! Or you should at least be checking with CELL checker to be sure the lowest cell isnt TOO low. Life cells stay at around the same voltage for much of the charge. Then drop off a cliff towards the end. A battery fuel gauge cant tell you anything other than, oops, we are done! When it starts to drop fast its over.

If the lowest cell was above 2.6V then you likely got away with it. As long as all cells balance easily, and the pack stays in balance. I suggest never going below about 3V per cell in use. You shouldnt be draining it beyond about 90% really. After this, stop!

[snaker]

@hotwheels_75: fit a voltmeter to monitor the pack's voltage. Stop and call a rescue if you see the voltage drops under 24.8V (22V is too dangerous). We had to spend a lot of money and time and labor to build the pack, we should protect it

[ex-Gooserider]

Motor comp is a value that you need to 'sneak up' on... Lower it 5mOhms at a time and test the chair thoroughly - if it responds smoothly and with good control go for another 5mOhms... If it seems 'jumpy' then go back to the previous setting....

Probably the simplest way to step down on the motors is to look for the motors used in the 6.5 mph version of your chair - check the parts manuals for the relevant part numbers. This typically will work because the manufacturers normally use the same style motors on the different speed options, with the only difference being the internals of the gearbox. Thus the different speeds are interchangeable on the same model chair...

What I've been told about the best way to do 'gas gage' on a Lithium pack is to get a 4-digit LED voltmeter and wire it to always read when the chair is on. As you use the chair, the voltage will drop under load - keep an eye on how much it drops, and especially how long it takes to recover back to the unloaded voltage. As the battery discharges it will drop further, and take longer to recover. With a bit of practice you will get a feel for how to 'read' that voltage drop pattern and know when it is time to recharge and how much it will take.

I have found very low cost 'bare board' meters on Ebay that use 3 wires.... I plan to wire the power wire across any lines I find in the pod that switch on and off, and the sensor to the XLR hot wire. I just need to figure out the best way to 'pot' the board and then glue it to the top of my Pilot+ pod...

ex-Gooserider

[hotwheels_75]

Guess I shouldn’t have trusted the joystick meter.

You can never trust a joystick meter even with lead. You certainly cant use it with lithium. As soon as 1 light goes out or possibly 2 depending on joystick, you are using. You may well be done! Or you should at least be checking with CELL checker to be sure the lowest cell isnt TOO low. Life cells stay at around the same voltage for much of the charge. Then drop off a cliff towards the end. A battery fuel gauge cant tell you anything other than, oops, we are done! When it starts to drop fast its over.

If the lowest cell was above 2.6V then you likely got away with it. As long as all cells balance easily, and the pack stays in balance. I suggest never going below about 3V per cell in use. You shouldnt be draining it beyond about 90% really. After this, stop!

Lesson learned. I was curious what my max range was between charges. Everything appears to be fine so far. Balanced no problem, took 11 hrs to fully recharge though.

@hotwheels_75: fit a voltmeter to monitor the pack's voltage. Stop and call a rescue if you see the voltage drops under 24.8V (22V is too dangerous). We had to spend a lot of money and time and labor to build the pack, we should protect it

Silly thing is, I have one, just not installed yet. not sure where to mount it. I won’t let it drop that low again. There was no reason other than testing max range, to let it go that long without charging.

Motor comp is a value that you need to 'sneak up' on... Lower it 5mOhms at a time and test the chair thoroughly - if it responds smoothly and with good control go for another 5mOhms... If it seems 'jumpy' then go back to the previous setting....

So it should be lowered and not increased? Mine started at either 40 or 45, I increased it to 50. Seems good and smooth now.

Probably the simplest way to step down on the motors is to look for the motors used in the 6.5 mph version of your chair - check the parts manuals for the relevant part numbers. This typically will work because the manufacturers normally use the same style motors on the different speed options, with the only difference being the internals of the gearbox. Thus the different speeds are interchangeable on the same model chair...

Unfortunately the chair I remodeled (Quantum Blast 850) is next to impossible to find parts for. There was a 6.25mph version, but I’ve never seen used motors and gearboxes for either version for sale anywhere... well except southwestmedical at $1600 each. and only the 8.5mph version was still available. I’ll keep looking, but Ill also consider any high torque motors that might be an easy conversion.

What I've been told about the best way to do 'gas gage' on a Lithium pack is to get a 4-digit LED voltmeter and wire it to always read when the chair is on. As you use the chair, the voltage will drop under load - keep an eye on how much it drops, and especially how long it takes to recover back to the unloaded voltage. As the battery discharges it will drop further, and take longer to recover. With a bit of practice you will get a feel for how to 'read' that voltage drop pattern and know when it is time to recharge and how much it will take.

I have found very low cost 'bare board' meters on Ebay that use 3 wires.... I plan to wire the power wire across any lines I find in the pod that switch on and off, and the sensor to the XLR hot wire. I just need to figure out the best way to 'pot' the board and then glue it to the top of my Pilot+ pod...

ex-Gooserider

I’m definitely going to add a voltmeter of some kind. I do have one, but I have the same issue of finding the best and easy to see mounting position and figuring out how to wire it. I won’t be going that long without a charge anyway. But it’ll still be good to have

Thanks for the suggestions.

[Burgerman]

Remember that each of the 8 groups of cells run out of power at different times. And that when you do the voltage of that cell group will drop like a rock only.

So if you are running low enough to get even close to empty you need to watch at the cell group level. You need a meter that shows 8 seperate voltages.

[hotwheels_75]

Remember that each of the 8 groups of cells run out of power at different times. And that when you do the voltage of that cell group will drop like a rock only.

So if you are running low enough to get even close to empty you need to watch at the cell group level. You need a meter that shows 8 seperate voltages.

Ok, thanks for the tip! Is that what you meant by Cell Checker? I’ve seen some online, you plug in a balance lead and it gives info on each cell. Would need to wire it to a switch some how.

[Burgerman]

Those work fine. But they run from cell number 1. So yes a switch in the negative wire. Or it will unbalance cell 1 over time.

[sin85]

are you saying that you drained 96Ah lithium pack after 10km?!? Must have been real rough terrain.

[hotwheels_75]

are you saying that you drained 96Ah lithium pack after 10km?!? Must have been real rough terrain.

Yup. Well I’m not sure of the exact distance but it was definitely under 15km. I’m guessing between 10 and 12km. I was surprised and a bit disappointed it drained that quickly. It was off-road but I wouldn’t consider it extreme at all. Mostly my back yard which is grass and soft ground and fairly flat. And 3 km on a public nature trail, which is uneven and slightly hilly is spots, but all hard packed. I guess This chair is very inefficient with its 8.5mph motors.

[Burgerman]

But thats 10Ah per kilometer. Thats 16Ah per mile?



Most are getting 45 miles or 65 kilometers from 90Ah. Eg expresso in new york. Or 100 miles from 150Ah like snaker.

They are then getting around 1 mile per 2Ah worst case, and 1.5 miles per Ah best case.

Now thats on a run. Electric motors on a chair draw the least current when travelling in straight lines on flat ground. Turns, take 10x more. Ramps, hills, can take a lot more too. But thats an extreme rate of power use! Teslas new 3 car, does more distance per Ah than you do! Something must be very wrong!

If you were on lead, you would have got just 2.5 km. Or 1.4 miles...

[sin85]

I have 140Ah and 9.3mph motor and cc 100km range on a run .

[hotwheels_75]

I’m not sure what’s up then. That’s what I was expecting, similar to what you guys have gotten and why I was surprised when it dropped so soon. It could be that my guesstimate is way off. It was very little straight line driving, a 100 trips up and down my driveway, and dozens of laps around my back yard and around my pond with a couple trips around walking trails.

I put two km on this morning on a smooth trail, after a fresh recharge. I’m clocking my distance much more accurately and will watch my battery a lot closer this time.

I should be able to plug a cell checker to a balance lead and wire that to a Dsub connector and use that to plug into my charging cable and check my battery occasionally? Would that work?

[Burgerman]

yep!

[Burgerman]

Housework, sweeping up, turning left right, grass, gardens, slopes, hills, all use easily 10x more power than driving in straight lines, so its possible to do what you said you did.

Turning left, at zero speed, uses 100A per motor to turn. Every time you do it.
Driving at max speed uses maybe 10A or 15A or so.
Driving up a hill, anything up to 100A or greater..
Grass? Doubles everything.
Solid tyres, add a few amps.
Tired less efficient motors, maybe adds 10% wasted energy
Nose heavy chair, eats power on turns.
I can kill a set of lead batteries leaf blowing the crap off my drive and garden. In say 1 hour. And get roll back and no power3 or 4 times over!
Same chair will go 3 hours at 6 mph non stop and do 18 miles. In a straight line. But not if I waste a load of power getting ready in a morning around the house. That halves it.

[hotwheels_75]

Housework, sweeping up, turning left right, grass, gardens, slopes, hills, all use easily 10x more power than driving in straight lines, so its possible to do what you said you did.

Turning left, at zero speed, uses 100A per motor to turn. Every time you do it.
Driving at max speed uses maybe 10A or 15A or so.
Driving up a hill, anything up to 100A or greater..
Grass? Doubles everything.
Solid tyres, add a few amps.
Tired less efficient motors, maybe adds 10% wasted energy
Nose heavy chair, eats power on turns.
I can kill a set of lead batteries leaf blowing the crap off my drive and garden. In say 1 hour. And get roll back and no power3 or 4 times over!
Same chair will go 3 hours at 6 mph non stop and do 18 miles. In a straight line. But not if I waste a load of power getting ready in a morning around the house. That halves it.

Well in that case, it’s definitely possible then. My chair is still a bit nose heavy and the front suspension I find really makes the front casters grip the ground, so it’s hard to spin them around at times depending on the surface I’m driving on. So far rollback hasn’t been a big issue, with the lifepo4 and setting rollback temp to 70°.

I’m currently using lawn tractor tires on the hegar wheels and the black scooter tires in the front.

I’d like to get out on some sidewalks and test range that way. Unfortunately I’m in the country with no sidewalks.but I’ll get it figured out eventually!

Do you think the R-Net 120 would be a big improvement over the Pilot+ 100 amp?

[Burgerman]

It will give you a 20% increase in very low speed torque, ie turning etc or curb climbing. If you need it.

But 100 extra settings.

[snaker]

@hotwheels_75: Can you fit a camera and record your off-road in a couple of km? I am really tempted to see the way you drain 10Ah/1km

A 4-digit voltmeter is easy but good and safe enough, fit it before your next 'draining test'.

[hotwheels_75]

@hotwheels_75: Can you fit a camera and record your off-road in a couple of km? I am really tempted to see the way you drain 10Ah/1km

A 4-digit voltmeter is easy but good and safe enough, fit it before your next 'draining test'.

I was actually thinking of doing that! It doesn’t seem that extreme to me. But this chair was never efficient even when new 16 years ago. Built like a tank and heavy. It gets a very mixed bag of reviews. http://www.usatechguide.org/itemreview.php?itemid=353

Some also claiming only 5 - 6 miles per charge on lead. Others claiming 25 mile range... those might be from Mark E. himself.

I’ll see what I can do for a video.

[Burgerman]

Best way to find out is to fit a hobby type watt meter. Set it to measure Ah and Ah used. And do a couple of measured miles at 3mph on a runway type surface. Then do it at 6mph. And see how many Ah or mah its using per mile like that. It will show you its best possible range ability.

Then turn left/right a few times, and watch how much it wastes!