Controller/Electronics options

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Re: Controller/Electronics options

Postby Burgerman » 19 May 2018, 15:59

Heres a link. I use one fitted with andersons to see how many Amps,Ah, watt hours, etc each chair takes. Under various conditions.

https://hobbyking.com/en_us/turnigy-180 ... tore=en_us

With lithium having no capacity diminishing peukert, it easily lets you see straight line range accurately by just testing say 1km. Although in hill testing, or rapid acc/dec testing you actually get more range than this shows as it ignores any reverse currents by regeneration that occur.
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Re: Controller/Electronics options

Postby hotwheels_75 » 19 May 2018, 18:46

I assume you plug it inline between the battery and the power module?
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Re: Controller/Electronics options

Postby Burgerman » 19 May 2018, 19:31

Yep. Or between charger and chair to watch the charger or bench supply, and see what it does and how much it puts back. Or hobby packs in flight. Etc.
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Re: Controller/Electronics options

Postby hotwheels_75 » 19 May 2018, 19:58

Ok! Sounds useful!

Would this be capable enough? Looks like an identical design, just 30Amps less, but I can get it in 2 days instead of 2 to 6 weeks.

https://www.amazon.ca/RENOGY-High-Preci ... B00PSQPSWQ
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Re: Controller/Electronics options

Postby Burgerman » 19 May 2018, 21:31

Hopefully.
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Re: Controller/Electronics options

Postby hotwheels_75 » 20 May 2018, 21:46

snaker wrote:@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 :worship :worship :worship

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


Here’s a video of one of my favourite spots. Not the greatest quality, I didn’t realize my GoPro Settings had reset. I sped up most of it. Sound quality was awful, so I added some cheesy music. :dance This trip is probably right around 2km. There’s lots of gradual inclines, it’s hard to see in the video. It’s pretty easy going though.

I have another video of around my yard but I haven’t uploaded it yet.
I’ll get better video when I get my settings sorted, and a better mount for the camera.

https://youtu.be/Wdr76PzkTzs
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Re: Controller/Electronics options

Postby snaker » 21 May 2018, 01:48

Yes, that kind of surface eats a lot power. But it's only about 2-3Ah/1km in my case.

In the video, was it a nature park? There are some nature parks in my province, deep green as tropical jungles, cool all day a year and plenty of fresh air to breath. But they are fairly far from my house, my powerchair does not have enough power and speed to go there :thumbdown:
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Re: Controller/Electronics options

Postby hotwheels_75 » 21 May 2018, 02:38

Yes it’s a public park. Used to be a town water reservoir, but it’s been out of use for decades. The town converted it to a public park and walking trail. It’s about 20km from my home so I have to drive there in my van.

There’s another one a bit closer, an actual wildlife marsh, but still need a drive there. I’m going to video that one too. They’re both maintained, so the paths are always in pretty good shape.

Where do you live?
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Re: Controller/Electronics options

Postby snaker » 21 May 2018, 09:49

Now I am free in the radius of 50km, 20km seems a modest distance to me :mrgreen:

I am in Vietnam. Maybe I use wrong words "nature park", I meant protected jungles to reserve the environment for plant, trees, animals etc ... They are all 100-200km far, out of my reach :fencing

I just had a nice ride along a sea side. The road was not good, this surface ate about 1.5Ah/1km.
https://youtu.be/FpMiLJZnN3A
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Re: Controller/Electronics options

Postby hotwheels_75 » 25 May 2018, 02:10

Awesome! The road I live on not safe for wheelchair travel. So if I want to go somewhere I have to go in my van 1st. The park in my video is not really a nature reserve, although there is 1 of those that I go to. I've made a video that one that I will post
https://youtu.be/hhlh-C4nr-4


I definitely have a power consumption problem! After fully recharging I mostly only drove on the hardpacked dirt trails, nothing too aggressive, no full speed or big hillclimbing. I checked my pack level yesterday with the PL8 PC software and I was still at 26.2 V approximately. I had gone approximately 8 km on the trails. I went for a haircut today and was only on paved sidewalks for a couple hundred feet. I went around my yard a little bit and spent the rest of the day in the house and noticed my green bars were dropping. It dropped to the orange bars just moving around my room so I stuck it on the charger to see and it was down to 24 V. I didn't even get 10 km this time.

I started charging 3 hours ago using a preset espresso just posted in another thread, I bumped the charge amps up to 25 and it appears to be about 90% done.

My battery amp hour metre and analyser is in the mail, so I hope to have some data to look at soon. I have a set of identical motors on different gearboxes, I wonder if installing those motors on my gearboxes would make any difference?
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Re: Controller/Electronics options

Postby shirley_hkg » 25 May 2018, 02:38

Chair eats a lot of power to steer / maneuver , if it is nose-heavy . Check it out .

90Ah for 10km worry me a lot , that your entire system won't last long . :fencing
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Re: Controller/Electronics options

Postby expresso » 25 May 2018, 02:43

i get at least 30 miles from 90ah which i did today 646 with lift and tilt and about 10 mph
Quickie 636 - 230ah LifePo4
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Re: Controller/Electronics options

Postby hotwheels_75 » 30 May 2018, 18:17

I got my amp hour meter and analyzer. Going to be a few days before I can test it. I’m getting a few things modified so I can move the seat back one more notch and make it less nose heavy. I don’t have high hopes that alone will magically triple or quadruple my range like expresso and others get, but I’m determined to figure out the problem.

I don’t know if this is normal, but my seat tilting module draws power even when everything is shut off and not in use. I connected my amp hour metre and there was a 0.05 amp draw and between 0.7 and one watt. I narrowed it down to the tilt module.

Very small, but I’m looking under every stone to see where my power is going.

I suspect it’s a combination of very inefficient motors and gearboxes on a very heavy chair, along with the way the suspension works.… Causing a lot of friction and effort to make the chair moved in every direction
.
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Re: Controller/Electronics options

Postby Burgerman » 30 May 2018, 19:22

Yep... And terrain, use. Maybe inneficient old motors. And 8mph eats double the power on every turn and at every speed compared to 4mph. Everything is a compromise. Inc Ah to lb weight of chair.
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Re: Controller/Electronics options

Postby hotwheels_75 » 31 May 2018, 17:58

Question: if a chair came in a 6mph and 8mph version. How do manufacturers normally get that speed difference? Is it different gear ratios? Or different motors? Or a mix depending on the chair/manufacturer?
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Re: Controller/Electronics options

Postby Burgerman » 31 May 2018, 19:18

Gear ratios. And very occasionally and incorrectly in programming, leaving 25% free torque and 25% free range on the table for no good reason.
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Re: Controller/Electronics options

Postby hotwheels_75 » 31 May 2018, 21:47

That’s what I assumed. Although with the blast 650 which is the 6.25mph version of my chair, they used 2 pole motors and a 70amp controller :| I assume it’s a different gear ratio too. Trying to come up with options to improve my range and maintain decent performance...without scrapping the whole thing. :problem:
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Re: Controller/Electronics options

Postby Burgerman » 31 May 2018, 22:24

There are usually these options:

4mph HD with 4 pole. For high torque bariatric use.
4mph 2 pole because its cheap slow gives adequate torque.
6mph 2 pole because its cheap! And useless...
6mph 4 pole because it works properly, and can make use of a bigger amp controller.
8mph 4 pole - same as above, but less torque and control, high drain, more speed, otherwise the same as above. OK on flat ground, and are skinny...
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Re: Controller/Electronics options

Postby sin85 » 01 Jun 2018, 01:07

Burgerman wrote:There are usually these options:

4mph HD with 4 pole. For high torque bariatric use.
4mph 2 pole because its cheap slow gives adequate torque.
6mph 2 pole because its cheap! And useless...
6mph 4 pole because it works properly, and can make use of a bigger amp controller.
8mph 4 pole - same as above, but less torque and control, high drain, more speed, otherwise the same as above. OK on flat ground, and are skinny...


a question from the ignorant (me):
if you have the same controller(rnet 120 single channel) and a 10km version uses a motor that develops maximum torque @3000 rpm but controller is limited @150A 30 sec burst and;
15 km version motor develops maximum torque @4000 rpm but controller has 180A 30sec burst (and it can be upped to 210 A burst) would that solve the torque issue?
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Re: Controller/Electronics options

Postby Burgerman » 01 Jun 2018, 01:57

All DC motors develop max torque at stall. So theres something wrong with your figures.

And the motor impedance tells us exactly how many stall amps each will take. Expect it to be around 300/400. Dont try it it will burn or break something. In use it never sees this as the controller limits it. The torque is directly proportional to motor Amps. Which is greatest at stall, This High natural stall amp, falls away as the motor speed increases. Until at max free running speed, its about 5 Amps, and in a theoretical motor with no friction would be zero. At half RPM (half volts) free running, this is again 0A.
With a controller this is limited to x Amps, at both stall, and at up to a specific speed under load. So torque is determined by controller amps. Motor impedance then determines efficiency, and the point where max controller limited Amps drops away due to motor RPM.

In your case you will need to know that allowing the motor to pull 210A wont break something or wont burn something. Theres a reason they limited it. But yes provided the motor has low enough impedance it will increase drive motor torque.
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Re: Controller/Electronics options

Postby hotwheels_75 » 05 Jun 2018, 01:04

I installed my wattmeter and power analyzer, still trying to figure it out. I videoed it in use, but it’s not in perfect focus and there’s a light glare on it. You can still see most of the ratings. Just cruising around my Yard the Amps drawn spent most of the time around the 30-40 occasionally 50-60A range and would drop to single digits going downhill/little to no load. Most of this was while in a profile with top speed of 7km/h. There were a couple of speed runs at 11km/h up and down my driveway. That’s when Amps drawn peaked highest. I only saw a split second in the 90s on video, but the meter recorded 116 at some point. I’m guess these ratings are rather high for the mild and pretty brief use?

The recorded values after 1-2km around my yard and a trip around the grocery store are as follows:

23.60Vm if I understand correctly this means at one point under load the battery dropped to this level.?
725.9Wh the amount of Watt hours consumed?
116.13Ap at some point my chair pulled a peak rating of 116.13A
2892.7Wp a peak rating of Watts used
16.364Ah I’m guessing this is approximately the Ah consumed from the the pack?
Pack voltage is currently at 26.49V
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Re: Controller/Electronics options

Postby hotwheels_75 » 05 Jun 2018, 01:05

Here’s pics of the other readings
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Re: Controller/Electronics options

Postby Burgerman » 05 Jun 2018, 01:26

23.60Vm if I understand correctly this means at one point under load the battery dropped to this level.?
Dunno. I would expect lower. I easily drop it to 18V. But it depends on programming. If it has turn acc, and forward acceleration set high as I do, you would easily see 200A peaks too.

725.9Wh the amount of Watt hours consumed?
Yes. But that doesent make sense or add up with the Ah used...

116.13Ap at some point my chair pulled a peak rating of 116.13A
Again, depends on programming. If it has turn acc, and forward acceleration set high as I do, you would easily see 200A peaks too.

2892.7Wp a peak rating of Watts used
Yes.2892W div by 24V then it means your 116A... Actually 120.

16.364Ah I’m guessing this is approximately the Ah consumed from the the pack?
Pack voltage is currently at 26.49V

Yes, but that makes the watt hours not add up. 752 div by 16.34 is 392 watt hours. Not 725!

What you really want to know is this.
a. Amps at full speed in a straight line.
b. Peak max Amps as you do a left/right/left zero turn on a thick carpet with as fast stick as possible. Worst case turn amps.
c. Ah used for 1 mile. Or 10 miles then divide by 10 to average.
d. Ah consumed before your battery is almost dead.
e. Amps consumed at 1mph cont speed.
f. max amps as you go from 0 to full speed up a steep slope/hill.
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Re: Controller/Electronics options

Postby Burgerman » 05 Jun 2018, 01:33

Amps drawn spent most of the time around the 30-40 occasionally 50-60A range and would drop to single digits going downhill/little to no load. Most of this was while in a profile with top speed of 7km/h. There were a couple of speed runs at 11km/h up and down my driveway. That’s when Amps drawn peaked highest.

Remember that a 74Ah battery will only give half that over 1 hour. So its really about 37Ah...
So you will be lucky to see 30 to 40 mins before a lead battery is dead at that rate!
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Re: Controller/Electronics options

Postby hotwheels_75 » 05 Jun 2018, 02:24

Burgerman wrote:What you really want to know is this.
a. Amps at full speed in a straight line.
b. Peak max Amps as you do a left/right/left zero turn on a thick carpet with as fast stick as possible. Worst case turn amps.
c. Ah used for 1 mile. Or 10 miles then divide by 10 to average.
d. Ah consumed before your battery is almost dead.
e. Amps consumed at 1mph cont speed.
f. max amps as you go from 0 to full speed up a steep slope/hill.


Ok, I’ll try and get those ratings. Today was my first time plugging in the meter and playing around with it. Figuring out how to record the outputs and what they meant.

My programming isn’t currently set as high as yours so that would explain the lower peaks maybe. I still have more programming to do. With my quad level function I found your settings too much.

Burgerman wrote:
Amps drawn spent most of the time around the 30-40 occasionally 50-60A range and would drop to single digits going downhill/little to no load. Most of this was while in a profile with top speed of 7km/h. There were a couple of speed runs at 11km/h up and down my driveway. That’s when Amps drawn peaked highest.

Remember that a 74Ah battery will only give half that over 1 hour. So its really about 37Ah...
So you will be lucky to see 30 to 40 mins before a lead battery is dead at that rate!


I’m using a 96Ah lithium pack.
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Re: Controller/Electronics options

Postby Burgerman » 05 Jun 2018, 02:44

So 2 to 3 hours. Thats why volts dont drop to 18...
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Re: Controller/Electronics options

Postby shirley_hkg » 05 Jun 2018, 03:13

Expresso, snaker and my ratings involve mostly cruising on long flat trips .

If yours were running in your yard, with lots of stop-and-go, scenario will be very different . cheers :dirtbike drunk2
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Re: Controller/Electronics options

Postby Burgerman » 05 Jun 2018, 08:58

And it will melt thin wires and blow small fuses! And damage low C rate cells. I have the T shirt!
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Re: Controller/Electronics options

Postby hotwheels_75 » 05 Jun 2018, 17:39

shirley_hkg wrote: Expresso, snaker and my ratings involve mostly cruising on long flat trips .

If yours were running in your yard, with lots of stop-and-go, scenario will be very different . cheers :dirtbike drunk2


I hope to try it out on a longer straight line flat trip soon. I don’t have easy access to good flat wheeling areas and Our weather is back to freezing! :thumbdown: :cussing


Burgerman wrote:And it will melt thin wires and blow small fuses! And damage low C rate cells. I have the T shirt!


My wires were all upgraded and I’m using the headway cells. So far no melting!
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Re: Controller/Electronics options

Postby Burgerman » 05 Jun 2018, 18:10

Sunny, blue sky, everything growing outside, inc weeds, and hot here. :admirer
Where are you?
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