Vermeiren Ceres 4 / s-drive program/modding questions

[swan]

Hi experts, i try to help some friend with his Vermeiren Ceres 4 and need your help with your knowledge.
I ended up here because I want to help an electric wheelchair user. His purchased electronic wheelchair (Vermeiren Ceres 4) stops halfway up his hill.
When he goes up the ramp in his van with the wheelchair, it only goes backwards....
The wheelchair has an S-Drive controller from PG-Technologies.
In the hope of getting the controller to output a little more current by modifying the current measuring resistor, I opened the housing. I couldn't find a current measuring resistor, but I took a few pictures of it.
After reading up a bit, I would first check whether the controller is parameterized correctly.
My current status:
I need
1. the programming software (Mobility PC Programmer)
are there several program variants for (A/Dealer B/OEM C/Manufacturer)
or different config files? I could
2. the interface cable (USB / S-drive)
3. Dongle? How is the differentiation between the variants of the Access Level (A/Dealer B/OEM C/Manufacturer) or is the secret in the PID ? (0xE128 ..0xE12A)



I have found the dealer version, but I still have to build the cable. I have found different cable variants on your site.

So I have a few questions about the interface for the S-Drive in particular.
Here is my status - please correct if wrong?

1. pin 3 & 4 bridged on 4 pole Molex connector == Data Line ( bidirectional / voltage level max. 9V?

2. TX inverted to data/ RX noninverted from data

3. FTDI driver chip - is adaptation with FTprog necessary?





To the s-drive controller - (70A) variant.
As the wheelchair climbs halfway up the hill - I now assume that the boost function (10s 70A) is responsible for getting us to the halfway point.
If I can't change the behavior with the normal settings, I would test the motor with an external PWM control to see if the motor has enough power, which I assume because of the size.
The electronics in the S-drive controller look solid - with 4 mosfets for 80A - with a boost of 70A. Measuring and identifying components was not possible due to the paint job and time frame.
- Has anyone ever "tuned" a smaller version in terms of current in software or exchanged the FET for a better one with more current - only the control must be compatible with the 040N06 installed.
- How is the current measured?

Sorry for all the questions and yes - I'm totally new to this topic

Best regards,
Frank

[Burgerman]

FROM a previous thread:

Do we mean DOWN the hill?
That cant be many things.
One possibility is a loose battery terminal.
Another is that he has fitted those terrible lead replacement drop in lithium batteries and the downhil regeneration current causes the BMS to disconnect the battery.
Is there any error code, does it restart, does it lose power, etc???

If you mean halfway UP a hill then it can be that the power module overheats and rolls back power. Doesent turn off, just wont "go"...
Up or down this hill?

When he drives up the ramp with the wheelchair in his van, it only goes backwards....
I'm here to find experts who might be able to help me with my wheelchair technology questions. Thank you very much for sharing your knowledge.

So wheels spin?
Or lacks torque?
Or what exactly?
Could be failed slipping gearbox, worn out motor or brushes, etc.
Could be damaged throttle pot.

[Burgerman]

Hi experts, i try to help some friend with his Vermeiren Ceres 4 and need your help with your knowledge.
I ended up here because I want to help an electric wheelchair user. His purchased electronic wheelchair (Vermeiren Ceres 4) stops halfway up his hill.
When he goes up the ramp in his van with the wheelchair, it only goes backwards....
The wheelchair has an S-Drive controller from PG-Technologies.

In the hope of getting the controller to output a little more current by modifying the current measuring resistor, I opened the housing. I couldn't find a current measuring resistor, but I took a few pictures of it.

There isnt one, and current is very carefully controlled by time, by current (probably hall?) and by temperature of output mosfets and programing.

After reading up a bit, I would first check whether the controller is parameterized correctly.
My current status:
I need
1. the programming software (Mobility PC Programmer)
are there several program variants for (A/Dealer B/OEM C/Manufacturer)
or different config files? I could
2. the interface cable (USB / S-drive)
3. Dongle? How is the differentiation between the variants of the Access Level (A/Dealer B/OEM C/Manufacturer) or is the secret in the PID ? (0xE128 ..0xE12A)

PM me

I have found the dealer version, but I still have to build the cable. I have found different cable variants on your site.

So I have a few questions about the interface for the S-Drive in particular.
Here is my status - please correct if wrong?

1. pin 3 & 4 bridged on 4 pole Molex connector == Data Line ( bidirectional / voltage level max. 9V?

2. TX inverted to data/ RX noninverted from data

3. FTDI driver chip - is adaptation with FTprog necessary?

They guy that used to know these details is no longer with us. RIP. WoodyGB.



To the s-drive controller - (70A) variant.
As the wheelchair climbs halfway up the hill - I now assume that the boost function (10s 70A) is responsible for getting us to the halfway point.

No. It only really works at max load at low speed. What slows you is the THERMAL ROLLBACK to try and protect the too small 70A controller. And the battery. And the motor windings from damage.

If I can't change the behavior with the normal settings, I would test the motor with an external PWM control to see if the motor has enough power, which I assume because of the size.
The electronics in the S-drive controller look solid - with 4 mosfets for 80A - with a boost of 70A. Measuring and identifying components was not possible due to the paint job and time frame.

Fit a bigger amp controller or fit a cooling fan.

- Has anyone ever "tuned" a smaller version in terms of current in software or exchanged the FET for a better one with more current - only the control must be compatible with the 040N06 installed.
- How is the current measured?

Not worth it. Use a bigger current controller with less resistance, less heat, less rollback, better performance. Fit a fan.

[Burgerman]

The cost or difficulty of making mods to the controller are more expensive than buying a more powerful controller module on eBay.

The real problem is that the scooter we are talking about isnt man enough for the job. It needs more power. So bigger battery like 80 to 100Ah, bigger motor, bigger cables, bigger controller (higher curent capability) etc to make it properly outdoor capable rather than a shopping scooter.

Its like trying to race a 50cc motorcycle up a hill against a 1000cc one...

[swan]

Thanks for so much Info.

The idea to use a bigger controller is good - i will look if i found one.

With your help - i got so much informations - i will study some time and then i will come back if i found out some usfull for the community.
If
* I know that the settings are correct ( eventually i will have some questions which cant answered by reading the Manuals)
- i will try to modify the hardware - or change to a bigger size of controller. ( which would be compatible? s-drive (90A/120A) ? or also other controllers? is the 14 Pin molex also used in other drive controller as s-drive ( compatibility) ?

HW-mod : the idea to replace the Fet by one of the better Rdson: used 80A/60V/ 4mR --> i found some which at least reduce the fet power loss to the half.
Also the thermal pad seems to me to be a cheap one.
This modification should affect the thermal behavior. ( as also the fan it will do)

But i have many things on my list, so if i can do all of the changes by modifying modules - it would be the easyer way.

I will give a feedback if someone isinterested.

Cheers,
Frank

[Burgerman]

Everything is a match.

If you manage to modify the controller to give more power, or fit a 120A version or whatever one, then the battery will suffer due to its high impedance and its chemical surface charge nature (pukert), so you still wont get the power needed and they will soon die. And the motors will then also die fast. Those heat up in proportion to the current they are fed (the load and the work that they do) too.

You need a bigger more substantial road going scooter to get a human up steep hills...

[swan]

Thanks for the fast answer. You are rigth - best way would be to have an powerfull drive. I try to help him - also as i told him about the change of controller or other topics. I dont know the personal situation of Member in the forum, but for example as far the disabled persons which i know have not high income. For him are 300€ for a controller not less. If he had enough money he can buy a good solution. My first comment was like yours - why you havent buy a better one - its take some time to understand why - because he was ashamed to talk about his low income. In the pst, i was not rich - but i had enough - for me and to help others. Also my situation changed so i can not offer financial support, but i can spend my time and knowledge. For him - it is nice if he can drive up the hill by scooter - its to another Part of the house - he goes 5-7 times to this location - one way is 20m - so it would help if he can drive. The user of this forum helped me much - as i'm new. replacing the thermal pad by a better one allows him to come two time - after this thermal limitation comes.

For the Interface i have some question - could someone post information read out Origin programmer cabler with FTPROG ( from FTDI ) and read the data of original OEM / and / or other types if available ? Or exist it somewhere ? in one Forumspost i see a file from your forum member and supporter WoodyGB (RIP). As you say he could answer all the questions ( if he would live) which i have about communication cables . I looked at his posts to find some informations out - he was a so active member.

[Burgerman]

By improving the thermal pad, or cooling the controller you now send more heat to the too small motor... So when that burns, your low income disabled guy now has a bigger bill...

Best solution, sell scooter, buy something more capable. Its cheaper and only sensible long term solution. Or move somewhere with no hills...

[ex-Gooserider]

Important to note that if on a tight budget, Ebay and similar sources are your friends - used mobility stuff is generally very low cost compared to list prices from vendors. As BM has said a large part of the problem is that the current chair is simply not adequate for the task. Far better to spend the time and money on replacing w/ something better suited than trying to hop up an inadequate unit.

ex-Gooserider

[Burgerman]

When you have a hammer then everything can be fixed with a hammer.

He likes electronics and software so... The soluton must be messing with some mosfets.

But it misses the point.
That scooter looks quite big. But its lacking where it matters. Motor, controller power output to drive a bigger lower impedance motor, heavier wiring, and batteries that can lift a human at higher current up a steep hill without the voltage collapsing. The whole drivetrain as a system is basically a slow speed, shopping scooter. Its 70A max. Thats around 20 or 30 continuous. The motor matches it an a couple of hundred watts.

Even my wheelchairs have 2x 550 watt motors and 2x 120A per channel.
So thats 1100 watts of motor power and 240A of current max, and 244Ah of low impedance lithium! A different league of power capability.

[swan]

Thanks for your answer.
You all are rigths - i have some hammers.
One of them is electronics - as it is my profession.
The scooter design is more or less cheap done in my opininion. I think it could be improved, step by step for less money.
Wire resistance , battery capacity , controller ability and motor power are the essential points.
It could be that i missed some points.
The wire resistance could be changed easy - by usage of bigger cables.
Controller current ability could be improved easy - from 80A Mosfet to bigger - to get 100A with low power losses out of contats should be possible - as i my measurment shows by a project.
The motor in this device is rated with 470W - but i will ask some experts for Motor construction / design. eventually we will do a power curve measurement to get the real power rating.
I'm so thankfully that you have such a good forum their - much thanks to all of you especially burgerman.
Some of you have the "luck" to be in the situation to have enough money as it is really expensive to be a disabled person.

For 2 weeks i was in an innovaction conference and talk with an inventor which develope an electric wheelchair with integrated therapeutic functions. Nice and powerfull design. But no health service would pay for it (50t€).
Nice but only possible if you have the necessary money.

Yesterday i had a conversion about this topic with a friend - i forgot that he had "reinvented" the wheel.
The wheel was for manual wheelchairdrivers. This was 1999. 14 Years later (he hold his patent only for 10 years) an israel people has reinvented this type of wheel again - but he was more sucesfull in marketing - eventually because radically improvements are to fast to german market.
With this wheel you can drive short stairs downward.
But i ask me exist today Wheelchairs which can climb stars?
if so it would be nice, exist good solutions for this is my questions to the group?

I find it nice and really good that you inform me about the risk - also for the friend with the scooter.
He has also a manual wheelchair - which he used before to climb his street - so in every case he is able to drive.
He wish that we look if it could be improved - as i do it for no money. He will get the material and all for free also the parts which will eventually destructed will be replaced by at least same performance parts.

In my world we should help each other as we are able - we all are humans in one world - World To Future instead of "WTF" or EOL.

naive - eventally - or not ;-)
I'm only 51 - so i have eventualy some time to learn :-)


Best regards,
Frank

[Burgerman]

Do you think that a 20% increase in controller current alone will make a noticable difference?

I doubt it will because it isnt a lack of amps thats the problem here hut the internal programming protections (thermal rollback, current reduction over time to protect motor windings, etc and battery impedance/peukert, and motor impedance).

If you change all of those things, what you really then have is a new scooter!

Think about this.
A lower motor impedance means more torque. If you half it, say from 60mOhm to 30mOhm, then you do not actually add ANY torque at low speed. Because that is limited by the various software controled current liit and power reduction (stall protections etc). Volts = RPMs Torque = Amps. But motor amps are much higher than battery Amps.
But now the motor stalls at HALF the voltage.At the same 80A. That means you get the same torque, as before, but now at HALF the battery current.
And so less heat, less battery impedance issues etc. So less thermal rollback, less voltage collapse as you climb that hill.

Just to think about. This is why bigger scooters work on hills. Same torque, half as many watts.