X8 configuration

[fishinjunky]

Then you should use 8S and your power module will likely last a lot longer. So far you have been lucky.

as i say you in my message before i used 8s for years and always big problems
since 3 years with 10s no problem even 1 very very very small

and for sure i am not lucky since i borned so no lucky with my x8
if it his working very well it is not luck, not with me ...

what size is the power module 120A or 90A ? would larger power cables get hot maybe 6awg?

[Micka7405]

all x8 since 2012 all x8 is with electronic module 120amps
and yes since i had the cells even with 8cells i using awg 8 for motor
awg 6 is to big for the hole

[Micka7405]

Maybe but your idea that it causes less heat on motor wires and power module breaks the laws of physics so that makes no sense. Quite the opposite. At full speed you are putting more watts through your motors than previously. So more heat. At high loads your power module limits motor amps to whatever its capable of (120A in this case) regardless of input voltage.

we do many testing the last days with dad and here is that is mesured before electronic module.
when i have use 30amps and 33volts (10 cells) wich is around 1000watts
i have 38amps and 26volts (8 cell) wich is too 1000watts
x8 need 1000watts to climb my test climb

at the same time when i using 30amps and 33volts (10 cells) before electronic module i have using 14amps using for the 2 right motors i think 7amps for each motors
i think it is same for 2 left motors and difference of 2amps is for the electronic module and joystick i think

when i using 38amps and 26volts (8 cells) i have using 18amps using for the 2 right motors

i can imagine it is the same ratio 25% if i using 10amps or 20amps or 70amps mesured before electronic module

so it is right with my 10cell my wires are less hot because of less ampere
in the USA where they using a lot of place 110v in the house they have big wire because with 110v they need more amperes for the same power they need with 230volts
and more amperes need big wire


that i writing is not assumption it is only real life testing and 3 real years using where since i using 10cells no more problem with my wires or electronic module over heat
as real is the fact not only my electronic module and motors are well working with my 10cells since 3 years but also my power locking steering my legs lift my seat tilt my 2 fans my led light all of them are for 24v but working fine and as i say since long time long hours long km
the only item wich is working but not before 10cells are under or at max 33volts is my usb charger over 33volts it sleep and at 33volts wake up and can charge

next week my boyfriend will send me a small ampere meter and i will try to install it on x8 with dad maybe i will ask for you helping

gracias

[Micka7405]

what is Log in as per screen

by logging in as a guest.

username: guest
password: Guest$01

gracias but whyy i can not see the magic mibility as bm shwo on its photo ?

[Micka7405]

Then you should use 8S and your power module will likely last a lot longer. So far you have been lucky.

Sunrise sell brushes no problem. I have a set on the shelf for all of my own chairs.

For e.g. Item no.: 13
Article no.: MM-MOTBHX8V6
Description: X8 and V6 Motor brush A9

And see below for other parts for X8 motors...

Go to sunparts, and follow on screen instructions. Hell I could order those today.

i can not see the same why ?

[Burgerman]

Site is not working? Or you are looking under the documents tab (wrong). I just looked! Or you are using a bad browser? Firefox works, apple stuff or phones dont.

next week my boyfriend will send me a small ampere meter and i will try to install it on x8 with dad maybe i will ask for you helping

gracias

Do you understand that the MOTORS draw much more Amps than the battery? And understand WHY?
The motors are supplied that battery voltage as a fixed pulsewidth % up until the 120A limit is reached. So that as you attempt to climb, turn, they draw the MAXIMUM Amps that the power module is capable of providing to the motors, at maybe 3 to 6 volts at high load/stall. At this voltage the motors are already pulling the 120A that the power module is capable of providing for a few seconds.
And so you will need to install your AMP METER into the MOTOR cable, and not the battery cable. As the battery the current will AT STALL be much lower than the motor current. BUT DONT fit it! Theres already a much better system already built in! See below.

And do you now understand that your battery voltage makes zero difference to motor current? The two are NOT the same. That is determined only by the combined motor resistance (ac impedance in fact) of your two motors per side. And the reduced pulsewidth required to limit them to the max 120A limit. At stall, they produce the max current allowed at around 4 or 5 volts (120A) in your case because of 2 motors. Stall the motors against a wall, and "measure" the max current. And you will see 120A regardless of battery current -- ONLY THE PULSEWIDTH changes.

You do not NEED to install your Amp meter! Dont cut up the motor wires for nothing.
The motor current, battery current (much lower) as well as battery volts, and motor volts can be directly monitored by your programmer in real world use. Its all built in!

HERE is a typical example below.
THIS is my own simple powerchair with 2 motors. M1 and M2. This is a TURN IN PLACE on a carpet and as you see it already draws 114A on one motor, 103A on the other, and motor voltage is much less than battery voltage. And motor current is much much higher than battery current. In yyour case it will hit 120A limit much more often. As you have 2 motors each side.

LOOK. With 2 motors in parallel your chair will want to pull around double the current (per volt) at stall. So at around 5V your chair will draw 120A per motor. Limited by the controller. This 120A max happens often, is what heats up your motors, wiring etc. Thats why your cables / motors overheat for e.g. The battery voltage has no bearing on the motor current. It only affect the battery current. Motor current is controlled by pulsewidth and is determined by motor impedance and load only.

Look at the battery currentbelow, compared to 2x the Motor Amps on here for e.g.
M1 + M2 is 114A + 103A = 217 total motor A. But the battery amps are just 24A...
Your argument is wrong because it does not agree with basic physics.

[Micka7405]

Site is not working? Or you are looking under the documents tab (wrong). I just looked! Or you are using a bad browser? Firefox works, apple stuff or phones dont.

the place where i connecting internet they using google chrome and firefox and with 2 computers we can not see the page you see you

And so you will need to install your AMP METER into the MOTOR cable, and not the battery cable.

it is exactely what we do with dad as i wright
1 ampmeter beteween cells and electronic module just befor cable is inside electronic module and 1 ampmeter between electronic module and the right motors juste out off electronic module right side

it is late time to go back my house

gracias

[Micka7405]

Cheap one of these! https://www.aliexpress.com/item/2255800580521647.html
200A one.

You do not NEED to install your Amp meter! Dont cut up the motor wires for nothing.

i think with the ampmeter Steve give me link i need to cuting wire but with the link bm give i do not need to cuting wire i am wrong ?

[Burgerman]

You dont need it at all.
If you want to know motor volts, or motor current, or battery volts, or battery current, the R-Net programmer already shows this in real time as you use the chair. As I already explained and showed above. And to do it with added meters you will need 3...

You would be doing what already exists in a less accurate and less useful way. And spending money for nothing.

If you only want to know battery Ah used, then yes, fit this to the battery wires. But far from reducing MOTOR amps, the thing that burns your brushes, motors or wiring, more battery volts will give exactly the same 120A output per side. And will do so more frequently at a higher speed with greater battery volts.

So while more volts will reduce the already low battery current further it will do nothing to reduce motor or wiring reliability. Quite the contrary. A basic understanding of how the system work, and physics tells you this long before you measure it. But I showed you this wuth the screenshot above.

Also, if you click the right things, you CAN see that same stuff I showed you from your country as I just tried it using my VPN from mexico. Try again, you do not want a PDF file! You do not want the documents tab.

[Paul]

She's right I log on the same page and can't see the MM line.
Maybe you have a pro account burgerman to have the MM option?

[Burgerman]

Thats the US .com site. Its not on that site.

use .EU

https://eparts.sunrisemedical.eu/indexi ... 83%2C77284

Use a (free) VPN site if needed... If it redirects you to .com.

Connects fine from mexico...

[Paul]

You will find your parts here.
https://eparts.sunrisemedical.eu/indexi ... 83%2C77284
Log in as per screen.

The link you sent is not the good one.
This is working for MM too: https://eparts.sunrisemedical.eu/indexi ... /path/%2C0

[Burgerman]

Both work fine for me.They are always slightly different if you are on a different page or logged in, the links change dynamically to the login screen page regardless. Either way as long as you look at the correct site it works. The .com (US) one is useless. Something to do with the US over regulated nonsense you use.

If she accepts risk of wrong parts ordered from EU site, lost in transit from me, etc then provided she paypals me the money I will order and ship to mexico. It cannot be that hard to do surely? Just looked. Not exactly cheap. 32 uk pounds shipping and a minimum order charge from sunrise. But thats fedex.

It must be cheaper to just order a set of brushes for the V6 chair in the US as its not the oposite side of the globe. They are the same. Or even order from a motor rebuild service in the US.

[fishinjunky]

Here are two places in the U.S you could check if they have the brushes you need.

https://store.eurtonelectric.com/?_ga=2 ... 1656418365


https://www.joystickrepair.com/

[Burgerman]

Also. Going back to your motor heat and burning out issues.

If you have the max 24V x 120A max (which is the maximum power delivered to the motor AS IT SPEEDS UP UNDER FULL LOAD, (e.g accelerating as you go up a slope) then thats 24V x 120A = 2,880 watts peak on your right side. And the same on the left side.

If you increase that to 33V for e.g, then you have the following change at peak load. 120A x 33V = 3960 watts per side at the very same 120A limit. Thats a much higher peak heat load on your motors and wires for longer as you accelerate. This occurs at whaever speed the max pulswidth occurs as you climb (around 1/4 to half speed) and accelerate. Thats a much bigger problem for your motors at the higher voltage at its peak demand.

Remember that power is watts. Motor efficiency remains the same regardless of voltage. So much more heat to try and get rid of. Or if you prefer torque x RPM = power which increases with voltage because motor impedance and peak amps (120) remains the same.

And that if you double the voltage that = 4x the power... And that you are gradually cooking the 6 large 35V electrolytic capacitors inside the power module that work with the 16 mosfets at a much higher rate than on the 24V nominal system they were intended for. Not enough headroom for noise or regen spikes. Electrolytic capacitors dry out due to higher voltages over time. And due to extra heat.

[fishinjunky]

Also. Going back to your motor heat and burning out issues.

If you have the max 24V x 120A max (which is the maximum power delivered to the motor AS IT SPEEDS UP UNDER FULL LOAD, (e.g accelerating as you go up a slope) then thats 24V x 120A = 2,880 watts peak on your right side. And the same on the left side.

If you increase that to 33V for e.g, then you have the following change at peak load. 120A x 33V = 3960 watts per side at the very same 120A limit. Thats a much higher peak heat load on your motors and wires for longer as you accelerate. This occurs at whaever speed the max pulswidth occurs as you climb (around 1/4 to half speed) and accelerate. Thats a much bigger problem for your motors at the higher voltage at its peak demand.

Remember that power is watts. Motor efficiency remains the same regardless of voltage. So much more heat to try and get rid of. Or if you prefer torque x RPM = power which increases with voltage because motor impedance and peak amps (120) remains the same.

And that if you double the voltage that = 4x the power... And that you are gradually cooking the 6 large 35V electrolytic capacitors inside the power module that work with the 16 mosfets at a much higher rate than on the 24V nominal system they were intended for. Not enough headroom for noise or regen spikes. Electrolytic capacitors dry out due to higher voltages over time. And due to extra heat.

im curious about the overheating issue. Most people on here with 8cells lithium have r-net 120amp power module without any overheating issues none that ive seen anyway. So im wondering why is she getting this issue with 8 cells but no one else is. Is it because the larger size capacity of her cells around 300ah compared to the 200ah to 230ah size cells most use here?

[Micka7405]

Here are two places in the U.S you could check if they have the brushes you need.

https://store.eurtonelectric.com/?_ga=2 ... 1656418365


https://www.joystickrepair.com/

¿¿¿ ??? i do not need brush yer mine are still very good
however gracias a todos por sus maravillosos comentarios

[Micka7405]

Also. Going back to your motor heat and burning out issues.

If you have the max 24V x 120A max (which is the maximum power delivered to the motor AS IT SPEEDS UP UNDER FULL LOAD, (e.g accelerating as you go up a slope) then thats 24V x 120A = 2,880 watts peak on your right side. And the same on the left side.

If you increase that to 33V for e.g, then you have the following change at peak load. 120A x 33V = 3960 watts per side at the very same 120A limit. Thats a much higher peak heat load on your motors and wires for longer as you accelerate. This occurs at whaever speed the max pulswidth occurs as you climb (around 1/4 to half speed) and accelerate. Thats a much bigger problem for your motors at the higher voltage at its peak demand.

Remember that power is watts. Motor efficiency remains the same regardless of voltage. So much more heat to try and get rid of. Or if you prefer torque x RPM = power which increases with voltage because motor impedance and peak amps (120) remains the same.

And that if you double the voltage that = 4x the power... And that you are gradually cooking the 6 large 35V electrolytic capacitors inside the power module that work with the 16 mosfets at a much higher rate than on the 24V nominal system they were intended for. Not enough headroom for noise or regen spikes. Electrolytic capacitors dry out due to higher voltages over time. And due to extra heat.

are you speaking about me ?
because i have not and zero problem with my wire or motor since i using my 10 cells
my poor english is why i can not explaining very well

[Micka7405]

Cheap one of these! https://www.aliexpress.com/item/2255800580521647.html
200A one.

i just receiving this one not exactely but very close
manual user guide is chinese and i do not understand nothing
inside the hole i must put 1 or 2 wire from cells i thinking one but not sure and if only one the negative or positive wire

gracias

[Burgerman]

are you speaking about me ?
because i have not and zero problem with my wire or motor since i using my 10 cells
my poor english is why i can not explaining very well

You explained fine. You just clearly dont understand the physics or what is going on.

I dont get it. What part of the above didnt you understand?

That thing you are fitting is not required, a better version is already built in to R-Net!

And no amount of testimonial talk changes the physics. I give up!

ONE wire. A Motor wire, eithr one. And you need one on the left, one on the right side, and a 3rd one on a battery wire.

[Micka7405]

no problem my x8 is working very good like it is and for 3 years and and that is most important

[Micka7405]

ONE wire. A Motor wire, eithr one. And you need one on the left, one on the right side, and a 3rd one on a battery wire.

i need 1 on the left and 1on the right i do not understand about what i need please said me

ok ONE wire thank you bm

[Burgerman]

You dont need ANY to monitor motor current or battery current None. Zero 0 wires.

Its already built in.

If you want it to monitor BATTERY Amp Hours used up over time it goes one of the battery wires. And this will not tell you about motor amps in any way.

[steves1977uk]

im curious about the overheating issue. Most people on here with 8cells lithium have r-net 120amp power module without any overheating issues none that ive seen anyway. So im wondering why is she getting this issue with 8 cells but no one else is. Is it because the larger size capacity of her cells around 300ah compared to the 200ah to 230ah size cells most use here?

It doesn't matter how many Ah's you have, as long as you keep in the recommended voltage range (21-30 volts, allowing for regen). Running a PM near it's max input voltage (33v+) will shorten it's lifespan, how long it can cope with being stressed is a guessing game. I have PM's that are 15+ years old and are still going strong because I keep them within their voltage specs. Adding a cooling fan will help the PM maintain it's max current draw for a little longer.

Steve

[Burgerman]

Its because an X8 has TWO motors each side. That means that they draw around double the current that a single motor would. Since it halves the impedance and doubles stall current and doubles the free running current. And the thing is used off road and is heavy. Which also hugely increases load and so current. Up to the max limit.

Double the weight of chair or user and you double the current. And its very heavy. Up to the 120A max limit.
Double the load on turns or on slopes off road and again you double the current. So wiring is heavily loaded. But it can only go up to 120A regardless.

The difference is that the power module, and motors, and wires are sat at the max allowed 120A for longer due to this. And more frequently. Hence wiring melts, brushed are burned and chipped due to heat, mommutators wear/burn more easily, and power modules heat up more often and for longer than on a 2 motor lighter wheelchair.

Now increasing battery voltage just makes it hit the higher motor amp loads for longer and more frequently than 24V does. But not by anything at all at stall, and only a little as speed increases to the point where batt voltage = 120A at the motor under load at a certain pulsewidth/speed.

So increasing the voltage reduces batt current by around 12% in this case but gives the exact same motor current of 120max at stall, and a little more for longer as you accelerate. Remember Volts = RPM, Amps = torque. Which causes both to increase as you accelerate from stall with higher voltage.

[fishinjunky]

Its because an X8 has TWO motors each side. That means that they draw around double the current that a single motor would. Since it halves the impedance and doubles stall current and doubles the free running current. And the thing is used off road and is heavy. Which also hugely increases load and so current. Up to the max limit.

Double the weight of chair or user and you double the current. And its very heavy. Up to the 120A max limit.
Double the load on turns or on slopes off road and again you double the current. So wiring is heavily loaded. But it can only go up to 120A regardless.

The difference is that the power module, and motors, and wires are sat at the max allowed 120A for longer due to this. And more frequently. Hence wiring melts, brushed are burned and chipped due to heat, mommutators wear/burn more easily, and power modules heat up more often and for longer than on a 2 motor lighter wheelchair.

Now increasing battery voltage just makes it hit the higher motor amp loads for longer and more frequently than 24V does. But not by anything at all at stall, and only a little as speed increases to the point where batt voltage = 120A at the motor under load at a certain pulsewidth/speed.

So increasing the voltage reduces batt current by around 12% in this case but gives the exact same motor current of 120max at stall, and a little more for longer as you accelerate. Remember Volts = RPM, Amps = torque. Which causes both to increase as you accelerate from stall with higher voltage.

Ok I see. You explained very well. BM, what do you think would be the best solution in this type of situation. Maybe 8 cells with larger guage wires an a fan to cool the pm like Steve mentioned? ( but I understand she is content with the 10 cell setup) I was just thinking of a solution to address the cause of the overheating issue.

[Micka7405]

i say you 10 times that that my x8 is working very very very well and since 3 year and 4000km for one year
do not care about my 10 cell it is working fantastic with me and again since long long long time gracias a Dios

for the ampmeter i get a few day before i do not need to know about motor amps dad do this with my boyfriend and me and we know
what i need to know is how many amps is in my cells that is important as fuel gauge in a truck
i hope this time my message will be understanding
time to go for my physio
gracias

[Burgerman]

When the motor impedance is lower than that of the wiring (it is whan using low impedance motors) then only increasing the motor wiring size by maybe 2 or 3x will help improve things at the voltages we are talking about.

We already have an issue with this wth 2 motors on a powerchair. But obviously not so badly.

The real answer is to move from the 24v motors to 48v or preferably much more. We are talking about maybe 96V or more ideally. That would allow us to use much higher impedance motors, thinner windings, and much less current to get the same exact performance with lower losses (heat) in the mosfets, and wiring, and brushes etc. More of the power ends up at the wheels and less warming the wiring and motors and controller.

Remember that just adding more battery volts doesent do that. And all it does is reduce battery current. Motor current at stall stays ecactly the same 120A, and at exactly the same voltage. Even peak voltage, not reduced by pulsewidth to maintain 120A max, is still exactly the same! Its set in programming to 22.5V max typically.

So the only way to reduce heat is lots of airflow, on motors, cables, power module. Or reduce weight.

[Burgerman]

i say you 10 times that that my x8 is working very very very well and since 3 year and 4000km for one year
do not care about my 10 cell it is working fantastic with me and again since long long long time gracias a Dios

It will not change heat (in fact it makes it slightly worse as speed increases under load)
The fact that you say its working well is irrelivant. Thats called testimonial evidence and it is subject to user error and bias. And I KNOW that you are not lying, but are just being lucky so far! With no benefit. And it cannot possibly be helping reduce motor or wiring melting or burning. The physics is extremely simple here! So what you have done is a mistake. You are welcome to continue. When it breaks down and leaves you stranded remember this! Sooner or later a mosfet will fail because a capacitor it depends on has dried out and isnt working properly.

for the ampmeter i get a few day before i do not need to know about motor amps dad do this with my boyfriend and me and we know
what i need to know is how many amps is in my cells that is important as fuel gauge in a truck

OK as a fuel gauge it will help, on a battery wire to count Ah.

But you WERE talking about stopping the wiring burning and motor problems. And claiming that more cells stopped this. And more cells do nothing to help with this motor current at all. Quite the opposite. If you understood the physics and how that power module worked you would understand this. All you gained is potential reliability isues of the power module. You dont even gain more speed from the extra cells, unless you additionally changed the max voltage from 22.x to say 28.x volts in programming.

[LROBBINS]

Operating voltage is only one of the specifications for electrolytic capacitors. There are electrical specs, such as ripple and leakage currents and tolerance, but they also have different temperature ratings - as low as 60oC, as high as 150oC with most being 105oC, and perhaps most important in this context they have a rated lifetime. For example, 560uF, 50V electrolytics are available with temp ratings from 85o to 150o and lifetimes from 2000 hours to 10000 hours, and very different prices. The controller manufacturer will be doing a balancing act - durability, failure rate, warranty repair cost and lost sales because of damage to reputation vs. COST. And the balance point very much depends on what you are building. If you expect to sell 10,000 widgets a year and the warranty return rate is 1 in 1000, you'll have to deal with only 10 unhappy customers a year (and most won't even complain). If you are building a 10 million automobiles a year, there'll be 10,000 unhappy dealers a year (and comments in the automotive press) bitching about unreliability. That's why component manufacturers make separate consumer (cheapest), industrial (slightly more expensive), automotive (substantially more expensive) and military (orders of magnitude more expensive) rated versions of many components. Unless you rip into the box and then get the spec sheet for the particular components used, you have no way to know what compromises were made by a manufacturer.

Those lifetimes are guaranteed at rated voltage and rated temperature. To put that 10000 hours in context, that's about 4 1/2 years when continuously used at their maximum ratings, and less than a year if the cap has a 2000 hour endurance rating. Obviously they won't last that long if the rated voltage or temperature are exceeded, but I haven't seen any rules for derating. In any case, our controllers are not at maximum voltage 100% of the time, so decent quality caps will still last a long time even if the rated voltage is slightly exceeded for short periods. And the failure is more likely to be a slow degradation rather than a sudden failure, unless the over voltage is pretty extreme in which case an exploding aluminum can is even possible.