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[PWM]

Yeah I hear ya Aaron, I should have kept my Cushman Eagle.

You can do it...works for keyless ignition on any firmware...took me a dozen attempts for the very first joy.

Hint, once you are on the settings screen-prompt you have 10-seconds to enter (12) side actuations and (1) push actuation for entry to be valid, so be deliberate, but not too fast...

BTW - the video was a good post to validate this engineering screen thing is real and for the source info...well heck, kudos for sharing...it should serve as a good tool to help troubleshoot on our own...

[wadejesu]

Bingo. I got it to work on my Ribelle, Just have to be quick about it,

[Specter]

I finally got mine to get in there, 3 pages of engineering gobblety gook, nothing that you can access as a standard user but interesting nonetheless.

Some battery voltages and temps here and there.  Could help with some troubleshooting but nothing that you'd be able to fix, save maybe a stuck t hrottle.

Aaron

[wadejesu]

Aaron

Just what I thought, was hoping for individual cell voltage,

[Specter]

Individual cell voltage, thats a lot of work there,  Idoubt you'll find any significant pack with that, a LOT of work, meaning cost, you'd have to wire EVERY battery and bring that harness up, and then monitor it, switch off somehow etc.  That'd be expensive as hell.   I could possibly see arm voltage or unit voltage, but yah some sort of reading would be nice.  I do think they have two sensors, so like side A and B we can see.

My racing bike has an extended screen it seems, I can see more stuff and there are places where it's showing cell volts around  4.xxx volts or so, plus battery pack some vector settings, torque and some other neat stuff.  One of these days Ill get my glasses and take a good look.

The only problem is, a lot of those values are instant values, like KW being burnt, hp being genrated, torque etc, you'd have to be actually looking at it while riding.  NOT a good idea at all, trying to squint down that small, find it while doing 140 mph !  Hell, not a good idea even at 40 mph, you need to be watching the road, not reading some screen.  If we had some sort of logger now.

Aaron

[DerKrawallkeks]

There is a wire running to EACH cell on ANY electric vehicle with a lithium battery.
Yes that's about 96 wires and 96 input pins on the BMS. All cars and bikes have it:) any device has it

[Specter]

But to monitor it.  The BMS, the balancing is easy just basically a Wheatstone bridge type of device but as far as monitoring them all, ugh.  I guess this is a good way to repurpose all those old parallel port printer cables   The balancing could actually happen passively, so the monitoring would only need to be done on demand id imagine.  Cant think of any reason to keep tabs on it real time unless you are trying to find a weak cell that's collapsing during a high load.  Thatd probably eat up some processing power pushing all those numbers.

Aaron

[PWM]

Cant think of any reason to keep tabs on it real time unless you are trying to find a weak cell that's collapsing during a high load.  Thatd probably eat up some processing power pushing all those numbers.

Aaron

Me thinks the engineering screen readout is real-time otherwise there isn't much utility in an engineering screen...should be able to setup GoPro / Osmo to record the ride session focused on screen as most parameters shown are worthless when static and cell voltage drop under load is precisely the info desired to characterize health of pac.

The BMS will manage the cell monitoring so no burden to VCU under running conditions ...BMS talks CanBus.

Have not tested real-time functionality yet need camera mount to make the effort worthwhile and safe...old-goat eye syndrome at play...

[Specter]

open the camera up enough so you can see what YOU are doing when the numbers change.  ok here is where i stomped the throttle,  here is where i turned, etc etc.  That might be a good idea, but there is a LOT of data crammed onto those screens,  those numbers are pretty tiny, goat eyes or not, by the time you blew them up to a size you can actually read  w/o the coke bottle glasses, it might be too distorted to read properly

Aaron

[svelectric]

I use this one with my experia.  https://www.amazon.com/gp/product/B011NSX27A/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Much more affordable than the one I linked to.  Thanks.

Do you use it with the Hans Cappele app?  Do you keep the dongle connected at all times?

I do use his app.  Connected while riding sometimes.  Using the obd setting.

[Pard]

What type of cell low/high imbalance are you getting under normal steady state riding load?

I see as much as 3.588 and 3.675 type differences when under throttle.  Less when just cruising.  Very tight balance of less than .010 at rest.

I assume that is normal since my battery is getting normal range and always balances easily under charging.

[PWM]

What type of cell low/high imbalance are you getting under normal steady state riding load?

I see as much as 3.588 and 3.675 type differences when under throttle.  Less when just cruising.  Very tight balance of less than .010 at rest.

I assume that is normal since my battery is getting normal range and always balances easily under charging.

Yes, normal...

At rest, the cell's terminal voltage is virtually the same as "open circuit" except for the residual current required by 12VDC-DC converter.

When running under load, the cell's terminal voltage drops because of the cell's internal resistance...higher terminal voltage under load equates to lower internal resistance.

For example, a fully charged cell will show ~4.0V after the surface charge disipates (charger applies 4.2V per cell max) this is why the pack charges to 100% but may show 99% an hour later.

Subtract the terminal voltage under load from the open circuit terminal voltage and divide by the cell's current to determine the cell's internal resistance.

4.000V - 3.558V = 0.442V

Assume for this example, the motor current is 300Amps (under modest acceleration)

The cell's current is half that because of the series / parallel cell arrangement.

0.442V / 150Amps = 0.00294Ohms = 2.94 mOhms

To get the true internal resistance one needs to capture actual motor current.

[Pard]

Interesting!  Thank you @PWM

[Demoni]

When running under load, the cell's terminal voltage drops because of the cell's internal resistance...higher terminal voltage under load equates to lower internal resistance.

Thank you! Great explanation of pack/cell Voltage sag under load and how each cell will react differently due to variations in resistance.
This is also why at very low SOC slow acceleration and minimizing throttle input will result in being able to travel further before "limp" mode is activated. Cell Voltage sag due to high current demand can trigger cells to dip below the permitted minimum level.

I can not go into details regarding communication between the BMS and VCU. But I can confirm that all cell Voltages are continuously monitored.

[Pard]

When running under load, the cell's terminal voltage drops because of the cell's internal resistance...higher terminal voltage under load equates to lower internal resistance.

Thank you! Great explanation of pack/cell Voltage sag under load and how each cell will react differently due to variations in resistance.
This is also why at very low SOC slow acceleration and minimizing throttle input will result in being able to travel further before "limp" mode is activated. Cell Voltage sag due to high current demand can trigger cells to dip below the permitted minimum level.

I can not go into details regarding communication between the BMS and VCU. But I can confirm that all cell Voltages are continuously monitored.

Thank you for the information,  @Demoni !