Is Wrongway right about V8S BMS?

[mrelwood]

5 hours ago, ursi said:

Is there a conclusive answer to the titular question somewhere in these 8 pages?

Not really, no. Although it seems to tilt in the direction of V8F and earlier (V10F possibly included) perhaps not having cell group balancing, and V11 onwards seemingly having cell group balancing. No info on the V8S, other than it’s BMS is clearly different than on the V8F.

[Mono]

5 hours ago, mrelwood said:

tilt in the direction of V8F and earlier (V10F possibly included) perhaps not having cell group balancing

Two pieces of evidence that should count against this tilt

• the V8 is probably the most ever sold wheel, yet I have seen very few complaints about its battery and zero fires IIRC
• I have seen almost no degradation of any of my V8 batteries over thousands of km which people claim to be impossible without balancing (I don't know, I just observed), where I charged to max voltage only every 7000Wh or so.

Just another funny observation: all my V8 continue to draw a charge current of 0.04A when fully charged whereas my V8F does not.

[rcgldr]

On 6/5/2023 at 8:32 AM, Mono said:

Just another funny observation: all my V8 continue to draw a charge current of 0.04A when fully charged whereas my V8F does not.

At what voltage do you see a charge current of 0.04A (which would correspond to 1K ohm resistors) on the V8?

What is the max charging voltage you see on the V8F before the V8F shuts off charging? Does the current go to near 0.00A (or at least less than 0.01A) on the V8F when it shuts off charging? This is what my V8F is doing after it shuts off charging, only using enough current to stay "awake" as it slowly discharges over the next 8+ hours down to around 82.6 volts before it re-enables charging again (which only runs for about 20 minutes before it shuts off charging again).

Edited June 7, 2023 by rcgldr

[Mono]

On 6/7/2023 at 7:04 PM, rcgldr said:

At what voltage do you see a charge current of 0.04A (which would correspond to 1K ohm resistors) on the V8?

Like 83.8V, IIRC.

On 6/7/2023 at 7:04 PM, rcgldr said:

What is the max charging voltage you see on the V8F before the V8F shuts off charging?

Same, I may have seen even 84.0V. I don't know whether it actually "shuts off".

On 6/7/2023 at 7:04 PM, rcgldr said:

Does the current go to near 0.00A (or at least less than 0.01A) on the V8F when it shuts off charging?

Yes, I see 0.00A on the V8F, no idea whether this is also close to 0.000A.

[rcgldr]

22 hours ago, Mono said:

Yes, I see 0.00A on the V8F, no idea whether this is also close to 0.000A.

That's because the V8F shuts off charging due to overvoltage detection of a cell group, only drawing just enough current to detect if a charger is still on and connected, a very tiny amount of current. All internal current is taken from the battery pack, just driving the blue SOC led lights next to power switch, bluetooth communications, and other related circuitry, which is why it takes 8+ hours to slowly discharge to 82.6 volts before it reenables charging, and I don't know if any balancing occurs during the slow 8+ hour discharge. If the V8F detects that a charger is not on or not connected, it shuts down completely, and there is no slow discharge. 

Edited June 10, 2023 by rcgldr

[rcgldr]

On 6/4/2023 at 10:26 PM, mrelwood said:

it seems to tilt in the direction of V8F and earlier (V10F possibly included) perhaps not having cell group balancing

It's been about 12 weeks and 100 miles since my last 100% charge, mostly 3 mile rides, so about 30 rides. I keep pack voltage at 76 volts (3.8 volts per cell), a short charge before, and another short charge after to return pack back to 76 volts, which would be 60 short charges at 3 amps (using eWheels charger). From today's full (100%) charge, I see the same peak voltage as 12 weeks ago (84.0 volts reported, set by Inmotion service during an online "calibration", I don't know the actual voltage). I don't know if the lack of change is due to low usage, luck, or some type of balancing. I'm now letting it do it's slow 8 hour discharge while connected to stock charger. I have EUC World running this time so I can see the minimum voltage before the V8F re-enables charging again.

Edited July 6, 2023 by rcgldr

[mrelwood]

56 minutes ago, rcgldr said:

I don't know if the lack of change is due to low usage

It is. 90 miles is maybe 4 full charge cycles. That is a very small amount of usage.

[rcgldr]

15 hours ago, mrelwood said:

It is. 90 miles is maybe 4 full charge cycles. That is a very small amount of usage.

Looked at the wrong log entry, 12 weeks, 100 miles, which would translate into 5.5 or so full charge cycles on a V8F with its 512 wh pack, not much. At least it seems that the 60 or so short duration charges at 3 amps doesn't seem to be an issue.

As for the reported current, I managed to get an 8 minute ride with average current of 3.1 amps, which only took about 6 minutes of charging at 3.1 amps to return the battery back to it's original voltage (actually original + about 1.0 volts, which the pack will drop in about 24 to 48 hours).

Edited July 6, 2023 by rcgldr

[meepmeepmayer]

Good info about the V5F BMS can be found here:

[v8nice]

Oui cela confirme bien qu'une partie des véhicules en mouvement n'ont pas d'équilibre comme beaucoup l'avait remarqué.sachant que v5,v10,v8 on ete fabriqué entre 2016 et 2018 et que le v8f fabrique en 2020 a toujours le meme circuit,au moins toutes ces roues la n ont pas d equilibrage et v11 v12 je ne connais pas Yes, this confirms that some of the moving vehicles do not have balance as many had noticed. Knowing that v5, v10, v8 were manufactured between 2016 and 2018 and that the v8f manufactured in 2020 still has the  same circuit, at least all these wheels have no balancing and v11 v12 I don't know

Edited July 7, 2023 by v8nice

[meepmeepmayer]

40 minutes ago, v8nice said:

Oui cela confirme bien qu un partie des véhicules inmotion n ont pas d equilibrage comme beaucoup l avait remarqué.sachant que v5,v10,v8 on ete fabriquée entre 2016 et 2018 et que le v8f fabrique en 2020 a toujours le meme circuit,au moins toutes ces roues la n ont pas d equilibrage et v11 v12 je ne connais pas 

Please post in English here.

Google Translate:

Quote

Yes, this confirms that some of the inmotion vehicles do not have balancing as many had noticed. Knowing that v5, v10, v8 were manufactured between 2016 and 2018 and that the v8f manufactured in 2020 still has the same circuit, at least all these wheels have no balancing and v11 v12 I don't know

[v8nice]

20 minutes ago, meepmeepmayer said:

Veuillez poster en anglais ici.

Google Translate:

Sorry i forgot.

[meepmeepmayer]

55 minutes ago, v8nice said:

Sorry i forgot.

No problem! You can also make a post in French and English, if you like. Maybe you want to keep the original along with the translation, if you wrote the original in French, so French speakers have it easier. That's fine. Just some English translation should be somewhere, as this is the common language for this forum

[v8nice]

After 450km i disassemble another Time the v5f battery to balancing battery another time...

You can see little différence balancing next time and now.

It s prety similar .

No balancing in this shit!

[rcgldr]

On 6/4/2023 at 10:26 PM, mrelwood said:

Although it seems to tilt in the direction of V8F and earlier (V10F possibly included) perhaps not having cell group balancing

I still have my V8F, 1423 miles on it now. On April 10, 2023, Inmotion did an online calibration, and I did a 100% charge, charge voltage 84.0 volts, pack voltage 83.9 volts just after V8F shut off charging. On September 24, 2023, I did another 100% charge and got the same numbers, charge voltage 84.0 volts, pack voltage 83.9 volts. I did another 100% charge today, January 6, 2024, and there was a decrease: charge voltage 83.9 volts, pack voltage 83.6 volts. 

I'm using the stock charger which continues to output voltage after LED goes green and V8f shuts off charging, even though the charger current is extremely small, as this will keep my V8F communicating with EUC World, which I'm using to monitor pack voltage. On the prior 100% charges, pack voltage slowly declined to about 82.5 volts in 8 hours, at which point my V8F re-enabled charging, and the stock charger LED changed back to red, and it took between 15 to 20 minutes before pack reached 83.9 volts and the V8F shut off charging. 

If the 1K ohm resistors are used for balancing, that's a max of 0.0042 amp (4.2 milliamps), much less than a charger would output if pack voltage was at 84.0 volts or less. If there is some form of slow balancing, I don't know if I should leave the stock charger connected with my V8F communicating with EUC World, or if I should disconnect the charger and let the V8F fully turn off. 

I left the V8F connected to the stock charger for a few hours and let the voltage drop to 82.7 volts, did a short ride, and charged again, same results: charge voltage 83.9 volts, pack voltage 83.6 volts. I switched to to eWheels rapid charger. On a non-degraded pack, while at 84.1 | 84.2 volts, charge current slowly decreases to 0.30 amps, then the eWheels charger shuts off, going into standby, and my V8F fully turns off within a minute. I tried this today,and the V8F shut off charging while the eWheels charger was at around 0.37 amps, causing an instant drop to .01 amps or less, and the charger shut off charging, followed by the V8F fully turning off within a minute, so it's clear the V8F is shutting off the charging, due to one or more cell pairs reaching max voltage. The numbers seen on EUC World were the same as before 83.9 volts with charger on, dropping to 83.6 volts after V8F shut off charging, and 83.5 volts just before V8F disconnected from EUC World.

I'll let it set at 100% for a few hours or maybe a day to see if anything changes. 

A second issue is my V8F doesn't wake up like it did before, turning on the blue battery leds and beeping. When new, it woke up within a few seconds. In November 2022, 18 to 20 seconds. Now it's 8 to 15 minutes. I don't know if this is relate to balancing. My next wheel will be a KingSong, probably an 18L (not 18XL) V2 (mabye NA dealers will get some in March, other dealers have it now).

Edited January 6 by rcgldr