Nikola 100v minimum voltage

[Patrick Robert]

As the happy owner of a brand new Nikola 100v 1800Wh, I was wondering about how to use that nice voltage meter on the side.

I have another 100v wheel, the Sherman. Its voltage goes from 100.8v (100%) down to 75.6v (0%), according to the manual and Marty Backe's videos. There's no mention of minimum (or tiltback) voltage in the manual for the Nik.

So far, as reported by EUC World, the values look similar on both wheels. Can anyone confirm (or update) the 0% voltage on the Nik?

[AtlasP]

Somewhere along the way I heard someone say that they consider it such that they have ~20v to play with on the 100v wheels, which would be from 100v down to about 80v. What I don't know if that was considering 80v to be the actual bottom, or just that they feel safe riding down to about 80v (as the equiv of like 20% battery left or something like that). Taken in combination with the other data points you've cited, maybe 75v is the bottom bottom but 80v is a good safe stopping point?

Just repeating something I've heard, so don't take this as gospel and hopefully someone else can chime in with a more definitive answer to OP's question.

Edited January 8, 2021 by AtlasP

[meepmeepmayer]

Also no definitive answer incoming:

Just check the voltmeter on the side of the wheel.

Likely it's either 3.3V per cell or 3.15V per cell, giving (times 24) 79.2V or 75.6V (like the Sherman) as 0% voltage.

Gotways used to use 3.3V but I don't know if that's still the case with their newer wheels. I would guess it is.

-

If you want, give a combination of

• voltage, as seen on the voltmeter on the side of the wheel or in an app
• charge percentage, as given by an app (if it's EUC World, make sure it's the old/classic/simple algorithm and not the newer custom algorithm that computes the percentage)

for any given charge state of your wheel (e.g. 75% and whatever associated voltage it displays). Then we can do the math what 0% should be (it's linear between 100% = 24* probably 4.1125V = 98.7V and whatever the 0% voltage is).

Edited January 5, 2021 by meepmeepmayer

[Patrick Robert]

Thx guys. Just got the Nik, forgot how much there is to learn about a new model of EUC. And brand: it's my first Gotway. 

 

On 1/5/2021 at 6:35 PM, AtlasP said:

I heard someone say that they consider it such that they have ~20v to play with on the 100v wheels

That would indicate 3.3v per cell, so 79.2v per pack being the 0%. I've read other threads that mention 3.3v as the min for Gotways.

 

On 1/5/2021 at 6:43 PM, meepmeepmayer said:

Just check the voltmeter on the side of the wheel.

I know, great feature. Still trying to find the battery indicator though, which I assume is part of the LED circle but somehow it's still elusive to me. The voltage level is better anyway (learned to interpret it with the Sherman, didn't think I would need to but glad I did), but only if you know what the 0% voltage is. Then yes, it's simple math to see where the current value is between the max and the min.

Went out today and ended a 16km ride at 96.5v (according to the wheel). EUC World reported 96.1v and... 95% battery? That didn't look right. I did set the wheel as a 100v model in EUC World, not sure if there's some other related setting. I know the wheel has a 24s4p configuration (with 21700s), so each cell's maximum is 4.2v, that seems certain. I'll take a few data points and try with the Gotway app, hoping that its percentage calculation is more accurate. I'll check with a 79.2v minimum and see if readings fit that.

[meepmeepmayer]

11 hours ago, Patrick Robert said:

Went out today and ended a 16km ride at 96.5v (according to the wheel). EUC World reported 96.1v and... 95% battery? That didn't look right.

Yea that makes no sense.

11 hours ago, Patrick Robert said:

I did set the wheel as a 100v model in EUC World, not sure if there's some other related setting.

Make sure the battery percentage calculation algorithm is the linear (old) one. EUC World offers two options, and I think the other might be the default.

Or just use the Gotway app and see what percentage (and voltage while you're at it) it shows.

Assume 4.1125V per cell, x24 = 98.7V is 100%.

Edited January 7, 2021 by meepmeepmayer

[mike_bike_kite]

On 1/5/2021 at 11:10 PM, Patrick Robert said:

I was wondering about how to use that nice voltage meter on the side.

To get a (rough) battery percentage from the volts reading just subtract 80 then multiply by 5. So if it says 88v subtract 80 giving 8 then multiply by 5 giving 40. Meaning 40%. This obviously only works on the 100v Nicola.

[Patrick Robert]

2 hours ago, mike_bike_kite said:

subtract 80 then multiply by 5

Nice! That fits with a minimum cell voltage of 3.3v, and 79.2v per pack. So the minimum voltage IS 79.2v.

I was using a more precise formula for the Sherman (which uses 3.15v / 75.6v), and memorized a table of approximate values (100, 98, 95, 93, 90, 88, 85, 83, 80, 78, and 76).

But that would be easy enough for it too: (V - 75) * 4. Or put another way, each voltage unit equals 5% for the Nikola, 4% for the Sherman. Couldn't be simpler.

Curious to do a full range test, and reach the tiltback voltage. If the Nikola operates like the Sherman, which engages the limp-home-mode at roughly 10%, it should start beeping and tilting me back at 82v then. That depends on the firmware I guess, not sure why Gotway uses 3.3v as the minimum instead of 3.15v, both types of batteries (the Sherman's NCR1850GA and the Nik's LG M50T) have the same operational range, from 4.2v down to 2.5v which is the absolute zero for the cells. Perhaps the 24s10p vs 24s4p has something to do with that.

Many thanks, that's exactly what I wanted to know!!!

Edited January 8, 2021 by Patrick Robert

[Patrick Robert]

10 hours ago, meepmeepmayer said:

Or just use the Gotway app and see what percentage (and voltage while you're at it) it shows

Today at the end of my ride the wheel was showing 97.0v. And the apps said:
* EUC World: 96.5v and 95%
* WheelLog: 96.5v and 87%
* Gotway App: 90% (wasn't showing the voltage, but it must have had access to the same 96.5v value through Bluetooth as the other apps)

Not sure why all the variations, as @mike_bike_kite just showed, it's a very simple calculation. WheelLog's algorithm seems closest.
With a more precise calculation, and with a minimum of 79.2v, we get 80,1% for 96.5v.
[(96.5 - 79.2) / 21.6 = 80.1]

[Murdomeek]

i have nikola plus 100v

It cuts off at 3.3v

 

at ~79v, the whole thing just tilts wayyy back so you're physically incapable of riding it.  no way you'd be able to get it to 76v

[mike_bike_kite]

6 hours ago, Patrick Robert said:

Not sure why all the variations, as @mike_bike_kite just showed, it's a very simple calculation. 

Mine was a simple calculation you can do in your head as you're riding along but it's an approximation because batteries don't drop voltage at a constant rate so there's room for leeway when showing the battery percentage left. The voltmeter on the side is useful but it would of been so much better if Gotway/Begode went the extra mile and showed the actual battery percentage.

[Patrick Robert]

8 hours ago, Murdomeek said:

at ~79v, the whole thing just tilts wayyy back so you're physically incapable of riding it

Thanks for confirming it!
 

5 hours ago, mike_bike_kite said:

The voltmeter on the side is useful but it would of been so much better if Gotway/Begode went the extra mile and showed the actual battery percentage.

Now we know why the Veteran people left Gotway: "we'll make a wheel with BOTH a battery percentage indicator AND voltage"! 😁

Agreed. In theory this could actually be done with a firmware update, could even be a setting in the Gotway app: show percentage or voltage on the side display.

By the way, is there a way to update the firmware through the app or EUC World? Haven't seen anything related to that. I don't even see the firmware version in EUC World, strange. Not that I have a problem I'm hoping to fix through a firmware update, but I'm curious.

[WasDevNull]

2 minutes ago, Patrick Robert said:

Thanks for confirming it!
 

Now we know why the Veteran people left Gotway: "we'll make a wheel with BOTH a battery percentage indicator AND voltage"! 😁

Agreed. In theory this could actually be done with a firmware update, could even be a setting in the Gotway app: show percentage or voltage on the side display.

By the way, is there a way to update the firmware through the app or EUC World? Haven't seen anything related to that. I don't even see the firmware version in EUC World, strange. Not that I have a problem I'm hoping to fix through a firmware update, but I'm curious.

Isn't % just an estimate?  I much prefer voltage as it is.

[Patrick Robert]

23 minutes ago, WasDevNull said:

Isn't % just an estimate?  I much prefer voltage as it is.

Ideally each rider would be able to choose his/her own preference. With my Sherman, I used the distance indicator (seriously). Once I knew what the total range was (an estimate too but pretty reliable nonetheless), I went with the ride distance on the display, which I always reset to 0 when leaving. I knew that 120 km was the range, so if I was at 80 km I knew I was good for another 40. Bottom line that's what I need to know.

The voltage is fine, once you know how to convert it to percentage. I try to never go below 20%, so at 60% I know it's time to turn back.
On my V10F (my first wheel), the battery indicator was simple and great. At 3 of the 5 bars remaining, it was time to head back. Simple.

Last night I was watching an old video of Marty Backe unpacking his Nikola 84v, and his comment on the display was priceless: "I use percentage, not voltage. So this is useless to me." (or something to that effect). Perhaps his view has changed over time though.

Edited January 8, 2021 by Patrick Robert

[mike_bike_kite]

21 minutes ago, Patrick Robert said:

Now we know why the Veteran people left Gotway: "we'll make a wheel with BOTH a battery percentage indicator AND voltage"! 😁

Agreed. In theory this could actually be done with a firmware update, could even be a setting in the Gotway app: show percentage or voltage on the side display.

You can't update the firmware on Gotways and, even if you could, I'm fairly certain that GW uses an off the shelf h/w module to report the voltage so that won't happen. It would be a nice upgrade if GW gave the option to see voltage, percentage or approximate distance left or distance travelled. They could be shown in different colours to avoid confusion.

18 minutes ago, WasDevNull said:

Isn't % just an estimate?  I much prefer voltage as it is.

Percentage might be an estimate but voltage alone means nothing unless you can somehow relate it to battery percentage left. 

[Patrick Robert]

6 minutes ago, mike_bike_kite said:

Percentage might be an estimate but voltage alone means nothing unless you can somehow relate it to battery percentage left. 

Exactly. Voltage itself will vary a bit whether you are riding or stopped, it's quantum physics after all 😉

Similarly, in a car I prefer to know the percentage of fuel in the tank rather than the absolute value of liters left (and calculate it in my head from the tank capacity).
And most newer cars can display an estimate of range remaining.

 

12 minutes ago, mike_bike_kite said:

You can't update the firmware on Gotways

Ah! Now I understand why the Veteran people didn't build the Sherman with an easy way to update the firmware. It's fine, I value performance and safety over ease-of-use.

Such a fascinating scene, the EUC ecosystem.

[Seba]

12 hours ago, Patrick Robert said:

Today at the end of my ride the wheel was showing 97.0v. And the apps said:
* EUC World: 96.5v and 95%
* WheelLog: 96.5v and 87%
* Gotway App: 90%

In short - all three apps are wrong, and all three apps are right at the same moment. I'll be repeating like mantra - there is no such thing like reliable battery level indication in Gotway/Begode wheels. Battery level can only be determined by constantly measuring energy flowing in and out of the battery. Even then resulting value will contain some error.

What we see as a battery level is just a rough approximation derived from battery level. And the algorithm used to make this approximation differs from app to app. While I can't speak for other apps, EUC World may use two builtin algorithms and third, based on custom voltage thresholds defined by the user. By default, EUC World uses own algorithm ("Optimized") that tries to display battery level as a percent of available range in relation to full battery. Of course, you have to account for changes in your riding style. Second one ("Standard") is more closer to the standard, Gotway/Begode app algorithm. What is important, EUC World also takes into account that voltage measurement done by the mainboard may be off as much as 1-2 V from real battery voltage. Some wheels are equipped with reverse diode as a protection, and this diode will lower maximum battery voltage by about 0.5 V. Finally, EUC World takes into account LiIon discharge characteristic that is not linear. Also, as voltage drops, current rises. This causes battery discharge rate to increase with battery level decrease. Well, this is much more complicated as one would think.

To make long story short - don't give the battery level indication too much attention. Get familiar with your wheel and use battery voltage to estimate how much juice you have at the moment.

[meepmeepmayer]

12 hours ago, Patrick Robert said:

Today at the end of my ride the wheel was showing 97.0v. And the apps said:
* EUC World: 96.5v and 95%
* WheelLog: 96.5v and 87%
* Gotway App: 90% (wasn't showing the voltage, but it must have had access to the same 96.5v value through Bluetooth as the other apps)

Not sure why all the variations, as @mike_bike_kite just showed, it's a very simple calculation. WheelLog's algorithm seems closest.
With a more precise calculation, and with a minimum of 79.2v, we get 80,1% for 96.5v.
[(96.5 - 79.2) / 21.6 = 80.1]

The bolded is the one to go.

• EUC World apparently uses some other algorithm.
• Wheellog with the simple algo is exactly right: (96.5 - 24*3.3)/(24*4.1125 - 24*3.3) = 89% (this is as exact as the voltage reading gets).
• Gotway app only does it in 10% steps as far as I know, unless they have a newer one now. So that gives you the 90%.

Everything is as expected. Sherman can go down to 3.15V with its 10p (!) configuration, the Nikola is 4p, and Gotway always used 3.3V anyways (as far as I know).

[meepmeepmayer]

13 hours ago, Patrick Robert said:

Curious to do a full range test, and reach the tiltback voltage.

Gotways start low-battery-beeping at 15% (linear alorithm) which is 3.42V / 82.1V. With the voltage drop from acceleration, 30% at stand still = 15% on acceleration = "I can only limp home with beeps now". You still have some km left, but the ridable speed goes down quite fast.

So Gotways are empty at 30% (Wheellog) as far as normal riding is concerned. Simple as that

Tiltback starts at 0%.

(And these battery % are meaningless as actual battery charge, but they are precise and reliable numbers because they are just the voltage in disguise.)

Edited January 8, 2021 by meepmeepmayer

[Patrick Robert]

2 hours ago, Seba said:

In short - all three apps are wrong, and all three apps are right at the same moment.

That's what I said, we're in the realm of quantum physics! Shrödinger's Battery Level Theorem 🤣

While we're on the topic of EUC World, something puzzles me. In the General Settings, the first battery option is "Battery level averaging", checked off by default. My 96.5v / 95% display was with it checked off.
If I check it (with the Nikola turned on), the other options don't enable, they stay blacked out. This is different than with my Sherman where they would be enabled by checking the first option, allowing to choose a different algorithm (as well as set the minimum voltage per cell i.e. 3.15v). @Seba do you know why that is?
Also, a selectable "clear theme" would be lovely. Nerds love dark themes (I know, I'm a developer), but I've always been different that way. Harder to see the grey on black display with my eyes, especially outside.

Today's ride gave me another data point (note that I'm starting to get used to the wheel and thus am going faster, temperature was about the same as yesterday: -10C with not much wind and a beautiful sunny day):
* Wheel reports 95.2v
* WheelLog: 94.9v and 79%
* Gotway App: 80%
* EUC World (without battery level averaging): 95.2v and 87%
* EUC World (with battery level averaging): 95.2v and 89%

Manual calculation from 95.2v: (95.2 - 79.2) * 21.6 = 74,1%. That's the number I'd like to see on the display or in an app. The voltage might fluctuate, that's fine, but like I said it's a simple calculation derived from this single value to get the percentage. I understand that an app needs to deal with a large assortment of different wheels though, each with different characteristics. If it was me, I'd recognize the wheel and use a built-in table with different factors for each.
 

2 hours ago, meepmeepmayer said:

they are just the voltage in disguise

Præcis! The percentage is just as reliable (or not) as the voltage, which is the "raw" value.

 

2 hours ago, meepmeepmayer said:

Gotway app only does it in 10% steps as far as I know, unless they have a newer one now. So that gives you the 90%.

I just installed the app this week, so I have the latest. The data from today's ride would support that (80%).
Again, consistent with the Sherman battery level indicator: 8 bars corresponding to the lower 80%, so one bar per 10%. Amazing. You can leave Gotway but not the Gotway mindset, apparantly! 🤣

[WasDevNull]

On 1/8/2021 at 9:49 AM, mike_bike_kite said:

You can't update the firmware on Gotways and, even if you could, I'm fairly certain that GW uses an off the shelf h/w module to report the voltage so that won't happen. It would be a nice upgrade if GW gave the option to see voltage, percentage or approximate distance left or distance travelled. They could be shown in different colours to avoid confusion.

Percentage might be an estimate but voltage alone means nothing unless you can somehow relate it to battery percentage left. 

Wrong. 

Edited January 10, 2021 by WasDevNull

[mike_bike_kite]

36 minutes ago, WasDevNull said:

Wrong. 

I think you need to elaborate what was wrong or are you saying everything was wrong?

[Seba]

On 1/8/2021 at 8:28 PM, Patrick Robert said:

If I check it (with the Nikola turned on), the other options don't enable, they stay blacked out. This is different than with my Sherman where they would be enabled by checking the first option, allowing to choose a different algorithm (as well as set the minimum voltage per cell i.e. 3.15v). @Seba do you know why that is?

If some battery options are disabled this means:

1. wheel is not connected, or
2. tour recording is active, or
3. data logging (CSV) is active.

On 1/8/2021 at 8:28 PM, Patrick Robert said:

Also, a selectable "clear theme" would be lovely. Nerds love dark themes (I know, I'm a developer), but I've always been different that way. Harder to see the grey on black display with my eyes, especially outside.

White ("day") theme is planned for release next after 2.4.

[Patrick Robert]

4 hours ago, Seba said:

If some battery options are disabled this means:

1. wheel is not connected, or
2. tour recording is active, or
3. data logging (CSV) is active.

There we go! I had setup EUC World to automatically record tours. As soon as I swiped over to the tour screen and stopped it, these options re-enabled themselves. Thx!
I will play with these settings this week to try to get a more accurate battery level reading.
 

4 hours ago, Seba said:

White ("day") theme is planned for release next after 2.4.

That's great, thanks again Seba!


One thing that I absolutely prefer about EUC World is that there's a companion client for Wear OS watches. Bought one for Google Maps on the road (and keeping the phone in my pocket), but EUC World's speed display on the watch was a nice surprise. If these two issues can be resolved, all the better!

One more thing: it's a good feeling to know it's maintained by a developer who believes in successive refinements. Top of my hat to you sir!

[mike_bike_kite]

On 1/10/2021 at 8:11 PM, mike_bike_kite said:

On 1/10/2021 at 7:29 PM, WasDevNull said:

Wrong. 

I think you need to elaborate what was wrong or are you saying everything was wrong?

You still haven't explained what was wrong with what I said or do you just need some time to build up a longer sentence?