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[PLEASE_DELETE]

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Edited March 17 by PLEASE_DELETE
New info

[mrelwood]

0.2V is nothing. The tolerance of the voltage reporting on wheels and the voltage when the green LED goes on is inaccurate, and can be off or drift off +-0.5V.

Or, since leaving the wheel to the charger got it up to the same 100.8V, it’s fair to assume that you successfully let the balancing do what it’s supposed to.

 Either way, no reason to worry!

[Chriull]

5 hours ago, /Dev/Null said:

I got my Nik+ earlier this year.  I've been charging to 100%, and then riding within 12 hours usually 10-20km, then the next 2-4 days I'll get it down to the 30-40%.  Then I leave it at that level & ride my inmotion V10 for a few days...same procedure...

Nice "strategy"! I assume you know that by riding in the 30%-40% range one has less safety margin. ... But your wheels are on the stronger side, and if one drives a bit more prudent safety margin should be fine...

3 hours ago, mrelwood said:

0.2V is nothing.

+1! Thats in the +/-0.1% range...

If one is interested if these are trends starting to show up, or just aging, temperature, humidity changes etc one could get someting like a BR867s - it has with 4 1/5 digits +/-(0.05%+2d) for the 500.00VDC range. So +/- 0.07V accuracy at 100V! And it's "just" ~150€ - always thought dmm's in this range are much more expensive...

3 hours ago, mrelwood said:

The tolerance of the voltage reporting on wheels and the voltage when the green LED goes on is inaccurate, and can be off or drift off +-0.5V.

Green light turns on once charging current gets below some threshold, as LiIon Cells should not be trickle charged. Batteryuniversity.com recommends 3% of C (Ah) as threshold.

[PLEASE_DELETE]

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Edited March 18 by PLEASE_DELETE

[Seba]

17 hours ago, /Dev/Null said:

So I'm going to ride the Nik+ tomorrow and now the charging light went off at 100.6v instead of 100.8......anyone have ideas?

As @mrelwood and  @Chriull wrote, absolutely nothing to worry about. Just a few degrees of temperature change may drift your charger output voltage, accuracy of your voltmeter or EUC mainboard. As this is a 24S wheel, 0.2 V translate into just 0.008V per cell - eight millivolts! It's like a grain of salt in the soup bowl. Just ride  

Edited July 12, 2020 by Seba

[Lefteris]

Well I didn't want to start a thread, but. 

I also bought it march 8th the Nikola Plus 1800Wh with 21700 cells, and July 11th was the 21st time I charged the wheel. 

I log everything down also use HS110 smartplug and keep log of W and switch it off after about 4h of charge. All my rides are auto saved in csv files. 

So, July 11 charged up to 97% with ~98,xx Volts. It usually takes from 35% to 100% in 3h and 45min that I find the charger silent and green. That time the charger was the same but the wheel wasn't charged at full. 

I contacted my dealer and he instructed me I do a series of tests, which I did, and the first was to deplete the wheel and do a full charge. Which I did yesterday. 

Again the wheel charged up to the same percent and same Voltage. GW app says the same, latest euc.world by @Seba says the same.

Next is to charge with another 100V charger when it's once again depleted, it's hard cause its a big batt 😅

If it fails, then there is the battery meter test which I'm not able to perform. 

Why does this happen to Nik+'s maybe it's a problematic batch? 

I don't feel safe riding it. 

Edit, the HS110 was giving out 308V if steady output to the wheel, but yesterday it gave 289V 😢

Edited July 25, 2020 by Lefteris

[Chriull]

1 hour ago, Lefteris said:

Edit, the HS110 was giving out 308V if steady output to the wheel, but yesterday it gave 289V 😢

W i'd assume, not V?! 

How does the logged power look like? At the end (once the green led turns on) power consumption should be quite low - just a bit above consumption of the charger without load.

1 hour ago, Lefteris said:

charged up to 97% with ~98,xx Volts

From were did you get the 97%. Somehow this does not really fit.

97% of 4.2V*24=100.8V would be only 97.8V!

Normally 100% are already shown for ~4.16V cell voltage - so overall battery voltage should be even lower.

Whats the output voltage of the charger?

You could test if and how much voltage drops once charging is finished.

"Fresh, orderly" li ion cells should have very low self discharge!

Also if the cells are imbalanced some balancing resistors are still active after unplugging the charger causing the overall voltage to drop until these cells are at 4.2V again.

Another simple test would be to charge both packs seperate - chances are high that only one is not behaving well. And differences can be found easier...

[Lefteris]

17 hours ago, Chriull said:

W i'd assume, not V

Yes sorry, i wrote that reply on my phone.

And :

That was 2 days ago.

And...:

Was July 11

And i want to note that i drove the wheel down to 27% about week ago, and suddenly it said i had 45% battery.. :-O

I really don't feel safe riding it.

[mrelwood]

 

3 minutes ago, Lefteris said:

And i want to note that i drove the wheel down to 27% about week ago, and suddenly it said i had 45% battery.. :-O

I really don't feel safe riding it.

The batteries recover soon after you stop riding, so depending on when exactly you took the values above, that may be perfectly normal.

 But not charging above 97.5V is an issue. If the charger output voltage is correct  (around 100.8V) and the charging stops abruptly wheel the charger LED turns green, a cell group is dying, and could be as low as 1.1V after charging. In which case it would no longer be recoverable.

 Did the power value in the smart plug drop immediately at the end of charge when the charger LED turned green? If it did, the battery BMS stopped the charging because some cell groups were going over 4.2V. Some cells being low enough to make a total voltage of only 97.5V could mean they are low enough to be done for.

 Either way, don’t do fast accelerations on the wheel until this is sorted. The battery may not have the power you’d expect.

[Seba]

38 minutes ago, Lefteris said:

Yes sorry, i wrote that reply on my phone.

And :

That was 2 days ago.

And...:

Was July 11

And i want to note that i drove the wheel down to 27% about week ago, and suddenly it said i had 45% battery.. :-O

I really don't feel safe riding it.

If you're looking at the percents of battery level, blame yourself for this  You're not only a beta tester, but also an EUC World Team member. While I don't urge you to be active during summer holiday , you should at least read discussions on our Slack group, especially when new release is prepared  As @Marty Backe said many times, optimized battery algorithm in Gotway was way too pesimistic and in last EUC World beta version it was changed to reflect battery level more accurately. This is why I was riding circles like a hamster to get Gotway battery discharge characteristics.

So please note - optimal battery level algorithm for Gotway will now much more accurately and reliably show remaining battery in relation to real battery capacity. It also accounts for some diodes that exists in charging circuit of many Gotways.

[Chriull]

3 hours ago, mrelwood said:

Did the power value in the smart plug drop immediately at the end of charge when the charger LED turned green? If it did, the battery BMS stopped the charging because some cell groups were going over 4.2V. Some cells being low enough to make a total voltage of only 97.5V could mean they are low enough to be done for.

 

22 hours ago, Lefteris said:

I log everything down also use HS110 smartplug and keep log of W and switch it off after about 4h of charge

So this could be nicely seen in these logs?

Or if one has droping battery voltage in the moment one unplugs the charger and/or slowly over the next day(s?).

20 hours ago, Chriull said:

Whats the output voltage of the charger?

You could test if and how much voltage drops once charging is finished.

...

Another simple test would be to charge both packs seperate - chances are high that only one is not behaving well. And differences can be found easier...

If you open the wheel to charge both packs independendly you can measure the battery voltage with the dmm and compare it to the reported voltage value from the wheel.

Charger no load voltage, fully charged battery voltage measured with dmm and wheel reported voltage should give some next clue.

Battery voltage can be measured nicely on the board at the legs of the two big capacitors.