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nickysneids

84.2v Rapid Charger Issues/Question

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Has anyone else has trouble getting the rapid charger from e-wheels to charge to 80 or 90% rather than 100%?

My darkness bot (73%) and gotway (80%) app both say my MCM5 is under 90% charge, but when I attempt to charge my wheel with the rapid charger it won’t charge unless I have it set to 100% full charge.

Is my wheel battery unbalanced, is my charger broken, or are both of the apps just too inaccurate to trust?

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37 minutes ago, nickysneids said:

Has anyone else has trouble getting the rapid charger from e-wheels to charge to 80 or 90% rather than 100%?

My darkness bot (73%) and gotway (80%) app both say my MCM5 is under 90% charge, but when I attempt to charge my wheel with the rapid charger it won’t charge unless I have it set to 100% full charge.

Is my wheel battery unbalanced, is my charger broken, or are both of the apps just too inaccurate to trust?

Set for 100% charging charges to ~84V? 

80 and 90% charging is not working at all?

With the normal stockcharger everthing charges fine to ~84V?

Best to get in contact with ewheels!

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That's how my charger behaved as well with my MSX.  It didn't bother me because I rarely needed a full charge and liked to go easy on the batteries.  In fact I normally set the charger to 90% which gave me 80% on the batteries.  

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1 hour ago, Chriull said:

Set for 100% charging charges to ~84V? 

80 and 90% charging is not working at all?

With the normal stockcharger everthing charges fine to ~84V?

Best to get in contact with ewheels!

I haven’t measured the voltage of a full charge to 100%, that’s just the voltage for the rapid charger.

The stock charger charges to 100% no problem and so does the rapid charger, the issue occurs when trying to only charge to 80/90% with the rapid charger.

You think I should contact eWheels?

1 hour ago, solocoyote said:

That's how my charger behaved as well with my MSX.  It didn't bother me because I rarely needed a full charge and liked to go easy on the batteries.  In fact I normally set the charger to 90% which gave me 80% on the batteries.  

I don’t think we’re having the same issue then. I’m ‘not’ able to charge to 80/90 option but I ‘can’ charge to 100.

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1 hour ago, nickysneids said:

haven’t measured the voltage of a full charge to 100%, that’s just the voltage for the rapid charger.

You don't need to measure - the app tells you. 100% charge shown is a very wide range and does not really mean too much. The shown voltage is the "real" value!

1 hour ago, nickysneids said:

The stock charger charges to 100% no problem and so does the rapid charger, the issue occurs when trying to only charge to 80/90% with the rapid charger.

You think I should contact eWheels?

Yes. Seems to be a prob with the charger.

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Posted (edited)

I think all charger have this issue!

I have not the eWheels Charger, but I think I have the same charger from 1radwerkstatt.de. 

I'm also not happy with the results in 80 and 90% charging. 

The charger is not only badly programmed, but also technically not able to reach a real 90%/82V battery voltage at 3-5 A charging rate setting, because the cut-off at 90% (82 volts) is the not the real battery voltage. 

One could adjust the voltage cut-off, but this could only lead to a real 90%/82V at the 1 to 3 amp setting. The 4 and 5 amp setting will not lead to a real battery charge of 90%/82V even if the cut-off voltage is increased to 84V (charger displays).

I think 85%/81V is the highest real battery voltage that can reached with 5A charging rate, because the voltage drop is around 3 volt after charger cut-off. 

The 80% (80V) setting could certainly be achieved by separately adjusting the cut-off voltage in all 5 amp levels.

Here are the results with the 90% setting. 

20190803_114441.jpg

SmartSelect_20190818-090734_Sheets.jpg

Edited by buell47

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28 minutes ago, buell47 said:

I think all charger have this issue!

@nickysneids has a different issue - his is just not working at all at the 80/90% setting.

Quote

I have not the eWheels Charger, but I think I have the same charger from 1radwerkstatt.de. 

I'm also not happy with the results in 80 and 90% charging. 

The charger is not only badly programmed, but also technically not able to reach a real 90%/82V battery voltage at 3-5 A charging rate setting, because the cut-off at 90% (82 volts) is the not the real battery voltage. 

The way to reach 85% "quickly" is just to use the constant current phase for charging up to the full voltage (84V).

Depending on the charging current the voltage settles afterwards - the more current used for charging, the more the voltage will settle (less charge accomplished, but shorter charging time).

The correlation between voltage and charge % is only true if one lets the battery rest/settle for ~15, better 30 minutes! The charge % shown in the app are just calculated from the reported voltage values. This charge % shown are just the percentage between some maximum voltage and the minimal used cell voltage - they do _not_ really show the state of charge of the liion. Especiall the 100% range is far to wide - imo the manufacturers try to "hide" battery degradation and measurement accuracy. So they don't get too much "my wheel does not charge to 100%" complaints...

Quote

One could adjust the voltage cut-off, but this could only lead to a real 90%/82V at the 1 to 3 amp setting. The 4 and 5 amp setting will not lead to a real battery charge of 90%/82V even if the cut-off voltage is increased to 84V (charger displays).

From https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries:

 

Charge V/cell

Capacity at
cut-off voltage*

Charge time

Capacity with full saturation

3.80

3.90

4.00

4.10

4.20

~40%

~60%

~70%

~80%

~85%

120 min

135 min

150 min

165 min

180 min

~65%

~75%

~80%

~90%

100%

Table 2: Typical charge characteristics of lithium-ion. Adding full saturation at the set voltage boosts the capacity by about 10 percent but adds stress due to high voltage.

* Readings may vary

Quote

...

Here are the results with the 90% setting. 

...

SmartSelect_20190818-090734_Sheets.jpg

V (charger cut-off) is the voltage shown at the charger just before cutting of? And V(app) the same from the app?

V after cut off is taken after which settlement time?

Ps.: Measurements of these voltages tend to be easily off:

 

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Posted (edited)
33 minutes ago, Chriull said:

V (charger cut-off) is the voltage shown at the charger just before cutting of? And V(app) the same from the app?

Yes, that's right 

 

33 minutes ago, Chriull said:

V after cut off is taken after which settlement time?

Just 1 minute after cut-off (I know about the rest time, but had less time to wait after the tests, because I tested all setting 3 times in just few hours ...riding below 80v...charging....riding below 80v...charging.... and so on :efefc8626c:

If I remember correctly, the voltage drops additional 0,3 volts after around 30 minutes. 

 

33 minutes ago, Chriull said:

The way to reach 85% "quickly" is just to use the constant current phase for charging up to the full voltage (84V).

Yes, that was my wish at 1radwerkstatt, but he said, he can't program this. 

 

33 minutes ago, Chriull said:

Especiall the 100% range is far to wide - imo the manufacturers try to "hide" battery degradation and measurement accuracy. So they don't get too much "my wheel does not charge to 100%" complaints...

Yes, I know, that's why I just use the displayed voltage, not the % 

Edited by buell47

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1 hour ago, buell47 said:

I think 85%/81V is the highest real battery voltage that can reached with 5A charging rate, because the voltage drop is around 3 volt after charger cut-off. 

Looks like normal to me. 5A current can only be achieved with a large enough voltage difference between the battery (while not charging) and the charger. Or in other words, current can be used as parameter to set the target charge percentage.

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Posted (edited)

Of course, looks also normal to me. :efee612b4b:

But if someone offered a charger with these funktions, then it should work as described, because we have payed for these funktion. I don't need a useless funktion and a standard 5A fast charger is much cheaper. The advertised function is not realizable with this charger due to hard- or software. 

Even with 1A you can only reach 81V and who buys a 5A quick charger if you have to charge with less ampere than with the original 1.5A charger? 

Example for the KS-16X:

If one come home late in the evening with an empty battery and want to drive again in the morning with 90% / 82V battery, then one need to charge a 1600WH battery with 5A, otherwise the time is not sufficient to reach 90% / 82V, but who wants to care for their battery, if that means that one start with 79 volts? 

79 volts are far away from 90%! It's rather 75% instead! 

100% Battery = 84 V

90% = 81,9 V

80% = 79,8 V

75% = 78,75 V

70% = 77,7 V

.....

0% = 63 V (20 cells x 3,15 V = 63 V)

If we charge with 90% and 1A to reach at least 81 V (approx. 85% capacity), then we need 2 days! :angry:

 

Edited by buell47

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So I’ve read a lot of the comments in this thread I’ve gathered two things:

1. I should be using the voltage readout in my app to have a more accurate battery charge.

2. I should probably contact ewheels and explain my issue to them because what’s happening to my charger seems pretty weird?

I guess all of this has made me wonder what the difference between battery voltage and percent charge is? Why is one more accurate? What is the difference between the percent charge value and voltage value?

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Posted (edited)
5 hours ago, Chriull said:

@nickysneids has a different issue - his is just not working at all at the 80/90% setting.

Don't agree, this is exactly the same problem what @nickysneidsdescribed

I don't have any issues with 100% setting. 

 

55 minutes ago, nickysneids said:

I should be using the voltage readout in my app to have a more accurate battery charge.

Yes...see below 

5 hours ago, Chriull said:

the 100% range is far to wide - imo the manufacturers try to "hide" battery degradation and measurement accuracy. So they don't get too much "my wheel does not charge to 100%" complaints...

 

My Inmotion V8 i. e. displayed 100% Battery after I ride already 5 km. If the voltage is over 82,5 volt, 100 % is showing. But this is wrong, because 84v is full 100%. Empty (0%) depends on model and type, sometimes 3,4v per cell is empty (tilt back starts), sometimes 3 v per cell is empty. This is the reason, why the battery % reading is different between different models. 

This example should theoretically be correct for the 16X, because tilt back (empty battery) starts at 3,15 v per cell (63 volt battery in App) :

100% Battery = 84 V (is the same on all 84 volt EUCs) 

90% = 81,9 V

80% = 79,8 V

75% = 78,75 V

70% = 77,7 V

.....

0% = 63 V (20 cells x 3,15 V = 63 V)

Theoretically!!! 

But no matter how the manufacturer has programmed the battery % display in relation to the battery voltage, this does not change the fact that in our cases 90% battery capacity does not mean 78.5 - 81 V, rather 82V is almost or exactly 90%!

Edited by buell47

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2 hours ago, buell47 said:

If we charge with 90% and 1A to reach at least 81 V (approx. 85% capacity), then we need 2 days! :angry:

I didn't calculate it but it makes sense. I needed to charge for 11 hours to get a full charge using the 1.5A charger, with a battery that I presume was at 30% (shipping charge). 1.5A is 50% more than 1A and I didn't have to charge from 0.

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I didn't calculate either, but one thing is clear, i. e. a nearly empty 1600 Wh battery is not charged to 90% by about 8 am when starting at 10 pm with 1A. This is one of the reasons why you buy a quick charger. 

If 2 days is also exaggerated, even 12 hours is too long. 

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Posted (edited)
20 hours ago, buell47 said:

I don't need a useless funktion and a standard 5A fast charger is much cheaper. The advertised function is not realizable with this charger due to hard- or software. 

Even with 1A you can only reach 81V and who buys a 5A quick charger if you have to charge with less ampere than with the original 1.5A charger? 

OK, it seems that the advertised functionality is there, but one needs to change the voltage-to-percentage mapping depending on the charge current (as to be expected). Annoyingly (but expectedly) any chosen setting is only valid for one charge current. This mapping also depends on the battery capacity, so the user needs to change it with all likelihood anyway from the factory setting.

Edited by Mono

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4 hours ago, buell47 said:

I didn't calculate either, but one thing is clear, i. e. a nearly empty 1600 Wh battery is not charged to 90% by about 8 am when starting at 10 pm with 1A. This is one of the reasons why you buy a quick charger. 

If 2 days is also exaggerated, even 12 hours is too long. 

Quick maths learned me that it would take 12.3h to charge the KS16X battery from completely empty to completely full, if the charger would output 1.5A all the time. Since we know it doesn't do this after the battery reaches a certain % of charge, it will take a lot more time.

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So I just did a full charge up to 100% on my MCM5 with my rapid charger and my app read out was 82 volts and 96% battery. At this time the charge was green and had stopped charging my wheel. This doesn't seem right, I'm going to test out if I can get to 84v with the stock charger tonight.

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11 hours ago, nickysneids said:

At this time the charge was green and had stopped charging my wheel.

What voltage and current was displayed on the charger?

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12 hours ago, Mono said:

What voltage and current was displayed on the charger?

I believe the voltage zeros out and the current fluctuates between 0.00 - 0.15 but I'm not certain.

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2 minutes ago, nickysneids said:

I believe the voltage zeros out and the current fluctuates between 0.00 - 0.15 but I'm not certain.

The simplest explanation why a charger does not charge to 100% is that it delivers a lower voltage than it should. I have seen this quite often with the cheap standard chargers. I don't know what the chance is that the displayed voltage of this more expensive charger is not accurate.

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Posted (edited)

Basic questions as everyone is "focused" on voltage :

1. Did ANYONE EVER SEE 84V after a charge in their app? (Or even better meassured it on batteries when in open loop) 

- Regardless if checked 5seconds or 5 hours after pulling the charge plug.

- Regardless of charger type and charge time

 

2. If not, what is the max you have seen?

 

A. I will start, 82.9V on my Gotway tesla after 4*8hour charging to balance the batteries with original charger (1.5A). Checked in app, directly after pulling charge plug. (3500km on batteries)

Edited by Boogieman

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1 hour ago, Boogieman said:

Did ANYONE EVER SEE 84V after a charge in their app? (Or even better meassured it on batteries when in open loop) 

On an InMotion V8, I recorded the values either from the app or from the charge doctor (I don't know which one I recorded): a final charge value of 84.1V in the beginning which was dropping to 83.9V after 50-or-so cycles of usage.

Given that on the V8 there is a diode between charger and battery, I think that the battery voltage is ~0.6V lower than the charger voltage, that is, the above values must come from the charge doctor.

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Yes, after a full charge until green led comes on I have 84,x V (charger disconnected) 

Mileage around 1400 km since April 2019 

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I've got two (2) of the 84V fast chargers from eWheels and both of them fail to charge the battery to 100% anymore.  Most of the time, it's randomly charging anywhere between 60 - 80%.  They worked great for the first 18 months (I got one for my Tesla and one for my MSuper V3s+).  The reason I know it's the charger and not the battery packs on my wheels is that when I use the original Gotway 84v charger that came with each wheel, both wheels charge to 100%.  Not sure what I might have done to the chargers to cause them to no longer charge properly.  I do keep the chargers plugged into the wall most of the time, even when they're not actively charging a wheel, so that may have contributed to the problem.  

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So I tested charging my wheel up with the original charger last night and found that even with the original charger I was only able to charge up 82.80v, 96%.

Does this mean that my battery packs have essentially degraded to not being able to hold 100%/84v charge?

This doesn't really solve my original problem of not being able to utilize the 80% or 90% charge function on the rapid charge but it does make me wonder about the integrity of my battery packs.

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