eWheels Fast Charger issues?

[Ben Kim]

Hi, I was always using a 67.2 2A "slow" charger with my wheel, but it has been misplaced, causing me to use the fast charger.  It appears that I can only charge up to 65.6V using this charger (per Darknessbot) (yes, the dial is at 100%)

Using the 2A charger, it would report 66.7V which is by all intents and purposes, full.  

Are there any known issues with the eWheels charger to prevent the wheel from charging/balancing properly?

My guess is that the standard CC/CV slow chargers continue to trickle low amounts of current into the batteries (100mAh or less) even when the light is green which is suitable for balancing.  Could it be that, or a larger issue present?  This is for a KS18S.  Wheel performs perfectly otherwise.

[Rywokast]

it should actually go up past 67.2.. albeit not for long at all, to be fully charged.. mine does, works perfectly always has.. have you tried just leaving the charger plugged in for longer like you would with the normal one? i dont want to jinx it but another member has actually had a very similar problem with his 18xl where it wouldnt charge to full, he was also using a fast charger.... this was shortly before a cut out.. now it wasnt determined that this had anything to do with the cut out yet.. but i mean its an older wheel and how many charge cycles has the battery had? could just simply be losing capacity

https://forum.electricunicycle.org/topic/14442-kingsong-ks-18xl-only-charging-to-85-faulty-battery-pack/

https://forum.electricunicycle.org/topic/14383-my-ks18xl-cutout-on-me/

these are way more severe than yours.. yours just sounds to me like an older battery that is declining.. but do try this, try setting it to 1A and 100% and leave it plugged in two hours after the fan stops.. see what the voltage is then

Edited July 9, 2019 by Rywokast

[Ben Kim]

19 minutes ago, Rywokast said:

it should actually go up past 67.2.. albeit not for long at all, to be fully charged.. mine does, works perfectly always has.. have you tried just leaving the charger plugged in for longer like you would with the normal one? i dont want to jinx it but another member has actually had a very similar problem with his 18xl where it wouldnt charge to full, he was also using a fast charger.... this was shortly before a cut out.. now it wasnt determined that this had anything to do with the cut out yet.. but i mean its an older wheel and how many charge cycles has the battery had? could just simply be losing capacity

https://forum.electricunicycle.org/topic/14442-kingsong-ks-18xl-only-charging-to-85-faulty-battery-pack/

https://forum.electricunicycle.org/topic/14383-my-ks18xl-cutout-on-me/

these are way more severe than yours.. yours just sounds to me like an older battery that is declining.. but do try this, try setting it to 1A and 100% and leave it plugged in two hours after the fan stops.. see what the voltage is then

I doubt this is the case - it was purchased Feb of 2019, and the wheel has 410 miles on it; still under eWheels warranty.  Hardly what I'd consider aged; I haven't noticed any issues with the way the wheel functions, it tilts me back when I lean too hard, it alarms and tilts me back when I approach my 30 MPH limit. 

This started happening when I switched over to the eWheels charger instead of the 2A slow brick.  

Edited July 9, 2019 by Ben Kim

[Rywokast]

2 minutes ago, Ben Kim said:

I doubt this is the case - it was purchased Feb of 2019, and the wheel has 410 miles on it; still under eWheels warranty.  Hardly what I'd consider aged; I haven't noticed any issues with the way the wheel functions, it tilts me back when I lean too hard, it alarms and tilts me back when I approach my 30 MPH limit. 

This started happening when I switched over to the eWheels charger instead of the 2A slow brick.  

oh ok then definitely not that.. i was assuming it was an old unit since to be fair, the 18s is not a popular seller anymore.. but then still thats even weirder that the original charger could not get up to full voltage, thats no good, it should be no problem.. if the original charger could always not get up to full then that suggests a larger issue now that i know its a new battery, you should contact kingsong or your dealer about this issue and perhaps they could perform some diagnosis somehow.. i know its benign now but that doesnt mean it cant be a serious issue down the line...

[Ben Kim]

4 minutes ago, Rywokast said:

oh ok then definitely not that.. i was assuming it was an old unit since to be fair, the 18s is not a popular seller anymore.. but then still thats even weirder that the original charger could not get up to full voltage, thats no good, it should be no problem.. if the original charger could always not get up to full then that suggests a larger issue now that i know its a new battery, you should contact kingsong or your dealer about this issue and perhaps they could perform some diagnosis somehow.. i know its benign now but that doesnt mean it cant be a serious issue down the line...

You have it backwards   the 2A slow stock charger had no issues.  The 5A eWheels adjustable fast charger is the one giving me issues.

Edited July 9, 2019 by Ben Kim

[Rywokast]

4 minutes ago, Ben Kim said:

You have it backwards   the 2A slow stock charger had no issues.  The 5A eWheels adjustable fast charger is the one giving me issues.

well, not really "Using the 2A charger, it would report 66.7V which is by all intents and purposes, full." 66.7 is not full.. it should surpass momentarily 67.2.. all of my wheels are able to get up to 67 and 84V

Edited July 9, 2019 by Rywokast

[Ben Kim]

1 minute ago, Rywokast said:

well, not really "Using the 2A charger, it would report 66.7V which is by all intents and purposes, full." 66.7 is not full.. it should surpass momentarily 67.2.. all of my wheels are able to get up to 67 and 84V

Are you talking about inside the app, or on the charger's voltage reading?  Inside the app it always read 66V = 100%. It makes sense since there would be no brakes if the batteries were fully charged to 67.2 due to regenerative braking.  

[Rywokast]

1 minute ago, Ben Kim said:

Are you talking about inside the app, or on the charger's voltage reading?  Inside the app it always read 66V = 100%. It makes sense since there would be no brakes if the batteries were fully charged to 67.2 due to regenerative braking.  

charger.. im pretty sure in the app too though, but if im being honest i cant remember 100% i will have to screenshot it next time when i charge to 100%

[Ben Kim]

Just now, Rywokast said:

charger.. im pretty sure in the app too though, but if im being honest i cant remember 100% i will have to screenshot it next time when i charge to 100%

The stock charger doesn't even have a voltrage readout.  just a light that turns red or green depending on status.

[Rywokast]

Just now, Ben Kim said:

The stock charger doesn't even have a voltrage readout.  just a light that turns red or green depending on status.

i havent used a stock charger in forever lol... im gonna try it out right now and ill report back what it says in the app

[Ben Kim]

2 minutes ago, Rywokast said:

i havent used a stock charger in forever lol... im gonna try it out right now and ill report back what it says in the app

If it makes any difference, the eWheels charger read out 67.2V as it was tapering down the current to 0 before it shut itself down.  I can't even get a multimeter reading on the port due to the inline diode.

[Rywokast]

Just now, Ben Kim said:

If it makes any difference, the eWheels charger read out 67.2V as it was tapering down the current to 0 before it shut itself down.  I can't even get a multimeter reading on the port due to the inline diode.

oh ok, well this is getting more interesting lol.. again assuming, i was thinking that 65.6 was what was displayed on the fast charger... now something i would like to point out is say when charging at 5A with the fast charger well say for example its charging and displays 58.2... if i were to then switch the dial from 5A to 1A the voltage would drop, very noticeably like from 58.2 to something like 56.8... thats why i suggested that you switch it to 1A and try charging to 100% to see what you get because i think it lies when charging fast for some weird ass reason, same thing when i charge to 90%.. if i charge to 90% at 5A the app will show like 87%.. but if i charge to 90% on 1A then the app will show like 93% strange behavior but i suggest you try it.. im going to charge now and check the app

[Ben Kim]

4 minutes ago, Rywokast said:

oh ok, well this is getting more interesting lol.. again assuming, i was thinking that 65.6 was what was displayed on the fast charger... now something i would like to point out is say when charging at 5A with the fast charger well say for example its charging and displays 58.2... if i were to then switch the dial from 5A to 1A the voltage would drop, very noticeably like from 58.2 to something like 56.8... thats why i suggested that you switch it to 1A and try charging to 100% to see what you get because i think it lies when charging fast for some weird ass reason, same thing when i charge to 90%.. if i charge to 90% at 5A the app will show like 87%.. but if i charge to 90% on 1A then the app will show like 93% strange behavior but i suggest you try it.. im going to charge now and check the app

Yup, all of this i'm aware of.  For reference, I'm not even charging at 5A; I'm using 2A using the eWheels "fast" charger.

[Rywokast]

1 minute ago, Ben Kim said:

Yup, all of this i'm aware of.  For reference, I'm not even charging at 5A; I'm using 2A using the eWheels "fast" charger.

gotcha.. yea honestly the only reason why i bought my fast chargers is to be able to set the percentage.. its very rare i will actually use more than 3

[Rywokast]

66.92 after about 20 mins of green light.. ill try another wheel with the fast charger when i get home to see what it gets to

[Chriull]

5 hours ago, Ben Kim said:

Hi, I was always using a 67.2 2A "slow" charger with my wheel, but it has been misplaced, causing me to use the fast charger.  It appears that I can only charge up to 65.6V using this charger (per Darknessbot) (yes, the dial is at 100%)

Using the 2A charger, it would report 66.7V which is by all intents and purposes, full.  

Are there any known issues with the eWheels charger to prevent the wheel from charging/balancing properly?

My guess is that the standard CC/CV slow chargers continue to trickle low amounts of current into the batteries (100mAh or less) even when the light is green which is suitable for balancing.  Could it be that, or a larger issue present?  This is for a KS18S.  Wheel performs perfectly otherwise.

If you take a look at the charging graph at https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries, you'll see that with a 1 C charger it takes about an hour for the first stage (constant current =CC) and then about 2-3 hours for the second stage (saturation charge, constant voltage = CV). The second stage ends somewhere once the current reaches around ~100mA.

If one charges with less than 1C the first phase gets accordingly longer (0.5C ~2hours, 0.2C about 5 hours, etc)

The second phase stays about the same - maybe a bit longer for the faster chargers.

The more current is used while the CC phase, the higher the cell voltages are "pulled" up while charging (by internal resistance and the chemistry of the cells). So if the charger stops at the "80% voltage" the battery goes back to a lower voltage after charging the more current was used.

If one charges the battery with a fast charger, the battery gets pulled up a bit more and reaches by this the CV phase with a bit less charge than with a slower charger. So the CV (saturation) phase should take a bit longer.

Regarding voltages, charge % reported by the wheel and shown by some chargers: that's unfortionately everything a bit inaccurate. 1% of 67,2V is already 0.67V and accuracies way below this for voltage measurements are "hard" to reach/should not be expected for "cheap" chinese products. (Or generally not for anything but "professional" measurement equipment)

Charge % are additionally calculated in a way that there is a wide range for 100% shown. So it's best to stay with the voltage reported by the wheel! (Taken some time after the charge, so the voltage can settle to a value really correlating to the charge)

So to compare chargers one should charge the batteries the full cycle until the charger shuts down at this roughly ~100mA. So for and empty battery ~ 1/C hours plus 2 to 3 hours.

After this you can compare the voltage values reported by your wheel.

Unfortionately its not uncommon that some chargers are just a bit/way off.

PS.: How to get the C Value:

Your 67.2V wheel has 67.2V/4.2V (4.2V is max cell voltage) = 16 cells in series.

So one divides the Wh of the pack by this 16 cells in series and then divides it by 3.7 (nominal cell voltage). That gives the Ah of the paralleled cells we need.

Now this C value is charger current divided by this Ah.

For example if you have the 1508Wh KS18S it has 1508/16/3.7=25.5 Ah.

So C= 2A/25Ah=0.08 for the 2A charger. Meaning 1/0.08 + 2..3 h ~ 14-16h for a full charge.

Edited July 9, 2019 by Chriull

[Ben Kim]

8 hours ago, Chriull said:

If you take a look at the charging graph at https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries, you'll see that with a 1 C charger it takes about an hour for the first stage (constant current =CC) and then about 2-3 hours for the second stage (saturation charge, constant voltage = CV). The second stage ends somewhere once the current reaches around ~100mA.

If one charges with less than 1C the first phase gets accordingly longer (0.5C ~2hours, 0.2C about 5 hours, etc)

The second phase stays about the same - maybe a bit longer for the faster chargers.

The more current is used while the CC phase, the higher the cell voltages are "pulled" up while charging (by internal resistance and the chemistry of the cells). So if the charger stops at the "80% voltage" the battery goes back to a lower voltage after charging the more current was used.

If one charges the battery with a fast charger, the battery gets pulled up a bit more and reaches by this the CV phase with a bit less charge than with a slower charger. So the CV (saturation) phase should take a bit longer.

Regarding voltages, charge % reported by the wheel and shown by some chargers: that's unfortionately everything a bit inaccurate. 1% of 67,2V is already 0.67V and accuracies way below this for voltage measurements are "hard" to reach/should not be expected for "cheap" chinese products. (Or generally not for anything but "professional" measurement equipment)

Charge % are additionally calculated in a way that there is a wide range for 100% shown. So it's best to stay with the voltage reported by the wheel! (Taken some time after the charge, so the voltage can settle to a value really correlating to the charge)

So to compare chargers one should charge the batteries the full cycle until the charger shuts down at this roughly ~100mA. So for and empty battery ~ 1/C hours plus 2 to 3 hours.

After this you can compare the voltage values reported by your wheel.

Unfortionately its not uncommon that some chargers are just a bit/way off.

PS.: How to get the C Value:

Your 67.2V wheel has 67.2V/4.2V (4.2V is max cell voltage) = 16 cells in series.

So one divides the Wh of the pack by this 16 cells in series and then divides it by 3.7 (nominal cell voltage). That gives the Ah of the paralleled cells we need.

Now this C value is charger current divided by this Ah.

For example if you have the 1508Wh KS18S it has 1508/16/3.7=25.5 Ah.

So C= 2A/25Ah=0.08 for the 2A charger. Meaning 1/0.08 + 2..3 h ~ 14-16h for a full charge.

Fully understand the C value, the 1C value is equivalent to 1A to 1Ah (at nominal voltage), that's not the issue here; the issue is that the eWheels charger will not fully charge the wheel to a full voltage whereas no such issues with the 2A stock brick.

I have a charge doctor attached to the eWheels brick right now charging at 1A.  The start voltage was reported at 66.0V on both the charge doctor and eWheels charger, I'm monitoring it.  Currently showing 66.6V on the eWheels LCD and 66.2V on the Charge doctor.  I multimetered +1 and -3 on the charger and it is showing 67.2 - 67.3V. Can't do this on the wheel because it appears to have a diode in line to prevent such readings.  

[Chriull]

40 minutes ago, Ben Kim said:

I have a charge doctor attached to the eWheels brick right now charging at 1A.  The start voltage was reported at 66.0V on both the charge doctor and eWheels charger, I'm monitoring it.  Currently showing 66.6V on the eWheels LCD and 66.2V on the Charge doctor.  I multimetered +1 and -3 on the charger and it is showing 67.2 - 67.3V. Can't do this on the wheel because it appears to have a diode in line to prevent such readings.  

For the battery voltage you can take the reported values from the app. Or measure at the discharge side.

The values are unfortionately a "bit" inaccurate, as written above. You can also compare this to 

i personally would trust the readings of the charge doctor - @hobby16 calibrates the with an precission voltmeter. Although this calibration can drift over time. You can take a look at your multimeters datasheet and look what accuracy could be expected.

Once you know which voltage is right, most chargers voltage can be adjusted. It's quite often the case that charhers are (getting) misadjusted.

Don't remember if there was not lately the same description for the ewheels charger?

Or if its still under warranty and too much of maybe get a replacement?

 

40 minutes ago, Ben Kim said:

Fully understand the C value, the 1C value is equivalent to 1A to 1Ah (at nominal voltage), that's not the issue here

This was mainly for the explanation that with different currents if not fully charging ( cutoff, no full saturation phase) one has to reach different charge states.

[Rywokast]

ok sorry i didnt get a chance to do it last night didnt get home until late, again this is after about 20 mins green light on the charger.. it displayed 67.4 last time i saw.. and heres a screenie from the kingsong app and from wheellog.. this is what is should be like from my experience.. like i said before, over 67.2 should be for a real, full charge

 

[Ben Kim]

i charged the thing at 1A with charge doctor connected, it fully charged to my expected 66.7-66.8V range. It’s so odd why 2A causes problems. 

[Rywokast]

1 minute ago, Ben Kim said:

i charged the thing at 1A with charge doctor connected, it fully charged to my expected 66.7-66.8V range. It’s so odd why 2A causes problems. 

strange.. btw, i had it set to 3A, but it shouldnt matter much since it goes way down to like .5 when it gets close to 100% anyways.. i wonder why 2 is being weird

[Ben Kim]

i got another “dumb” charger that is rated for 1.5A (more like 1.2A per charge doctor) 

Using this charger, the battery is resting at 67.1V after removing charger. 

I’ll chalk it to a one-off issue with the eWheels charger and monitor at higher amp charging. 

[Rywokast]

4 hours ago, Ben Kim said:

i got another “dumb” charger that is rated for 1.5A (more like 1.2A per charge doctor) 

Using this charger, the battery is resting at 67.1V after removing charger. 

I’ll chalk it to a one-off issue with the eWheels charger and monitor at higher amp charging. 

thats much better.. yea thats weird it must be.. but i guess you can just use the regular charger now for charging to 100 and the fast charger otherwise

Edited July 13, 2019 by Rywokast

[esaj]

4 hours ago, Ben Kim said:

i got another “dumb” charger that is rated for 1.5A (more like 1.2A per charge doctor) 

Using this charger, the battery is resting at 67.1V after removing charger. 

I’ll chalk it to a one-off issue with the eWheels charger and monitor at higher amp charging. 

Sounds like the fast charger output voltage is too low. I adjusted a friends' fast charger (bought from Wheelgo, Jason McNeil's UK-company before he moved to US) a couple of years back because the output voltage had dropped to too low, it was around 66V or even a little bit below, don't remember exactly anymore.

It's normal for the battery voltage to drop a bit after removing the charger, to get "full" 67.2V after removing the charger, you have to wait until the charging current drops to near zero (which can take hours after the charger light already turns green) and all the cells have charged to full. Even the relatively small current required to run the electronics and keep the wheel upright at standstill (when it's own) can drop the voltage somewhat.

With KS's and other wheels having reverse protection for the batteries, you can't measure the battery voltage directly from the charge port (and Charge Doctor won't turn on when plugged to the wheel without the charger plugged to power outlet), what you see during the charging in CD or similar, or in the charger itself, if it has voltage display, is the charger output voltage, which is higher than the actual battery voltage as long as current is flowing (once they reach the same voltage, the current has dropped to 0).

Edited July 13, 2019 by esaj

[Rywokast]

if youre comfortable opening it up.. same deelio