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Draining the battery to Zero


SlowMo

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Posted

I never let my batteries go below 25% to lengthen the battery life and also due to my being afraid of having a face plant due to lack of remaining juice. Is there any body among our forum members that consumes their battery capacity to the max whenever they travel specially with Gotways? How does the EUC react in real experience?

Posted
17 minutes ago, SlowMo said:

I never let my batteries go below 25% to lengthen the battery life and also due to my being afraid of having a face plant due to lack of remaining juice. Is there any body among our forum members that consumes their battery capacity to the max whenever they travel specially with Gotways? How does the EUC react in real experience?

I am glad my earlier question in another thread caused you to start this topic :) 

i drained the battery a few times. But i have a kingsong, august 2015 version which didnt really let you drain the battery to zero. And what IS zero? Its not zero voltage anyway..so if the wheel says the battery is zero, iam sure its got some juice left.

on kingsing, the max speed would decrease, tilt backs would be more common, and the battery indicator woukd start flashing all the way, also there was a special beep pattern. At the end the pedals would be tilted back all the way making it impossible to ride. The only thing you could do at that point is roll the wheel but it would be beeping

Posted

I have drained the battery of my electric scooter once. There was no warning beep. It just shut off the motor even though the battery was still at around 20%. Yesterday, I was worried about my son's Kahuna wheel when we were on the way back. I was following him and was keeping an eye on the led indicator if it would turn to rapid blinking but it never happened. I was not paying attention to the IPS Zero which was far ahead ouf us and only realized that it was drained to 24% when we finally stopped. My daughter did not complain of any slow motor movent or any tiltback which was a good sign.

Posted

Off topic, but how is your new board doing with the wheel in the center, whatever that thing is called :) 

Posted

I think there is no problem to drain the EUC battery till the indicator begins flashing and indicating it is to zero, because it should be protected not only by the EUC controller main board, but also by the BMS inside the battery pack.  So it cannot be discharged beyond its lower usage voltage.

Obviously i'm referring to all those EUC that are well projected and manufactured.

Posted
14 minutes ago, Cloud said:

Off topic, but how is your new board doing with the wheel in the center, whatever that thing is called :) 

No comment so far except that I fell on my butt twice already. Luckily, we were training on grass. :P My daughter seems to balance well even though she still doesn't let go of my hands.

11 minutes ago, Frankman said:

I think there is no problem to drain the EUC battery till the indicator begins flashing and indicating it is to zero, because it should be protected not only by the EUC controller main board, but also by the BMS inside the battery pack.  So it cannot be discharged beyond its lower usage voltage.

Obviously i'm referring to all those EUC that are well projected and mafactured.

Actually, I am not worried of the batteries being drained. What I am concerned with is the reaction of the EUC when riding and the battery drained (face plant).

Posted
1 hour ago, SlowMo said:

Actually, I am not worried of the batteries being drained. What I am concerned with is the reaction of the EUC when riding and the battery drained (face plant).

 

Yes I understand your concern, but I hope the manufacturers test their projects before a mass production to avoid a faceplant for  everyone that uses their EUC till the end of the battery power.  This should be one of the first security requirement for every EUC.  

I'm always referring to well known and reliable brands such as Gotway, Kingsong, Ninebot and so on.

Posted

For IPS EUCs, because of the BMS is integrated in the mainboard, you get a warning and tilt back when any single cell is low, thus avoid faceplant even if you drain the battery to the last drop. My T260 has been brought for over 17 months and still 85% of its original capacity(Ah) left when I tested using an electronic load the other day.

For many other EUCs(including Gotway and Kingsong), there are no output protection of their BMS. The EUC estimate the battey conditions based on the total output voltage of the series connect pack. Even the voltage of the pack is not reaching to the critical low situation, the voltage of one of the cell may became too low(in a off balanced condition, which theoretically happens all the time). Therefore, riders should take precautions not to let this happen. Namely if you encounter a low battery warning(4 lights flashing together with the two-beep warning sound for Gotway), just stop riding so that not to receive the warning again.

There got to be a weakest cell in a series connected pack. Draining the pack will make this cell to suffer(voltage too low or zero or even reverse-biased) first and become even more weak(increased internal resistance, decreased capacity, more leakage current). If this situation happens frequently, the weakest cell will certainly damaged soon.

Posted
6 minutes ago, SlowMo said:

@zlymex, have you ridden your MCM2s until the battery gets too low? How did the EUC react? 

Never. I did ride my MSuper2 to the warning point(which is 55.6V total voltage by my measurement, 3.475V per cell by average) several times. It is said that if the total voltage reaches to 53.2V(this may not very accurate), you will get a tilt back.

Posted
44 minutes ago, SlowMo said:

have you ridden your MCM2s until the battery gets too low? How did the EUC react? 

I once reached on my MCM2s the low battery signal, it was a continuous beep... I actually forgot if there was a tiltback or not. I recall that the wheel refused to go, I think it became "super-soft", like a soft mode on steroids. I was very close to home and managed to get back just by turning it off and letting it to "rest" a bit, then proceeding very slow. If I get to this point ever again, I'll try to memorize the pattern :)

Posted
57 minutes ago, trya said:

I once reached on my MCM2s the low battery signal, it was a continuous beep... I actually forgot if there was a tiltback or not. I recall that the wheel refused to go, I think it became "super-soft", like a soft mode on steroids. I was very close to home and managed to get back just by turning it off and letting it to "rest" a bit, then proceeding very slow. If I get to this point ever again, I'll try to memorize the pattern :)

Thanks! At least the engine doesn't turn off which is very reassuring.

Posted
40 minutes ago, SlowMo said:

Thanks! At least the engine doesn't turn off which is very reassuring.

You should try it once in a controlled environment and see what happens. Just dont try it on your kids first :) 

Posted
49 minutes ago, Cloud said:

You should try it once in a controlled environment and see what happens. Just dont try it on your kids first :) 

You're right. I should try to test my units.

Posted
41 minutes ago, SlowMo said:

You're right. I should try to test my units.

Alternatively, you can wait until i get a gotway and try it out. I will be sure to test the low battery behavior at least once. This could happen as early as april or whenever these new models come out!

Posted

I did so once on the mSuper2, and once on Jason's KS14C. I wrote a thread on the Gotway (escapes me now,) but I think the beeps came on earlier (lower and lower speed,) all four lights flashed, and I don't remember if there was a tilt-back. When the lights flashed, I didn't push it, and just cruised a few miles under beeps. Don't remember voltage - might be in the thread.

The KS14C, tilt-back and beeps came on earlier, lights flashed, and I was forced to slow to a crawl. Resting the EU allowed the voltage to recover some, and I limped home. I'm pretty sure voltage was around 55v, but there was a delay before I thought to check it, and it certainly recovered some.

Neither cut-out. YMMV.

ETA - the EUs have 850w/hr & 840w/hr packs, respectively

Posted

I strongly recommend to not let children ride EUCs and electric hoverboards because they smply are not safe enough. We learned about some serious accidents on this forum that resulted in surgery and longer stays in hospitals. For now it is irresponsible to expose kids to such risks. 

Posted
2 minutes ago, ScooterB said:

I strongly recommend to not let children ride EUCs and electric hoverboards because they smply are not safe enough. We learned of some serious accidents on this forum that resulted in surgery and longer stays in hospitals. For now it is irresponsible to expose kids to such risks. 

Then we should prohibit the use of EUC's and Hoverboards to include adults who are the most reported to have gone to the hospitals.

Posted

I have a Ninebot One E+.

I almost never drain the battery all the way, because at the end it becomes near impossible to drive it, due to tiltback. This is of course as it should be!

With an almost depleted battery, the Ninebot One can continue very slow, until it goes completely dead. At that point there is (almost) no danger of falling because of the very slow speed. 

I am not sure what is best for the battery, but I heard somewhere that depleting it once in a while is a good thing, as long as you charge it directly afterwards. Is this true?

Posted

I always thought that draining the battery was a good thing, to help balance the cells and condition the battery to know Where "0%" is. But I herd on here that its actually bad for the battery.

Posted
4 hours ago, johrhoj said:

I have a Ninebot One E+.

I almost never drain the battery all the way, because at the end it becomes near impossible to drive it, due to tiltback. This is of course as it should be!

With an almost depleted battery, the Ninebot One can continue very slow, until it goes completely dead. At that point there is (almost) no danger of falling because of the very slow speed. 

I am not sure what is best for the battery, but I heard somewhere that depleting it once in a while is a good thing, as long as you charge it directly afterwards. Is this true?

It might be useful once in a while with "smart" battery systems that can then calibrate the battery meter, but with the wheels, the battery meter seems to be just a simple volt meter, and there's nothing that would actually measure the charged / used amp- or watthours, so not sure if it's of any use.

 

3 minutes ago, uniler said:

I always thought that draining the battery was a good thing, to help balance the cells and condition the battery to know Where "0%" is. But I herd on here that its actually bad for the battery.

The "conditioning" comes into play with those "smarter" battery meters, but not with the wheels. Balancing occurs during the end of charging, not when discharging. Lithium-batteries don't have the "memory effect" like some batteries, where you need to charge and discharge them in full cycles to prevent the capacity from lowering.

AFAIK, excessive discharge of a lithium battery is bad for the cell, although most (if not all) wheels should stop you before the critical voltages (around 2.5V per cell or so for most lithium-chemistries, excluding LiFePo and Li-titanate). The cell does get stressed at low charge though, if large currents are being drawn.

Posted

No !

The battery needs a Minimum

voltage to maintain chemical function.
A Lithium Ion cell with 3,7V should never reach 3,2V or it will be damaged.

The common shut off Voltage is 3,4V.

The good cells can be recharged aprox. 1000x, a harsh undervolting can kill the cell
at once or can reduce the lifetime, so the cell can perhaps only 100x recharged.

I fly multicopter and a great amount of money goes into the battery and the charging.

The BMS of the EUCs are all bad chargers with simple electronics.
The BMS only measures the Voltage of the complete Cells and cuts the power of
the charger. Meanwhile the charger load the battery with full power.
This is oldschool for cheap car battery chargers and really not the way to achieve
1000 cycles.

I hope, there is balancing between the cells, but i doubt it.

 

Posted

I think the BMS has to look at the voltages on the individual cells when charging. Otherwise when the cells become unbalanced, if the charger only looks at the total voltage, it will be pushing current into cells that are already full and then you have a fire.  I have seen this with RC batteries, if you try to charge without connecting the balancing lead, if one cell is full but another is still not full, the charger thinks the battery is not yet full and continues push charge into both cells: instant fire!

Posted
12 hours ago, Sonopanic said:

No !

The battery needs a Minimum

voltage to maintain chemical function.
A Lithium Ion cell with 3,7V should never reach 3,2V or it will be damaged.

The common shut off Voltage is 3,4V.

Hmm, but I'm pretty sure I've read here that some wheels let the voltage drop to around 3V or slightly below before the final warning. The sources I've read state the critical voltage around 2.5V (after which permanent damage like capacity loss start to occur), but for the longevity (lifetime) of the cell, less deep discharge is always better. A deeply discharged cell, if left in that state for too, is said to start form metallic deposits (different from overcharge lithium plating) that can cause an internal short circuit. But I believe it was said that the cell must dwell below something like 2V for a week or so for this to occur. After that charging it shouldn't be attempted. This is all knowledge I've read around the internet (mostly Battery University), so I have no personal experience.

 

12 hours ago, Sonopanic said:

The good cells can be recharged aprox. 1000x, a harsh undervolting can kill the cell
at once or can reduce the lifetime, so the cell can perhaps only 100x recharged.

I fly multicopter and a great amount of money goes into the battery and the charging.

The BMS of the EUCs are all bad chargers with simple electronics.
The BMS only measures the Voltage of the complete Cells and cuts the power of
the charger. Meanwhile the charger load the battery with full power.
This is oldschool for cheap car battery chargers and really not the way to achieve
1000 cycles. I hope, there is balancing between the cells, but i doubt it.

I believe the BMSs actually do balance the cells,but the balancing seems to only occur towards the end of the charge, so if continuously only partially charged, the cells probably will get out of balance. There are lots of good posts and information about the BMSs used in the wheels in these forums alone, but those posts might be hard to find (especially looking for a word like "balancing", which occurs everywhere in the discussions ;)).

 

 

 

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