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The MiniPro has a stated nominal voltage of 54.3v.  Dividing that by 3.7 (the nominal voltage of 18650 cells is 3.6 - 3.7v) gets us 14.6.   Dividing by 3.6 gets 15.08v.  So we could say the battery is likely 15S.  So to get that 5700mAh capacity the MiniPro battery should be in 15S2P (15 series 2 parallel) configuration and the cells should be about 2850mAh each. 

I found this image of the Ninebot Mini battery which appears to have 30 x 18650 cells in 15S2P configuration.  So now we are onto something.  If the battery has 15 cells in series (and another 15 in parallel) the fully charged voltage should be 63v if the system is allowing a 100% charge.  If it is only allowing an 80% charge the voltage should be roughly 58.9v. The stock charger has a stated output of 59.5v which is very close (roughly half a volt over) to the 80% charge voltage.  This points towards the battery only charging to 80%.  Can someone with the aftermarket MoreforMini charger post a pic of the back showing the output voltage or at least tell us the voltage?

56db30ea9dd90_9botminibatteryvs9b1battery_jpg_80e18613a417f243c8450bd09e7e0b31.jpg

Edited by RooMiniPro
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Ok I did a little more investigation and found this charger which states an output of 63v.  This strongly suggests that the people getting more range with the aftermarket one are in fact correct and that the stock charger only charges to 80% and that Segway are either lying to me or the tech support rep is mistaken.

 

  

charger.jpg

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3 hours ago, kasenutty said:

How surprising :D

Since you're the one with the aftermarket charger and getting the increased range, can you confirm that the output on your charger is 63v?  Can you upload a pic of the specs? 

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They're fucking lying and I knew it right away, sorry if I was aggro about it, but I know they're lying and have been stewing on it for a while.

 

Its stupid too, because my minipro goes super far and I'm totally happy with it. I just don't like companies bullshitting us when it's obviously true.

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Yeah I'm really happy with the range I'm getting, even if it's only 80% of the true capacity. If it's a design decision to greatly improve the longevity of the battery I don't see why they don't just say that.  It's nothing to be ashamed of.  I actually like the idea of my battery lasting for a couple of years longer, at the cost of a bit of range reduction per charge.  At the same time, it would be nice to have the option to charge to 100% once in a while, for days when I know I will need that extra range.  I have emailed Segway back with my findings and asked them to let me know if it's an intentional battery preservation design choice or if we have just been sent chargers with the wrong output voltage.  There's no way a firmware update is going to change the output voltage of the charger haha.

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That would add about 8km to the range.  Hmmm this is interesting.  I'm sure Segway/Ninebot know what they are doing with this, but why they would not be transparent about it, I'm not sure. If they are shipping MiniPros to most countries with 63v chargers then the units are designed to handle it just fine. 

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Ok so here's how the communication has been going with Segway tech support so far (names have been omitted from conversation):

ME:

Dear Sir/Madam,
I bought a Segway MiniPro several days ago and I absolutely love it. However, after a full charge, including leaving it plugged in overnight, the battery only charges to 4813mah, giving 25km range. After talking to other owners and reading on forums, I learned that most owners' units charge to the full capacity of the battery (5700mah) and get an app-indicated range of 30km. I was told that some people have had to replace their chargers in order to get the full capacity.

I was wondering if you could tell me if this is an issue with my unit.

Thanks

 

SEGWAY TECH SUPPORT:

The issue is not due to the capacity of the battery and its ability to charge or a faulty charger instead, it’s due to a BMS error in the way it records the battery when it is fully charged. This issue is known about, some of the Batteries used on the miniPRO have an error in the battery capacity algorithm. It does not affect to performance of the machine, just the display of voltage when fully charged. Please keep in mind that 25 km is the typical range on a fully charged miniPRO, not 30 km (as stated in the manual).

Our Ninebot engineers are aware of this issue and are planning on a firmware update to correct the issue that is affecting some of our units. This firmware update is scheduled to be released shortly.

If you have any additional questions, please feel free to contact me directly.

Regards,

 

ME:

Hi, 

Thanks for the explanation.  However, I have done some investigation and determined that this explanation does not seem to be correct.

Here is what I have worked out: 

The MiniPro battery has a stated nominal voltage of 54.3v.  Dividing that by 3.7 or 3.6 (the nominal voltage of 18650 cells is 3.6 - 3.7v) gets us 14.6 or 15.08v.  So we could say the battery is likely 15S.  So to get that 5700mAh capacity the MiniPro battery should be in 15S2P (15 series 2 parallel) configuration and the cells should be about 2850mAh each. 

If the battery has 15 cells in series (and another 15 in parallel) the fully charged voltage should be 63v if the system is allowing a 100% charge.  If it is only allowing an 80% charge the voltage should be roughly 58.9v. The stock charger has a stated output of 59.5v which is very close (roughly half a volt over) to the 80% charge voltage.  This points towards the battery only charging to 80%.  The aftermarket charger outputs at 63v rather than the stock charger's 59.5v and so the aftermarket charger is charging the battery to 100% and the stock charger is charging it only to 80%.  Some people in the forums are using the aftermarket charger and getting considerably more range from their units.

As this is caused by the output voltage of the charger, the firmware update you mentioned would not be able to fix this.

I have come to the conclusion that this 80% charging is likely by design, in order to allow the battery to have a much larger number of charge cycles, as Tesla does with their batteries.  Would you be able to find out for me if this is indeed the case or if actually the charger I received is the wrong output voltage for the MiniPro and my charger should be replaced with one that charges the battery fully? 

Thanks,

 

SEGWAY TECH SUPPORT:

Hi, 

As I stated, this is a known issue and is being addressed in the next few weeks with a firmware update. 

Regards,

 

ME:

Hi,
 
As I stated, a firmware update cannot change the output voltage on the charger. The charger does not have upgradeable firmware.  Some owners received their MiniPros with the 63v charger and are getting full capacity, whereas myself and others received the lower voltage charger which cannot charge to full capacity.   Aftermarket 63v chargers do charge the units to full capacity.  
 
As you don't appear to want to answer my question honestly, or perhaps you just don't understand how this works, could you please put me in touch with someone who does so that my question can be answered? I and others in the MiniPro community would appreciate an honest answer to this.
 
Thanks,
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Update:

SEGWAY TECH SUPPORT:

Hi,

Sorry, I sent the wrong email, I had not finished yours but in my attempt to multitask I inadvertently sent this instead of the one I was working on. What I also wanted to say, I will contact you once the firmware update has been released to then check with you to see if this corrected the issue. If it has not, then we will then look into if it’s the charger or the battery that’s the cause of this issue. However, we do in fact have an issue that is affecting some of the batteries BMS on the miniPRO that is giving a false record. As I stated, the information being displayed is incorrect but it will not affect the overall performance of the machine. It does operate within the parameters it was designed for even thought the displayed information is incorrect

Please confirm that you have updated the firmware on this machine (there was a previous patch but unfortunately, it did not correct all the batteries affected by this incorrect algorithm.

 

ME:

Hi,
 
I understand that you have a BMS issue on some units, but as I have explained, this appears to be a simple case of some MiniPros shipping with 59.5v chargers which can only charge to about 80% capacity (because the 15S battery would need 63v to charge fully) and some MiniPros shipping with 63v chargers which do charge the batteries to 100%.  It appears that most of us in North America receive the lower voltage chargers and customers outside North America receive the 63v chargers with their MiniPros.  We have a forum thread going in which we are posting photos of our chargers and discussing this issue, trying to get to the bottom of it.  Some people have bought aftermarket 63v chargers in order to charge their batteries fully and get up to an extra 5 miles (8km) of range. 
 
I am just trying to find out if the 59.5v chargers were shipped in error or if it's an intentional decision to only charge our batteries to 80% for longevity reasons.  I would really like the option to charge my battery fully for days when I need the full range the battery can offer, just as our European friends can enjoy with theirs.  I appreciate you working with me on this and I hope you understand what I am trying to find out here. 
 
Thanks,

 

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17 hours ago, Vik's said:

 

Yeah, 63v charger here. Both for 9b1 and MiniPros

IMG_20170406_074538.thumb.jpg.870624e7bcadceda02969421e6fad9e8.jpg

That's interesting, wish I could post a photo of mine, but it says output 61VDC 1.9A  led green 120mA and the charger itself is white.  So I have a lower voltage charger.  Seems the charger has changed more times than the firmware.  But at about 60% charge on the app, one hour on the charger will show 100 percent charge on the app even though the charger light is still red. (not balancing)    But I am happy with the range, never rode more than an hour at a time (6-10 miles I'm guessing)  Still, I wonder how the performance of the Ninebot would feel charged by a more powerful charger?  It always feels best when it has charged to green and a little longer to balance the cells.  The lower the battery goes the less the performance and feeling of power.

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17 minutes ago, steve454 said:

That's interesting, wish I could post a photo of mine, but it says output 61VDC 1.9A  led green 120mA and the charger itself is white.  So I have a lower voltage charger.  Seems the charger has changed more times than the firmware.  But at about 60% charge on the app, one hour on the charger will show 100 percent charge on the app even though the charger light is still red. (not balancing)    But I am happy with the range, never rode more than an hour at a time (6-10 miles I'm guessing)  Still, I wonder how the performance of the Ninebot would feel charged by a more powerful charger?  It always feels best when it has charged to green and a little longer to balance the cells.  The lower the battery goes the less the performance and feeling of power.

@steve454, You're totally correct! I've grabbed two of my miniPros chargers and didn't give it second thought! My 9b1 charger is of course white-coloured and giving out 61V... My bad!

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10 hours ago, RooMiniPro said:

Hmmm so we have 3 chargers: 63v, 61v and 59.5v.

They probably have 3 different suppliers for chargers. It is almost a guarantee that Segway does not manufacture the charger or the batteries themselves.  Kinda like how an iPhone has as many Samsung manufactured parts as it does Apple parts. 

My thought would be that the allowances on the batteries and the smart charging chips in the chargers/minipros compensate for the variances. Sure some chargers may "top-up" a little higher but everything still falls within the specs of the mini.  

Personally, I would say if you have the higher voltage charger you should top up and enjoy the range. We are talking about thousands of potential charges here so if the number of charges drops a little it is still unlikely that most people will continue to use the same Mini for that long. I for one can be sure that if I end up riding mine for thousands of charges that would equal years and years of riding. I would have likely purchased a new model (upgraded) by then and sold or handed down my original mini pro. 

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