Jump to content
Knifa

Ninebot One S2 - Only one side charging?

Recommended Posts

Hey there,

I picked up a Ninebot One S2 on eBay and had a great time riding it over the last couple of days.

However, I've noticed that in trying to charge it, only one battery side seems to charge. If I unplug the battery on the good side, when plugging in the charger the LED doesn't change at all. Stays totally green. I'm still struggling to get into the side with the one that isn't charging (these plastic tabs are insane!) so haven't tried disconnecting/reconnecting it yet.

On the app, everything shows normal (though with both batteries in, it complains they are out of balance understandably)

Any ideas on what it could be? Is this battery toast?

Cheers!

Share this post


Link to post
Share on other sites

Don't think I can edit my posts?

Managed to get the cover off. Everything looks OK inside. One thing I noticed is that the battery on the good side has a blinking green LED, whereas it's solid on the other one.

 

Plugged it in to charge. Battery LED is now flashing red. Charger LED only stayed red for a little bit but back to green. :(

 

Looking at the app, I'm guessing the cells inside are maybe unbalanced. "Battery cell of battery 2 is in a big differential pressure."

Share this post


Link to post
Share on other sites
4 minutes ago, Knifa said:

Don't think I can edit my posts?

Editing is just possible for some limited time.

4 minutes ago, Knifa said:

Managed to get the cover off. Everything looks OK inside. One thing I noticed is that the battery on the good side has a blinking green LED, whereas it's solid on the other one.

Be very carefull - if you get your second battery pack „online“ again there could be quite some voltage differrence between the two packs which could lead to enourmous currents to equalize them...

this could in the worst case lead to burning battery cells!

Both packs are secured by a bms (battery managment system) which can cut-off the input side and/or the output side. As long as the batteries are „unbalanced“ (have different voltages) one of the packs will always be „cut-off“ by its bms.

there could be a connector problem with one of the packs?

does the s2 have fuses, where one could have melted?

The s2 has imho some logic/communication between the bms and the mainboard? Maybe there is somthing wrong, or there is some diagnostic available by the app?

  • Upvote 1

Share this post


Link to post
Share on other sites

Connectors look OK, not too sure if there are fuses anywhere. The only thing the app tells me is that the battery is unbalanced. It weirdly still states that battery status is "normal" so I'm not too sure what the deal is, hah.

 

Share this post


Link to post
Share on other sites

 

50 minutes ago, Knifa said:

 

However, I've noticed that in trying to charge it, only one battery side seems to charge. If I unplug the battery on the good side, when plugging in the charger the LED doesn't change at all. Stays totally green.

 

14 minutes ago, Knifa said:

Looking at the app, I'm guessing the cells inside are maybe unbalanced. "Battery cell of battery 2 is in a big differential pressure."

The one battery not charging is battery 2?

“in big differential pressure“ should mean the voltages of the cells in this pack have different voltages. This normaly is prevented by leaving the charger plugged into the wheel for some hours after the charging process is finished. So maybe sou have good luck if you charge the wheel with just the unbalanced pack installed, also the charger led shows no charging.

but unfortionately some wheels are known to balance quite insufficiently. You‘ll see if your pack can be revived by this...

Share this post


Link to post
Share on other sites

I'll leave it on for a while and see if it sorts itself out. :)

I swapped battery sides to see if it made a difference but it looks like it's the battery itself.

Share this post


Link to post
Share on other sites

I have been unplugging it right away as it turns green. Could that have caused problems?

Share this post


Link to post
Share on other sites
1 minute ago, Knifa said:

I have been unplugging it right away as it turns green. Could that have caused problems?

Yes - but not already after a couple of days/some charges. Becoming unbalanced takes longer...

so presumably the cells in this one pack already were in a „bad/not so good“ condition, or there are, as mentioned before other probs. (Connectors looking ok tells as good as nothing about their state, for example...)

Share this post


Link to post
Share on other sites

I will leave it on and hopefully it comes back alive!

Since it does the same thing when swapping sides, the problem must be the battery. Do you know where I can purchase replacement batteries at all if it comes to it? Spare parts for the S2 seem very difficult to find.

Share this post


Link to post
Share on other sites
3 minutes ago, Knifa said:

I will leave it on and hopefully it comes back alive!

But with just the "bad" battery pack inside!

3 minutes ago, Knifa said:

Since it does the same thing when swapping sides, the problem must be the battery.

So the good battery works and can be charged at both sides, the bad one at no side?

3 minutes ago, Knifa said:

Do you know where I can purchase replacement batteries at all if it comes to it? Spare parts for the S2 seem very difficult to find.

With some bad luck just at official segway shops?

Speedyfeet has it listed as out of stock on his website...

Share this post


Link to post
Share on other sites

The good battery works on both sides, yep. The bad battery doesn't work on either side.

No listing on the Segway shop site. I've sent them a ticket so maybe they can be of use. Even a google for "Ninebot One S2 battery" only gives Speedyfeet.

Share this post


Link to post
Share on other sites

One of the weird things is that even though it lists low capacity (e.g., 7%) the voltage is still at charged level --- the same as the good battery.

Share this post


Link to post
Share on other sites
12 minutes ago, Knifa said:

One of the weird things is that even though it lists low capacity (e.g., 7%) the voltage is still at charged level --- the same as the good battery.

If this pack is really unbalanced, but shows normal full voltage (4,2V x 15 or 16 cells) this would mean, that some cell has to have above 4,2V. So again be carefull with this pack - also with the balancing charge you just give him. Don‘t leave this unattended.

Share this post


Link to post
Share on other sites

The battery seems to have fully drained (from the point of the BMS). Light is blinking red, unit won't power on. I'm not sure the charger is doing anything at all.

I think she may be dead.

I've started the return on eBay --- hopefully they will take it back even though I have scuffed it up a bit more.

 

Share this post


Link to post
Share on other sites

Looking at the pictures again, I've noticed that the solder job on the battery is like... really weak. Are half of these not even soldered properly or what?

Untitled.thumb.jpg.47f85b247b579634d7c68eff0c4f8989.jpg 

Share this post


Link to post
Share on other sites
2 hours ago, Chriull said:

Mabye they are just soldered from the other side and the blobs seen here is just the tin that came through?

I hope so!

Share this post


Link to post
Share on other sites

After riding a lot today, I've ran into the same problem. We're going to try replace the cell so I'll post up how it went soon!

The existing cells inside are made by LG and have the identifier LGABMG11865. They're 2850mAh 10A cells, and I think the series is called MG1. These are turning out to be pretty tricky to get a hold of on the UK so we'll need to put one with a larger capacity in. Thankfully, it looks like the BMS uses the lowest cell voltage to give a capacity remaining for the whole battery, so as long as it's close enough it should be fine.

  • Like 1
  • Upvote 1

Share this post


Link to post
Share on other sites
26 minutes ago, Knifa said:

After riding a lot today, I've ran into the same problem. We're going to try replace the cell so I'll post up how it went soon!

The existing cells inside are made by LG and have the identifier LGABMG11865. They're 2850mAh 10A cells, and I think the series is called MG1. These are turning out to be pretty tricky to get a hold of on the UK so we'll need to put one with a larger capacity in. Thankfully, it looks like the BMS uses the lowest cell voltage to give a capacity remaining for the whole battery, so as long as it's close enough it should be fine.

For sure, this low cell which had 2,8Volt is defect! It is not just for fun at this low voltage, you should have changed it from the start on ;-)

There are a lot of cells you can choose from. Most important part is: This cell also must have the same max continuos amperage draw than the other cells, whiich i guess is 10Amp per cell! Thats much more important than hitting the same amount of „mah“...

No problem when the batterie is abit higher in mah...but it is imporatnt it can stand the 10Amp...

Perhaps this:

https://www.nkon.nl/rechargeable/18650-size/lg-inr18650mh1-3200mah-3c-battery.html

or

https://www.nkon.nl/rechargeable/18650-size/samsung-inr-18650-30q-3000mah-button-top.html

or a Panasonic 18650pf might be ok.....( the PF would be the best by numbers if you can not get the MG1)

And your BMS has done it completely correct...with such a different in voltage it is important, that it stops working :-) and no, it is not only relying on this „first“ cell  :-)

Edited by KingSong69
  • Upvote 3

Share this post


Link to post
Share on other sites

@Knifa:thats what happens while balancing ( "trickle charging") - this ~50mA are lead around the charged cells and just go through the cells still in need of charge (lower voltage).

Unfortionately there are quite some limits how many and which cells can be bypassed (at least with the controller the ninebot one e+ used for the bms) and also this just internal balancing is quite limited (power dissipation inside the ic) - "active" balancing with external mosfets has more abilities...

There where some (quite qualified) reports that the ninebot one e+ bms with just internal balancing did not get it.

Maybe also sonething in the balancing circuit has gone bad, so this one cell gets all over the time bypassed by the controller (partially)?

However, great report and have fun driving!

  • Like 1

Share this post


Link to post
Share on other sites

@Chriull it's interesting that they state in the manual that when the charger is green (trickle charging) that the machine is good to go. Balancing is really important! I guess with good cells though, they should all drop in line (it probably stops the fast charging once at least one cell has hit the max voltage?)

In this case, it looks like the cell was just bad. With the new cell everything charges OK and with the good pack in, they fall to the same capacity. Previously, the one with the bad cell would drop much quicker than the other.

I checked the cell after charging (including a long time on the trickle charge) and it was sitting at 4.1v, with the rest at 4.2v. This makes sense as the capacity is higher (but it should still try balance it out?)

Also instead of returning to the eBay seller, they gave me a great discount for the battery issue, so all is well. Thanks for following the journey! :)

Edited by Knifa
  • Like 1
  • Upvote 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×