Jump to content
Lukasz

Ninebot Z10 Smart BMS - battery low temperature monitoring

Recommended Posts

22 minutes ago, Lukasz said:

So - in winter conditions - never leave it in the car trunk or any other place with temperatures below room temperature -  keep it warm before the ride - during ride battery will heat itself , and after the ride - put it back to the warm room. Do not make longer stops outside if weather is cold, for sure if it is below 0 Celsius.

Very good advice, for any wheel. One should treat a EUC like one would treat a pet (or maybe another person). If you wouldn't do it to them (keep them out in the cold), you shouldn't do it to your wheel🥶 Same for hot car, etc.

For any 10°C temperature difference, the rate of a chemical reaction approximately doubles or halves. I assume that applies to the electrochemistry in batteries as well (not sure). If that's the case, going from 25°C to 0°C is an 80% reduction in peak power output! Easy to see how with a cold battery, a sudden power requirement spike might be a problem while being perfectly fine with a room temperature battery.

Share this post


Link to post
Share on other sites

Thats interesting, for what I always read, the cold was not really affecting Lio-Ion Batterys more than a capacity decrease, (it should even reduce battery wear ) as opposed to the heat wich increase the capacity but decrease battery life.

The only thing you should never do is to charge a LI-Ion battery bellow 0 degres at wich point bat stuf would permanantly affect the anode.

Also if you store a Li-ion battery with a low charge state , the cold could decrease the voltage bellow the minimum theshold causing again damage and possibly killing the battery

 

 

Edited by Krom68

Share this post


Link to post
Share on other sites
22 hours ago, Krom68 said:

Thats interesting, for what I always read, the cold was not really affecting Lio-Ion Batterys more than a capacity decrease, (it should even reduce battery wear ) as opposed to the heat wich increase the capacity but decrease battery life.

The only thing you should never do is to charge a LI-Ion battery bellow 0 degres at wich point bat stuf would permanantly affect the anode.

Also if you store a Li-ion battery with a low charge state , the cold could decrease the voltage bellow the minimum theshold causing again damage and possibly killing the battery

 

 

This is what I have read (Battery university) as well, it is temps over 30C that will speed lion degradation whereas cold will not. However, charging should not be done in subzero temps. When I still had my electric bike, I had no issues with the battery in -10C, but charging I did inside.

I just tried to turn on my Z10, which I keep on my balcony. It did not turn on and it is about -2C. And the battery should have aboit 75% charge.

 

Share this post


Link to post
Share on other sites
3 hours ago, Ziiten said:

I just tried to turn on my Z10, which I keep on my balcony. It did not turn on and it is about -2C. And the battery should have aboit 75% charge.

Eh, all these temperature variations (and cold temps in the first place) can't be good for the wheel and especially the batteries.

Share this post


Link to post
Share on other sites
10 minutes ago, meepmeepmayer said:

Eh, all these temperature variations (and cold temps in the first place) can't be good for the wheel and especially the batteries.

Yeah, I was planning to take it inside for winter, but mostly because of the humidity. I took it now inside and about 1/2h later it turned on again. The charge was only 51%, maybe I remembered wrong or it dropped by itself.

20181125_161045.jpg

Edited by Ziiten

Share this post


Link to post
Share on other sites
On 11/24/2018 at 2:57 PM, Krom68 said:

The only thing you should never do is to charge a LI-Ion battery bellow 0 degres at wich point bat stuf would permanantly affect the anode.

EUCs have recuperation, that's why it isn't good to ride when temperature <0. 

Share this post


Link to post
Share on other sites
28 minutes ago, palachzzz said:

EUCs have recuperation, that's why it isn't good to ride when temperature <0. 

Due to some power losses inside battery, during ride it is usually at least few degrees above ambient temperature. Of course it's beneficial to keep wheel inside building before ride and don't make longer breaks.

Share this post


Link to post
Share on other sites

I am guessing that taking a room temp wheel to even negative temps wont be a problem because of the heat generated on discharge. At least if the ride isnt excessively long.

Share this post


Link to post
Share on other sites

Yes, I put it wrong: when the battery temperature is below 0.

I travel 40-50 minutes everyday and even at -8 outside, Z battery has a temperature 25-38C on arrival, depending on the aggressiveness of the ride. 

But the problem is: if battery temperature below 0-5C, Ninebot Z won't turn on.

Share this post


Link to post
Share on other sites

I did a test ride: I took my z10 with 50% battery at room temperature (22C) and rode it in -6C for 3 km with a short break to do some groceries while the wheel was in semi warm inside parking lot. After I rode it back (total 6km) the wheel temp was 11C, 41% charge left. So, after such a short ride and a steep drop in temperature of the wheel I cannot recommend riding the Z10 in subzero temps for extended periods of time because it might shutdown when reaching 0C.

Edited by Ziiten

Share this post


Link to post
Share on other sites
On 11/28/2018 at 12:39 PM, Ziiten said:

I did a test ride: I took my z10 with 50% battery at room temperature (22C) and rode it in -6C for 3 km with a short break to do some groceries while the wheel was in semi warm inside parking lot. After I rode it back (total 6km) the wheel temp was 11C, 41% charge left. So, after such a short ride and a steep drop in temperature of the wheel I cannot recommend riding the Z10 in subzero temps for extended periods of time because it might shutdown when reaching 0C.

I am confused when I read your recommendation. A number of posts above say the the battery is heating itself while riding and that sub-zero temperatures are not an issue as long as you are riding and not leaving the wheel outside without riding. AM I missing something 

Share this post


Link to post
Share on other sites

Actually did my very first ride today in Sub zero temp and the battery and BMS seems to behave very well. I ode continuously so it did not have time to get cold but the battery consumption seemed normal

Share this post


Link to post
Share on other sites
1 hour ago, Emmanuel Schalit said:

Actually did my very first ride today in Sub zero temp and the battery and BMS seems to behave very well. I ode continuously so it did not have time to get cold but the battery consumption seemed normal

Unless really cold like -10 Celsius - if You start the ride with warm battery (wheel taken out from room/apartment temperature) and ride continuously  - it should be no problem. 

However - if You take the wheel (any type - Ninebot/Gotway/Inmotion/Kingsong etc) frozen out from the trunk of Your car which stayed at -10 C for the night - none of those wheels will be ready to ride - even if the wheel will turn on - do not expect the torque, also - battery degradation will be much bigger due to such riding - especially when breaking - Li-Ion batteries do not like to be charged when they are cold.

Share this post


Link to post
Share on other sites

Panasonic battery specs:

tinyurl.com/y7kejguh  

Each EUC ride means discharging, but also charging at each breaking .... 

See Panasonics specs -  charging tempreature +10 Celsius to +45 Celsius! 

Share this post


Link to post
Share on other sites
On 12/8/2018 at 1:08 PM, Emmanuel Schalit said:

Is the temperature you quote the vehicle temp or the battery temp? See at the top of this thread for difference)

Sorry for the confusion. You are right, I have been looking at the vehicle temp. But I think the battery level dropped quite substantially after a short ride when I left with a cold (~5C) wheel, so it is definately recommendable to keep it in room temp if going for a bit longer ride.

 

Edit: Did some more testing. I left with the battery temp at 7C and charge at 75%. Rode for 4,5 km and the charge dropped to 55% and the battery temp rose to 10C, ambient temp was 4C. I had a 5 min pause with the wheel turned off and the charge recovered to about 61%. Rode another similar distance and the charge dropped to about 48%, battery temp now at 12C. Average speed during ride was about 20 km/h. Wind was 6 m/s SE.

Edited by Ziiten

Share this post


Link to post
Share on other sites

I did a more extensive test today during my morning commute to understand how the Z10 fared in low temp.

  • Starting conditions : Battery at 100% , Unicycle at room temperature (22°C)
  • Ride: 10 kilometers in -2°C at 7:30am in NYC, on flat terrain at moderate speed (Between 20km/h and 25 km/h)
  • No interruption of the ride, other than stopping for traffic lights
  • Condition on arrival: Battery at 96%, battery temp at 17°C, vehicle temp at 14°C

So it seems to confirm the theory that if you start with a warm unicycle, even in low (not extreme) temperature, and as long as you do not let the wheel coold down, you will have no issue. I have not yet tested more extreme (-10°C) temperatures because at that level the rider may become the problem :)

Edited by Emmanuel Schalit
typos

Share this post


Link to post
Share on other sites
6 hours ago, Emmanuel Schalit said:

Condition on arrival: Battery at 96%, battery temp at 17°C,

Just two small things 

1.  % counting in Ninebot Z10 is not linear - 96 % displayed means in fact around 90% actual charge, percentage will stay higher above 50 % of real charge, and drop a lot faster if You get below 50 %

2. Be aware that if your battery percentage go to 10% - it means in fact that You have 2 km range left

3. If battery goes down below 5% - and You switch the wheel off - it will not turn on any more unless you recharge it first... (which is not so nice surprise)

4. Thermal capacity of the warm battery is quite good due to the fact that it is packed well inside the wheel.

5. With practice You will start with more aggressive accelerations / breaking = this will produce more heat, so You may end up with battery easy around 30degC even at cold weather

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...