Below 0°C and lithium battery charging

Batteries, Chargers, and Battery Management Systems.
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scootergrisen   10 W

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Below 0°C and lithium battery charging

Post by scootergrisen » Dec 01 2019 7:55pm

So it seems lithium batteries or at least some lithium batteries should not be charged below 0°C.

Below 0°C have come. I see frozen water outside.

So what do people do?
And how do you know the temperature of the battery is below/above 0°C?
And does the BMS protect the battery from being charged below 0°C?

You have removeable batteries ok take them inside.
You have non-removeable batteries ok put the scooter inside.
You have non-removeable batteries and is not able to put the scooter inside... now what?

I guess you can make a heating element around the battery and then heat some time before charging.
Or put insulation around the battery.
It seems discharging the battery makes it hot so if the battery have a charge maybe you could power the heating element/heat blower with the battery. That way the battery gets hot both from the inside and outside. But maybe a bit silly to discharge the battery just to recharge it, but if it works it works.

I dont think i have read/seen anything about solutions to this problem for scooters with lithium battery.

I think maybe the solution is a heating element around the battery and then the BMS should have a temperature sensor and only allow the battery to charge when above a certain temperature.
So you just connector the charger to the socket and if to cold the heating starts until temperature is ok and then the charger starts.
That way you dont have to look at the temperature and start the heather manually and return later to start the charger.
But i dont think i have seen any scooters with battery heather.
I guess the battery heather could be inside the battery as well as outside.
If inside the battery maybe its more effective and not so much heat will go to waste.
Or maybe have the heating element connected to a AC socket and then the charger starts when the temperature is good.
Or maybe not so good solution ... have a timer so when the heather have been on for a set amount of time the AC for the charger is turned on.
I would want to avoid having to manually turn on/off the heating element etc. because then you having to come back multiple times and this gets annoying.

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amberwolf   100 GW

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Re: Below 0°C and lithium battery charging

Post by amberwolf » Dec 01 2019 9:55pm

There are some threads with info that may help:

search.php?keywords=winter+charg*&terms ... mit=Search

search.php?keywords=freez*+charg*&terms ... mit=Search

and some of the various "winterizing" threads also discuss it.


These may also have info, but ther'es lots of irrelevant stuff in there:
search.php?keywords=winter+charg*&terms ... mit=Search

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tomjasz   10 GW

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Re: Below 0°C and lithium battery charging

Post by tomjasz » Dec 02 2019 1:00am

Some of us use the heated clothing kits from Aliexpress. But not warming for charging. I charge battery indoors in an ammo can modified for containment and cord protection.

USB Charged Clothes Heating Pad 5V Electric Heating Sheet With 3 Gear Adjustable Temperature Heating Warmer Pad For Vest Jacket https://www.aliexpress.com/item/3296196 ... 4c4d205Sk1
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Below 0°C and lithium battery charging

Post by j bjork » Dec 02 2019 2:36am

Audi etron has heating on the batteries when DC-chgarging at -10 degrees and colder. So they probably allow AC charging (slow charging) at a lot colder temperatures.

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Re: Below 0°C and lithium battery charging

Post by Pajda » Dec 02 2019 4:45am

There is no magical "wall" for lithium batteries at 0°C. All is about safety and manufacturer warranty. In general only qualified person should operate with bare lithium cells. But common people can operate a battery (cell with some kind of protection/BMS). So for example all major cell manufacturers strictly forbid the use of their bare lithium cells in e-cigateres, but they allow to use protected cells. Similar approach is for the low temperature chaging. The most problematic electrochemical effect - lithium plating is dependend on temperature and charge rate as well. So if you make precaution in your battery, that BMS is able to fully control charging current (not only turn it on/off) by controling onboard charger or DCFC system, you can charge lithium ion batteries even in -20°C at very low charge rate like 0.05C and 0.1C at -10°C with exponential trend.

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scootergrisen   10 W

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Re: Below 0°C and lithium battery charging

Post by scootergrisen » Dec 02 2019 11:13am

Maybe the 5 heating pads are not bad, one on each side and one on the bottom.
How long would it take to heat up a battery that is at -10°C with those heating pads?
Even if i have a temperaturesensor inside the battery would it be precise to show the cell core temperatures and not heat up faster.

Are you saying my battery says "Charge environment: 0°C~45°C" because of the BMS and that it might say "Charge environment: -20°C~45°C" if the BMS was different/better at controlling the charge at low temperature?

I dont feel like connecting the charger below 0°C to see what happens but it would be interesting to see.
See if the charge current starts out very low.

As far as i can see there is no temperature sensor inside the battery.
If there was i would expect it to be mounted on a cell and not on the BMS.
Or somehow have a temperature sensor that heats up the same way the cells does.
Like a fake cell with a temperature sensor inside.
Or maybe its good enough to mount the sensor on the nickel strips.

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Re: Below 0°C and lithium battery charging

Post by Pajda » Dec 02 2019 12:58pm

In fact yes, all batteries designed in accordance with safety standards must have temperature sensor (even so called protected cells does have integrated temperature sensor on a protective PCB). Almost all "consumer" batteries (which can be easily moved to the heated enviroment) works that they simply do not allow charging under 0°C.

Only batteries with advanced BMS in combination with charging current control can be charged in low temperatures. Those are in particular batteries for BEV (for example VW e-Golf and e-UP! does not have any heating element or TMS inside the battery)

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scootergrisen   10 W

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Re: Below 0°C and lithium battery charging

Post by scootergrisen » Dec 02 2019 2:32pm

My cells says:
MX18650-26P
Dynabat

In another topic i got this link:
http://www.enershare.cn/BatteryCellc.aspx

That says:
Operating Temperature
Charge 0 to 45℃

I dont see anything about the cells having protection other then:
Protection rating IP34 PCS room

I dont see anything that might be a tempeatur sensor inside my battery.
Pictures at https://scootergrisen.org/forum/viewtop ... f=3&t=3612

It would suck if lets say someone borrowed your scooter and did not know about this and then charged it below 0°C and the battery got ruined.

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amberwolf   100 GW

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Re: Below 0°C and lithium battery charging

Post by amberwolf » Dec 02 2019 9:58pm

scootergrisen wrote:
Dec 02 2019 2:32pm
It would suck if lets say someone borrowed your scooter and did not know about this and then charged it below 0°C and the battery got ruined.
Well, then, I would say never to loan out your scooter. ;)

Unless you first give them lessons, that you trust that they really learn, before loaning it. It's hard to trust people with stuff like this, though, which is why it's better to have the protection cutoffs inside the pack to start with.

If you think someone might loan it to themselves without your permission, you should probably put some form of electrical security on it, that disconnects the battery from both discharge and charge ports.

An easy way to do this is install two Anderson SB-50 panel-mount connectors (or the PP45 panel-mount, if you prefer something smaller and easier to remove), stacked on top of each other, somewhere you can easily reach but is not in the way, preferably out of sight. Wire the positive output of the battery to one side of one of them, and the positive input of the scooter to the other side of that same one. Wire the positive input of the battery to one side of the other one, and the positive output of teh charger port to the other side of that one.

Then on a second set, not mounted on the scooter, but also stacked together, wire a loop from one side of one connector to the other side of the same one, and another loop from one side of the other connector to the otehr side of that one. This set is a "key" without which the scooter can't be charged or started, unless someone sticks something in the connectors capable of shorting them together enough to let that much current flow.

I prefer the SB-50 series because they have mounting holes for T- handles (which are also available for them, if you don't want to DIY one), which make this kind of key really easy to make and use. :) The PP series dont' directly have such mounting holes, though you can engineer something to do this if necessary, rather than just pulling on the wire loop.

The Anderson SB or PP is better than other connectors for this because they have sacrificial tips designed to handle the spark of connecting live circuits together, without damaging the actual contact surface.

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scootergrisen   10 W

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Re: Below 0°C and lithium battery charging

Post by scootergrisen » Dec 02 2019 10:10pm

I had another idea...

How about using the charger as a heating device underneath the seat.
So the charger and battery is both under the seat in a somewhat enclosed area so the charger could blow warm air around inside the box.
Perhaps there could be a airway below the battery so air could circulate well.
Then you connect the charger to AC socket and if its to cold the the fan and a heather inside the charger blows warm air around inside the box until the temperature is good enough to start the charging.
Since the box is somewhat enclosed maybe there would not be so much heat waste.

Maybe this could also be used in hot areas if the battery was to hot and then the fan could cool the battery before charging.

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scootergrisen   10 W

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Re: Below 0°C and lithium battery charging

Post by scootergrisen » Dec 03 2019 11:01pm

Now i notice it says "environment" on the battery:
Charge environment: 0°C~45°C
Discharge environment: -20°C~60°C

I dont say the battery/cells have to be that temperature but the environment.

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