# Li Ion battery and cold weather



## digibud (Sep 21, 2009)

I just got some NiteRider dual 400 lights. They come with a Li Ion battery. Upon inquiring, the company commented to me that the battery must not be charged when it is cold. It has to warm up to room temp. I live in AK and will run this light at -20F. If I come home at 10PM and want to be able to ride in the AM when I get up....I'd have to set an alarm for 1AM or something. That doesn't sound good. Nor does a spare expensive proprietary battery but that's an option.
Years ago I ran a light system on a 7200mAh NiCad. We didn't run them much over an hour at a time and I do want this to last more than one hour a run. Any thoughts? The NR lights look good...just not sure I can live with the "warm the battery before charging" directions.


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## radirpok (Feb 1, 2006)

Put the battery under your insulation layer (eg. under your coat) while riding, so it won't get that cold. LiIon doesn't tolerate minuses too well, NiCd is the best in this department.
Or you can charge your batteries during the day, and put them on the charger shortly before you leave in the morning.


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## JohnJ80 (Oct 10, 2008)

NiCd/niMH aren't damaged by the cold but they lose capacity horribly in the cold. Li-Ion maintains it's capacity much better until it freezes.

j.


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## yetibetty (Dec 24, 2007)

Make an insulated pouch to keep the battery in when you ride, pehaps from expanded polystyrene or something so that it never gets that cold.


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## JohnJ80 (Oct 10, 2008)

Here, you have to carry it on your body. Cold in MN is COLD to anyone else.

J.


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## verslowrdr (Mar 22, 2004)

Ask your neighborhood dog musher... batts in the coat for best performance.


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## digibud (Sep 21, 2009)

*battery in coat*

I'll have to think about how or if I can keep the Dual400 battery in my coat. I'll check with niterider to find out if their proprietary cord has an extender available. 
As far as MN being COLD to anyone else. Heh...well...here in North Pole, Alaska we've had -75F at the house (we don't bother talking about Wind Chill either) and my wife and I commuted to work (ten miles each way) for a Winter whenever the temperatures warmed up to -25F or warmer. We used a massive NiCad battery and a big motorcycle headlight and a 7" diameter barricade light in the rear. I'm hoping my tiny Dual400 lights and their tiny battery will work for an hour or two at a time in the cold. It will be an expensive experiment if it fails since I bought a set for both my wife and myself.

Interestingly I note that my Cateye computer goes flakey when I turn my lights on. The lights and the battery are right next to the Cateye. I haven't played with it to figure out which is causing the problem...battery or light.


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## sdnative (Aug 10, 2008)

If the Li-Ion cells freeze, say good by to em  

I have 4 cell pack that only partially works now after a mountaineering trip.

The interference may be due to the high switching frequency of the LED driver. Apparently this is more of a problem with boost type drivers.


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## spec306 (Sep 30, 2007)

digibud said:


> I'll have to think about how or if I can keep the Dual400 battery in my coat. I'll check with niterider to find out if their proprietary cord has an extender available.
> As far as MN being COLD to anyone else. Heh...well...here in North Pole, Alaska we've had -75F at the house (we don't bother talking about Wind Chill either) and my wife and I commuted to work (ten miles each way) for a Winter whenever the temperatures warmed up to -25F or warmer. We used a massive NiCad battery and a big motorcycle headlight and a 7" diameter barricade light in the rear. I'm hoping my tiny Dual400 lights and their tiny battery will work for an hour or two at a time in the cold. It will be an expensive experiment if it fails since I bought a set for both my wife and myself.
> 
> Interestingly I note that my Cateye computer goes flakey when I turn my lights on. The lights and the battery are right next to the Cateye. I haven't played with it to figure out which is causing the problem...battery or light.


Looks like NR has what you are looking of on their on-line store.....
MiNewt/Sol/TriNewt 36" Extension Cable
$29.99
Sku# 6460


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## digibud (Sep 21, 2009)

*seriously?*

I have not heard before the admonition that Li Ion cells can't freeze. That doesn't sound possible. Nobody would be able to use li ion cells in winter. Mine will freeze. I can promise that. It will freeze to -10F or -20F to be sure. If it fails I'll be more than slightly bummed. Can you point me to independent confirmation that Li Ion batteries are harmed by being in temps under 32F ?

On a positive note, the problem with my lights and cat eye cyclometer is fixed. Moving the battery to my top tube away from the cyclometer was all it took and there was just enough cord on the Minewt Dual 400 to make it work. Now about that battery...


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## mtnbykr©™ (Jan 6, 2004)

i have a nr torch hid battery that acts the same way. about 30* or so the runtime drops off. it's ziptied to my helmet. 

does that li-ion battery need to be kept warm??

tia


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## scar (Jun 2, 2005)

Never had a a problem with my Li-Ion's sitting on top of my helmet or mounted to my frame, been down to 18 degrees. Ride year round. My batteries are rubber dipped, don't know if that helps a little?

note pulled from Battery University -



> Lithium-ion works within the discharge temperature limits of -20°C to 60°C (-4°F to 140°F). The performance is temperature based, meaning that the rate capability at or below -20°C is reduced due to the increased impedance of the electrolyte. Discharging at low temperatures does not harm the battery. Lithium-ion may be used down to -30°C (-22°F) with acceptable results. Larger packs will be necessary to compensate for the reduced capacity at these temperatures.
> It is not recommended to discharge lithium-ion at temperatures above 60°C. A high discharge rates combined with elevated temperatures can cause self-heating, an effect that could permanently damage the separator and electrodes of the cells.


Let your batteries come to room temp before trying to charge!!!!


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## jeffscott (May 10, 2006)

digibud said:


> I just got some NiteRider dual 400 lights. They come with a Li Ion battery. Upon inquiring, the company commented to me that the battery must not be charged when it is cold. It has to warm up to room temp. I live in AK and will run this light at -20F. If I come home at 10PM and want to be able to ride in the AM when I get up....I'd have to set an alarm for 1AM or something. That doesn't sound good. Nor does a spare expensive proprietary battery but that's an option.
> Years ago I ran a light system on a 7200mAh NiCad. We didn't run them much over an hour at a time and I do want this to last more than one hour a run. Any thoughts? The NR lights look good...just not sure I can live with the "warm the battery before charging" directions.


Get another battery pack, switch them up...cold kills batteries, don't care what kind....


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## itsdoable (Jan 6, 2004)

...late comment to an old thread... (but not that old...)

The reason NR tells you not to charge the batteries when they are cold is because the smart circuits will think the battery is full or faulty, and will not properly charge it. This happens to most batteries (NiMH, Lead Acid, NiCd) unless they are temperature compensated. Letting them warm up to room temp (~1hour) is all you need. You can always put a timer on the charger so it comes on after a few hours, and stays on indefinitely.

Most batteries will be damaged if the chemistry actually freezes, but the chemistry is not water, and freezes at a much lower temp. The cells also generate heat when discharging, which prevents freezing.

Battery performance decreases at low temperatures, but that's not permanent.


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## mtb_robs-x (Dec 13, 2009)

battery expert ,...
nah,... but still learning a lot,..

li-ion batteries should not be charged below freezing, since it will damage, and severly shorten the live, on top of it, if the charge circuit overcharges the battery, it can turn into flames,.... some mil batteries need to thaw , 4-6hrs, befor charging,.... 
good old hot water bottle, could probably get you there in under an hour,....

for li-ion discharge,... for most parts, down to -20C should work, they do loose a capacity, but not like nimh, or lead acid,... when you get down to -30C, problems start to get serious,... the problem is, also, that , a discharged lithium battery , like all others, be more vurnable to freezing stage, due the empty stage, as such , the rule of thumb,
at least double +, the actuall capacity you need. 

anybody live at the north pole, or alaska ? cold, freezing mtb rides ? 
below -20C,... -30C,... 
pm me, would like to learn some more , to improve a couple of things.


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## JohnJ80 (Oct 10, 2008)

I live in Minnesota - which at times can resemble the North Pole. We routinely get deep subzero (fahrenheit) temps. 

It's correct you shouldn't freeze Li-ions, but that really isn't a problem. If you keep them in your jacket next to your body when you are using them and then put them in the device. If they get too cold, you get a low battery warning and then you just put it in your coat. The low battery warning will be well before they freeze. Using an extension cord can be helpful. Run the device in the cold, keep the battery in your coat. Some of the Black Diamond headlights that are often used for winter search and rescue work that way.

Many chargers and batteries won't charge if they are frozen. They do temp sensing and hold off on charging until they exceed a minimum temp. That depends on the actual charger and/or battery design.

J.


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## mtb_robs-x (Dec 13, 2009)

what kind of light do you run? battery is probalby small, to fit in jacket, and not a bottle battery? how many watts does the light need ?
most chargers, do not have a temperature sensor, nor does the battery,
the circuit just won't recognize the battery correctly, and refuse to charge it, because.
the low battery warning, usually would trigger early, since it was not accounted for, cold weather use, but is still helpfull,... keeping it in the jacket , is a good workaround.
works well , on smaller batteries, but once larger and havier, they need to be carried in a backpack, then things get tricky.


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