Are Eneloops affected by cold weather?

[AMD64Blondie]

I just got 8 new Sanyo Eneloop AAs (along with a Titanium M8800 Smart Fast 8 Bay AA/AAA Battery Charger)..and I'm wondering,if when I install them in my new Fenix TK40 (it's arriving today!!) and go out for a walk tonight... will the batteries be affected by the cold temperatures? (Forecast is for temps about 25 degrees F tonight.)

 

[Navin_R_Johnson]

I used Duraloops in my LD20 & RC-I3 yesterday when it was in the low 30's. The LD20 was attached to the handlebar of my bike & the RC-I3 was on my helmet. Both were getting lots of cold wind and not being warmed by my hands. I had no issues. Both ran for the hour I needed them to and were still going strong. My Imedions or Duracell 2650mah in similar conditions only last about 20 minutes in the LD20 or 40 in the RC-I3.

My guess is that if you are walking and holding the TK40 in your hand, you will not have any issue at 25F with the Eneloops.

 

[StarHalo]

The problem is that the lowest operating temperature listed for a battery is the temp at which it's pretty much guaranteed to fail - it will still be erratic at any temperature near that value; For example, alkalines have a minimum operating temperature of 0F, but they'll start getting iffy around 20F. NiMHs and Li-Ions are only rated to 20F, so anything below freezing is pushing your luck (we have had CPF members use Li-Ions in ~0F conditions, but at least one reported that the battery lost capacity/was damaged by it. Again, a good rule of thumb is no rechargeables in extreme heat or cold.) Lithium primaries are good down to -40F, so even approaching the temp where they'd be questionable would be quite difficult..

 

[sfmartin]

I had Eneloops in an outdoor digital temperature sensor. When the temp got down around 40F I got a low battery signal. The batteries had been recently charged. I replaced them with AA lithiums. The Eneloops have a lower voltage to start with, and in this (low drain) application any drop at low temperatures is a problem.

 

[baterija]

Some interesting graphs of their cold weather performance here

It's important to remember that when you walk out the door to go on your walk the cells are not at the outside air temperature. Even with the light off it will take a while for them to cool down enough to cause big issues. With the light on both the LED and the cells themselves will be generating heat.

 

[Mark620]

The problem is that the lowest operating temperature listed for a battery is the temp at which it's pretty much guaranteed to fail - it will still be erratic at any temperature near that value; For example, alkalines have a minimum operating temperature of 0F, but they'll start getting iffy around 20F. NiMHs and Li-Ions are only rated to 20F, so anything below freezing is pushing your luck (we have had CPF members use Li-Ions in ~0F conditions, but at least one reported that the battery lost capacity/was damaged by it. Again, a good rule of thumb is no rechargeables in extreme heat or cold.) Lithium primaries are good down to -40F, so even approaching the temp where they'd be questionable would be quite difficult..

Unless you need a light to carry a pail of propane across Antartica....
(at about -50F Propane remains liquid and will not boil/evaporate)

 

[Egsise]

I just got 8 new Sanyo Eneloop AAs (along with a Titanium M8800 Smart Fast 8 Bay AA/AAA Battery Charger)..and I'm wondering,if when I install them in my new Fenix TK40 (it's arriving today!!) and go out for a walk tonight... will the batteries be affected by the cold temperatures? (Forecast is for temps about 25 degrees F tonight.)

No they are not, search AA freezer test ;)

 

[T0RN4D0]

Going for a walk with it shouldn't ever be a problem, since the batteries never get even close to the outside temps. If its turned on the could should actually increase the LEDs performance, and the heat from the LED and cells will keep the batteries nice and cozy in there :p

If you leave your flashlight in a car at 0F or something, that might be another story...

 

[Egsise]

Going for a walk with it shouldn't ever be a problem, since the batteries never get even close to the outside temps. If its turned on the could should actually increase the LEDs performance, and the heat from the LED and cells will keep the batteries nice and cozy in there :p

If you leave your flashlight in a car at 0F or something, that might be another story...

Like i said, search AA freezer test...