Pilas and the Weather

[this_is_nascar]

One of the benefits of 123-cells like SureFire, Duracell, etc is it's long shelf life and the ability to better handle extreme tempatures. I know that the Pilas, as well as other NiMH cells do start losing voltage each day they are not used. What about this extreme tempature usage (cold and hot). Do they not perform optimally in these types of conditions or are they in-line with the performace of the SF type cells?

 

[Doug S]

[ QUOTE ]
this_is_nascar said:
One of the benefits of 123-cells like SureFire, Duracell, etc is it's long shelf life and the ability to better handle extreme tempatures. I know that the Pilas, as well as other NiMH cells do start losing voltage each day they are not used. What about this extreme tempature usage (cold and hot). Do they not perform optimally in these types of conditions or are they in-line with the performace of the SF type cells?

[/ QUOTE ]

Ray, the relative performance of primary CR123 type cells vs Li-ion rechargeables at low temperatures varies somewhat with load current and temperature but in general at fairly heavy load currents that I think are of interest to you the li-ions do somewhat better than the CR123 [I'm looking at some -20C graphs at discharge rates of 0.2C and 1.0C]
BTW, the self-discharge characteristics of li-ion are very good. For moderate storage temperatures, you can expect a reasonable % of initial capacity remaining at a year post charge. They are not as good as lithium CR123 though in this regard.

 

[HarryN]

Doug - You and I live in relatively moderate climates.
(-20 C) is not really that cold - only around 0 F. The US has had much colder weather this year than that.

What I see missing from the consumer market are batteries with real performance at (-40 C). As far as I can tell, the only batteries that hold up are the SAFT D cells like HDS sells. Maybe there are others, I just have not found them yet.

 

[this_is_nascar]

Thanks. So it sounds like keeping Pilas in an automobile during the East coast winter should not be a concern to me. That's what I was really interested in. I know that alkalines in this type of setting are terrible, but it sounds like that's not the case with Pilas (Li-ion).

 

[Doug S]

[ QUOTE ]
HarryN said:
Doug - You and I live in relatively moderate climates.
(-20 C) is not really that cold - only around 0 F. The US has had much colder weather this year than that.

What I see missing from the consumer market are batteries with real performance at (-40 C). As far as I can tell, the only batteries that hold up are the SAFT D cells like HDS sells. Maybe there are others, I just have not found them yet.

[/ QUOTE ]
Right you are, Harry. Most LiMnO2 [CR123 chemistry] and Li-ion datasheets give a -20C to +60C operating range. I'm looking at a Saft LiSO2 datasheet with specs of -60C to +71C. I think this explains why the D size LiSO2 cells are the cell of choice among the Alaskan dogsledding enthusiasts. BTW, the LiFeS2 chemistry [this is the Eveready AA and AAA lithiums] is specified from -40C to 60C but performance suffers badly at -40C. Even at -20C at heavy loads the li-ion does better.

Ray: Right, it sounds like Li-ion would be fine for your application. The real storage problem would be summertime glovebox storage in Tucson, AZ.