I’d like to have some spare batteries and a backup flashlight in an emergency kit in our cars. And the hope is the batteries won’t be dead when they are needed at some point.
What’s the conventional wisdom on battery types that hold up better than others for in-car medium-term storage?
Although this is the consumable batteries forum, I’m open to rechargeable too.
Energizer lithium AA is good for 10 years.
>Energizer lithium AA is good for 10 years.
Just to clarify, I’m specifically concerned about all the temperature ups and downs typical in cars. The actual performance is more important to me than the on-paper rating. Is this 10 years from in-car use, or are you talking about what they say on the package?
I have some energizer ultimate lithium which beat 10 years and go out to 20 years (on paper) but I don’t know how they do in heat/cold cycles… am hoping this forum has already hashed out this question.
Ni-Mh Ladda from IKEA are good option.
Alkaline battery as a back up also will do the job but must change onece per year does not matter if they are full or not.
Lithium AA are very expensive.
They are marketed as able to withstand extreme temperatures, I remember one guy on here using the below zero. As for heat it says temps up to 60c going by a quick Google search.
I made a thread very simlar to this year’s ago, if I can find it I’ll give you the link but there wasn’t a lot of info but it might help.
>They are marked as able to withstand…
by “they” do you mean lithium, or ultimate lithium, or something else?
I found some good threads (after posting, silly me) now with keywords “car storage” (without quotes).
A good lithium primary is going to hold it’s charge much better/longer than any secondary (rechargeable) cell, especially in “harsh” conditions. So, I’d stick with quality (and fresh) name-brand lithium primaries. Heat is the real battery killer I think. So, years of heat cycles in a car (which can get very hot in CA summers) will definitely shorten their shelf life, regardless. Just plan on replacing them every few years (you can always check voltage levels once a year or so as well). As far as form factor/size, I keep a small stockpile of CR123a cells around for the same application, as I have several different lights (handheld, WML, etc.) that are cross-compatible with those. YMMV. 
I couldn’t find the thread I was talking about, perhaps it was someone else’s thread that I was posting in.
If you have a look for the differnt Energizer lithium spec sheets online you will be able to compare, here they average to about $2.50 per battery but I think in the US I’ve seen them work out to around $1 per battery which is good value I think.
As above there is also the CR123A batteries, I think Fasttech has some Panasonic ones for a good price… actually I just went to find the link and the 4 for under $4 are discontinued and the new ones are nearly $4 each but yoy might find some good deals if you shop around.
Both are good choices but genrally you will get more runtime using lower power and AA batteries would be easier to find in emergency situations if needed.
Imo, the choice of battery depends on how long you want to be able to wait before replacing or recharging
bottom line, if you don’t want to think about it for years, use Ultimate Lithium
LiIon, if replaced every month, can work
NiMh, replaced every 6 months, can work
LiIon, does not need to be replaced for 15 years
storage at 140F
Primary Lithium retains more than 90% capacity after 15 years
Secondary Lithium drops to 60% capacity in 3 months
NiMh drops to 70% after 1 year
how hot does it get in a car, rule of thumb, 50 degrees F higher than outside… so a car will get to 140F if it gets to 90F outside.
===
derived from these links:
“_LiIon, 60% after 3 months
NiMh, 70% after 1 year_”
http://www.led-resource.com/2011/10/introducing-energizer-ultimate-lithium-runtime-tests/
Ultimate Lithium “Retains 90% capacity after 15 years.”
risks of over discharge of LiIon, potentially explosive failure of LiIon,
“Li-ion cannot dip below 2V/cell for any length of time. Copper shunts form inside the cells that can lead to elevated self-discharge or a partial electrical short. (See BU-802b: Elevated Self-discharge.) If recharged, the cells might become unstable, causing excessive heat”
how hot does it get in a car?
http://acprocold.com/blog/hot-car-get/
“After 90 minutes, the average temperature difference is 48 degrees. On a 90-degree day, that equates to 138 degrees
…
Interestingly, these temperature increases are roughly the same no matter what the outdoor temperature is. Even on a beautiful 75-degree day, the temperature after 90 minutes will be over 120 degrees. If you’re in a desert heat wave and the outside temperature is 110, expect a car interior around 160 degrees.”
I mostly agree with this assessment. I live in the mountains in Northern Calif. near the Oregon border and I keep two lights in my car loaded with CR123 primaries and spares and have for the past 3-4 years.
It gets 80-100 degrees regularly here in the summer and into the teens and 20’s in the winter. This past summer we had lots of 90-100 degree days. So far so good. Lights working fine and spares still good.