Fenix TK45 with 8AA in trunk?

I have lost lights in the house do to alkaline leakage. I know NiMh can perform poorly in bad weather. The question is if I leave the light in the trunk with eight Li primaries and the head turned 3 times to prevent drain am I at risk of damage to the light?

Normally I have a Fenix UC 35 in briefcase but I commute far each day. If I was to need to use the trunk light it would be a real emergency. I would probably need the light fast and would not want to load all 8 cells if kept in a separate case.


Any any guidance would be helpful. I know I risk break in as I live near a city but safety is my main concern as we have no sidewalks or street lights were I live.


Thank you and sorry if a dumb question.

You should be fine. I do the same with lithium primaries in a flashlight and a headlamp in my car. Only thing I suggest, if anyone else uses your car, is to stick a note on the flashlight stating "Tighten head to use".

I've carried my lights in my car for years in ambient temperatures ranging from -35° C to +35° C without any problems. I change the batteries every few years, using the old ones in EDC lights.

I think you should be fine. Since you are unscrewing the head and using lithium primaries that shouldn't leak I don't see where there could be a problem.

lol, if i put Fenix TK45 with 8AA in trunk of my little brother's car, i'll double its value.

now on topic, i have surefire g3 in my glovebox, it is there all the time, i do not remember ever having any problems with it in either season, granted they are not primary aa but primary cr123, but they are still primary lithium.

also i used to have a camera in a glove box of my old car, i used aa lithiums in it, also no problems.

alpg88 said:

lol, if i put Fenix TK45 with 8AA in trunk of my little brother's car, i'll double its value.

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Lol good one

"lol, if i put Fenix TK45 with 8AA in trunk of my little brother's car, i'll double its value."

The car or the Fenix?

Str8stroke said:

"lol, if i put Fenix TK45 with 8AA in trunk of my little brother's car, i'll double its value."

The car or the Fenix?

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Technically, it doesntmatter. If either doubles the value of the other, then one is of equal value to the other.

dc38! Right on! Thats like a flashlight double entendre!

^^^LOL, y'all are great!

blah9 said:

I think you should be fine. Since you are unscrewing the head and using lithium primaries that shouldn't leak I don't see where there could be a problem.

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and +1 to this!

I Just ordered one of the Nitecore EAX to use with 8 AA. Will load it with Enloop NiMh batteries. I have a big Fenix that uses D cells, but it is so big and heavy, although it does put out a lot of light.


I like my lights that use some of the "speciality" or not so common batteries, but do like the ability to walk into any store and pick up batteries, which will usually be the common AAA to D cells. I may load my car lights with the lithium ( non rechargeable ) batteries because of the long life, and light weight.

jkingrph said:

I have a big Fenix that uses D cells, but it is so big and heavy, although it does put out a lot of light.

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Are you talking about the TK70 ? I usually carry mine with the shoulder strap. It makes it easer to manipulate. You can also carry it by resting the light on your shoulder (like carrying a D cell maglight).

bullpup said:

I have lost lights in the house do to alkaline leakage. I know NiMh can perform poorly in bad weather. The question is if I leave the light in the trunk with eight Li primaries and the head turned 3 times to prevent drain am I at risk of damage to the light?

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You'd probably do fine with low-self-discharge NiMH cells, and would save some money in the long run. Someone on this forum did a test with Eneloop AA's left in a car in Texas for a full year, and the batteries still retained their stated capacity even after being left in that heat (he parked outside).

As for cold, Panasonic says that Eneloops can be used down to -20C. I can confirm they still operate well at that temperature, although there's likely a decrease in run time. If you need colder than that, then lithium primaries are probably necessary.

Alkalines perform very poorly in the cold, and risk leaks, as you've found out. If you can find lithium primaries cheap, then they're probably the way to go, but around here they're ridiculously expensive so Eneloops are a far better option.