Alkaline batteries vs. Li-ion

jdl6mm

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Is it ok to use alkaline batteries or not? I know that seems like a dumb question, but let's say you're modifying a six D cell mag light. Shorten it to use different batteries or alkaline ok?
 

flatline

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Assuming alkaline batteries can provide the current/voltage that you need, they're fine. Just don't let the sit in the light when it's not in use just in case they leak. Also, get in the habit of inspecting alkaline cells before you use them, even new cells.

I have several D cell flashlights around the house. I keep at least one under every sink in the house (along with a fire extinguisher and a first aid kit). The flashlights have LSD NiMh cells in them but I keep an unopened pack of D cells right next to each light so that if the light is needed for more than casual use, there's a fresh set of cells with long run time. If they haven't leaked in the package, then it's very unlikely that they'll leak inside the light for at least the next couple of days.

--flatline
 

StarHalo

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- You wouldn't shorten a 6D Mag, you would just buy a lesser-cell Mag or body tube; cutdowns require sending the light out to a machinist and paying him for his time, a new light/host is cheaper.

- Alkalines give poor regulation but max runtime; You get 100% output when the battery is new, which falls quickly to ~25% in ~2 hours, but then the output will hang there for many hours, very slowly dimming to zero. This is why your Mag always seems brightest when you first install new batteries - it is. NiMH/Eneloop batteries give max regulation but mediocre runtime; output is 100% nonstop for a few hours, then instant death. Alkalines can eventually swell/leak, Eneloops do not. Alkalines will begin to get iffy at freezing temp, Eneloops will continue working to 0F.
 

fivemega

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Is it ok to use alkaline batteries or not? I know that seems like a dumb question, but let's say you're modifying a six D cell mag light. Shorten it to use different batteries or alkaline ok?
I never use alkalines because they leak and ruin the flashlight. I mostly use rechargeables because operation cost is less in long term and can provide higher current.
If your modification requires for example 5, 4, 3, or 2D size cells then buying new makes more sense but if you need for example 3.5D to accommodate 3x26650 or 1.2D to accommodate single 26650, then your choice is to shorten and rethread longer flashlight.
Please let us know about your decision and plan.
:twothumbs
 

DIWdiver

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I use Duracell alkalines in applications where I expect them to last for more than a couple years, like remotes. I also use them where the extra voltage is needed, like in some smoke detectors. These will generally let you know the battery is dead before it leaks.

I have not used any other brand in at least 20 years, and probably won't. I have had only one bad leak, in a flashlight that hadn't been used for many years.
 

jdl6mm

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May 11, 2015
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Thanks everyone. I have a few choices to make. Pretty certain I'm going with 26650, probably three, maybe four. Will make some measurements, look at specs on drivers and emitters and will keep the post going and let you know. Gonna try to stick with one emitter, but may switch it up to three. This is my first build. Go easy on me. Was even thinking about cutting factory switch placement out, shortening light, and doing tailcap switch. Get things in the lathe tomorrow I guess.
 
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