Battery Tech

[NutSAK]

Currently, there are several types of battery technology for a flashlight user to choose from.  Here are some of the options, and what I feel are the pros and cons of each.

Let me know which technologies you use, and your opinions of them.  I have preferred NiMH AA's for powering my flashlights in the past, and have recently moved on to the excellent characteristics of the Ni-MH Hybrid technology.


Alkaline:

pros:

• inexpensive
• readily available nearly everywhere
• decent shelf life of 3-5 years

cons:

• poor power for high-current devices
• leakage (never good)
• non-rechargeable

NiMH: (Nickel-Metal Hydride)

pros:

• excellent power qualities for high-current devices
• can be recharged repeatedly
• low loss of recharge capacity
• good availability

cons:

• moderately expensive (short term)
• high rate of self-discharge (poor shelf life-will discharge completely in storage of 2-3 months)

NiMH Hybrid: (Sanyo Eneloop, Ray-O-Vac hybrid)

pros:

• same as NiMH
• low rate of self-discharge (85% power still remaining after 1 year of shelf life)
• great choice for moderate-use appliances like flashlights and digital cameras

cons:

• moderately expensive (short term)

Lithium:

pros:

• excellent shelf life of 10-15 years
• excellent power qualities for high-current devices
• lightweight

cons:

• expensive
• non-rechargeable
• poor availability (especially at reasonable prices)
• potentially dangerous lithium chemistry (especially when used in multiples)

Lithium-Ion: (Li-Ion)

pros:

• decent power delivery for high-current devices
• high maximum power output
• can be recharged repeatedly

cons:

• high rate of recharge capacity loss
• expensive
• poor availability
• very dangerous if not monitored for minimum and maximum voltage (VENT WITH FLAMES)

[zackhugh]

Hello,

I'm new here after just finding this forum yesterday so I hope you don't mind my posting.  I was actually kinda wondering when this type of forum would pop up since I'm a multitool junkie myself.  And of course, multitool addicts are normally also interested in knives, gadgets, and flashlights. 

I have many lights too and have used most of the batteries you are talking about.  I just happen to use whatever tends to work well with the specific light.  For example, in one custom light I have, the NiMH AA's works best as I can use the light guilt-free and it tends to work better than the lithium 123 cell it originally was configured for.  For the Surefire (SF) lights, including my EDC, I use the SF or Batterystation lithiums and that tends to work well for long-lasting intermittent use.  Some people take Li-On batteries and use them in the SF lights but I haven't done that yet.  For a couple other custom lights I have, they were designed specifically around a rechargeable Li-On battery and for that it works well since on low levels it can stay on for a very long time and still handle high-level brightness when needed.  For some of my smaller/cheaper lights the Alkalines are the best bet, but I gotta remember not to leave them in there for fear of corrosion.

Steve

[J-sews]

Hi zackhugh, welcome to the forum for multitool addicts and junkies.  (Keep in mind though, we are not the cure, we are the desease!) 


Hey NutSAK, very interesting battery comparison. I read through it yesterday and felt pretty naive. I didn't realize there was that many options in batteries. I would have expected one type to be the best, and another type to be the cheapest, no need for anything else. Silly me.
 
A question: what is the potential danger you refer to about Lithium batteries?

[665ae]

I don't deal much with Lithi's... but there exists a possibility that the battery can build up pressure and rupture the case.  When it does, it's usually accompanied with a significant amount of flame

http://www.equipped.com/blog/?p=42

[Grant Lamontagne]

Now that I think about it, I am sure that's a bad thing, but it also seems pretty cool!

Maybe the reason lithium batteries are so expensive is because they are saving up for the lawsuits?

Def

[665ae]

Hehe... I think the "Vent with Flame" is pretty cool too. 

Although, it's not as cool as when a car battery explodes

[NutSAK]

Litium primaries (non-rechargeables like CR123A) are generally very safe when used by themselves.  The more batteries an appliance requires, however, the more the possibility of danger.  This is because the amount of "charge" each battery has can vary significantly when they are not produced correctly.  The problem arises when one battery that has a high charge is combined in series with one of low charge (as in a two-cell flashlight).  The battery with high charge will actually reverse-charge the low charge battery, increasing the possibility of VENT WITH FLAMES.  This is the reason you've always been told to not mix brands of batteries, and batteries with differing charges.

Li-Ion (Lithium Ion) rechargeable batteries are fairly safe, if they are voltage protected.  Voltage protected Li-Ions have a built-in protection circuit that does not allow the voltage of the battery to go above a certian threshhold (when charging), or below a certain threshhold (when in use).  Either of these conditions is very bad for Li-Ion, and could cause VENT WITH FLAMES.  The electronic protection circuit is like a fuse.  If the voltage goes outside the protection circuit's parameters, it will "cut" an internal connection, rendering the battery useless.

[J-sews]

......The battery with high charge will actually reverse-charge the low charge battery, increasing the possibility of VENT WITH FLAMES.  This is the reason you've always been told to not mix brands of batteries, and batteries with differing charges.

That sounds like a lesson someone, somewhere, learned the hard way!   

Now that you mention it, I've often read that notice about not mixing brands and types of batteries. I confess though, that I never paid much attention to it. 

Guess I will from now on!!