Battery Types

[Outback in Idaho]

 Was looking over information on battery types, mainly used for flashlights, when I ran across this article on NiMH vs. NiCad vs. Li-Ion. Seems will be sticking with NiCad this winter in my LED Lenser M5, as NiMH does not perform well in cold weather.
 Next year will have to find a set of Li-Ion batteries in both AA and AAA, and a suitable charger. Bad part about Li-Ion is the batteries fail if drained, and well... flashlights often drain the batteries.


 "What is the difference between NiMH and NiCd. How do Lithium Ion batteries work compared to the others?"

 To tackle this question we have to look at the criteria for making the power tool battery decision. And then bring Lithium Ion into the equation to round out the choices when you're next making a power tool purchase decision.

 Read closely - your power as a consumer lies in your understanding of the products available!

 Criteria for Making Your Power Tool Battery Decision
 According to Building a Better Power-Tool Battery you should be looking at a battery's run time, life cycle, volts and amp-hour rating.

Run Time:
• Quite simply run time is the amount of work a tool can do before its charge runs out.

Life Cycle:
• Life cycle is how many times the battery can be recharged during its life time.

Volts (Power):
• Volts will determine work output of the tool. John Sara, cordless product manager for Milwaukee Electric Tool, says "Individuals currently using a 18-volt NiCad battery, should see 2 - 21/2 times more work output from a V28."

Amp-Hour Rating
• The higher the Amp-Hour rating the longer the battery lasts - be aware that power tool batteries of the same voltage will often have different Amp-Hour ratings.

NiMH vs. NiCad vs. Li Ion: Picking What's Right for You

Nickel metal hydride (NiMH) Batteries:
 I don't think I could define it better than wiki pedia: 'A nickel metal hydride battery, abbreviated NiMH, is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but has a hydrogen-absorbing alloy for the anode instead of cadmium. Like in NiCd batteries, nickel is the cathode.'

Nickel metal hydride (NiMH) advantages:
• lighter than NiCad
• 2-3X capacity to equal size NiCad

Nickel metal hydride (NiMH) disadvantages:
• fewer life cycles compared to NiCad
• shorter run time
• performs the worst in cold temperatures, so keep that in mind if you plan to use tools powered by NiMH outdoors in cold weather
• higher self-discharge level than NiCad
• voltage drop at near-discharged levels

Nickel cadmium (NiCd) Batteries:
According to Wiki pedia: the 'nickel-cadmium battery (commonly abbreviated NiCd and pronounced 'nye-cad') is a popular type of rechargeable battery for portable electronics and toys using the metals nickel (Ni) and cadmium (Cd) as the active chemicals.'

Nickel cadmium (NiCad) advantages:
• longer life cycles
• performs in cold temperatures (perform well to 20F)
• lower self-discharge level than NiMH
• no voltage drop at near discharged levels

Nickel cadmium (NiCad) disadvantages:
• Heavy, making it harder to use for longer periods of time
• May suffer from 'Memory Effect' or 'False Bottom Effect' if constantly discharged half-way and then recharged (wiki pedia)

The Lithium ion (Li-Ion) Battery:
The new comer to power tool batteries, Lithium Ion are hot because they have 'one of the best energy-to-weight ratios, no memory effect and a slow loss of charge when not in use,' according to Wiki pedia.

Lithium ion (Li-Ion) advantages:
• High performance in cold weather - to 0F - great for winter outdoor use
• Light weight. You can lift tools powered by Lithium Ion over your head all day.
• Increased life cycles over NiCad and NiMH, so it keeps going past other batteries
• more rapid charge times that get you back on the job more quickly

Lithium ion (Li-Ion) disadvantages:
• less tested than other battery formats - in early stages of development
• has a shelf life based on life of battery, not related to charge or charge time
• can sometimes erupt or explode in high heat - hot cars, direct sunlight, etc, or sometimes after tampering. a more dangerous battery than the others
• permanent damage to battery if stored at too-low discharge level, so be careful and keep these charged well

 What battery is right for your power tool decision? Clearly there are many different options, and many different pluses and minuses for each battery type. That's why it's imperative that you come to your purchase prepared with knowledge that will help you make the right decision for your situation.

 Plus you are certain to impress the guys at the big box tool depot when you display your knowledge about the different types of batteries and their different merits.

 Now you know what to look for - life cycles, run time, volts and Amp-Hours and you know the three major battery types. I hope that with that information you'll be better equipped to make the decision between a NiCD, NiMH or Li-Ion battery!

[dks]

I would also add that :

NiCd batteries contain Cadmium which is quite toxic and a big reason for the fact that they fell out of favour.

NiCd batteries should perform better in high drainage applications, a reason why many drills still use them.

NiCd are quite hard to find nowdays

NiMh nowdays can keep their charge for quite a long time (read their label).

LiIon have been around, now, for many years and are used in many cameras and Laptops, so they are not really untested technology. They cost more but I consider them the best overall too.

Battery cycle numbers work for me only with good original Camera LiIon batteries. For NiMh and NiCd they appear greatly overestimated.

oh, and make sure you do not drop any of these batteries as that tends to damage them significantly.

Lastly, get a good fast charger.

[Neil]

I think the original article must be a few years old.

When looking for batteries for your torch just choose low self discharge NiMH cells rather than the older type. These are now common but you'll normally pay a ten to twenty percent premium over older style NiMH and they have a slightly lower capacity (often around 2100 mAH compared to 2400mAH in AA).  LSD NiMH charge in a normal NiMH charger.

They don't like the cold much but if you keep your torch in your pocket rather than your bag that's not going to be an issue.

If looking at Lithium based cells for a torch always choose ones wit a built in protection circuit.  This should get around the problem of damage due to over discharge.

Do keep in mind that there is a slight but not rare possibility of "venting with fire" from lithium cells.  Not very likely at all if using them individually but odds of something bad happening increase significantly if using more than one in a torch at a time .

[Heinz Doofenshmirtz]

For cold weather lithium primaries are the best choice.  Either something like Energizer Ultimate Lithium (which are available in both AA and AAA sizes) or CR123 if that's the format you've got.  Duracell is coming out with some advanced lithium primaries now too, but I haven't had a chance to try them out yet to see how they compare.

I second Neil's comments on nimh's and RCR's.  Eneloops are much better than standard nimh's, and do better in cold weather.  RCR li-ion cells don't have any real problems in the cold, unless it's really cold, and if you stick to quality brands with protection circuits like AW, RediLast, or Kallie's, you shouldn't have a problem.  The only drawback, and it's a small one, is that protected cells have a very slight parasitic drain on them because of the protection circuit.  As long as you're willing to invest in quality cells and a good charger for them, it's very unlikely you'll have a problem with them.  (Just make sure the light you use is designed for them.)

[badwolf]

Not much to add but this is very true, I found out a the cost of £50
"• permanent damage to battery if stored at too-low discharge level, so be careful and keep these charged"
Li-Ion's must be stored with a charge

[Heinz Doofenshmirtz]

Li-Ion's must be stored with a charge

Yup.  Always top them off whenever you can. 

It's not hard to get yourself in the habit of swapping out the cell in your EDC light every other day, or two, depending on your usage.  I keep one of those little desktop plastic drawer organizers on my workbench next to my chargers with all my different rechargeables in it.  Whenever I swap out a cell, it goes right into the charger and I can just grab a fresh one right away.