Lithium batteries in flashlights?

[Stormin Mormon]

Yeah, but what is the cosine of that? Then, I'm also curious for the

3rd root to two sig figs, and using slide rule is legal in case the power is out.

[RicodJour]

There's a geek for _everything_.

I thought I'd gotten 3 for under $20, but it mighta been 3 for under $30. I just picked them up from Costco, and I can't find the receipt. Here's the same thing from Amazon @ $30.

Don't be fooled by the multi-LED lights. A single CREE or Luxeon is superior. CREE LEDs also produce very white light so there's very little color distortion. And there are also replacement LEDs for Maglites, which is a great upgrade as whatever batteries you're using will last much, much longer.

R

[clare]

Powergenix are rechargeable nickel-zinc - and about the ONLY rechargeables that have a high enough voltage to keep something like the LUMIX happy for any length of time.

[clare]

Alkaline batteries do not do well in higher current applications - where heavy duty carbon zincs "shine" They have an awfull shelf life - that is true. Alkaline batteries were not designed to meet the very high power demands of today's electronic devices. Alkaline batteries have a high rated capacity, but they can only deliver their full capacity if the power is used slowly. A 3000mah rated alkaline only delivers about

700mah in a high drain application like a digital camera. About 1000mah on a flashlight, and 3000mah on a simple transistor radio. Carbon Zinc AA batteries will put out up to 950mah (fresh battery) under the same load.(.7 amp - flashlight) (Heavy duty Zinc Chloride - not the el-cheapo basic LeClanche type).And at well less than half the price.

[willshak]

Stormin Mormon wrote the following:

$20 ($19.98) plus tax at Sam's Club.

[Stormin Mormon]

was one page that has some about the matter. From what I've learned over the years, carbon zinc cells are nearly useless for high current draw applications. It's nicad and NiMH that do well with high current. I don't think carbon zinc cells would do as well.

About 20 or so years go, I did an informal test of carbons versus alkalines. I tried high drain (Pocket flashlight, might have been AA size mini mag) versus low drain tape recorder that I used about an hour a day (four C cells). In both tests, the alkalines lasted four times as long as carbons.

I encourage you to feed your Lumix one carbon, and one alkaline. Replace the carbon as the camera goes into low battery, and let us know how many carbons equal one alkaline. Actually, I may buy a pack of four AA carbon zinc cells at the Dollar Tree, one day. And take a bunch of pictures around the house just for fun.

[Jim Yanik]

Frank wrote in news:i9ammg$647$ [e-mail]:

the Everready lithiums are made for high current drain applications(charging the flash on a camera),so a flashlight isn't going to bother them.

[clare]

For which part? 2/3 of it is from Wiki, and 1/3 from experience several years ago.

As other sites have stated, load testing can give a distorted picture, but cyclic testing with a 2.2 ohm load (700 ma draw) yeilded just over an hour before the voltage dropped to the minimum spec (cannot remember what that was - something like .85 if memory serves correctly) while the duracell lasted less than 1 1/2 hours.

It was a fresh "industrial grade" heavy duty battery - cannot remember the manufacturer but I THINK it was Japanese.

[Robert Green]

Yabbut - the whole point of a flashlight, IMHO, is that you pick it up and it works. Since you're probably going to be reaching for it in an adverse situation (lights out, something's lost, etc) you just want it to work.

Just yesterday I just pulled some CZM batteries (Bexels that came with a remote I bought) out of a penlight that had been hanging bulb down from a hook. One of the batteries had leaked and all the goo reached the reflector and turned it black. The other battery, the one not near anything that a leak could damage, was fine.

Aside from trying to remember to store them bulb UP next time, I think I will still be using alkalines in flashlights just because of the longer run time.

You may be right about CZM batts being as good as alkaline in flashlights, in general tasks, but I want something that's going to work at full power every time I fire it up. These new long shelf life "precharged" NiMH "Eneloop" type batteries *may* be what I am looking for, claiming up to hold up to 80% of their charge after sitting for one year. So far, my tests have been mixed, and already have 1 Sanyo Eneloop that lost all its charge sitting in small penlight for three months. It's going back to Sanyo soon. The other Eneloop in the same flashlight with it showed a reasonable charge after six months. Both were from the same pack charged in the same charger. Go figure.

I just went and bought a whole mix of "precharged" NiMH's from Fry's to test for retained charge now that I have my fancy LaCrosse chargers with the cell by cell readouts. Got cells from Sony, Ray-o-Vac, Sanyo and one other whose name escapes me. Charged them all up, tagged and bagged them and six months and then a year from now I will see which cells remain charged and to what voltage and capacity.

Informally, as another test, I measure how much additional charge these supposedly precharged cells take when I first remove from the packages. The results are not encouraging. Since no manufacturer open dates these cells in an obvious fashion, I can't say how long they have been sitting other than by a copyright date on the package. All of the "precharged" cells I've taken out of the pack have absorbed significant recharging - some nearly

3/4's of their capacity. Others have been amazingly close to being fully charged. Same manufacturer, same battery package of 4 with significantly different results within a single package.

So, I won't really know until six months (and then a year from now for test phase II) how well they do. Using NiMH has the advantage of enforcing a three month cycle of flashlight inspection and the disadvantages of NEEDING a three month cycle of recharging. (-: A six month inspection cycle is a lot better than a three month one, IMHO, so these precharged cells might be the ticket.

The precharged NiMH cells might be especially useful in my old Nikon 950 cameras that are notoriously power hungry and can't sit for a month with normal NiMH's without dropping their voltage too low to be useful. I've augmented some with add-on lithium rechargeable packs, but add-on packs are always a nuisance.

The one downside of precharged cells is that the longer shelf life seems to have a cost. The precharged cells all seem to be in the 2000mAh range, where you can get close to 3000mAh in the really high capacity NiMH batteries.

Yes, choosing the right battery these days really is "rocket surgery." (-:

-- Bobby G.

[Stormin Mormon]

I'm also curious. From what I know, carbons are only useful for low load applications. Alkalines are much better under load. Nicad and NiMH excell under heavy load, as also the new lithiums. As I write, I'm doing a battery "shoot out" and will publish the results in an hour or so.

[Stormin Mormon]

Just finisheed a primitive battery test. As Clare had said that carbon cells last longer with high drain applications. Today I visited the Dollar Tree, near me. I bought an 8 pack of carbon zinc cells, and a two pack of alkalines.

When I got home, I put one each of the carbons and the alkalines into my digital camera. I set the flash to "forced on" and started to take pictures.

The camera went dead after 121 picture. I checked the batteries, and the carbon zinc cell was lower. So, I put another carbon cell in. With the part used alkaline. I kept taking pictures.

104 pictures later (all with flash) the both batteries were low, with my swing meter tester. I used a Battery Manager Ultra, to check the voltage. The carbon was 1.33, and the alkaline was reading 1.34 volts.

I put in a new carbon cell, and got about 10 more pictures out of the combination of batteries. One new carbon zinc cell, and one used alkaline.

For fun, since I had a lot more carbon zin ccells, I tried two of them (new). The camera would turn on, pause a second or two, and then turn back off. Aparently, my Panaonic Lumix LS-70 does not run on carbon zinc batteries if two are used. Even if the two are brand new.

What surprised me, was the ratio 2:1, which is different than my flash lights at 4:1. And my tape recorder, which was also 4:1.

[clare]

You were drawing a lot more than 700 ma - and I never said you could use carbon batteries in a CAMERA. Particularly not the LUMIX. I can't run it on NiCads or NiMh batteries either - Fresh out of the charger they are good for a few pictures within a day or so - a week out of the charger and the camera won't even turn on. It's either alkalines or Lithiums - I generally use lithium E2 Energizers in mine. Also, were these standard cheapy cells or the heavy duty cells?

I guess I should repeat my test again with currently available zinc/carbon batteries and monitor the current and voltage throughout the cycle. My numbers would be a little off because I assumed constant current draw - with declining voltage the current would drop off somewhat. Don't know if I still have the 2.2 ohm 2 watt finned power resistor I used back then either. Don't know if the industrial cells I tested are still available here either - most likely only cheap chinese crap.

Current draw was determined based on KPR222 Krypton flashlight bulb used in 2AA flashlight..

[Robert Green]

That's actually a big difference in the world of cameras like my Nikon 950's and 2100 that shut down when the voltage drops below a certain point (which happens to be right around the voltage of most NiMH cells except for hot out of the charger). Fortunately, cheap lithium rechargeable packs are available for the 2100, but not the 950's (the greatest camera for close-up and "low angle" photos ever made, perfect white balance and wide dynamic range - has a head that swivels and can focus to 1mm but sucks down batteries faster than I can feed them and, of course, also has an incredibly badly designed battery door - the only ones that aren't broken are ones that have never been used).

4x1.2 = 4.8V but 4x1.6 = 6.4V so to a camera looking for 6.0V, it's easy to see why the lithium cells are such better performers. They also perform far better than alkalines at low temperatures. I use them in all my remote temperature and PIR sensors outside the house where they last 3 years compared to an alkaline's 2 years. Any maintenance I can skip outside is welcome, so the extra cost of the batteries is offset by the decrease in the nuisance factor. Shelf life is 7+ years and I have yet to have one leak or explode. (Knocks on wood!)

-- Bobby G.