Ni-MH vs Li-Ion cells

uk_caver

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The only reason the camera and portable electronic designers dropped the AA/AAA cell form was because of packaging considerations. The consumer wanted super slim and light electronics to carry.
I guess that designers also like to do different things even when there's no great pent-up demand, and there's also more than a little profit in selling proprietary batteries.
 

qwertyydude

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Maybe the Japanese car companies are worried about lithium batteries because sony just can't seem to make a laptop that doesn't blow up :laughing:
 

drmaxx

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In short, I strongly advocate conservation of resources rather than generating or drilling for more resources. [...] I consider the LSD form of Ni-Mh to be good competition to the Lithium-something cells. LSD Ni-Mh cells are one of the many reasons why I am slowly converting back to Ni-Mh cells. Batteries of any form provide a bridge between the times when mains voltage/current is available, or simply that from an automotive alternator. Just do not assume that the main electric supply is normally available!

Not much to add there - I completely agree. It is interesting to see that people who encountered supply shortages of any kind are much more critical to our current generouse use of ressources. We have this initiative here in Switzerland, called the 2000W society. The idea is, that we cut down from our current total energy consumption, expresses as a power, of 6000 W per person (average Europe; approx 10,000 W in the USA). First, I thought that this is a kind of utopic goal - till I realised that this was the energy consumption in the 60s! And they lived quite well then...

On an other note. There was a research project here that looked into using the batteries of electric cars as a buffer for the electric grid. The idea is that in the future peak energy demand could be provided by the electric cars not in use. The user could allot a fraction of his battery to the electric grid and would be compensated for the energy provided. Much more efficient then having power plants just for peak demand. This shows that batteries could play an important role in our future energy supply. Lithium? I don't know - might not be the worst solution.
 

LuxLuthor

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Just to throw in an other thought: I bluntly claim, that most flashlight users do not need the energy density of a (rechargable) lithium battery. I look at my light use and I rarely run batteries down. Usually, you have the possibilty to recharge the light - and with frequently used lights you also do.
So, increase the capacity of supercapacitors by about a 5 (from 6 Wh/kg to 30 Wh/kg; see also http://lees.mit.edu/lees/posters/RU13_signorelli.pdf) and I would have the perfect energy storage for my flashlights 80% of the time. Charged in seconds and last as long as my LED...

All I try to say is: it's not always about the most energy in the smallest package - sometimes convinience and longetivity is a good argument too.
I stopped buying 2700 mAh NiMH and go almost exclusively for 2000 mAh eneloops. Just way more robust -even if I do not need the LSD most of the time.

Just to "go American" on you...there are those of us who are not all that impressed with LED's in terms of color spectrum, throw, and lumens (see list in my sig). Our interest and demand for higher power applications trumps conservation or the admittedly superior LED efficiency.

In many instances, we need the Lithiums for their higher voltage per cell. I still enjoy NiMH for many setups, but there are many benefits to various Lithium primary & secondary batteries, hence the burgeoning demand for them.

I just don't see there will be enough Lithium to move the automotive
industry to non-polluting vehicles. But then I don't buy the whole man-made cause of global warming anyway...so gasoline/natural gas is fine with me.
 

csshih

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I use Lithium.. because have a bunch from old laptop battery packs.
Moldyoldy, want to sell off your old lights/batteries? :)
 

moldyoldy

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Not much to add there - I completely agree. It is interesting to see that people who encountered supply shortages of any kind are much more critical to our current generouse use of ressources. We have this initiative here in Switzerland, called the 2000W society. The idea is, that we cut down from our current total energy consumption, expresses as a power, of 6000 W per person (average Europe; approx 10,000 W in the USA). First, I thought that this is a kind of utopic goal - till I realised that this was the energy consumption in the 60s! And they lived quite well then...

<snip>

I have relatives in Switzerland, just came back from there this summer. I rarely see so many solar cells on top of roofs as in Switzerland. The Swiss gov actively subsidizes solar cells. The fierce independence of the Swiss is demonstrated in many ways and is simply a reflection of Switzerland itself as the "Confoederatio Helvetica" - the Latin name for the confederation of the Helvetians. Note that Switzerland is NOT a member of the European Union! Long Live the Swiss Franc! :) ok, enough of politics.... :)

When I commented on the extensive solar cells on house roofs in Switzerland to an Austrian school teacher in his house in southern Tirol, he said that the Austrian Gov gives a very low subsidy for energy upgrades. On the other hand, his oldest son was a flashaholic and had modified various Fenix and other brands of flashlights to his interests, and had them on display in his room! In Germany where my other relatives live, the solar cell subsidy seems to vary widely by the state the people live in.

Back to the topic of batteries - I fully agree with you that those people who have experienced supply shortages tend to be much more careful of their supply and consumption. On the mountain "Calanda" above Untervaz in Switzerland, a couple refurbished a stone cabin set into the mountainside far from any mains electric grid. The "cabin" had absolutely beautiful interior wood finishing will normal amenities - and a large solar cell panel on the end of the house with a two large storage batteries and an inverter inside the house. Last summer I was sitting sipping a beer with him outside and I asked him how well the solar panel served him. He said that the only time the batteries were fully discharged was when they played cards all night long and lost power about 0500. :) Most of my relatives and acquaintances in Germany, Austria, and Switzerland can find a working flashlight quicker than the average US citizen!

As for a whole-house electric consumption, my single-family one-story house has an average electric consumption of 150KWH/month, so I already passed the 2000KWH/year level. The goal of energy efficiency in at least one state in Germany was set at 1500KWH/year. That level of electric consumption will be difficult to reach for even me without changing the house!

However, we need the flashaholics and experimenters to push the limits of both batteries and LEDs to drive innovation. The rest of us can purchase the latest lights and batteries to fund the early production. and then maybe we will also realize how far we have come from a 2D flashlight with a standard filament bulb of the 40's and 50's!
 
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LuxLuthor

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I have no idea how much energy I use, but you got me curious enough to go look at last month's bill. It was 1,494 KWh for the last month, and that was without air conditioning since the weather was nice! LOL! Then we have natural gas heat that is a whole other bill for the winter.
 

moldyoldy

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I have no idea how much energy I use, but you got me curious enough to go look at last month's bill. It was 1,494 KWh for the last month, and that was without air conditioning since the weather was nice! LOL! Then we have natural gas heat that is a whole other bill for the winter.

Wow! BTW, my house does have central airconditioning unit, but when the old one failed, I installed a high-efficiency AC - undersized for the house. The AC is rated at 18500BTU - for a whole house. The primary intention was to dehumidify the house and cap the temp below 80deg F. If I let the AC run all night long, the AC can pull the temp down to 70deg F and the house feels cold. When it was time for changing out the gas furnace, I choose what technically was an undersized gas furnace size for the house. The high-efficiency AC, the medium-efficiency gas furnace (85%), and the high-efficiency refrigerator, and all compact fluorescent lamps in the house have made quite a difference in energy consumption in that house! The upgrade project this summer was to replace the 1971 windows with a modern U 0.31 window. Another wow difference! Last months electric charge was 126KWH for the month. nice. Gas usage is down as well.

Back to batteries and Ni-Mh vs Li-Ion. In an effort to cut electric usage even more, my primary use of flashlights is avoidance of turning a "normal" interior house light switch. Yes, I also have a wooded backyard where all sorts of animals wander thru at night and trip the IR security lights, whereupon I try to find them with one of my 200+ lumen flashlights. My wife even looks for them with a flashlight! FWIW, the use of flashlights has been instilled in me since any age I can remember, and has been reinforced by many adult years what many Americans would consider less than ideal circumstances - no electric grid power or limited "on-time" for mains electric power. In the house I still use a flashlight in ceiling bounce mode for working on the laptop (to see the keyboard) whenever I do not have to read any printed material on my desk. I use a flashlight to get ready for work in the morning, including a shower. etc.

At any rate, the most significant complaint I have against Li-Ion cells is the sensitivity to being discharged too low. Either the protection circuit cuts off the current - leaving me in the dark! - or the life of the unprotected Li-Ion cell is shortened excessively. Ni-Mh cells at the end of their charge give me at least a chance at changing batteries.
 
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moldyoldy

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I just read in the German weekly magazine Der Spiegel that Obama evidently has plans for a million electric vehicles on US roads by 2015. Hmmm, with which batteries?

For those of you who read Deutsch:

Während Merkel in Brüssel der deutschen Autoindustrie Aufschub bei den CO2-Standards verschafft, will Obama durchsetzen, dass schon 2015 eine Million Elektrofahrzeuge auf amerikanischen Straßen unterwegs sind.
 

LuxLuthor

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Get ready for future bailouts of the electric car industry then...oh and if Somali pirates can plunder to their hearts content, how hard could it be to steal Bolivia's lithium?
 

snakyjake

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Great thread!

I'm still choosing Li-Ion cells because of the size, runtime, output in 1xCR123 lights. I like to carry my light in my pocket, and rather not notice it being there. However, the slimmer size of a 1xAA might be better to wear on some occasions. I'm trying to keep an open mind on my next light purchase.

I'd like to learn more about the fires of the Li-Ion. First, the battery is enclosed in a metal tube. The battery is small. The battery tube is usually sealed well, so not sure how much O2 is getting in there for a fire. Not sure what kind of fire can be made from a 1xRCR123 cell in a metal tube. Even if there was a fire/burn, it's not like I haven't been burned before. What I wouldn't want is for the light to catch fire when I'm not around and destroy something expensive.

A car battery is much larger and has a gasoline tank near by. Plus the liability concerns to the manufacturer.

Any fire or smoke on an airplane will always get people freaked out.

So my choice is going to have to be made on something other than safety.
 

mdocod

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Lithium Ion (Lithium Cobalt) cells, have a far better track record of safety here in flashlights than any CR123 primary cells. If Li-Ion is going to explode, it is most likely to happen during charging, not discharging. Whereas CR123 primaries obviously aren't to be recharged, they explode during discharge, or sometimes, even after the discharge has been terminated and the cell is just sitting there.

Eric

Great thread!

I'm still choosing Li-Ion cells because of the size, runtime, output in 1xCR123 lights. I like to carry my light in my pocket, and rather not notice it being there. However, the slimmer size of a 1xAA might be better to wear on some occasions. I'm trying to keep an open mind on my next light purchase.

I'd like to learn more about the fires of the Li-Ion. First, the battery is enclosed in a metal tube. The battery is small. The battery tube is usually sealed well, so not sure how much O2 is getting in there for a fire. Not sure what kind of fire can be made from a 1xRCR123 cell in a metal tube. Even if there was a fire/burn, it's not like I haven't been burned before. What I wouldn't want is for the light to catch fire when I'm not around and destroy something expensive.

A car battery is much larger and has a gasoline tank near by. Plus the liability concerns to the manufacturer.

Any fire or smoke on an airplane will always get people freaked out.

So my choice is going to have to be made on something other than safety.
 

JakeyCakez

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Throw a Li-ion battery in a fire and you'll see. CR123's when heated enough will blow the positive seal/top off and ignite instantly.

Interestingly, you can cut a CR123 apart with a hacksaw and pull out and unroll the plates and nothing will happen, except for the battery leaking out it's electrolyte, since these batteries are pressurized. I think the autoignition temperature for the lithium compounds used in these batteries is around 160F. once it ignites it burns very hot though, as most metal fires to (magnesium anyone? flame temp is ~3100C)

I don't advise anyone cutting open a cell either..


Oh, I personally pefer high quality NiMh cells (not those damn 2500mAh ones) because in most cases they will still be kickin 3 years later.
 
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bob_ninja

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I mostly stick with NiMH just due to availability. Also LSD pretty much resolve major issues NiMH used to have. I just got a flashlight using a 3W LED, 2 AAs. Amazing how much light it produces.

Cars are complicated. Toyota and Honda used NiMH simply because at the time it was much more mature and had better availability. In the past few years A123 and others developed some amazing Lithium based packs. However, they are still *VERY* expensive and availability is still limited.

Therefore, Toyota and Honda prefer to stay with NiMH simply because they think more expensive Lithium packs would cause car price to be to high. When you look at the present financial crisis so far they are right.

GM for Volt picked Lithium because they have nothing to loose and need to skip ahead of Toyota and Honda, so need a bold big advance. While I would love to drive a Lithium powered EV like Volt, I think during the weak car market Toyota and Honda will do far better with their cheaper NiMH packs.
 
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