I glanced through this thread but here is my take
Lithium ion holds more energy per weight/volume
They come in higher capacities and more sizes then NiMH
NiMH is better in almost every other way.
You can store them fully charged without losing capacity
They hold their charge well (at the cell level li ion is ok but in a product the electronics are always phantom draining it)
They last more cycles.
Temperatures don’t bother them as much
In a pinch you can use alkaleaks to replace them
They have no explosion risk
Chargers are easier to get chinese chargers are luck of the draw in my experience)
They will still have virtually all their capacity years from now
And so on.
I would like to see more 4AA lights and hosts, but lithium ion is more sexy and has essentially cornered the market.
Agreed. Duracell and Energizer probably spend millions advertising disposable batteries. I know both companies make NiMh cells, I see them at WalMart and what not. I have never used them so I can’t attest to their quality. I imagine if the quality is there and everyone stopped using Alky’s and went to NiMh, they would lose many many millions. No use in making a product that makes you less wealthy. You know the same reason we can never seem to cure any ailments or diseases, no money in the cures, only money in the treatments.
I have successfully got most of my family and friends to invest in NiMh for all their normal battery needs. Remotes, kids toys, clocks, everything. Most things now days seem to require back up batteries for some reason. Quite some time ago I was looking for a alternative to Eneloop for the family. Something cheaper but would still work well with their needs. Found a set of 10 2500mah EBL AA NiMh for like 11 bucks or so. I ordered some and put them to work around my house. Great batteries. Work just fine in just about anything I put them in. The family started buying them up off Ebay and they haven’t bought AA’s or AAA’s in a very long time now. I use them in some of my AA and AAA lights and they perform just as good as any other cell I have tried. The Amazon brand of NiMh seem to be pretty decent as well and go on sale quite often.
You won’t find a Energizer or Duracell in my house.
I’ve read through this thread as i sure can learn some things about rechargeable batteries.
However, my understanding is Ni-MH and Li-ion cells pretty much have the same energy density per volume. If you factor nominal voltage times capacity you get about the same numbers.
What’s interesting with Li-Ion is they provide a higher more convenient voltage and can deliver more amps depending on chemistry?
As for decent cheaper alternatives to Eneloops i use BPI 2400mAh AA Ni-MH which have been tested and reported ‘fine’… I’d say quite good, especially for the price. I have tons of them i bought from FT over the years. Mainly in use in garden lights and AA lights. Nothing to complain about so far. https://lygte-info.dk/review/batteries2012/BPI%20AA%202400mAh%20(White-orange)%20UK.html
That may be true, even the wikipedia article says they can provide comparable energy densities.
However lithium ion is what everyone is using for high power applications, NiMH was patent encumbered till recently (wikipedia also has an article on this) so the technology was leapfrogged, large capacity NiMH was never developed and little research is being done on NiMH chemistry today which means it will never become a big player, and not because it does not have potential.
I typically use Eneloop, just wait till they go on sale, or Ikea brand Ladda batteries which are cost competitive and have decent enough performance.
Actually, the best lithium ion cells have upto 250Wh/kg, while the best NiMH cells have up to 125Wh/kg.
The problem is that above capacities of 2500mAh in the form of AA NiMH cells, the cells’ self discharge rates go tremendously.
We do have 2700mAh cells(Powerex) which are genuine capacity, but drain completely in 3 months.
Once upon a time, we even had 3000mAh AA NiMH cells! The problem?
They self discharged in 2 weeks.
While I do agree almost every point about Eneloops, the one thing that they can’t beat lithium ion at is energy density and power density, along with cost, and with different types of lithium ion chemistry other than 3.6V ones, better cycle life, like with LTO and LiFePO4.
In batteries like life things are a compromise, todays lithium ion could have more capacity but have to balance cycles, ignition resistance, discharge rate and other factors as well. Maybe even self discharge. That said i am happy with Eneloops, i just wish more flashlight hosts were available for 4AA in series
Yesterday’s lithium ion batteries were built in to consumer electronics that would typically be replaced in 2-5 years. Today’s lithium ion batteries are being built into cars that will last 10-20 years, and stationary energy storage that probably have 20-30y depreciation cycles. Keep up, man!
Lithium ion batteries beat NiMH on volumetric energy density, but don’t forget energy/gram, too. Lithium is the lightest metal. Nickle isn’t Uranium, but it more than 10x as dense as lithium.
Interesting factoid I found in an article about Opportunity, the solar powered Mars rover, who has been on Mars since 2004. (Which is currently in the middle of a planet wide dust storm blotting out the sun. There is a chance that she will not make it. :( )
14 years, 5000 (presumably shallow ) charge-discharge cycles, on freaking Mars, and still 85% capacity left! That's what happens when you treat batteries right.
Hopefully we don’t have to store our batteries in a near-vacuum at –50C.
I’ve put 20 new lithium-ion cells in the refrigerator, charged to 3.75v, and sealed them in a can. I plan to test them every couple of years, and see how well they store. They’re mostly 30Q’s, VTC6’s, and GA’s.
the number of Nimh Eneloops I use might be higher than the number of 18650´s I use but Nimh´s are covering for me FAR LARGER array of appliances or places to use.
(for example my Peltor Active radio/noise mufflers, Burrel Trail cam - other cameras, remote controls, clocks, stupidly large amounts of my kids toys etc etc.)
BUT:
For power + performance I always use 18650 in my pocketable lights. Over 90% of times. It just adds “so little” as in weight and size but packs so much more.
This is, ofcourse, a personal opinion and I have had a lot of for example AAA-lights also in my use.
Nowadays, I seem to use them less and just go with all-rounder 18650 light.
Mars lander (and other planetary missions) keep their cells warm with heaters through the night (Mars has an slightly greater than 24 hour day). Let’s hope the dust storm doesn’t kill it. I dare say the mission planners are on the case, but there is only so much that can be allowed to freeze, not just the battery.
As do geostationary satellites through the night, and much worse, the eclipse season for geosats.
Interplanetary missions are in sunlight 100%, but the further they go, the dimmer the light. Still it’s all designed in. NASA tries not to use radioisotope thermal generators any more, kept for the Mil. with limited Plute stocks (even buying some from Russia) but that’s what’s still keeping Voyager going, such technology and reliability, massive respect.
If they ever go flat and freeze, it’s all over.
Toyota still have NimH in some of their Priuses, I have a Swiss friend with a 12 year old one and it is good as new, despite being hammered most days (that’s what happens in a hybrid with a small battery.) and doing 20-30K miles/year, she commutes from Zermatt to London every few months, and refuses not to drive.
And it works well when frozen for a week at –20C, no Liion can do that.
PS: the next lander (insight) is on it’s way.
Launched by an Atlas/Centaur (also relying on Russian RD-180 rocket motors)
I also use lithium ion in my hotrod lights because thats the hosts that are commonly available.
I would like a good 4AA host series, but today interestingly my most used light is the Xtar Moon RC2, i use it maybe a dozen times a day whereas my lithium lights are now used maybe once a week. That said the RC2 has a non removable li ion no name ( :confounded: ) battery but its the light distribution and form factor that make it so versatile.
