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.
Those batteries are barely degraded DESPITE being in a cold near vacuum. It's not doing any favors for the battery.