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>1. It’s ok to keep laptop plugged in, even at 100% battery It might be "ok" to keep it plugged in at 100%, but if your laptop has a "battery conservation" mode that limits the charge to 80% (or similar), that's even better.
If you're on a Mac, you can install the free version of AlDente: https://github.com/AppHouseKitchen/AlDente-Charge-Limiter I keep my MBA at 60% since it basically never goes for more than a couple hours within being plugged in.
I wish I could find this information for LFP batteries. There’s a lot out there, but it’s all mixed with advice for LiPo; I can’t find anything I trust to tell me the optimal voltages for maximum lifetime.
For general advice, they like it cooler[1] than other kinds of lithium batteries. Try to keep them between 15-25°C. Other than that, charge LFP batteries to whatever percentage you want whenever you want.
They are simply better than every other kind of lithium chemistry. Their practical downside is lower cell voltage (3.2 vs 3.8), and slightly lower energy density. I've spent the last 7 years building LFP-powered lawnmower-sized robots, and in practice, the lower voltage and doesn't matter. And, unlike other chemistries, they don't catch fire when you stab them.
For other kinds of lithium batteries, to maximize lifetime, keep them between 40-60%, avoid big charge swings (10-90%), and keep them warm (above 25°C).
[1]: At 35°C, tests show they lose about 5% more capacity after 2,000 cycles compared with 25°C. But even that isn't really a problem, because they don't get to 20% capacity loss until 4,000 cycles. See: https://iopscience.iop.org/article/10.1149/1945-7111/abae37, fig 3.
The article mentioned heat. I park my ev in the sun in CA. Definitely hotter than 86 degrees. Does the car protect the battery somehow with cooling, or do I need to find shade asap.
Varies by EV. The 1st generation Nissan Leaf was famous for overcooking its own battery pack because it didn't have the capability.
Some tools I use to actually follow this advice on various devices: I use Chargie devices (chargie.org - no affiliation) to control maximum charge level, and set thermal limits on smartphones and other small devices that can't limit charge internally with software. I also use a Peltier cooled phone holder and charger in the car (about $50 on Amazon), so it keeps the phone cool when charging and processing hard during…
I just clip my phone cradle to an AC vent on the dash. I've been doing this since [checks calendar] 2014, when I retired the last phone I ever had that had a specialized window mount accessory available. It cools when it is hot, and sometimes it warms when it is cold. Both things can be useful functions. (Even on old junk I've had without functioning aircon, turning the selector to "Vent," the temperature to "Cold,"…
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Do you know if it is true that a battery reporting 100% is really only 80% and 0% is really about 20%? I heard that somewhere, but have had trouble confirming it. At least for something like a common smartphone.
Probably depends on the device,but I bet that marketing incentives suggest most won't. I mean do you buy the device that says10 hours battery live or 8 hours battery life?
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Do you know if it is true that a battery reporting 100% is really only 80% and 0% is really about 20%? I heard that somewhere, but have had trouble confirming it. At least for something like a common smartphone.
I think it's hard to define "the true 100%". It's always a matter of finding a tradeoff between capacity and lifespan – by defining a voltage range.
Like making anything last, don't operate at the limits of its envelope. * Limit max temperatures * Reduce maximum currents in and out * For lithium batteries, limit peak charge to 3.92V, do *not* charge to over 4.1V or 30degC I can't find the specific research study, but NASA did a study that last I read was going on for over 30 years with a neglible drop in capacity by only operating in the flat portion of the charg…
About 5 years later Apple bragged about how their new laptops without discrete batteries were 2x the run time of the previous generation due to the batteries being 1/3 bigger, 1/3 more power dense, and the operating system being 1/3 better at managing battery life. I’m fairly certain the latter came from someone reading those papers and taking them to heart. They had an advantage for the next few years.
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If you're on a Mac, you can install the free version of AlDente: https://github.com/AppHouseKitchen/AlDente-Charge-Limiter I keep my MBA at 60% since it basically never goes for more than a couple hours within being plugged in.
Also batfi - https://github.com/rurza/BatFi
It looks really really sharp, the UX is definitely much more visually appealing than AlDente. I might have to check it out.
Anyway, the way this is currently solved e.g. in Android is clearly suboptimal. You can only configure charging in the settings, but obviously it depends on your current situation whether you want to use your device immediately and need a full charge.
I wish I could find this information for LFP batteries. There’s a lot out there, but it’s all mixed with advice for LiPo; I can’t find anything I trust to tell me the optimal voltages for maximum lifetime.
I was told that LFP is difficult because the battery management system (BMS) cannot reliably guess the state of charge using the voltage. The voltage is a mess on LFP. Even though a lower voltage prolongs the battery, you have to charge to 100% regularly to help the BMS. Thankfully the LFP chemistry doesn’t seem to mind high state of charge as much. As a popular source, Tesla recommends to daily charge the LFP batter…
That's a weird statement. The voltage curve for LFP [0] is just a lot flatter. That's nice for your electronics, but makes it hard to estimate state of charge based on the voltage alone. So the BMS needs to keep track of total energy used to calculate state-of-charge.
[0] https://www.jackery.com/blogs/knowledge/ultimate-guide-to-li...