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How to prolong lithium based batteries

batteryuniversity.com

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Re: How to prolong lithium based batteries

#71

Post by Filligree »

andruby wrote: post #50
speedgoose wrote: post #14

Earlier quoted context omitted.

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…

> The voltage is a mess on LFP 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...

Excellent link, thank you!

Re: How to prolong lithium based batteries

#72

Post by muzika »

sitkack wrote: post #36

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…

3.92V is very conservative, that is a good voltage for long term storage even. It should be safe to charge to 4.05-4.10V regularly.

Re: How to prolong lithium based batteries

#73

Post by fy20 »

speedgoose wrote: post #14
Filligree wrote: post #7

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…

The 100% charge thing is also for balancing, as most BMSs are pretty dumb and only use passive balancing.

When an individual cell reaches a set voltage, a resistor is turned on which bleeds the excess power preventing that cell from overcharging. When the pack reaches 100% theoretically every cell should then be at the same voltage.

Re: How to prolong lithium based batteries

#74

Post by Havoc »

I've been doing 80% >> 45% for a while on a 14 pro max....on a best effort manual basis.

Appears to be working...I'm on 93% battery health today while googling suggests others where hitting So unscientifically it does seem to matter, though whether it is worth the hassle is another question

Re: How to prolong lithium based batteries

#75

Post by Zak »

I've been using ACCA[0] to set limits on battery charging on Android devices for years. Note that it requires root.

ACCA can limit charge percentage, allowing the device to operate plugged in without charging beyond a certain point. It can also pause charging when the temperature exceeds a threshold, limit the charge rate, and several other tweaks to charging behavior. By default, I use a charge limit of 60% and a charge rate of 500 mA, increasing those when needed.

[0] https://f-droid.org/packages/mattecarra.accapp/

Re: How to prolong lithium based batteries

#76

Post by sghiassy »

Havoc wrote: post #74

I've been doing 80% >> 45% for a while on a 14 pro max....on a best effort manual basis. Appears to be working...I'm on 93% battery health today while googling suggests others where hitting So unscientifically it does seem to matter, though whether it is worth the hassle is another question

For what it’s worth, I don’t pay attention to my charging habits and my iPhone 14 Pro Max is at 92%

Re: How to prolong lithium based batteries

#77

Post by pkulak »

mnw21cam wrote: post #62

I have had my phone for 4.5 years. I charge it every night to 80% - I have Accubattery installed, so it pings to tell me to unplug it, and it also does a fairly decent job of measuring the capacity. I charge on a fast charger (10W) instead of the super-fast charger (18W) because that keeps the temperature from rising too much. I use the phone a fair amount, so I'm usually charging from around 50%. Therefore, the batt…

I just use the hell out of my phone battery and pay 50 bucks every 3 years to replace it.

Re: How to prolong lithium based batteries

#78

Post by chasil »

mnw21cam wrote: post #62

I have had my phone for 4.5 years. I charge it every night to 80% - I have Accubattery installed, so it pings to tell me to unplug it, and it also does a fairly decent job of measuring the capacity. I charge on a fast charger (10W) instead of the super-fast charger (18W) because that keeps the temperature from rising too much. I use the phone a fair amount, so I'm usually charging from around 50%. Therefore, the batt…

On Android, I use the "Advanced Charging Controller" module for Magisk.

If you have some way of rooting your phone and installing Magisk:

https://magiskmanager.com/

Then you can download the ACC module and set it to halt charging at 80%:

https://github.com/VR-25/acc

This functionality should be native to Android and iOS. Yesterday.

Re: How to prolong lithium based batteries

#79

Post by speedgoose »

izzydata wrote: post #29
speedgoose wrote: post #8

I’m not a battery expert but some coworkers from the battery lab at work are, and they say that charging more often is better than doing big cycles. On most chemistries. In more concrete terms, it’s better to keep the state of charge between for example 60 to 30% compared to for example 80% to 15%. Big cycles like 100% to 5% are the most damaging over time.

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.

It depends on the BMS. Some have big buffers, some don’t. One simple clue is how fast it charges relative to the state of charge. If the battery takes a while to go from 95 to 100%, it more likely goes to a full state of charge. If the battery charges very fast to 100%, it probably has some buffer.

In my experience, vacuum cleaners and smartphones are designed to destroy the battery as fast as possible, while most car manufacturers will have a big buffer and lie about the true 100%. With some notable exceptions though, like Tesla that allows to charge to 100% with some scary warnings or Nissan that designed some early Leafs battery pack without longevity in mind.

Re: How to prolong lithium based batteries

#80

Post by speedgoose »

andruby wrote: post #50
speedgoose wrote: post #14

Earlier quoted context omitted.

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…

> The voltage is a mess on LFP 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...

True, it’s very flat. And If you add some major temperature changes over many days and a descent amount of non full charging cycles, it’s more challenging. Maybe I wasn’t told it was a mess, but it’s how I remembered it.
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