Don't stress the 'slow' charging (your battery sure doesn't)

[Wiley_11]

This isn't a fact, it's a falsehood that's been repeated so often, people believe it to be true... And one that's lead to the premature demise of many a battery. Some phones will turn off the charging circuit, but only temporarily until the phone drains the battery a bit, at which point it will start charging again.

Other phones will step the charging current way down in an attempt to create a situation where net discharge is 0%.

In both cases, they are still pushing current into battery that's either fully charged or damn near close. And this will cause premature wear on LiPo batteries.

"The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe."

How to Prolong Lithium-based Batteries - Battery University

So according to B.U. your statement is false.

 

[Mike Dee]

"The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe."

How to Prolong Lithium-based Batteries - Battery University

So according to B.U. your statement is false.

Not sure why but going to that site brought up one of those bogus virus warnings

 

[LeoRex]

So according to B.U. your statement is false.

Understand context. Read the whole link you posted

"When lithium-ion batteries must be left in the charger for operational readiness, some chargers apply a brief topping charge to compensate for the small self-discharge the battery and its protective circuit consume. The charger may kick in when the open circuit voltage drops to 4.05V/cell and turn off again at 4.20V/cell. Chargers made for operational readiness, or standby mode, often let the battery voltage drop to 4.00V/cell and recharge to only 4.05V/cell instead of the full 4.20V/cell. This reduces voltage-related stress and prolongs battery life.

Some portable devices sit in a charge cradle in the ON position. The current drawn through the device is called the parasitic load and can distort the charge cycle. Battery manufacturers advise against parasitic loads while charging because they induce mini-cycles. This cannot always be avoided and a laptop connected to the AC main is such a case. The battery might be charged to 4.20V/cell and then discharged by the device. The stress level on the battery is high because the cycles occur at the high-voltage threshold, often also at elevated temperature."

Got a Dell laptop? Go in there and look at the smart charging feature... There will be a link or two explaining why leaving a fully charged LiPo battery on a charger will shorten it's operating life.

Believe what you want though, it's your stuff.

 

[Aquila]

Question, I use Android Auto which charges while using. Yesterday I didn't get below 90% as me and my girl made a lot of small stops plus the battery seems really hard to drain.

Will those little charges throughout the day be harmful to the battery?

Many shallow discharge/charge cycles is better for your battery than few long discharge/charge cycles. The ideal state is to keep devices between 40% and 80% as much as reasonably possible. But, if you have a choice between going below 40% and charging to above 80, including going to 100%, going up is better than going down. And if your choice is further extreme, such as going below 20% or staying at 100% for a couple hours, going up is still better than going down.

 

[Aquila]

When lithium-ion batteries must be left in the charger for operational readiness, some chargers apply a brief topping charge to compensate for the small self-discharge the battery and its protective circuit consume. The charger may kick in when the open circuit voltage drops to 4.05V/cell and turn off again at 4.20V/cell. Chargers made for operational readiness, or standby mode, often let the battery voltage drop to 4.00V/cell and recharge to only 4.05V/cell instead of the full 4.20V/cell. This reduces voltage-related stress and prolongs battery life.

This is by far the most common setup on mobile devices made after 2010.

 

[Wiley_11]

Understand context.

Some portable devices sit in a charge cradle in the ON position.

Operative words: *On position*. If it was at 100% charge and kept charging while *on* you would have a point, but it doesn't in my usage.

Anyway my Li-ion batteries have lasted longer than anyone else I know over the last ~10 years so I'll keep doing what I do.

 

[Ca_lvn]

I have a two year warranty that's long enough for me

 

[Aquila]

I have a two year warranty that's long enough for me

This is an excellent point. I'd care WAY more if I were the type to use the same phone for more than 6-9 months.

 

[PowrDroid]

Operative words: *On position*. If it was at 100% charge and kept charging while *on* you would have a point

Exactly.

 

[openwheelracing]

Slow charging? Seems quite fast to me...

 

[X-Nemesis]

So the comment about seeing a lot of Dash charge batteries being ruined in a year. FUD or is Dash charge inherently bad for battery longevity?

 

[Aquila]

So the comment about seeing a lot of Dash charge batteries being ruined in a year. FUD or is Dash charge inherently bad for battery longevity?

If you go out of your way to abuse a battery, killing it (making it noticeably worse) is really easy to do in 6 to 12 months. Things that contribute to that are multiple deep charges per day, letting it get down to 5% or to where it turns itself off, leaving it on the charger for 12+ hours nearly every day, exposing it to extreme temperature swings, etc.

 

[LeoRex]

Operative words: *On position*. If it was at 100% charge and kept charging while *on* you would have a point, but it doesn't in my usage

You power down your phone when you charge? You are in the minority of that's the case. That is what this refers to: A device that is actively drawing power while it's being charged.

If your phone is on, at 100%, and connected to a charger, it most certainly is still charging. It's not pulling enough juice to overcharge.. it's just pulling enough power to maintain a full charge. Here's a recent chart from my 2XL

That middle column is the current in mA. Negative numbers mean charging. A typical idle draw for this phone is about 45 mA... Once the battery hits full, the current is 2 mA, the only way that can happen is if it's still pulling down power.

Sure, it's not a ton, but it's still charging. You do that for 6, 7 hours a night, every night, that stress will add up.

 

[PowrDroid]

That middle column is the current in mA. Negative numbers mean charging. A typical idle draw for this phone is about 45 mA... Once the battery hits full, the current is 2 mA, the only way that can happen is if it's still pulling down power.

Sure, it's not a ton, but it's still charging. You do that for 6, 7 hours a night, every night, that stress will add up.

Sure, sure. Applying a charge of fifty-eight thousands of one percent of the battery's capacity is dreadfully damaging.

 

[Golfdriver97]

https://support.google.com/pixelphone/answer/6090612

Google even suggests to 'not keep it charging more than needed'. That bit is located under the Keep it cool drop down.

 

[LeoRex]

Sure, sure. Applying a charge of fifty-eight thousands of one percent of the battery's capacity is dreadfully damaging.

I never said it was dreadfully damaging, only that it will reduce the life of the cell. You let it sit overnight, every night, that's what, 2000 some odd hours over the course of a year? A little bit of stress over a long time.. that can, and will, add up. There are other factors, of course... As I mentioned earlier, the peak charging voltage is just as crucial here. Phones that pushed that to the limit (such as the 6P) will degrade much quicker... And that phone was just 50mV higher than usual.

 

[Jaycemiskel]

Sure, sure. Applying a charge of fifty-eight thousands of one percent of the battery's capacity is dreadfully damaging.

I never said it was dreadfully damaging, only that it will reduce the life of the cell. You let it sit overnight, every night, that's what, 2000 some odd hours over the course of a year? A little bit of stress over a long time.. that can, and will, add up. There are other factors, of course... As I mentioned earlier, the peak charging voltage is just as crucial here. Phones that pushed that to the limit (such as the 6P) will degrade much quicker... And that phone was just 50mV higher than usual.

I'm with PowrDroid. I don't think it's a big deal. And I most certainly won't be keeping ANY phone for a long time.

 

[Tim1954]

Haha, love that analogy Leo! Well done!

 

[Mike Dee]

I never said it was dreadfully damaging, only that it will reduce the life of the cell. You let it sit overnight, every night, that's what, 2000 some odd hours over the course of a year? A little bit of stress over a long time.. that can, and will, add up. There are other factors, of course... As I mentioned earlier, the peak charging voltage is just as crucial here. Phones that pushed that to the limit (such as the 6P) will degrade much quicker... And that phone was just 50mV higher than usual.

Some folks won't be keeping the phone long enough to care what happens to it for the next user. I like to take care of my things regardless.

 

[LeoRex]

Some folks won't be keeping the phone long enough to care what happens to it for the next user. I like to take care of my things regardless.

But most do. There was a study earlier in the year that showed that the average consumer keeps their phone about 21 months. In the US, it's 22, up 2 months since 2014. And one of the most common complaints that users have is that their phone's battery just doesn't last as long as it did when they bought it. If you saw the Pixel 2 ads, Google made it a point of emphasis that the 2 should do better in this regard...

Now, granted, there are kiosks in malls across the country that specialize in quick battery swaps, but I think everyone would prefer to not have to drop $50-$100 to do this.

In a perfect world, I suppose it would be nice if a phone gave you the option; either charge with a focus on speed or to maximize longevity. But given the choice, the best choice for an OEM is to pick the latter. And this is exactly what Google has done... A full charge from 15% takes about 2.5 hours. If you give consumers the choice between a 2h charge and a battery that will only last a year before going downhill, or 2.5h and give them 2 years, I think most will take the longer choice.