charging phone to 80% prolongs battery life

[Rex Sanders]

To feed my expanding universe of USB-rechargeable devices, I put together two more gadgets to keep things charged, but not overcharged, while reducing phantom power usage.

#1 – Belkin Conserve Socket ($13 list)

This is a simple power timer. Select 1/2, 3, or 6 hours. Push the button on top, and the face socket is live for that length of time. I chose 3 hours.

#2 – Anker PowerPort 6 ($30 list)

Six USB-A ports, 60 watts total power. No need to go crazy on power-per-port, since slow charging means longer device life. Originally thought I had only 3 USB devices needing recharging, so 6 ports should last me a long time. As soon as the Anker arrived, I dug through my junk drawer looking for short cables (to reduce the rats nest effect), and discovered two more devices! Sigh.

Plug #1 into the wall, #2 into #1, a bunch of USB cables into #2, and a variety of rechargeable devices into the USB cables. The mess is on a low bookshelf in my home office.

As before, every week or two I reach over and click the button, then forget it. A day before a trip, I click the button, and every possible device is fully charged before I leave. When I return, plug stuff back in, click the button, and forget it.

Currently on the charger:

• inReach Mini satellite messenger
• Nitecore NU20 headlamp
• Aputure Amaran AL-M9 pocket video light
• Two ASUS 10,000 mAh battery packs (don’t know how I ended up with two)

Works great so far.

My iPhone is on a separate wireless charger – very convenient!

— Rex

[William Chilton]

As before, every week or two I reach over and click the button, then forget it. A day before a trip, I click the button, and every possible device is fully charged before I leave. When I return, plug stuff back in, click the button, and forget it.

Rex, if I understand you correctly, you’re saying that you constantly leave your devices close to fully charge. As I understand it, that is bad for battery life and that it’s best to leave electronic devices at about 40% charge while unused.

[Jerry Adams]

I use my phone every day, but my headlamp, inReach, USB power supply, bluetooth headphone I charge once per trip so I’m not doing so many charge cycles so they are less likely to die from battery lifetime issues, so less important to use battery lifetime preservation techniques

For example, I do one charge cycle on my InReach Mini per trip.  maybe 12 trips per year.  If a battery does 500 cycles before it loses 80% of it’s capacity, that would be 40 years.  If it lasts 40 years that’s well past my lifetime : )

If I just charge them when I get home, they’ll be ready.  Sometimes I’ll want to use a device between trips, nice if it’s charged up.

All of my other devices turn off when they’re fully charged.  The phone stays on, trickle charging, which they say reduces it’s battery lifetime.

 

[Rex Sanders]

I don’t worry about keeping most battery-powered devices near full charge. All devices lose battery charge over time while turned off, some faster than others, but manufacturers usually don’t tell us how fast. Yet when I need to use a device, I generally want it fully charged. And it’s hard for me to predict when I’ll use many devices.

My bigger worry, based on first-hand experience, is is killling battery lifespan by letting devices drop to 0% charge and stay there for weeks at a time. My scheme keeps infrequently used devices from a premature death, perhaps at a slight reduction in battery lifespan. According to Apple, there’s no battery lifespan difference (for example) charging from 95% to 100% every week versus 40% to 100% every 12 weeks (~3 months).

I would love to see realistic tests of different charging strategies and their impact on battery lifespan for many common devices, which vary in battery design and charge drain. That would be expensive and time consuming if done correctly.

Tradeoffs and choices based on too little information. Yours may be different from mine.

— Rex

[Jerry Adams]

yeah, good idea

battery lifetime just isn’t very important to anyone

maybe that will gradually change as technology matures so people want to keep their phones longer

[M B]

Most people don’t keep a smartphone long enough for it to matter. About 2 -3 years on average. as soon as they’re eligible to upgrade that’s what they do. They get their phones on the installment plan with their service.

 

Much Ado about nothing at all today. Just a few years ago batteries weren’t lasting as long, and they were also half the size they are today. It was a bit more of a problem then with battery is going bad.

 

There are better battery technologies better more expensive. Military uses some. Lithium titanate.  Can be fully charged to 100%in minutes, safer, 20,000 cyles.

 

[Roger Caffin]

maybe that will gradually change as technology matures so people want to keep their phones longer
Industry stats are that this is already happening. This is good.

Cheers

[Derek M.]

I have a USB C charger.  Maybe I should switch to a regular USB that limits to 500 mA.

Jerry,

A high quality USB-C charger with Power Delivery (PD) is going to be better than an old USB-A charger every time.

The amount of voltage and amperage (but mainly the amperage, I think) that a USB-C PD charger will deliver changes depending on the charged state of the battery it’s charging.  You can watch this happen in real time if you have a USB multimeter hooked up between your phone and the charging device.  I believe new phones will do this anyway though, controlling how much they are pulling from the power source, but I’m not positive on this one.

Anyway, the net result is that the power being delivered to your phone will ramp down over time.  So you may be seeing 18W total (let’s say 12V 1.5A) at the beginning when charging a depleted phone, and this will drastically decrease as the battery gets more and more charged.  This is done to preserve battery life, I believe.

I’ve been reading through this thread, and I suspect that a real battery expert (I must confess, I’m not one) would look at this thread and think we are doing way too much hand wringing here…

My take is that you could put a bunch of effort into this, but it will likely yield very little In real world returns.

[Jerry Adams]

yeah, I just use USB C charger and call it good.  I tired a regular USB charger but it’s funky, like sometimes it only charges to 75% or something.

I agree one could excessively hand wring over this : )

On the other hand, I used to just leave it on overnight.  Quite a few sources say leaving it charging like this can reduce lifetime.  It’s just about as easy to use that app that beeps when it reaches 80% and try to recharge before it goes below 40%.  If this gives me an extra year of lifetime that’s a good thing.

Too bad they don’t have a preserve battery lifetime charging mode with the ability to select fast and/or 100% for those occasional times that would be useful

 

 

[Author]

Posts