Usb chargers, 1 amp and 2 amp output

[fhills]

Have taken to using a high capacity anker powercore powerbank for my camping touring trips.

It seems that it benefits from being charged by a charger with a 2 amp output - faster without doing any damage - so one is on order from 7 day shop.

I gather that the chargers commonly supplied with tablets etc are usually only 1 amp output and peering at the small print on mine they seem to be.

Questions.

When this charger arrives can i use it to charge my tablets/kindle etc for a faster charge without doing any damage?

And if so why aren't tablets etc supplied with 2 amp output chargers in the first place?

Faster non damaging charging is clearly useful on tour as i won't often have the luxury of an overnight mains charge. It will be more a matter of grabbing an hour or two top-up in bars, caffs etc. And if possible it seems desirable to top up tabs directly where possibly as i am aware that there is an inevitable efficiency loss with all powerbanks, even the best, and so far the anker seems to be a quality product.

[Kim]

USB power supplies are a constant-voltage device (that is, they behave a bit like a battery).  The current rating reflects the maximum that you can draw from them before the voltage drops out of its specified range (or the output is temporarily switched off).  A higher current rating does *not* mean it will somehow 'push' more power than a device wants to draw^[1].  It is therefore safe to use any USB supply to power any device, although some may have an inadequate current rating and charging will fail (or take *ages*).

It's (perhaps marginally) more expensive to build a charger with a higher current rating - higher spec components have to be used, more care has to be taken to deal with excess heat and so on.  Therefore, to save costs (and weight), devices are usually supplied with a charger with a current rating that matches their charging ability.  You can reasonably infer that a device supplied with a 1A charger isn't capable of charging at more than that - when connected to a 2A or 4A charger it will still draw 1A.  IME tablets tend to be capable of charging at 2A and are supplied with 2A chargers.

Of course, a 4A charger (with multiple sockets) means you have the capacity to charge your 1A phone and your 2A powerbank at the same time...

(Also note that current draw while charging batteries isn't constant.  As the battery gets full, the current will taper off.  This is controlled by the charging circuit inside the device, which prevents damage or overcharging the battery.)


_{[1] Indeed, we have a term for this - it's called 'voltage'.}

[hbunnet]

Thanks for that Kim, useful and well explained.  I will be copying it to family members.
<edit> who insist on using several chargers

[Ham]

Remember also, all chargers are not equal.

I'm very happy using a 6 port version of this https://www.amazon.co.uk/iClever-Desktop-Charger-SmartID-Technology-Black/dp/B0156HKR7W which adapts charging to the device and fast charging if supported. As it uses IEC C7 (figure of eight) connector, it is a simple matter to change the lead when using abroad.

[Biggsy]

Remember also, all chargers are not equal.

Cables, too.  Excessive wire resistance can end you up with a reduced charging current (even with the supposedly clever Anker and Aukey chargers I have that claim to make up for such losses).

[frankly frankie]

USB power supplies are ... [lots of useful info] ... which prevents damage or overcharging the battery.

In other words, er ... they're foolproof ? 

[Kim]

USB power supplies are ... [lots of useful info] ... which prevents damage or overcharging the battery.

In other words, er ... they're foolproof ?

There's always a better fool - for example the system for a given charger identifying its capabilities to the load is a complete mess (hence tablets "charging slowly" and Garmin Edges going into USB storage mode and similar annoying but not safety related shenanigans).

Also beware of Cheap Shitty Pink USB Chargers From China...

<a href="http://www.youtube.com/v/ioAq7PI1Uwg&rel=1" target="_blank">http://www.youtube.com/v/ioAq7PI1Uwg&rel=1</a>
https://youtu.be/ioAq7PI1Uwg

[mrcharly-YHT]

It seems that it benefits from being charged by a charger with a 2 amp output - faster without doing any damage - so one is on order from 7 day shop.

That bit seems unlikely to me. Most modern phones come configured by default to trickle charge mode, to extend battery total life. Fast charging 'wears out' the battery.

[Ham]

It seems that it benefits from being charged by a charger with a 2 amp output - faster without doing any damage - so one is on order from 7 day shop.

That bit seems unlikely to me. Most modern phones come configured by default to trickle charge mode, to extend battery total life. Fast charging 'wears out' the battery.

Fast charging something that isn't meant to (if that's possible) might, Quickcharging Qualcomm ^TM style doesn't, allegedly. And anyhow, it's bloody worth it 

[mrcharly-YHT]

It seems that it benefits from being charged by a charger with a 2 amp output - faster without doing any damage - so one is on order from 7 day shop.

That bit seems unlikely to me. Most modern phones come configured by default to trickle charge mode, to extend battery total life. Fast charging 'wears out' the battery.

Fast charging something that isn't meant to (if that's possible) might, Quickcharging Qualcomm ^TM style doesn't, allegedly. And anyhow, it's bloody worth it 

I can believe that a device might have a special charging mode (pulsing, maybe) that enabled to charge faster than some other devices with lesser wear. However the fundamental battery technology is absolutely identical, device to device. Higher voltages and heat are the main causes of degradation; lets have heatsinks and fans in our phones.

[Ham]

Qualcomm quickcharge operates @ 9v, somehow. Clever these Japanese.

'ere you go https://lifehacker.com/charge-your-phone-in-half-the-time-quick-chargers-expl-1682276989

FWIW, on my Nexus 5X the additional heat is not noticable. I've experienced higher temperatures during discharge, often. My phone has just gone from 15% to 80% in 40 minutes, and it is barely warm.

[mrcharly-YHT]

Nothing in that article contradicts what I've already said.

Heat degradation kicks in around 30c, so cooler than body temp.

Think on this; Qualcomm make money from sales of devices such as smartphones. Most smartphones have fixed, non-replaceable batteries. Selling a device that increases the convenience, but shortens the lifespan of a device increases sales for Qualcomm

[fhills]

It seems that it benefits from being charged by a charger with a 2 amp output - faster without doing any damage - so one is on order from 7 day shop.

That bit seems unlikely to me. Most modern phones come configured by default to trickle charge mode, to extend battery total life. Fast charging 'wears out' the battery.

Hi Charly - I thought Kim's informative and exhaustive post said that it wouldn't do any harm at all. In any case I am primarily getting the 2A charger for the Anker powerbank and they specifically recommend a 2A charger.

As for phones I am that rarest of beasts these days, a non smart phone user. My phone battery lasts ages, extracts little power from the powerbank for a full recharge and the battery is replacable. So, touring, not only am I assured of phone coverage for emergencies I am spared distracting alerts and internet nonsense - when I want/need the net I retreat/advance to a spoons or suchlike and get the tab out of the pannier.

[fhills]

thanks for your post above ham.

Encouraged me to go looking.

Think I may also get this:

https://www.amazon.co.uk/Anker-Charger-PowerIQ-Technology-Motorola-Black/dp/B016LPMFUA/ref=pd_rhf_se_5?_encoding=UTF8&pd_rd_i=B016LPMFUA&pd_rd_r=Z7QFD74FWNYQWN8JPQBT&pd_rd_w=FpoQN&pd_rd_wg=UXIyy&psc=1&refRID=Z7QFD74FWNYQWN8JPQBT#Ask

folks feel free to point out any issues with it.

2 ports will be fine for my travels I think - I only usually have 3 devices to charge - powerbank, tablet, phone. The phone charges in no time and can  be recharged from the powerbank without extracting much from it.

It also plugs straight into the socket with no lead making it more compact/less obtrusive.

[frankly frankie]

Having a lead between charger and socket can often be an advantage, if the only socket is awkwardly-positioned.

... I am spared distracting alerts and internet nonsense ...

Phones can be switched off you know 
(full disclosure - I too am a non smartphone user)

[Morat]

Having a lead between charger and socket can often be an advantage, if the only socket is awkwardly-positioned.

Yes! Some hotels like to put the only useable socket immediately above a fixed shelf/table.

[Ham]

thanks for your post above ham.

Encouraged me to go looking.

Think I may also get this:

https://www.amazon.co.uk/Anker-Charger-PowerIQ-Technology-Motorola-Black/dp/B016LPMFUA/ref=pd_rhf_se_5?_encoding=UTF8&pd_rd_i=B016LPMFUA&pd_rd_r=Z7QFD74FWNYQWN8JPQBT&pd_rd_w=FpoQN&pd_rd_wg=UXIyy&psc=1&refRID=Z7QFD74FWNYQWN8JPQBT#Ask

folks feel free to point out any issues with it.

2 ports will be fine for my travels I think - I only usually have 3 devices to charge - powerbank, tablet, phone. The phone charges in no time and can  be recharged from the powerbank without extracting much from it.

It also plugs straight into the socket with no lead making it more compact/less obtrusive.

I've got one of them. too, which I tend to use in weight sensitive scenarios, works as advertised. Anker quality appears pretty reliable.

[fhills]

Phones can be switched off you know 
(full disclosure - I too am a non smartphone user)

yes they can frankie.

But of course it is rare for them to be - the deadly temptation is too great.

And not to mention the never ending updates.

[Mr Larrington]

Having a lead between charger and socket can often be an advantage, if the only socket is awkwardly-positioned.

Yes! Some hotels like to put the only useable socket immediately above a fixed shelf/table.

Once stayed in a place in Billings MT where the only unoccupied socket was behind, and at the exact same height as, the unit with the telly on it.

[mrcharly-YHT]

It seems that it benefits from being charged by a charger with a 2 amp output - faster without doing any damage - so one is on order from 7 day shop.

That bit seems unlikely to me. Most modern phones come configured by default to trickle charge mode, to extend battery total life. Fast charging 'wears out' the battery.

Hi Charly - I thought Kim's informative and exhaustive post said that it wouldn't do any harm at all. In any case I am primarily getting the 2A charger for the Anker powerbank and they specifically recommend a 2A charger.

As for phones I am that rarest of beasts these days, a non smart phone user. My phone battery lasts ages, extracts little power from the powerbank for a full recharge and the battery is replacable. So, touring, not only am I assured of phone coverage for emergencies I am spared distracting alerts and internet nonsense - when I want/need the net I retreat/advance to a spoons or suchlike and get the tab out of the pannier.

Nothing in Kim's post was about total battery life. I agree with everything she wrote.
If you have a need for fast charging, then you have a need for fast charging. I was just disagreeing with the statement that charging at a higher current is better for lithium ion batteries.

[Morat]

I'm not sure that you can say that most modern phones are configured to trickle charge. My two Samsungs (S7 and Note8)  and my previous Sony will use rapid charging where available, by default.

[Kim]

"Trickle charge" in my mind implies constant-voltage charging, which Li-ion charge controllers (which I'll reiterate is a chip inside your phone, not the thing you plug into the wall to power it) will switch to automatically when the battery reaches a certain voltage.  It's what you have to do to fill the last 10% or so.

I don't think you're likely to see a real-world battery life benefit from powering a 2A-capable tablet from a 1A supply, unless there's a serious design flaw in the charging logic (which should be designed to keep charging current within the spec that the battery will safely tolerate).

On the gripping hand, I can't remember the last time I had a smartphone-like device suffer from battery failure.  Actually, I can: it was a Nokia E52 (with easily-replaceable battery).  These days - in the absence of physical damage - it's the inevitable march of software bloat that gets them well before the battery capacity becomes a problem.

[mrcharly-YHT]

'tis temperature that is the problem for li-on batteries (when talking about total battery longevity). Keeping voltage down is the solution to that - but charging at high current from a low charge point will get the battery hot, just as using a high voltage will make it hot.

So a really smart charging system will vary the current and voltage - go high for a bit, back off, high for a bit, etc. Best to have a wall-wart supply (or USB3.0 socket) that can keep up with the demand.

Just ramming in current as fast as possible isn't the best thing.

My nexus definitely had an advantage over other makes when it came to lack of software bloat - the vanilla android pushed out by Google was relatively 'clean'. Battery totally died before phone became slow, after about 2.5 years.

[fhills]

Many thanks for all the advice folks.

The anker 2 port charger I linked to above is on order, along with this lead:

https://www.amazon.co.uk/gp/product/B019Q0U31A/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I may be back with a separate thread about the maybe fraught subject of charging powerbanks from dynamos.

Thanks again.

[frankly frankie]

Aren't modern phone batteries Li-pol, rather than Li-ion?