16 replies to this topic

[TYREDNGRUMPEE]

Been down to PC World to buy x2 of these Portable PNY PowerPack CURVE 10400 at £12.49 each.

 

Figured that they would be a useful addition for touring or whatever crops up.

 

x2 of these, come to the same price as the next power storage offer and together have a capacity of 20800mah vs £25.00 & 12000mah.

 

There's x2 of them too, so they can be in two places at once.

 

Wonders, how many times can I say to, too, two, x2?

Edited by TYREDNGRUMPEE, 23 November 2016 - 07:42 pm.

[dmmsta]

Thats a good price for a decent branded power pack!

[TYREDNGRUMPEE]

Thats a good price for a decent branded power pack!

 

Which is what I thought when I dashed out to get them.

Then I checked the reviews on Amazon and saw that they got a real slating.

BUT

Had a closer look and saw that most/all the reviews were of the 2500mah models that would barely stroke a modern smartphone battery and hardly gave a true picture.

So don't pay any attention to the Amazon numpties that don't understand the concept of ma Hours.

It took my 2.5A wall chargers about 2.5hrs to bring the units to full charge from half, out of the pack.

Then checking that my phone (a Motog3) charges at 1A from the wall, connected to the 1A port and can say that charging takes place at at least 80-90% the rate of a wall socket, all the way to 100% phone capacity.

[fixitsan]

It took my 2.5A wall chargers about 2.5hrs to bring the units to full charge from half, out of the pack.

Then checking that my phone (a Motog3) charges at 1A from the wall, connected to the 1A port and can say that charging takes place at at least 80-90% the rate of a wall socket, all the way to 100% phone capacity.

 

 

You sometimes need t o be a bit careful making these sorts of assumptions.

A 2.5A wall charger has a 2.5A output at peak demand, but there is no reason to assume that the 10400mAh battery charges at 2.5A because of the fact that it has it's own inbuilt charging circuit which could be charging the cells at 1.5A instead

 

Typically the cells inside these devices are from the lower end of the quality spectrum, with very low peak C ratings, which in turn means that their charging current has to be limited.

 

A reasonably reliable way to measure instead (if you can't actually measure the current leaving the wall charger, is just to use a plug in power meter, the sort with an LCD display which are sold to help people use electricity more efficiently......assume a 90$ efficiency for the wall charger and 90% efficiency for the charging circuit inside the powerbank itself and you'll get pretty close to the number of Wh being stored.

 

Another thing is that 10400mAh is a bit meaningless on it's own. What voltage is that  measured at ? If the cells are Lithium ion then you can assume a nominal 3.6V per cell......so is it then 10400mAh at 3.6V ? Presumably it is so thats about 36Wh. What if the cells inside are NiMH cells and it's 10400mAh at 1.2V, then there's only about 12Wh.  I prefer to think of capacity in terms of Wh and not just mAh.....A plug in charger in the back of a consumer power meter can display Wh easily....I would expect to see at least 42Wh being used to charge one of those puppies anyway !

[TYREDNGRUMPEE]

You sometimes need t o be a bit careful making these sorts of assumptions.
A 2.5A wall charger has a 2.5A output at peak demand, but there is no reason to assume that the 10400mAh battery charges at 2.5A because of the fact that it has it's own inbuilt charging circuit which could be charging the cells at 1.5A instead
 
Typically the cells inside these devices are from the lower end of the quality spectrum, with very low peak C ratings, which in turn means that their charging current has to be limited.
 
A reasonably reliable way to measure instead (if you can't actually measure the current leaving the wall charger, is just to use a plug in power meter, the sort with an LCD display which are sold to help people use electricity more efficiently......assume a 90$ efficiency for the wall charger and 90% efficiency for the charging circuit inside the powerbank itself and you'll get pretty close to the number of Wh being stored.
 
Another thing is that 10400mAh is a bit meaningless on it's own. What voltage is that  measured at ? If the cells are Lithium ion then you can assume a nominal 3.6V per cell......so is it then 10400mAh at 3.6V ? Presumably it is so thats about 36Wh. What if the cells inside are NiMH cells and it's 10400mAh at 1.2V, then there's only about 12Wh.  I prefer to think of capacity in terms of Wh and not just mAh.....A plug in charger in the back of a consumer power meter can display Wh easily....I would expect to see at least 42Wh being used to charge one of those puppies anyway !

There are 3 USB ports
1x 2.5A/5V to charge the pack
1x 2.5A/5V charging output
1x 1.0A/5V charging output
tf complicated or confusing about that?
You know, that thing, where standardisation makes our lives simpler.
There should be a weekly limit to how many threads a user should be permitted to derail. naughty step

[fixitsan]

All I'm saying is you cannot charge a lithium battery directly with 5V. Unless you're trying to start a fire.

Every device with a lithium battery has its own charging circuit, which limits the current to the battery.....limited current to the battery means reduced current fron the USB supply....


Just saying, it might be capable of providing 2.5A but theres no reason to assume it operates at peak current at all times.


The charging methodology for lithium is usually CC/CV -constant current to 4.2v then constant voltage at 4.2v till the charge current falls to a predetermined minimum...... the last 25% of the charge cycle could easily be at as a low a current as 100mA in the case of these packs. So if you mistakenly assume that you were charging at 2.5A when actually its at 0.1A, then calculating how true the capacity is compared to the labelled capacity based on that just gets you into bother

Edited by fixitsan, 24 November 2016 - 10:04 am.

[Kelpie]

Thanks for the heads up TNG. We have a 8400 mah which has proved invaluable for camping and dead intercoms etc. This one looks even better.

[TYREDNGRUMPEE]

Thanks for the heads up TNG. We have a 8400 mah which has proved invaluable for camping and dead intercoms etc. This one looks even better.

 

   You could afford a His & Hers. 

There were loads in the standing wire baskets, that could be found dotted around the store.

They keep them around the mobile phone area or in a dedicated PowerPack area that lived by the eReaders and Tablets too.

Edited by TYREDNGRUMPEE, 24 November 2016 - 06:45 pm.

[Kelpie]

Got it. One's enough for us along with the wee one.

[TYREDNGRUMPEE]

Brill.

I've found that the PowerPack charges as well as my 240v charger.

Red = me messing last night after fully charging the pack.

Blue = Steep / rapid charge @ normal rate from 55% to full.

Green = Charging rate as throttled by the battery logic.

 

Seems to be robust to me.

Perhaps at least 4x charges for my 2 day battery of my moto G3.

Happy.

 

[fixitsan]

Ain't

 

Brill.

I've found that the PowerPack charges as well as my 240v charger.

Red = me messing last night after fully charging the pack.

Blue = Steep / rapid charge @ normal rate from 55% to full.

Green = Charging rate as throttled by the battery logic.

 

Seems to be robust to me.

Perhaps at least 4x charges for my 2 day battery of my moto G3.

Happy.

 

 

 

Didn't have any doubt it would charge...... they would be total crap if they couldn't do that.

 

Just need to be sure you measure capacity the right way.

 

I once bought 200 10000mAh units, to strip out the cells. The cells were badged as 2500mAh and there were 4 in parallel......working capacity at a 2A drain turned out to be 7000mAh.....and at 1A output it rose to 8800mAh

 

They're good devices when they work well, and hardly worth the money when they don't.......it's when they're stuffed with this sort of cell below that you start and wonder.....

 

 fakelith.jpg   44.96KB   0 downloads

[TYREDNGRUMPEE]

Ain't

 

 dude!

[fixitsan]

And they're only £9.99 with free delivery if you go mail order (or collect in store)

http://www.pcworld.c...152486-pdt.html

Edited by fixitsan, 24 November 2016 - 09:31 pm.

[Bjørge]

And they're only £9.99 with free delivery if you go mail order (or collect in store)

http://www.pcworld.c...152486-pdt.html

 

What kinda batteries are these ? Li-ion ?

[fixitsan]

 

What kinda batteries are these ? Li-ion ?

 

 

I'm guessing a form of lithium (-ion,-cobalt or -polymer)

 

10400 mAh is bang on for 4 x 2600mAh LiIon cells.....but that's not definite.

 

I'm picking one up today anyway (I went to look at one I had already to find it has been snaffled by my daughter !)  so I'll let you know. Hopefully it isn't lithium polymer (firecracker chemistry !)

[fixitsan]

What kinda batteries are these ? Li-ion ?

Yup li-ion. 38.5Wh capacity in total. 2A maximum input current. Dual outlets ..... 1x1.0A and 1x2.4A.... outputs can be active while the unit itself is being charged (some similar products don't allow it)

Edited by fixitsan, 25 November 2016 - 01:39 pm.

[TYREDNGRUMPEE]

The PNY PowerPack CURVE 10400 also comes with a built-in LED torch.
A single bright LED is activated or turned off if a button is held for a total of 2 seconds.
Press once for an indication of the power stored.
The torch seems to be powerful enough to be a useful camp site / tent tool.