Help ID'ing this 18650 from charger pack

Hey there, eagle-eyes,
I popped open an underperforming iPad charging battery pack and found this set of six 18650 cells. I was wondering if anyone here could decode the inkjet on the cell wrapper. I'd be interested in whether this is a standard type or high current cell and the capacity. I am considering scavenging the circuitry and upgrading the pack to a sextet of 3700mAh 26650s.



Any help would be appreciated.
Wilkey

Unprotected LG 18650s?

Chris

Ginseng said:

Hey there, eagle-eyes,
I popped open an underperforming iPad charging battery pack and found this set of six 18650 cells. I was wondering if anyone here could decode the inkjet on the cell wrapper. I'd be interested in whether this is a standard type or high current cell and the capacity. I am considering scavenging the circuitry and upgrading the pack to a sextet of 3700mAh 26650s.

Any help would be appreciated.
Wilkey

Click to expand...

They look like old LG's, specifically - LG ICR18650S3, their nominal capacity is 2200mAh but they might have lost quite a lot capacity since you say they're underperforming.

Why 3700mAh 26650's btw? You can use 3400mAh 18650's and have almost same capacity at half the volume, and less weight too.

Good point! I may have to let these cells go. Thanks!

Wilkey

If go through with the upgrade, please let us know how the surgery turns out!

Well,

I opened the case of the HyperMac MBP060. See here:



And the pack I found inside really bore no resemblance to the specification on their website here.



The specs tout 16,000 mAh/60Wh. And this doesn't jibe with their stated delivery voltage, so what is going on here? The pack consists of six 18650 cells of 2200 mAh capacity in a 2p3s configuration for 4,400 mAh nominal capacity or 22Wh at 5V. Even if you totalled up the capacity of all the cells in this pack in a 6s config, you'd still only get 13,200 mAh. So it certainly seems like they are being deceptive in their spec sheet.

The explanation the guy in support gave me as to why the MBP was not delivering it's rated power was gibberish...until you realize that it's consistent with what I found when I cracked it open.

So what do you think? Do I make a stink? There is no way in hell their product is what they say it is and no possible way that it will do what they say it will do.

Wilkey

Hmmm... I think you have a beef, especially if you tested the output and it was below their specs.

I for one really really do not like false advertising. Rounding up is one thing, but this is completely different.

Well the advertise a 60Wh pack, and delivered a 47.5Wh pack, so there is some obvious false advertising going on. To get 60Whrs they would need to use ~2800mAH cells. The Blue LG's are 2200mAH.

Their fully recharge an iPhone battery "up to 14x" is obviously bs too. Lets do some basic math, and assume the lowest capacity iphone battery of 1400mAh.

So in order to charge any USB type device your going to need to somehow regulate 5v. Either boost or buck typically. Lets be very generous and assume 90% regulated 5v efficiency for the hyperjuice. Lets also assume a very generous 90% iphone charging efficiency (remembering that the iPhone has to step the 5v down to ~3-4.2v depending on the SOC).

So the total packs capacity is 47.5Whrs * 90% * 90% = 38.5Whrs max going to the iphone. iphones battery is 1400mAh @ 3.7v which is about 5.2Whrs. So 38.5 / 5.2 = 7.4 . So in the best case scenario you could recharge the smallest capacity iphones battery up to 7 times. My guess is real world it would be about 5 times max.

Assuming 2400mAh cells and a voltage of 4.2V. Capacity is 2400x6=14400mAh.
Estimated Wh would be: 14400x4.2=60480mWh or approximately 60Wh.

Can you fully charge a cell and discharge it to determine approximate capacity?

Found LG 2200mAh cells here that are just like yours.

so assuming 2200mAh capacity: Wh= 2.2 x 6 x 4.2=55.44Wh which 'can' be rounded off to 60Wh...

eebowler said:

Assuming 2400mAh cells and a voltage of 4.2V. Capacity is 2400x6=14400mAh.
Estimated Wh would be: 14400x4.2=60480mWh or approximately 60Wh.

Can you fully charge a cell and discharge it to determine approximate capacity?

Found LG 2200mAh cells here that are just like yours.

Click to expand...

Hmmm,

I'm a chemicals guy, not electrical so I hope I'm not being too obtuse about this.

Isn't 6 x whatever the cell capacity not the mAh deliverable by this pack? There are six cells, but the fact that they're two in parallel and then these parallel pairs a three in series means the total capacity is 2 x 2400 mAh or 4800 mAh. The voltage, however, is 3 x 4.2V at 100% or 13.2V.

Wilkey

eebowler said:

so assuming 2200mAh capacity: Wh= 2.2 x 6 x 4.2=55.44Wh which 'can' be rounded off to 60Wh...

Click to expand...

You calculations of Wh is wrong, a LiIon battery does not stay at 4.2 volt during discharge.
While doing battery test I have been measuring Wh and 2200mA is more like 8Wh.

HJK, thanks The practical values ARE wrong but, (sorry for not being clear,) this is possibly how the manufacturer came up with the numbers.

Ginseng, if there are three pairs in series, then the max voltage will be 4.2X3= 12.6V so Wh will be 2.4 x 2 x 12.6 =60.48Wh

Okay,

What I'd like to know is how much of the iPad3's 42.5Wh battery I can expect to charge with the MBP060. Based on their specs and the above calculations, it seems like it should provide a full recharge from empty and then some. However, I've found that a fully-topped MBP060 only fills 75% of the iPad for a practical delivery of about 32Wh or half of their claimed capacity. Or am I thinking about this wrong?

Wilkey

Ginseng said:

Okay,

What I'd like to know is how much of the iPad3's 42.5Wh battery I can expect to charge with the MBP060. Based on their specs and the above calculations, it seems like it should provide a full recharge from empty and then some. However, I've found that a fully-topped MBP060 only fills 75% of the iPad for a practical delivery of about 32Wh or half of their claimed capacity. Or am I thinking about this wrong?

Wilkey

Click to expand...

You should take into account those things:
1. Charging a battery is not 100% effective even in case of Li-Ion / Li-Ion Polymer (to charge 10Wh battery, you might need to put 11Wh or even 12Wh into it, depending on cell quality, age, wear etc)
2. The MBP060 outputs 5V to the iPad, so there is some efficiency loss here (typical 3-4.2V to 5V boost converter would have efficiency of 80%)
3. iPad's charging circuitry is not 100% efficient either, so to put those 11 or 12 Wh into battery, iPad needs to use more energy than that.

Shadowww said:

You should take into account those things:
1. Charging a battery is not 100% effective even in case of Li-Ion / Li-Ion Polymer (to charge 10Wh battery, you might need to put 11Wh or even 12Wh into it, depending on cell quality, age, wear etc)
2. The MBP060 outputs 5V to the iPad, so there is some efficiency loss here (typical 3-4.2V to 5V boost converter would have efficiency of 80%)
3. iPad's charging circuitry is not 100% efficient either, so to put those 11 or 12 Wh into battery, iPad needs to use more energy than that.

Click to expand...

Understood, and thanks for that elaboration.

So what is the base issue here? Can HyperMac be rightfully and accurately accused of misleading specifications and performance? Or is what they've presented in the realm of possibility.

There's a real solid motivation for me to ask these questions as I've found the actual performance of their device to deviate rather significantly from expectations (which may be more or less founded). Also, the responses of their technical support staff have been confusing, contradictory, and unhelpful. Heck, I broke apart a $170 device just to find out why this is and I don't want other people spending this kind of money to be so let down.

Wilkey

Hello Wilkey,

Looking into my crystal ball and adjusting for real world use and tossing in some fudge factors, I would expect your external battery pack to about double the normal run time of your iPad3.

While this is less than the advertised

"- Extend iPad battery life by up to additional 24 hours"

they actually didn't specify which iPad unit they were referencing... Traditionally battery performance claims are optimistic, and it looks like they went with tradition. A more realistic approach would take 90% of the cells initial capacity and use 3.7 volts per cell for the voltage.

The question is what kind of run time are you getting?

Tom

Ginseng said:

So what is the base issue here? Can HyperMac be rightfully and accurately accused of misleading specifications and performance? Or is what they've presented in the realm of possibility.

Click to expand...

Well, considering it's battery pack is 3.7*2.2*6 = 48 Wh, and they advertise 60Wh (it maybe would be okay if they rounded it to 50Wh.. but 60Wh - no way), they indeed have misleading specs.

Ginseng said:

Okay,

What I'd like to know is how much of the iPad3's 42.5Wh battery I can expect to charge with the MBP060. Based on their specs and the above calculations, it seems like it should provide a full recharge from empty and then some. However, I've found that a fully-topped MBP060 only fills 75% of the iPad for a practical delivery of about 32Wh or half of their claimed capacity. Or am I thinking about this wrong?

Wilkey

Click to expand...

As mentioned above, the pack is not 60Whrs, and the efficiency is not going to be 100% when charging and regulating the output voltage for the ipad. 47.5 Wh pack x 90% x 90% = 38.5 Whrs. And that is being very very generous with both the regulated 5v output efficiency and charging efficiency. I think your results of charging the ipad3's 42.5Whr pack to 75% is spot on.

Thank you for all your help, gentlemen. I'm going to noodle on this and try and come up with a way to present this. Will be back with what I'm thinking.

Cheers,
Wilkey

Dang what a rip