Question about Powercore+ 26800 PD

#1

I’ve a question about the powerbank and bundled charger combo. When the battery was almost depleted (remaining 5%), I started charging it via the included 30W charger. I’m seeing 8.95V @ 2.85A. So, that’s around 25W. I guess assuming some loss in efficiency, it is close to the 27W Anker is claiming.

My question is this, Anker says this is a 26800mAh powerbank @ 3.7V. So, converting this to 5V, it is actually 19,832mAh. Further assume a 5% loss in efficiency, it is approx 18840mAh. Now, charging it at say 3A, we are looking at approx 6+ hrs. But Anker says this can be charged in 4.5hrs.

I’ve tested it twice and both times, the charge ended in approx 4.5hrs as claimed by Anker providing 11553mAh (98283mWh) and 11720mAh (99606mWh). Solely based on mAh, I see it is very much less than the 18840mAh I’m expecting.

However, taking the mWh, 98283/5V = 19656mAh and 99606/5V = 19921mAh. I’m dividing by 5V coz’ I’m assuming if I charge my phones using the usb-a port, it is providing 5V, so I will get 19000+ mAh which is consistent with the specs.

Can someone clarify the following:

  1. When charging at approx 3A, how is PD able to allow complete charge in 4.5 hrs? 18+mAh/3 = ~6 HRS.

  2. Why does the usb-c power meter showing 11,000+ mAh total?

For reference, I’m using the included 30W Anker usb-c charger with the included usb-c cable. The white cable is an OEM usb-c cable from Apple that came with the MacBook Pro from the 87W usb-c charger.

I’m also using the UM25 power meter measuring tool.

Thanks.

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#2

You’re aware the voltage changes over time?

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#3

I observed the charging process from the beginning to the end intermittently. It never went above 9V. Besides, these are the specs of the charger:

Output: 5V@3A, 9V@3A, 15V@2A, 20V@1.5A

What I’m seeing is approx 9V @ 3A charging. If you read my post, you can see the ending mAh was recorded by the power meter is showing 11553mAh. It is suppose to be approx 19000mAh.

I think I’m understand the numbers now. This is a powerbank rated for 26800mAh with 3.7V cells. So, if the charger is charging it at say 9V, then:

26800*3.7/9 = 11017mAh

So I guess it is correct at least what the power meter is outputting. Let me clarify I’m not saying if my iPhone battery is 2600mAh, I should see 10 full re-charge coz’ I understand the rating of 26800mAh is based on 3.7V cells. But charging via regular USB is limited to 5V. Hence the need of conversion which brings the 26800mAh down to 19000mAh.

I think my powerbank is ok. Even if it shows 11553mAh and 11720mAh in both my testing, it is correct.

#4

What are you trying to figure out exactly?

#5

Well… my initial 2 questions were:

  1. How is the included 30W wall charger able to charge in 4.5hrs a 26800 mAh powerbank? Simply based on the max Amp (which is 3A), I simply took 26800mAh/3A = ~9 hours. Other competitors with say 20000mAh says they best they can do (via PD) is 4-5hrs

  2. Trying to understand the final output of the power meter showing approx 11000mAh and 99Wh

#6

Ok. The german company where I worked is very well known for electronic test equipment.
And there is a saying in german, which says: “Wer misst, misst Mist” Try to translate. But please: take it easy ! :wink:

The answer to your question : It is kind of easy to figure out the power of a charging device. You know the formula: V x A is VA or W. And the production of a charger is very well determined. (But I think you - and Anker - agree, that there is a certain deviation allowed)

But:

it is very hard, perhaps not possible, to figure out the exact capacity of a battery - even if it is brand new produced. I guess it will be hard to find two exactly equal batteries - having the exact values which are printed on it.

And it is even harder to figure out these values after decharging and recharging .

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#7

But it is a 100Wh (a little less) of energy and a 30W charger so 100Wh / 30W = 3.3h. You need to do the math in energy as its simpler.

It takes more as once you get to 85% charge the wattage drops to trickle charge, usually 50% power at 85% then about 10% power at 95%. Hence 4.5h. So roughly its 3.33hr x ( 0.85 + 0.1 *2 + 0.05 * 3 ) = 3.33h x 1.2 = 4 hours. If you allowed for some energy loss, say 10% loss you get to 4.4hrs.

Make sense?

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#8

Yes, I’ve a better understanding now. I just got the power meter and was testing all different power banks, adapters, cables etc.

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