pkcell 14500. surprise! rated 750mah got 844@500ma

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JPLight
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Box wrote:
Got 4 X of their 18350 900mah. I’ll discharge test two and report back. I’ll do some ceiling bounce test with a cheap lux meter against Keeppower 18350 too. Haven’t got the Aspires yet

Subscribed Wink

Box
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Discharge four 18350 at 0.5a. Got 888, 892, 893 and 909mah.

Also did a ceiling bounce test with a cheap UNI-T luxmeter and Emisar D4 XPL. Pkcell got 240 and Keeppower got 284.
I got four Pkcell for $10aud. So they are a bargain. The same seller on ebay even sells 12 for $23aud.

JPLight
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Good numbers for a first 500mA discharge. Thumbs Up

snakebite
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give them a few cycles to break them in.

JPLight
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14500 cells arrived today.

They all came with 3.84V.

First test on one cell, charged to 4.2V@300mA (4.19V after 5 minutes), shows 831mAh at 500mA discharge current. Cut off voltage 3.0V (as specified in the data sheet).
Nice numbers for the moment.

JPLight
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2nd cell shows the same numbers and as I am pretty shure all the other cells will do the same, I will not continue testing.
snakebite did the test @1A. I´m sure my cells would just confirm his numbers.
It would be interesting to see some discharge diagrams in near future.

So far I recommend this cells.

snakebite
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i need to order more of both the 10440 and 14500.
they all left in restomodded vintage lights with friends.

Jerommel
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Would be nice if HKJ tested these.
I guess for ‘high drain’ (but not too high..) usage the Windyfires are still the best?
But for €11.13 i can get 5 14500 PKcells with free shipping, which is nice. Smile
https://www.aliexpress.com/item/5PCS-ICR14500-14500-750mAh-3-7v-recharge...

Agro
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HKJ said that he had 14500 in the pipeline. But not 10440.

anycolourfloyd
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Box wrote:
Discharge four 18350 at 0.5a. Got 888, 892, 893 and 909mah.

Also did a ceiling bounce test with a cheap UNI-T luxmeter and Emisar D4 XPL. Pkcell got 240 and Keeppower got 284.
I got four Pkcell for $10aud. So they are a bargain. The same seller on ebay even sells 12 for $23aud.

hi Box, what was the name of the ebay seller?

Box
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anycolourfloyd wrote:
hi Box, what was the name of the ebay seller?

Hey mate.
https://www.ebay.com.au/itm/142272998192
anycolourfloyd
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Awesome, thanks. This looks like it could be good, they have NiMH batteries and all!

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JPLight wrote:
Tempted as well, but I will wait for those 14500 first.

Has anybody ordered Pkcell 16340 ?


They’re in my AliExpress cart..
JPLight
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Jerommel wrote:
JPLight wrote:
Tempted as well, but I will wait for those 14500 first.

Has anybody ordered Pkcell 16340 ?


They’re in my AliExpress cart..
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d_t_a
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I got a few of the PKCell ICR18350, IMR18350 and ICR14500 batteries from AliExpress (fortunate to have ordered them last month, when they had free shipping via Turkey Post; just checked right now, and they’re only offering expedited shipping options US$40+ Fedex — seems like Turkey Post is not shipping batteries anymore).

What current should I charge them with? Standard charge current? Rapid charge current? There doesn’t seem to be a spec sheet. The seller’s page in AliExpress only indicates max continuous discharge current (2C for the ICR type, and 10C for the IMR type). How about discharge current (when testing discharge capacity), is 1C too high or still OK (for the ICR types).

based on the seller item page description:
PKCell ICR14500 750mAh max continuous discharge current = 2C = 1.5A, cut-off voltage = 3.00v

PKCell ICR18350 900mAh max continuous discharge current = 2C = 1.8A, cut-off voltage = 3.00v
PKCell IMR18350 700mAh max continuous discharge current = 10C = 7A, cut-off voltage = 2.75v

So far I did discharging of the above batteries at 0.25A discharge current and also getting around 800-900mAh (the ICR18350 900mAh and IMR18350 700mAh seem to have similar capacity?)

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Cheers 

The Light Innocent I am

Deleting a post and redoing it causes the forum thread answer notifications to become invalid. Thus, if you need to change your just published post, edit it. Thanks.

Jerommel
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update on the PKcell 16340

a little over 700mAh and internal resistance around 120mR so it’s not high drain.

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Jerommel wrote:
update on the PKcell 16340a little over 700mAh and internal resistance around 120mR so…

Jerommel, ≈120mΩ?

Fenix 16340 700mAh ARB-L16-700 (Orange-Black), top dog in capacity but ≈190mΩ of internal resistance. Those figures of yours… to be believed. It would be great, of course.

 

Cheers Party

Originally posted on Tue, 10/10/2017 - 13:04; lil fixup. Smile

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Jerommel
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I calculated it here

snakebite
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keep in mind my ir testing was impedance at 1khz.
thats the most common method in most datasheets.
and testing at 3.5v is testing a discharged cell.
ir goes up as cell is discharged.
quote.

Okay, i calculated the internal resistance of one of my PKcells, i think i did it right.

The Voltage of the cell was 3.5 V without load.
I put on a load with a 1.35 Ω resistor, giving a Voltage of 3.2 Volts over the resistor, I=U:R so the current was 3.2 V : 1.35 Ω = 2.37 A
Now i can calculate the total resistance. R=U:I so R = 3.5 V : 2.37 A = 1.47 Ω
Subtract the 1.35 Ω from that, so 1.47 – 1.35 = 0.12 Ohm or 120mΩ

When I (current) is 2.3 A (M3 turbo mode) P (power) wasted as heat in the battery is P=I²×R —> I² = 5.29 —> 5.29 × 0.12 Ω = 0.63 Watt heating up the battery, which is nothing to worry about i.m.o.

Anyway, with Ri=120mΩ this is not a high drain cell at all…

PS: The numbers could be off by 15% (or something) due to my equipment.

Jerommel
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3.5 Volts is not discharged, 3.0 Volts is discharged.
But thanks for the point you make, i will test it again with a fully charged cell and one ‘half full’ at 3.7 Volts.
I didn’t know it depends on the charge.

I wouldn’t know why i should test at 1kHz, and i’m not sure of you mean a PWM-ed load with 50% duty cycle at 1 kHz or what.
I was testing with a similar load as the turbo mode of a OTR M3 flashlight, which is a constant load of 2.3 Amperes.

snakebite
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3.5v open circuit is damn close to empty.
and at the steep rise in ir with the low state of charge.this is partly how fuel gauges in devices determine state of charge.
i am using a esr meter for capacitors but it does well for telling me state of health of pulls i am grading.i can test a group of the same cells from many packs in different states of wear from new to totally worn out and tell you which ones are new,useable,or a waste of time to charge.
its also great for spotting fakes once you record the results of a known real cell.
your dc ir test is sound but test again with a charged cell.
and dont expect this to match the ac test.esr meter=ac milliohmeter.

dchomak
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snakebite wrote:
keep in mind my ir testing was impedance at 1khz.
thats the most common method in most datasheets.
and testing at 3.5v is testing a discharged cell.
ir goes up as cell is discharged.
quote.

Okay, i calculated the internal resistance of one of my PKcells, i think i did it right.

The Voltage of the cell was 3.5 V without load.
I put on a load with a 1.35 Ω resistor, giving a Voltage of 3.2 Volts over the resistor, I=U:R so the current was 3.2 V : 1.35 Ω = 2.37 A
Now i can calculate the total resistance. R=U:I so R = 3.5 V : 2.37 A = 1.47 Ω
Subtract the 1.35 Ω from that, so 1.47 – 1.35 = 0.12 Ohm or 120mΩ

When I (current) is 2.3 A (M3 turbo mode) P (power) wasted as heat in the battery is P=I²×R —> I² = 5.29 —> 5.29 × 0.12 Ω = 0.63 Watt heating up the battery, which is nothing to worry about i.m.o.

Anyway, with Ri=120mΩ this is not a high drain cell at all…

PS: The numbers could be off by 15% (or something) due to my equipment.


You did it right. Thumbs Up
But here is a short cut.
In general, the internal resistance would be the change from open circuit voltage divided by the change in current.
(delta V/delta I)
In this case it would be (3.5V – 3.2V)/(2.37A – 0A) = 127mΩ
You came up with a little less because you truncated your total resistance to 1.47 when it calculates to a little more than that.
Jerommel
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Thanks for the feedback, guys. It’s helpful.

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good battery,if sanyo 14500p 840mah out of stock, choose it

Trisky

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