Jeansy's battery tests (new impedance tests)

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Jinx
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Jeansy's battery tests (new impedance tests)

Hi everyone,

I am discharging a few cells to see how they preform and thought some of you guys might be interested. Im sure there are better was to test but this is how i have quickly set it up. My Fluke meters are calibrated by an external company (Pullman instruments), these give a accurate idea whats actually being drawn from the cell.

 

Ok just to explain what the pictures show. The Fluke 179 on the right is wired in series with the cell and charger, so what ever current goes through the cell goes through the meter, this shows that the hobby charger is actually discharging at the correct rate as they are far from accurate in some cases.

The Fluke 123 on the left is displaying the voltage across the cell, this again shows how accurate or not the charger is. In this case it shows that infact the cells are being terminated early so the capacity reading will be lower than could be expected should you discharge further, ie 2.7volts.

 

If the two figures are multiplied then the result is the power consumed, eg 3.8v X 1a = 3.8watts.

 

The other variable for my charger will be the timer itself so perhaps I will stick a stop-watch next to the counter and ensure that is accurate. Edit:Tested to within 2seconds at 2hours.


[Added 1-5-12]

Please only compare my results within themselves, my methods mean that lower readings will be obtained compared to other people's. Within themselves these results should be very accurate and representable of performance.

Little table with Impedance readings and some random calculations i was interested to compare:

Why Impedance is important: The output capability is determined by the Impedance if nothing else limits the cell, ie in a direct drive light, lower impedance = more current and more output (or a blown emitter). Impedance also steadily increases with age and gives a good ability to trend and thus monitor ageing. Impedance matching is also more useful than voltage matching cells for multi-cell set-ups, it tends to give far more accurate results, tho DC matching is still essential.

 

Edit:

So far:

King Kong 26650 - 4031

Panasonic NCR18650A 3100mAh - 2609>2619

Sanyo 2600 - 2256>2339

SenyBor SYB18700 2600mAh - 2219

 

SoShine 2800mAh - 2095

TrustFire Flame 2400mAh - 1817

UltraFire 'blue' 2400mAh - 913

Trustfire flame 14500 900mAh - 640 (1a)

TrustFire tr 10440 600mAh - 243 (0.5a discharge)

Ultrafire (silver) 14500 900mAh - 124 (1a)

 

 

 


 

 

Anyway, SenyBor first:

0min

10min

 

30min1 hour

2 hours

end of discharge

Please comment if these are usful and i will add some more as i do them (Trustfire Flame discharging at present)

Edited by: sb56637 on 08/26/2014 - 17:40
Jinx
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Jinx
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Panasonic 3100, first cycle (as other cells), sourced from HKE. Not a great result but as you will notice the charger is terminating early, still interesting to directly compare with my other results....

 

 

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SoShine 2800mAh

mitro
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So your charger is reading ~0.3v low? You are really only discharging down to 3.3v then. Looking at my discharge of a 3100 it looks like your numbers are right for discharging to 3.3v (even though this is 1.5A):

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Yes terminating around 3.3v, bit annoying but i dont really want to take them lower than 3.0 anyway so reluctant to use the NiMH discharge setting. My UltraFire 'Blue' 2400mAh did less than 1000mAh lol, maybe it could of got there down to 2.5v!

Oxy Moron
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Very interesting. Thanks, Jeansy. Smile

Please keep them coming.

ralf
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If your B6 is consistently reading 0.3 volts high, just set the NiMH discharge termination voltage to 2.7 volts....

Mine reads dead-on compared to my DMM at the jacks, but has 0.1 ohms in the alligator-clip cable and thus reads 0.1 volt low compared to the battery itself on a 1A discharge. So to terminate at 3.0 volts, I use the NiMH program set to 2.9 volt termination.

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Cheers Ralf, will look into that although I want to directly compare cells so will have to keep an eye for the 3.cut point or re-test the above.

 

Anybody have any requests, could do with a couple more so will be ordering soon

Oxy Moron
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Well... I know I am not being creative but since you have calibrated equipment and most of us aren't fortunate enough... Wink TF Flame 14500s and 16340s, perhaps? Personally, I'd also be interested in seeing how various 10440s perform side-by-side. But I do realize that 10440s aren't particularly popular. Also, could you please add where you got your samples from? Thanks again.

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Panasonics, HKE

Soshine & TF Flames, DX

Senybor, Scottish EBay seller

I have some 10440s on route (DX silver TF) for my Olight but couldn't find many, any links? At present I have no use for the other sizes but maybe some 14500s soon

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Very nice Jeansy! Thanks for your hard work and the great details.

Sticky'd.

Budget Light Forum ...where Frugal meets with Flashlight!

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Excellent test, i like how you discharge to 3.3v if i understand correctly. This gives us single cell users a more realistic although lower figure. As the only way the discharge to 2.5v or even 3v is a multicell light or some fancy electronics. Some cells hold a higher voltage over the usefull part of the discharge cycle in a single cell light which translates to longer run times, although they might not show a higher capacity if taken down to 2.5v, it doesnt matter as the light will be putting out as much light as a glow worm by then anyway.. +1 for the 14500/10440. I saw some 5000mah 18650's on ebay it would be fun to test one of those, i find it frustrating that sellers can rip people off so openly. Oh well thank goodness for people testing and enlightening us.
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Top post updated with trust fire 10440(silver) & 14500, both from Manafont, charged on delivery and first discharge, will update more when I have some time.

Unless indicated everything is at 1a discharge.

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nice photos!! (i dont really understand why i am seeing there.. but they should be helpful once i get my first hobby charger)

*FMI* i got 4 i/o sh
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Hi JEansy, did not see your thread. Interesting!

Yeah, i have the genuine IMAX B6 too.  I see it to 2.6V termination.  Just measured 2.82V termination on the DMM (UT-58E).  So pretty high. ~ 0.2V difference. 

Though low, it is definitely realistic and won't harm the cells, well not to the extent that we are using our lights and cells (we have way too many cells).  Some drivers' LV protection do terminate at such levels, looking at the end open-circuit cell voltage after letting the cells rest.  The PCB also does not cut in that early or with low amps.

 

For my pro photography - i have like 10 packs and whack the hell out of them sometimes (eg over the weekend i took nearly 8k frames over 4.5 full-day weddings relatively speaking, it was 20-11-2011 and 2 weeks ago it was 11-11-11...heh), i still have batteries that run pretty "ok" though i can feel that they have aged and don't hold a charge too well.  But they have been with me for > 5 years!

Flashaholics with 20-30 18650s will never feel any "degradation" from over-discharging to 2.8V esp if you mix the cells around across your whole collection.  Unless you use them daily 1 or 2 full cycles per day and tag a few to certain lights that you use often....then probably it could happen maybe in 2 or 3 years.

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Ok, i quickly had access to our Hioki battery tester. This is a calibrated, dedicated battery tester, as you can see below it measures the DC voltage but much more interestingly the internal impedance. The tester is a great indicator of battery condition if results are trended. Low readings are better and give an indication of outright power avalible.

The tester doesnt look overly impressive but it retails in England at approx £1500 or approx $2000USD!

I will try and write up the complete results soon, at least two of all the cells were tested (bar the King Kong)

 

nekdo12
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Which cell is the last one(pink)?

viffer750
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Values seem too low for me.

unique engrish language... Smile

 

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Sanyo cell is the pink ored from intl-outdoor. 

Viffer, this is calibrated and used commercially. It is endorsed by Yuasa also. I would suggest other readings you have seen are high Wink

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Jeansy wrote:

Sanyo cell is the pink ored from intl-outdoor. 

Viffer, this is calibrated and used commercially. It is endorsed by Yuasa also. I would suggest other readings you have seen are high Wink

 

The tester probably uses AC impedance test, that gives a considerable lower value than DC impedance/resistance test (Like I do in my battery test).

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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Yes it uses an AC algorithm to measure impedances, the way our systems are tested this is the only reliable method without disruption, it is also quick and convenient. It matchs the results of our BitBox testers also which iirc use a simple 50hz waveform but at much higher currents, not suitable for these small cells tho as the minimum AC current is approx 10a

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Wow thanks for doing this!!  I was suspecting the volt meter on my hobby charger was all off-whack.  Its reading about .15V low.  I never really thought to meter the thing while discharging.

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These readings are much lower than the rest of the testers.

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Yes IR & mAh

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Please only use these results to compare within themselves. My capacity readings are inline with others but I terminate the discharge early. The impedance readings are measured with dedicated, calibrated machine, this gives lower results than hobby charger calculations etc. the AC current will also interact differently to the protection circuits I suspect.

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OK a quick look at the protected Panasonics avalible from DX, ok lets compare with a unprotected version bought from HKE last year:

So that was the most recent discharge, they have done about 4 cycles now and have increased slightly, most noticably on the second discharge. The cells were charged on a WPII v2

Protected #1 started at 4.24v and gave 2414mAh (i think the high DC is because i topped the cell off from a very high state of charge already)

Protected #2 started at 4.19v and gave 2561mAh

Compare those results with the unprotected, charged on the same charger and discharged on the same Imax at the same settings, the difference is between 205mAh and 48mAh. I realise two cells is a very limited comparision but its 2 better than none Wink

 

If anyone has protected Panasonics from the other suppliers please feel free to post pics for comparision, as always please dont compare my results to others but only with my other results, thanks.

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I tested these a lot in another thread and got higher mAh, to get the most out of them they need to be discharged to 2.5v i like 3 volt cut off as thats about the lowest most of my torches can go, but at 3 volt there is mot much of a gain over cheaper batteries. These have come a long way down on price and are more common now. Ive been noticing a little less mAh with protected batteries while discharging & higher internal resistance as the pcb uses power from the cell to run, but it looks like yours where the other way round. Very good batteries. But the protected ones i got preformed so bad i had to remove the protection, the batteries work really well now and the seller has corrected the pcb issue. Other wise ill post my results.

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benckie wrote:

Ive been noticing a little less mAh with protected batteries while discharging & higher internal resistance as the pcb uses power from the cell to run, but it looks like yours where the other way round. 

Hi Benckie, no that's the same as mine, slightly reduced power from protected version, as you say almost certainly down to protection PCB increasing impedance/consuming power. I was concerned they may be fake cells but they certainly appear and perform as originals. Where did you source yours?

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It,s the same with all cheap protected cells Ive tested once Ive removed the protection they read lower internal resistance and a slight gain in mAh.

I brought them from IO the early protected ones and got poor results, I'm told the new ones with better PCB,s are good but i have not brought any more.

Here is the link to the old thread.

http://budgetlightforum.com/node/5269

My testing did not start till post #64 and you can see how much a bad or poor PCB protection circuit will affect performance. In case you don't want to read through it all ill post some of my results.

My tests before i removed the protection PCB,s

Cell A internal resistance 127 milliohms

Cell B internal resistance 129 milliohms

For the internal resistance test's you need to take into account the magnets i used on my charge leads and my soldering.

Cell A 3 amp discharge from 4.18 volt to 3.013 volt i got 1229 mAh.

Cell B discharged from 4.18v to 3.194 volt at 3 amps I was not even able to extract more the 1000 mAh.

With the bad PCB protection units removed i got

Cell A Internal resistance 103 milliohms

Cell B Internal resistance 98 milliohms

For the internal resistance test's you need to take into account the magnets i used on my charge leads and my soldering.

discharged from 4.18 volt to 3 volt @ 3amp 2485 mAh (averaged out over the two cells)

discharged at (1C) 3.1 amp to 2.5 volt 2876 mAh (averaged out over the two cells)

discharged at (2C) 6.2 amp discharge from 4.16 to 2.5 volt i got 2876 mAh

discharged from 4.15 volt to 2.5 volt at 0.5 amps 3020 mAh

discharged from 4.163 volt to 3 volt at 0.2 amps 3033 mAh

So in light current draw like 0.2, 0.5 amps there is not much difference from a discharging cut off between 3 volt and 2.5 volt, but at higher draw like 3 amp there is a difference thats is noticeable. Good cells if you get the genuine ones and or with good pcb's with at lest 2 mosfets.