Is this normal for a Liitokala Lii-500 charger?

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MAD TM26
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Is this normal for a Liitokala Lii-500 charger?

Did anyone else notice this abnormal behavior when charging 4 cells at once? Very high IR on outer bays.


Also why does it charge up to 4.21V and 4.22V?

This is on brand new KeepPower 18650’s 3500mAh (2nd cycle)

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Edited by: MAD TM26 on 12/04/2016 - 10:55
atbglenn
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I’m doing a nor test with Efest 700mAh V2 16340 cells purchased at the same time

Bay 1 68mR
Bay 2 74mR
Bay 3 45mR
Bay 4 62mR

I’ll update with voltage readings when it’s finished

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flydiver
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On mine charging to 4.22 on the screen is fine per voltmeter when I take them off. The difference between 4.21 > 4.23 is 0.02v, a trivial difference and probably not within the chargers actual accuracy range, or your voltmeter most likely.

IR on this charger is useless. I get about the same IR on all my batteries, good or crappy.

IR is somewhat better on the Opus, one of the areas the Opus is clearly superior, but I wouldn’t call it ‘accurate’. It’s mostly just a reference measurement to compare a battery against itself or others over time. None of these small chargers do IR accurately.

chops728
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yes that’s normal- this is a good charger mostly —pretty good for testing smaller capacity cells unless you have lots of time— 500 mah discharge is very slow—- the biggest pain is when you put 4 cells in charger—it almost takes a screwdriver to get them out

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chops728 wrote:
yes that’s normal- this is a good charger mostly —pretty good for testing smaller capacity cells unless you have lots of time— 500 mah discharge is very slow—- the biggest pain is when you put 4 cells in charger—it almost takes a screwdriver to get them out

I carefully use a plastic spudger on the positive side to get my 18650’s out. It works great.

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Fellows, let me explain you a few facts:

In order to measure battery internal resistance(s), these charging devices use algorithms which, basically, calculate dV/I, for given charging currents and voltage deltas which are measured at some point inside the machine. What does this mean?

This means these chargers are measuring the resistance between the voltage reading points: sum of the battery internal resistance plus the rail contact resistances plus any other possible significative inneficiencies in the involved current path.

Now, may any of you explain to me why two or more high quality brand new cells exhibit such a disparity in the internal resistance figures? What is more, how ftfoi is the same cell going to measure differently each time I reinsert it in the bay?

Conclusion: the aforementioned stray resistances are quite significative, and potentially difficult to avoid. The dV measurement points should be firmly attached at the very battery terminals for these innaccuracies to dissapear.

And please, stop moaning about the Lii-500/BT-C3100 accuracies in this regard. The BT-C3100 does it better a gnat's ass less crappy? Maybe it's because its bays are of slightly better metal/design, but my conclusion is still the same:

Glad to be of help. Smile

 

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hIKARInoob
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Barkuti wrote:

Conclusion: the aforementioned stray resistances are quite significative, and potentially difficult to avoid. The dV measurement points should be firmly attached at the very battery terminals for these innaccuracies to dissapear.

Sup Barkuti, how are you doing today?

Ok, I think I need to object. But first let me explain how I interpret your statement. I think you’re saying that the internal resistance of the battery, which you want to measure, is distorted due the the resistance between the two battery ends and the poles of the charger (you call stray resistance); have I interpreted this correctly?
Ok, based on this assumption I have my doubts and need to disagree.
Take any arbitrary piece of electrical resistance, let’s say R=100 Ohm. We’re going to measure its resistance with a DMM. The DMM is going to tell you that it’s 100 Ohm (+/- a couple of %). The additional resistance between the electrical resistance and the two probe pins are fairly negligible, independent of how hard you press the probes against the electrical resistance right? Therefore I believe that the effect of how much force is applied on the battery in the charger should be negligible as well.
Secondly, one of the oddities is the symmetry of the measurements; the outer resistance values are identical, and the inner values are identical. Statistically this is very unlikely. Therefore I believe that something else must be the cause.

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hIKARInoob, battery bay/terminal resistances of just a few mΩ potentially invalidate measurements on a device (battery) whose resistance is also a handful of mΩ. If we could measure/predict accurately such resistance, there would be no problem as we could use that info to compensate/calibrate the measurement, of course. I gave up trying to measure battery voltage flimsily on my charger's rail with a mV accurate voltmeter, got the gist of it when I found a way to steadily attach the voltmeter probe wires to the battery terminals.

A 100Ω resistor is of course a no problem thing when the leads are probably about 0.2Ω. Now, try to measure an R050 and report results…

 

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hIKARInoob
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Barkuti wrote:

hIKARInoob, battery bay/terminal resistances of just a few mΩ potentially invalidate measurements on a device (battery) whose resistance is also a handful of mΩ. If we could measure/predict accurately such resistance, there would be no problem as we could use that info to compensate/calibrate the measurement, of course. I gave up trying to measure battery voltage flimsily on my charger’s rail with a mV accurate voltmeter, got the gist of it when I found a way to steadily attach the voltmeter probe wires to the battery terminals.


A 100Ω resistor is of course a no problem thing when the leads are probably about 0.2Ω. Now, try to measure an R050 and report results…


 


Cheers Party

You’re absolutely right, silly me ;-). Ok, I’m gonna do some thinking again here. Cheers!

Edit:

Checked out HKJ’s review of the Lii-500: http://budgetlightforum.com/node/41442
Check out the “internal resistance” section; it seems that this feature is a complete joke if I’ve understood correctly…

atbglenn
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I don’t take the resistance measurement seriously on the Lii-500. It’s not accurate from what I’ve read, but you can still compare one cell to another of the same type just as a reference. I’ve swapped batteries around in different slots and basically get the same numbers on a given battery. What do you expect from a 4 bay charger that cost $15 without a PS? I think it does a pretty good job for what it is.

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teacher
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atbglenn wrote:

I carefully use a plastic spudger on the positive side to get my 18650’s out. It works great.
Hey Glenn, I think these two guys collaborated and invented the “spudger” many years ago.

Wink

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Avoiding the iR mR discussion entirely.

I have noticed that it’s voltmeter when charging often will step in .01 volts from 4.20-up to 4.25 and then as the charge continues it drops back down to 4.20.

some cells go to 4.22 some to 4.23 but always the last 6 ish minutes are in that small arc up and back down.

so for me it matters what it ends at. which is 4.20 typically.

.02

Ok I cant keep it in.

On the iR mR issue I and maybe others are hoping that if we kvetch enough then maybe they will improve that often used function.

And no it is not normal, on my multi year old 500 the #4 position is less consistent then the others but still with in 10mOhm of what it would read in bay 1-3

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teacher wrote:
atbglenn wrote:

I carefully use a plastic spudger on the positive side to get my 18650’s out. It works great.
Hey Glenn, I think these two guys collaborated and invented the “spudger” many years ago.

Wink

RIP Lumpy Dumpy. I thank you for inventing the spudger. Knowing Eddie Haskell, he probably had nothing to do with it, but took credit… Poor Lumpy Sad

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atbglenn wrote:

RIP Lumpy Dumpy. I thank you for inventing the spudger. Knowing Eddie Haskell, he probably had nothing to do with it, but took credit… Poor Lumpy Sad
Hmmm, I did not realize Frank Bank (Lumpy) had passed away back in 2013. Sad
Your probably right about Eddie too Glenn…. Wink
I thought you might get a kick out of this………. Party

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Chuck, I got a major kick out of it. Yeah, it’s too bad about Lumpy, Whitey, Ward, June, Miss Landers, etc from the show. It was and still is one of my all time favorite shows along with Car 54, The Munsters, Bewitched, etc, etc. I miss the old days of TV. Sad that most of the stars from those shows are long gone.

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atbglenn wrote:
I’m doing a nor test with Efest 700mAh V2 16340 cells purchased at the same time

Bay 1 68mR
Bay 2 74mR
Bay 3 45mR
Bay 4 62mR

I’ll update with voltage readings when it’s finished


Hi, just curious if you also got very high IR on bay 1 & 4 like I did?

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atbglenn
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MAD TM26 wrote:
atbglenn wrote:
I’m doing a nor test with Efest 700mAh V2 16340 cells purchased at the same time

Bay 1 68mR
Bay 2 74mR
Bay 3 45mR
Bay 4 62mR

I’ll update with voltage readings when it’s finished


Hi, just curious if you also got very high IR on bay 1 & 4 like I did?

No. I just tested a 2 year old Panasonic 18650 in all 4 slots and they all read close in the high 20’s.

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teacher
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I just tested IR an Eneloop AA made in September 2007 (07 – 09 SA) (#2). Below are the IR results in ‘mR’. (whatever “mR” stands for?? I ‘assume’ it is milliohms… but “assume” is the operative word cause I really have no idea if that is correct or not.)
Anyway, the battery was moved to a different bay each time and the order was random.

Bay 1__ 36__32__29__28__31
Bay 2__ 27__33__33__29__34
Bay 3__ 36__40__29__27__34
Bay 4__ 44__35__40__45__33

Below are the IR results for a UltraFire 18650 2400mAh Protected. (Yeah I know… now anyway. FacepalmFireWink ..)
Not sure how old this battery is, but it is real old. Probably one of the first LiIon batteries I bought…. back before I knew better. Smile

Bay 1__ 65__68__71
Bay 2_ 125__64__69
Bay 3__ 76__56__91
Bay 4__ 66__59__61

(All done on my Lii500)

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Ronin42 wrote:
Avoiding the iR mR discussion entirely.

I have noticed that it’s voltmeter when charging often will step in .01 volts from 4.20-up to 4.25 and then as the charge continues it drops back down to 4.20.

some cells go to 4.22 some to 4.23 but always the last 6 ish minutes are in that small arc up and back down.

so for me it matters what it ends at. which is 4.20 typically.

.02

Ok I cant keep it in.

On the iR mR issue I and maybe others are hoping that if we kvetch enough then maybe they will improve that often used function.

And no it is not normal, on my multi year old 500 the #4 position is less consistent then the others but still with in 10mOhm of what it would read in bay 1-3

The voltmeter in my Lii-500 also has similar behaviour.

I find that the position if the cell in the bay can affect the IR measurement, more of an issue for smaller cells that can be slightly off centre on the contacts.

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Read Barkuti comments again, and HJK’s review. IR on this charger is close to worthless. You guys are minutely inspecting what is essentially garbage data.

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flydiver wrote:
Read Barkuti comments again, and HJK’s review. IR on this charger is close to worthless. You guys are minutely inspecting what is essentially garbage data.

Bit harsh. It is not completely garbage, but there is a large degree of inaccuracy. Using a DMM would be recommended, and XTAR’s approach to measuring iR in the Dragon VP4 Plus may be interesting.
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flydiver wrote:
Read Barkuti comments again, and HJK’s review. IR on this charger is close to worthless. You guys are minutely inspecting what is essentially garbage data.
No need to read them again ‘flydiver’, I know exactly what they both said and do not disagree.

And the stuff I posted is just about as far from “minutely inspecting” as anyone could get. Smile

You never know how a horse will pull until you hook him up to a heavy load./"Bear" Bryant 

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Ronin42
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flydiver wrote:
Read Barkuti comments again, and HJK’s review. IR on this charger is close to worthless. You guys are minutely inspecting what is essentially garbage data.

First (Why so harsh?)…dude.

Second I think the max for the mR measurement is 275 (but it might be higher) lets say its 300. so a one percent change is 3 points. If we go =/- 1% that’s a range of 6 points. lets say for argument sake that “most” readings fall with in +/-3% (+9/-9) points, that a range of 18 points.

When I can get information that is within +/-3% and is unavailable to me other wise I call that useful information not “minutely inspecting what is essentially garbage data”.

So I respectfully disagree with both your (harshing my buzz man Wink ) and with you position. But hey my using my charger does not cost you a penny.

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Didn’t realize it came across that way. Sorry.

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The charger measures the resistance quite good, but it measures the resistance from the wiring and contacts as well

if you want accurate readouts the voltmeter needs seperate wires to the battery with no current flow, but a regular slot charger cant do that

Lexel
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The charger measures the resistance quite good, but it measures the resistance from the wiring and contacts as well

if you want accurate readouts the voltmeter needs seperate wires to the battery with no current flow, but a regular slot charger cant do that