"internal resistance" test comparison of several popular chargers (with summary)

Using some very old AAA NiMh (the Eneloops are 10-years old, the Panasonic may be older)

Zanflare C4

Opus BT-C3100 v2.2

SkyRC MC3000 v1.13 firmware

Liitokala Lii-500 Engineer

Miboxer C4-12:

The Zanflare C4, Opus BT-C3100 and SkyRC MC3000 results correlate (for the very high resistance "Panasonic" NiMH, the MC3000 actually usually reads an incorrect "1 mOhm" reading, but was able to capture one time when it didn't).

The Miboxer C4-12's highest reading is 999mOhms, so it's also correct.

The Lii-500 gives a bogus resistance reading.

testing #2: a set of “high-resistance” 18650s:

Zanflare C4:

Opus BT-C3100 v2.2:

SkyRC MC3000:

Miboxer C4-12:

Liitokala Lii-500 Engineer:


The Zanflare C4, Opus BT-C3100, SkyRC MC3000, Miboxer C4-12 sort of correlates even if they’re not the same resistance values.

(In the above, I switched the slots of the BT-C3100 and very surprisingly it gave almost exactly the same resistance reading; my MC3000’s contact points are probably not as good anymore so there’s some variance between re-readings).

The Liitokala Lii-500 Engineer just gives some bogus readings.

3rd set: comparing a Sony VTC6, Samsung INR18650-30Q, LG HG2, Panasonic NCR18650B

Zanflare C4:

Opus BT-C3100 v2.2:

SkyRC MC3000:

Miboxer C4-12:

Liitokala Lii-500 Engineer:

Once again, the Zanflare C4, Opus BT-C3100, SkyRC MC3000, Miboxer C4-12 correlate with each other…

Surprisingly, here the Lii-500 Engineer seems to be correlating too.
(However, when I did a re-test, the Lii-500 Engineer was giving inconsistent results again… so it’s not sure when the Lii-500 will give “sort-of-correct” readings versus when it’s not giving correct readings…)

Table summary:

(readings #1 & #2 are generally when the battery is changed to a different slot to get a second reading)

(Nitecore SC4 tested but pictures not yet shown above).

Basically, the ZanFlare C4, Opus BT-C3100 v2.2, SkyRC MC3000 and MiBoxer C4-12 internal resistance readings correlate.
(ZanFlare C4 seems to give a bit lower iR reading sometimes)

It’s unclear whether the Liitokala Lii-500 Engineer correlates or not, but the figures are somewhat inconsistent.

The NiteCore SC4 does show high resistances for high-resistance cells, but not always correctly…
(SC4 wasn’t able to determine that the VTC6 & 30Q has lower resistance than HG2 and NCR18650B; unlike the other “good” resistance readings which definitely indicate the VTC6/30Q having lower resistances than HG2/NCR18650B)

SC4 doesn’t seem to read IR anymore for Li-Ion batteries if their voltage is at around 4.15v or higher (it will just show a steady “120” mOhms — I had to discharge them to around 4.10v from “fully-charged” before it reads IR)

So you’re saying it’s a complete crapshoot then? :smiley:

Well, I thought it would be nice if the charger can identify “crap” batteries versus “good” ones. Which is part of the reason I’m using some “crap” batteries for testing.

So far, the Lii-500 doesn’t exactly recognize crap batteries that well (“77mR” is bad while “39mR” is good???)

NiteCore SC4 seems to recognize really crap batteries, but not all the time (really bad batteries, it does identify, but somewhat “bad”, it doesn’t identify clearly. And it couldn’t exactly identify the “best” low-resistance batteries from the “OK good” batteries — eg. it rates the VTC6/30Q similarly as the NCR18650B).

The rest of the bunch seem to do pretty well (able to clearly identify the VTC6/30Q from the NCR18650B), and also high-resistance (old) batteries will show really high resistance). The max display of the Miboxer is 999mOhms only though, but I suppose a battery with less than that is already considered not good…

Hmm it’s looking much much much better now that you’ve added the lithium ion cells. When i posted, all you had up were the AAs :slight_smile:

Very useful comparison - makes me want to get an Ri meter. Thank you.

Looks like the Opus BT-C3100 v2.2 wins the low budget test. At least with Li-ons, tighter groups than the SkyRC MC3000 which cost twice the money.

Thanks for the testing and through results.


Actually, I’m not sure if the “not-that-consistent” readings of my MC3000 could be because the spring contacts might be getting loose (it’s the more “used” unit - I do a Refresh capacity test of almost all my batteries with the MC3000), while the rest are still quite new chargers (so their contacts are still pretty good).

I notice the battery holder “post” of my MC3000 slot 1 and slot 4 are getting a bit bent already from regular usage. So that could also affect the resistance readings somewhat.

I have an Opus, a couple Zanflare C4, and a couple (I’ve had 3) Lii-500.
In ‘general’ the Opus and Zanflare both work and give somewhat consistent results. The higher the IR, the more the readings tend to not be consistent, but they ARE high, which points out crap batteries.

The Lii-500 has never worked. I consider IR on that charger to be useless. Otherwise a decent charger/analyzer. IMO that makes the Zanflare a better buy. I just like using it better.

Thanks for the work and the post.

Thanks for posting. Interesting results.

i find the Lii-500 reliable for Li-ion only
but the values are different when charged (lower) and discharged (higher)

The charger measures 1KHz AC IR, this means it momentarily injects an AC current into the cell rails. However, since it can not raise voltage above the 4.2V maximum, if cell resting voltage is close to that value the charger cannot measure properly, and high internal resistance cells just add fuel to this fire.

To have meaningful AC readings I keep cells below 3.9V before reading and settle them properly in the rails wiggling them at least to remove any superficial unseen contact debris. Take various measurements and use the lowest figure or average of lowest figures to minimize rail contact resistance involvement.

Result still won't be comparable to a proper DC measurement, but this requires different equipment and methodology.


Lii-500 measures 1KHz AC IR?? Isn’t it AC IR testers are different than those reported by most analying chargers (which measure DC voltage, and thus DC IR?)

While I do not really know which exact method or algorithm the Lii-500 or any other analyzing charger uses, I know for sure it is not DC IR because I can do DC IR and my figures are different to those of the charger.

It is already a miracle that these devices can even do AC readings, because in order to determine internal resistance voltage measurements have to be taken right at the battery terminals. If not, any resistance in between will cause a drift, with unpredictable contact resistances the main hurdle here.