I recently purchased the LiitoKala Engineer Lii-500 so I could properly test the (4) Samsung INR18650-30Q batteries that I bought from Banggood as well as (4) I just got from Amazon. When i did a charge of the new batteries, they only registered 2497 and 2481mAH and I was concerned that these might not be authentic. I am going to run all (4) of the batteries through the Normal test to see if I get different results, but I was wondering what sort of results BLF members have seen with these batteries.
Since I was unable to buy some new 30Q’s from the same set/original group, I really wanted to see which of the 8 batteries are the best matched to use in my new BLF Q8!
A charge from an unknown charge state will not be anywhere near accurate. You have to to the [normal test]. Most of the time batteries I test get near but do not meet the so called specification, even good batteries.
i recently bought 8 samsung 30Q button top at banggood, got them in my mailbox 11 days ago.
They all came with voltage around 3.4v, i immediately launched a fast test capacity when they arrived (discharge from 3.4v to 2.8v then full charge to 4.2v to evaluate the mah).
All battery finished the test between 2920 mah and 2970 mah, all battery came with an internal resistance between 31mO and 44mO, that's good and what i was expecting.
I have no way of testing the discharge current rate, but both of my BLFQ 8 are brighter with 4 Samsung 30Q than before with 4 of my 1 year old LGHG2, so discharge current rate seem really good to me.
If you batteries came like mine with a voltage around 3.4 volts your results are good if you only charge them to 4.2v.
In charge mode the Lii-500 measures current into the cell(s) from their given state of charge. If your 30Q cells were at ≈3.3V no-load voltage prior to charging them your capacity figures make sense.
To get full capacity figures use FAST and NOR tests. FAST measures capacity in, so it first depletes the cell down to 2.8V then charges. NOR measures capacity out, for this it requires cells to be full so it first charges them.
appreciate the clarification between the two test modes. Will they both tests show the same results? or is one test mode preferred over the other for capacity testing?
—i did read this from HKJ’s review: “The fast test works fine on LiIon, but with NiMH it shows too much capacity (the full test looks more correct).”
I believe I’ve asked this question to HKJ, and I think the reply was something like, for a good Li-Ion, the capacity-in and capacity-out (from discharged state, let’s assume something like 2.80v) should be almost equal (I have tested high-resistance old batteries where the capacity-in (charged capacity = Fast test) is notably higher than capacity-out (discharged capacity = NOR test)… the reason being with higher resistance, it needs more charging current to get it to full.
(I’ll have to check again the reason for NiMh charged capacity not exactly a good measure of discharged capacity… but maybe the reason could be that NiMh uses a different charging algorithm, and the charge current may affect when the charging termination occurs, and this will then affect “how much capacity” was charged into the battery. For instance, one could do very low trickle charge on an NiMh, and the voltage may not really increase or signal termination (NiMh battery full) depending on the charging scheme/termination characteristic. Anyway, that’s my limited understanding. Kindly correct my inaccuracies for those more knowledgeable than me…)
Essentially to charge NiMh, you pretty much have to over charge it. d-t-a has it correctly, the termination method is entirely different. Depending on the battery condition (old/poor batteries make it harder to get right), the level of charge (too high or too low), and the charger termination method it is entirely possible to:
- terminate too soon > getting a low capacity; sometimes very low as it stops almost immediately.
- terminate too late > showing high capacity; more usual as the battery gets older with higher internal resistance.
or in some cases not terminate at all > showing whatever capacity was put in until you finally stop it (a ridiculously high capacity)
Discharging NiMh from full to a known stopping voltage is the only reliably accurate way to test them. Even that has issues if you use too high a discharge current on a battery that can’t handle it.
It’s actually harder to charge NiMh properly than Li-on. It’s just when you screw up the consequences are not as nasty (usually).
