Test/review of LiitoKala INR26650-50A 5000mAh (Black)

The 50A label of these cells is derived from the manufacturer cell model they started rewrapping, PLB INR26650-50A.

True, but because of lack of consistency. I sometimes build battery packs and for this cells with poor consistency suck in one way or the other.

Excuse me but given two cells of the same model (which means same chemistry and internal construction) the one with higher capacity will also be more current delivery and power capable.

Yep. These batteries are definitely not capable of 50A output and even the cells in HKJ’s tests show a maximum rational current of 20A.

Yes, and this worries me a bit. My cell measured at 5436mAh on its first full cycle, so it may improve further during the next few cycles. That’s far out of line with both the Cyan and Black cells tested by HKJ. This suggests that the cells have changed. I have no method for doing high-current testing, but am very curious how the cells currently being shipped compare to the HKJ cells, which offered surprisingly good performance for the price.

I’ll be using the cell in an Astrolux FT03, which is a 9.5A light with the best cells and somewhat less with this LiitoKala. How much less? I just don’t know and my clamp meter broke years ago… oh well :wink: .

I would assume they did NOT have the same chemistry and internal construction. If they did, how could there be such a big gap in capacity? Almost 900mah more is a really big gap. Do you think they accidentally stumbled upon a way to get 5900mah, without sacrificing the performance?

Maybe the more logical reason is that the Lii-500 charger is not so good at measuring capacity? IDK.

You don’t need the best batteries to perform well in that light. The 48G cell did just fine and that is not a high drain cell, it’s a high capacity with a 10A continuous rating. So I would not be worried.

Agreed, its a matter of overall better cell quality. As for the consistency, 10% variance is within acceptable limits since it’s above the rating. Stating 5100 and having 5400+ is certainly more reliable than stating 5100 and having 4800-5300.

The cell should work fine in the FT03, but I am curious about whether they are still the same cells that HKJ tested. Those were barely 5000mAh even at 0.2A, yet many people in this thread have reported substantially higher capacities when testing with the Lii-500 charger.

Perhaps the charger reads high, but HKJ’s tests of this charger (in 2015) show expected capacities with a Normal test of li-ions. If you look at the chargers he tested around the same time, you can see how each one fared on the collection of test cells he was using at the time. I don’t see enough difference to explain why so many of us are seeing around 5500mAh from these Lii-50A cells.

I just wonder if LiitoKala has changed suppliers. I guess another explanation would be that they changed the charger somehow, but I doubt that. Manufacturers tend to strip components out of products in order to shave production costs, but I don’t think this would lead to exaggerated capacity measurements. Possible? Yes. Likely? I don’t think so.

:question: Okay, as you can see in the photo (also shown in a prior post), the battery voltage has dropped to 3.96 after the test has completed. Is this normal?

Out of curiosity, I popped the cell back into the charger today thinking the voltage would spike back up, but instead the charger has now put 870mAh into the cell over the past 1h 45m (default 500mA as I did not expect it to run for long). I removed the cell at 4.18V.

Oh, and I’ve experienced no heat issues when charging at 700mA; the cell never gets noticeably warm at all. I mention this because I’ve heard that someone recently had a Black Lii-50A catch fire :(.

I haven’t seen batteries drop that much. It’s usually from 4.20 to 4.15. Something like that. I’m not real sure, though.

Does that charger show all cells to have higher than rated capacity?

I have some data of the measuring differences between slots in my Lii-500 and they are within ±1.2%, mostly due to small differences in maximum charging voltage.

All of this capacity measurement divergence is a sign of something. I do not like it.

Outrageously unacceptable for cells in series without battery management system.

Cheers ^:)

@Barkuti - for any sensitive systems you must use BMSs. You can have identical cells and one could still die-off way faster, therefore if you need to ensure balance you needs BMSs. Otherwise it’s an improvisation anyway. Other systems like flashlights of course won’t need any.

I pretty well understand all of that Overmind. Still, how about flashlights with 2 or more cells in series? Bad cell consistency increases the risk of over-discharging the weaker cell in such conditions, a flashlight driver does not have independent cell voltage monitoring. I am responsible of keeping my cells matched in any case.

This cell consistency problem means LiitoKala is doing something fishy with their cells, something which is more than proven already anyway.

^:)

Well only long term testing can prove how reliable they are. Hope they are, as I got some quite at a quite cheap price.

Yea, I expected a drop to no less than 4.10V while still on the charger. The charge had been completed for a few hours, but likely no more than 3.

I’ll test this with a Samsung 30Q. Please hold…

A way to get a good idea of a given charger's slot measuring divergence is to do charge/discharge tests in it with the same cell or cells doing away with the older the cell, the lesser the capacity effect via swinging slot selection. Any cell is tested twice per round in each slot and its capacity averaged out of the two figures. For a 4 slot charger this is 1 2 3 4 then 4 3 2 1 or 4 3 2 1 then 1 2 3 4, as an example. Bear also in mind how does the charger scores the capacity figures, in a Lii-500 a mAh is scored only when the elapsed time per mAh has passed, thus any capacity figure should be added ½mAh.

I would unwrap the cells and carefully look for factory markings, top and tail shape, condition, etc. For sharing, making good and detailed photographs is of help.

^:)

Well, the Samsung 30Q measured fine at 700mA. I received this cell from BG 3 months ago and this was only its 3rd charge, so I consider it new. I was busy elsewhere when the charge completed, but no more than 1 hour had passed since completion. Notice that the voltage dropped to 4.02V, which is nearly identical to what we saw with the Lii-50A. I used the same bay for consistency, but I will test with another bay tomorrow (~12 hours) if it helps.

So far, the capacity measurement seems okay, but the substantial voltage drop is bizarre. I don’t like to cycle cells unnecessarily, but I apparently need to do more testing and actually witness a charge cycle ending. I do know, however, that the cycle reaches about 4.20V as I witnessed voltage at 4.18 and rising when I last pulled the Lii-50A.

I did initially start on-topic as I was showing the capacity of an Lii-50A in this charger, but now that I’m discussing an issue with the charger I would be happy to move my issue elsewhere if anyone prefers.

Looks like the charger does not disconnect the cell after testing. That’s not a good design if you intent to test over night.

You think it fully charges the cell then starts to discharge it? Possible I guess.

You would need to remove the cell after charging and maybe use a DMM to check voltage. I suppose it should be at 4.20 to 4.18. Then let the cell sit several hours and see if the voltage drops a little or a lot.

The capacity for that 30Q seems fine so it’s probably not reading high. That’s odd, I thought the PLB-55A cell was the highest capacity at about 5750mah. Interesting.

That wouldn’t be a good design, period, but other people are not reporting this issue with this charger, so it’s possible that there’s something wrong with either the charger or just bay #1. When I made the first post, I was mostly reporting on the currently-shipping Lii-50A capacity, but while cropping the photo I noticed the 3.96V reading and began wondering. Now I have a mystery to solve, though I didn’t want one :wink: .

Unless the cell has some wear-down, there is no reason to drop voltage that fast.

Also, a 30Q should not show under 3000mAh, specially tested at low current, unless again it has wear-down.

I don’t think that’s true. Most 30Q’s test under 3Ah.

Here's HKJ's test:

And here's zeroair's recent test:

Zeroair does get over 3000mAh, but only at 250mA. I don't have many li-ion cells to choose from, but this one makes a good test case as it's a known quantity and Samsung has very high consistency with them. The above tests were done 3.5 years apart, but the shapes of the curves are largely identical. The 2019 cells do seem to have somewhat higher capacity at low currents, but this could be an artifact of different test environments.