Test/review of Keeppower 18350 1200mAh UH1835P (Black) 2017

These cells are now in stock from nkon.nl, a highly reputable European vendor (no affiliation).

They do however state that the cells are 39 mm long. Which makes me wonder if they’ll fit properly in my Emisar D4?
The springs should have enough play, but I’ll hold my order until I at least get home and try to cram a measured battery with a spacer in there!

Or can anyone verify that these cells will work in a D4?

HKJ states 35 mm though, and “highly reputable” is the least of his accolades. But different batches, different specs? Fake cells? Or just misspelled on nkon?
I’ll be back with a solution to the conundrum when I have it, unless solved by another.

35mm is unprotected cell and it can be seen on my photo that the cell is unprotected.
39mm is a protected probably button top cell.

Nice cells, allowing small lights with multiple emitters to shine, the closely resemble the Vapcell 18350 purple.
Still, the Aspire cells were even better but extremely hard to gome by………

Tnx for testing!

Cheers,
Nico

I have the aspire 1100, keeppower 1200, and the vapcell 1100, pretty sure the only difference is the wrapper.

Hei Imp…

My
Aspire 34.91 long (fit D4)
Keeppower 35.09 long (fit D4)
Ultrafire (protected button top) 38.78 long (do NOT fit D4)

So there you go…

I received an answer from nkon. Despite the time being post 5 pm on a Friday!

So it seems like they’re fine. Although Hunter’s post makes me curious as to the measurements and batches, if nothing else…

I’ll order a bunch anyhow!

Hi Imp…

Yes it must be batch variations. Mine Keeppowers are 35.09 to 35.19 in length and 18.27 to 18.29 in width.

Otherwise, exactly the same battery as described.

The Aspire, Vapcell, and this Keeppower are same cell, all made by the same factory. Yongdeli New Energy Battery. Tony, the owner of Aspire E-Cig is part owner in the battery factory. At least he was a year ago.

I have now received my five batteries. They are indeed about 35 mm long.
The measurement of 39 mm corresponds to Keeppowers protected 18350 cells, so the error was probably made by looking at the wrong specs, but has since been corrected.

The cells arrived in retail boxes of two, including a case for two 18350 or 18500. With a bit of cutting they can be made to fit three 18350s though! (And the fifth cell came in another of the same case, even though I ordered several other cases, one of which was used to package the two HG2s I also bought).

Furthermore, the Keeppower case for one 18650, which is apparently made with protected cells in mind, can just about fit two of these cells, with a very thin insulator! With a little bit of cutting it should be possible to fit a somewhat thicker piece of plastic in between, making it a very compact case for the job! :slight_smile:

Thanks for the info. With regards to the insulator thing, no need for it strictly speaking unless you aim to prevent any scuff marks, ?

Cheers ^:)

No, I’m more after a “spacer”, or something to hold the cells in place, as the case is on the large side and they will rattle and move if there’s only one in there. Yes, “insulator” may have been a bad choice of word, but it was natural in the circumstance.

What's up, fellows?

Just dropped by to ask how these cells are doing lately, or how are these cells being made right now. I at least hope their performance is up to par.

I am namely asking because after looking at their sale advertisement in the Convoy store, this is what I see in the pictures:

I see a six lobe cell top with round disc atop of it, a clearly different shape than before. Did anyone purchased this cell recently to confirm this?

Also, any comments with regards to this cell's lifespan and self-discharge are appreciated. I may use it to build a custom power tool battery pack.

Thank you and cheers.

I ordered two of Keepower (UH1835P) cells on May 2021 from a different Aliexpress seller. The cells looks different from HKJ’s review and appears to be the same as the one sold on Convoy store.

Both of my cells show very high self-discharge rate. One lost 0.20v from full in 26 days and the other in 20 days. I am not sure if these cells generally show very high self-discharge rate, but I have not yet come by other information that shows otherwise.

However, the cells seem to pump the high current it claims.

Here are my previous discussion on these cells:

Barkuti, good to see you on here again. I have a couple of those that I got a year or so ago from either Illumn or Liion Wholesale here in the US…looks like the same cell (same model, same button). I have not see the self discharge in my pair that Limsup did. I don’t use them a lot but have been impressed with what they can deliver. I only have maybe 8 or 9 cycles on them so I can’t offer anything there.

For the love of God, for the love of God… That you are saying there is terrible.

Long ago I once tested a bunch of old laptop pack scavenged 18650s for self discharge, leaving them to rest for a couple weeks after being charged in parallel to a non-stressful voltage level (can't recall the exact figure, but fairly sure it was between 3.8 and 3.9 V). Some of the cells in that laptop pack were initially found slightly below 2 V, and besides a capacity check I did that self-discharge test to determine which cells to discard. I discarded a couple cells which lost very few mV, keeping only the ones whose voltage was rock solid set at the initial value.

I do not expect any decent quality li-ion cell to lose any significant amount of energy from self discharge, that is the reason I think what you say is really piss poor performance. Comparatively speaking, low self-discharge NiMH cells do a lot better than that!

Hello :-) Correllux. Yes, I do no longer post here very often; I don't feel the need and I certainly have much more imperative things to spend my time at now.

Its nice to hear that their discharge performance is good, but I have binned cells with much less self-discharge rate if I am to take Limsup's figures seriously… I certainly do not want to buy cells like that.

So, could you make a test for me? Correllux or whoever is willing to who purchased the cells from a reliable provider (I really hope Simon gets top quality cells). A simple test like charging a cell or cells to 3.8 - 3.9 V, measuring their voltage at rest and noting it down, and a week later repeating this last step. One week of wait time can be enough to check if there is any discernible loss of voltage and energy in the cells.

Thanks and cheers. ;-)

I can probably do that but it might have to wait until this weekend. I don’t have a bench supply so I’ll have to eyeball the display on my MiBoxer and pull them. I’ll try a 0.2C charge and take voltage right off the charger and after an hour…unless you’d like some specific procedure. :slight_smile:

0.2C charge? That's 220 (200?) mA for a ≈1100 mAh capacity cell, which model of MiBoxer do you have? This is slightly off topic, but the second channel in my Lii-500 suffered a malfunction months ago and ended up literally cooking one of my AAA Ni-MHs, as it didn't terminate and kept pumping the full current until I stopped it many hours later. The cell ended up so hot that its wrap melted and there was plastic debris over the positive terminal of the charger. :FACEPALM:

It does not really matter which device you use to charge the cells, so eyeballing the charging voltage in your MiBoxer is fine; just let it charge the cells until you see ≈3.9+ V on its display. Since the voltage is measured somewhere in the charger's PCB, the voltage at the cell terminals will be slightly lower because charging current times rail and contacts resistance is a voltage difference. So, you will measure slightly lower voltage at the cell terminals once removed from the charger. I suppose you have some decent multimeter. O:)

Measuring the resting voltage after an hour or a little more off the charger is adequate. Thanks.

Ouch about the melted wrap on your cell! I watch my NiMH cells carefully…actually just recently started to use a slightly higher charge current for them than I traditionally have. I usually use the Maha for those, though, but the MiBoxer seems to do ok. I have the first version of the C4-12 that had the single grey button (the second version had two yellow buttons). I’ve been really satisfied with it other than the IR readings (typical, though) and I don’t usually let it run automatic since it likes to choose high currents if the cell’s IR is low. I’d buy another if MiBoxer were still in the charger business…I’m hoping the new Vapcell S4+ will have improvements and take 26800 cells.

This charger will let you select 200, 300, 500….on up. I think it might even do 100 on li-ion but maybe not (it will for NiMH though). Pretty versatile. Yes, I do have a decent meter that I trust for 1/100th of volts…lately I use it more than my others. It’s the Brymen-made EEVBlog unit from a few years ago. Nice features and more accuracy than I usually need…well suited for general electrician and automotive use and enough features/quality to handle the majority of hobby and electronics uses.

I put the cells on my desk at home so I won’t forget about this. :slight_smile:

The EEVblog multimeter, Correllux? That should be either a 121GW or a BM235, both of which are out of my league O:) and needs; but it's nice to know that the voltage measurements are going to be accurate.

Concerning the next Vapcell charger, I hope for the best but I won't place my bet on it. Are you following the suggestions thread which vapcell Dennis started in that regard? }P Too much complaining and little actual knowledge about cells or batteries, vapcell Dennis.

And what I just said is also common with other brands of chargers (like Liitokala), its like if they have or hire n00bs or ignorants to decide what to implement in a charger, because one way or the other their devices always end up having some hiccups or inconveniences (like trickle charging cells, what the hell?). Its hard not to be judgmental with all of this. :-|

I'll be patiently waiting for the self-discharge test results, Correllux, it's going to be a 10+ day wait. No hurry at all from my part, by the way. Thanks again.

date(mdy) v
11/6/2022 4.1876
11/14/2022 4.1072
11/17/2022 4.0954
11/25/2022 4.0734
11/29/2022 4.0582
12/4/2022 4.0314
12/7/2022 4.0062
12/26/2022 3.8913
12/29/2022 3.8808
1/30/2023 3.7539

Here are my measurement data on one of my cells. I used YR1035+ for the measurements. I don’t think this is normal, but I noticed it too late to file a dispute or ask for a replacement.

On the other hand, batteryuniversity.com documents that fully charged li-ion batteries can lose 20% of its charge in a month. (See Table 4 in the first link) According to the website 70mV drop is is roughly 10% of a li-ion battery capacity, so 140mV drop in a month in my data can be considered normal in the batteryuniversity standards. However, I have not noticed these kinds of voltage drops in other batteries. Maybe recent li-ion batteries have significantly improved self-discharge rates.

Average self-discharge rates documented in batteryuniversity.com are about 1~2% capacity in a month for a half-full li-ion battery at optimal temperature. (See Table 3 and 4 in the first link) That is roughly 7~14mV per month. The monthly self-discharge rates on my cell on sub 4.0v voltage is above 100mV, so my cells have high self-discharge rate even according to the website’s numbers.

To summarize, self-discharge on my “fully” charged UH1835P is in the normal range, but the self-discharge rate is very high when the battery is half-full (below 4.0v).