Does anyone know what cell the Cyansky BL1834U battery uses internally, or otherwise its detailed specs?

Batteries and Chargers Rechargeable Batteries
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As per the subject. I just received my GAW prize (thanks again, @Cyanskyflashlight), and I’m wondering what are the best/recommended parameters to recharge this battery (and then discharge it to check its capacity).

I sent them a message, but given it’s already Saturday on China, I don’t expect to receive a response from them until Monday – and the itch to test that battery in my MC3000 is biting hard :wink: so I thought of availing myself of the BLF community wisdom.

I found its page on CyanSky’s website, but it does not mention the following data:

  • Recommended discharge current, in order to reach the 3400mAh nominal capacity;
  • Recommended discharge cut-off voltage (ie, at what voltage the battery discharge should be stopped, again in order to reach the nominal capacity;
  • Recommended charge termination current (so the battery is maximally charged and will, during discharge, reach the nominal capacity).

Alternatively, if you can tell me the brand and model of the original cell they use to manufacture yours, then I can search for and get these values from its datasheet.

TIA!

PS: @Mandrake50 I see you were the other winner of the GAW. Presuming you received yours already, (1) did it come with the same battery as mine? And (2) did you refresh-tested it on your MC3000? if yes to both, what parameters did you use? TIA!

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I didn’t test mine. I think I just topped it off at 1 amp and called it good.

I am not sure why you would need to tailor your test so tightly. But when I test cells I use the same setting for all of them. Maybe I am not nursing the last few mAh out of them, but I can directly compare results of many cells.
IOW, performance at set conditions (I think) is more reflective of real world results when comparing multiple cells.

Think about it, your flashlight will not come close to discharging the cell in accordance with the manufacturers specs.

BTW, I too would be interested in knowing what cell is under the wrap.

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Ok, so you didn’t set any discharge parameters. Besides 1A charging current (which BTW is what Cyansky recommends in the page I linked to), did you set anything else, specially charge termination current?

Short answer: because I’m a pernostic, detail-obsessed, perfectionist effing NERD! :nerd_face:

Long answer: I want to give this flashlight a good, honest review (to be published right here in BLF, of course), and this cell’s claimed capacity of 3400mAh makes me very suspicious, therefore I want to test it exactly according to the manufacturer’s recommended parameters so there’s no excuse if it doesn’t measure up.

Granted, specially because my cells’ day-to-day use is much less demanding in order to extend their life. But see above :grin:

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I looked… the program that I used uses 0.18. So that and 1 amp charge current, 4.2 volts termination voltage.

Yeah me too.

BTW, I get it, but I wonder how many reviewers go to this length to test cell capacity. Or how many slap them in a Vapcell or Xtar unit and just let them run at the defaults. Not that you are somehow wrong in doing it “better”. Just the comparison thing again. It would be interesting to see your test with kind of “standard” 18650 settings versus giving the thing special treatment. But yeah, if just trying to test the capacity claim, I guess the closest you can come to duplicating the Cyanski test conditions is to stay tight with the manufacturers specs… if you can get them.

BTW, I don’t know if you are setup to test it, but I would be interested in knowing the parasitic drain on the headlamp. I charged the cell and it was at 4.17 volt resting (30 minutes). I just checked it and it was at 4.07 volts. That was what, after maybe 6 weeks. I think this thing might disappoint if left to sit for 6 months or a year without mechanically locking it out.

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Guess what ??? I took a closer look. I didn’t get the same cell that you did. Mine is a BL 1826. A 2600 mAh cell. Notice no “U” in the designation. It has no USB charging port I see their web page lists the 1834U with the light. But that is not what I got… But what do you want for free…??? :expressionless:

BTW, have you tried to take the light out of the bracket. It took me about 20 minutes and a few tools to get mine out. I think it took longer to get it back in… very unhappy with that. It may be worth mentioning in a review.

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Thanks for looking! 0.18A seems a little high, tho (I’m used to seeing this at under 0.1A for the other batteries I’ve been using)

Meanwhile I’ve been looking at ‘real’ manufacturer aka OEM cells (of which all others are supposedly rewraps) and it seems that (according to Parametrek ) the closest to the BL1834U is the Sanyo/Panasonic NCR18650GA, Parametrek lists it as 3430mAh while Panasonic’s product page indicates a nominal capacity of 3400mAh (average of 3350mAh minimum and 3450mAh typical).

So I dived a little deeper into the NCR18650GA and posted my findings and further questions here: Sanyo/Panasonic NCR18650GA: recommended MC3000 parameters for charging/discharging in order to reach nominal capacity?, if I fail to obtain more specific information (ideally from CyanSky) I may try and test mine with these parameters.

Agreed. In the end it might make very little difference – but we won’t know until we test.

Exactly! Let’s give them a few days to respond to my PM.

:frowning: unfortunately my only multimeter (an Uni-T UT210E) isn’t able to measure current with its testing probes (which would make that really easy (to say nothing of precise), only with its clamp :expressionless: so I would have to find a way to get a piece of wire (large enough to make a loop to place the clamp into) to make contact with both the bottom of the battery and the unanodized edge of the flashlight tube… hummrmrmrm… OK, I will try and figure it out.

Meanwhile, have you seen the 1Lumen’s excellent HS5R review? It does list “Parasitic Drain” as 19.1uA, which is quite low.

Agreed, disappointing and (unless you have a bad cell) indicating a much higher parasitic drain than 19.1uA. I presume this was with the cell that came with your HS5R? Perhaps its not that great of a cell after all :expressionless:

WTF?! So Cyansky shipped your light with a different (and much inferior) cell than the BL1834U they themselves indicate at their HS5R product page?! This sounds like (at best) a mistake on their part. I would contact them and ask for a replacement, the cell you received is much inferior both in capacity and in function (as it has no USB port), to say nothing of being possibly bad (as per the voltage drop you measured with the flashlight shelved). Alas, my HS5R kit came with a missing USB charging cable – not as bad as the battery swap they made with yours, but it seems to indicate their packaging/shipping departments do have problems.

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Cansky put a type-c charging port on that battery so that’s how you should charge it. If that was a bad move on their part then let the chips fall where they may. They don’t want you to know what’s under the wrapper and they may not be using the same battery in 6 months so they’re not going to tell you all of the battery specs that you want.

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I’m really averse to use a battery’s USB port for charging, given I have an MC3000 that gives me much more control and allows me to record full telemetry of all operations. The way I see it, built-in USB charging ports are there for emergencies, not for normal operations.

And the BL1834U product page even gives explicit indications for using a charger, right in its first paragraph: “Charger Charging: Recommended 1A Max 2A”; it’s just that they don’t give all info desirable for using a more sophisticated charger like the MC3000.

They don’t want you to know what’s under the wrapper and they may not be using the same battery in 6 months so they’re not going to tell you all of the battery specs that you want.

Well, I respect your PoV but I think it’s not directly implied by what we do know, so I will give CyanSky the benefit of doubt and wait at least a few days for their response before concluding they are purposefully omitting information per a hidden agenda.

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They make lights ,not batteries. They also tell you that the charging port will charge at 1.4 amps. Why did you leave that out? I’m not really implying a “hidden agenda”. With supply chain issues or various factors again they may not be using the same battery in 6 months so putting out the specs that may change would be foolish on their part. I don’t think any re-wrappers put out all the specs that you want.

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Perhaps, but it sure can’t hurt to ask, now can it? Maybe we will be pleasantly surprised.
So far they have shown a willingness to work with us…

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Because it’s not relevant for my use case (ie, charge the battery in a MC3000 charger).

I’m not really implying a “hidden agenda”.

Glad to hear it! Conspiracy theorists are almost the worst kind of people in the world, second only to the conspirators themselves! :grin:

With supply chain issues or various factors again they may not be using the same battery in 6 months so putting out the specs that may change would be foolish on their part.

I don’t think so: if specs change, just change them right there at the web page. Sorry if I’m missing something, but I fail to see why that would make anyone ‘foolish’…

I don’t think any re-wrappers put out all the specs that you want.

Right from the top of my head, I can mention at least one: Vapcell. Eg for their H10, they publish all the specs I want (and even many that I don’t ;-)): https://www.vapcelltech.com/h-pd-44.html

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Exactly! And in the age of the web, it didn’t even cost me $0.02 to send them the PM asking for that :slight_smile:

Agreed. Fortunately this seems to be the rule here in BLF rather than the exception, not just great users but also great vendors.

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In that vein, I think I will PM them and ask about the battery error with my headlight. It may be too much to ask to get a replacement shipped from China, especially with the rules about shipping bare LIION cells Internationally. But I guess I can try.

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Sure thing! Please let us know how it goes, and if you think it’s proper, you can mention to them that I have asked you to help me with a review of the HS5R and its battery, to be published here in BLF, and that it would help a lot you having the same BL1834U battery that I do, so as to make sure that their flashlight doesn’t end up showing bad performance because of an inferior battery… :slight_smile:

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I sent them a PM… we will see.

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So, I managed to obtain the missing data:

  • Recommended discharge current, in order to reach the 3400mAh nominal capacity: → 650mA
  • Recommended discharge cut-off voltage (ie, at what voltage the battery discharge should be stopped, again in order to reach the nominal capacity: → 2.5V
  • Recommended charge termination current (so the battery is maximally charged and will, during discharge, reach the nominal capacity): → 50mA

As for the “what cell underwrap” question, I’m pretty sure it’s a BAK N18650CP as the above parameters are exactly the same, except for the capacity which is 3350mAh (CyanSky may have rounded it up a little).

I hope this is useful to someone else – it sure is useful for me! :smiley:

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Hmm