@Barry0892, @Sofirn: I’m creating an MC3000 charging profile for this battery, and I really need more detailed data for this battery than you provide on your product page: 2*21700 5000mAh Batteries
Can you please provide a detailed datasheet, or at least tell me the brand and model of the original cell you use to build yours on?
Thanks, but I think you may have missed this a little further up in the other thread I pointed to above:
And in fact some of the specs in the (incomplete) list on Sofirn’s product page disagrees with the LR2170SD datasheet. And the battery’s negative terminal shows a circular vent in Mooch’s review/test post:
There’s more than one sofirn 5000mAh 21700. One is probably that lishen SD. Almost definitely.
Decide for yourself. Here’s my pictures of the 5000mAh unwrapped next to Mooch’s pictures of a Lishen lr2170sd. His pictures are the ones with his watermark obviously.
The other one they have is higher discharge. Idk what it is but it is 5000mAh and has a different positive terminal. Here’s that one (with the wrap still on). I did unwrap one at one point and I don’t remember seeing any markings anywhere. It doesn’t have that bottom vent either.
Edit: my bad. took those screenshots awhile ago and got messed up. Those pictures from mooch are from his review of the 4500mAh Lishen lr2170sf. So idk what the deal is there.
Agreed, and the first one you posted a pic of indeed looks a lot like the LR2170SD, specially since it has the exact same groove-like vent in its negative terminal as Mooch depicted.
But as you can see above, mine definitely isn’t, and hasn’t. Can’t say whether it’s the same as the second one you mentioned, as neither yours or mine have any distinctive markings like Mooch’s groove.
That’s why I’m asking Sofirn for the exact battery they’re using and/or its detailed datasheet.
I mixed up Mooch’s Lishen photos, I used ones he took from a 4500mah. But close enough. It could go either way. My photos are of a sofirn cell labelled 5000mah.
I wouldn’t expect sofirn will give much info on it. And what they do give I wouldn’t trust anyways. That’s not a fault against sofirn, most of them won’t usually give you details on batteries. Plus it changes all the time. But who knows.
I do hope you’re wrong, as I’ve had nothing but the best service from Sofirn every time I needed them, and @Barry0892 specially has been great in his outreach and interactions here in BLF.
That’s not a fault against sofirn, most of them won’t usually give you details on batteries.
I was able to get complete data on my BL1634U battery from CyanSky, which is a much smaller vendor with significantly less BLF exposure, that’s why I expect Sofirn to respond to my questions about their battery. But we shall all see, I guess.
I did ask them a few months ago what make the different 5000mAh cells were. I don’t want to post a screenshot of the conversation, it’s really not interesting anyway, they just politely side stepped the question. I got the idea they weren’t going to tell me. I said well whatever it is it’s better than the lishen lr2170sd and they said “that’s true”
Sorry for the late reply but I really don’t know what details of the battery are . I believe data from anyone who can test batteries would be better.
Anyone can help testing the batteries?
No problem, actually not late at all. And thanks for responding.
Seriously? Ok, ok, so from the “zippered mouth” emoticon you used, I gather it’s confidential or something.
I can (my MC3000 can do a fairly decent test, if not as good as the pro equipment that eg @HKJ and Mooch use), but that’s not the issue: there’s some battery parameters that can’t be determined by testing, quite the opposite: instead they need to be obtained from a datasheet or similar in order to configure the equipment for the test (eg, residual charging current). There’s also some other parameters that have nothing to do with testing (eg, recommended voltage for storage) but are needed by enthusiasts like me and most of the folks here in BLF in order to best deal with the battery.
If you can’t tell us the brand/model of the battery you’re rewrapping, nor supply us with its datasheet (even a partial datasheet, redacted of any names or whatever you consider confidential, would be a big help), can you please give us at least the following data?
The aforementioned “recommended voltage for storage” (ie, the voltage the manufacturer recommends the battery to be stored at in order to mitigate/minimize any internal damage during long-term inactivity);
Ditto, “residual charging current”, aka “charge termination current”: the current at which the charging should terminate after switching from the initial CC phase to the final CV phase;
“residual discharging current”, aka “Discharge reduce”: the analogue of the above for discharging, ie the current at which the discharge should be terminated after the battery reaches its minimum voltage and the discharger switches from CC to CV (that is, starts to reduce the charging voltage as needed to keep the battery at the minimum voltage).
“maximum operating temperature”: the temperature at which any (charge or discharge) ongoing operation on the battery should be interrupted;
If you can give us these 4 numbers, no datasheet or brand/model names are needed and all is well, I (and everyone else needing this) can proceed with configuration and testing.
Thanks, and I’ve found its datasheet, but basic data like dimensions and weight do not match what Sofirn publishes on its product page (unless we start adding/subtracting tolerances, but then it’s a stretch IMO).
We better wait and see whether @Barry0892 comes up with at least the 4 numbers I asked, then we will have an official position and it’s much better than trying to guess and end up with an unoptimal charging profile.
These materials are too professional for me, I found manufacture and asked about the relevant information, hoping to help you：
recommended voltage: Battery stored in a long-term(more than 3 months) should be kept in a dry, cool place.The storage voltage of battery pack is 3.50V - 3.95V.
residual charging current: The standard charge method is charged parallel 0.5C to the battery, and charge while the combined voltage 4.25V to constant 4.25V till the current ≤0.02C .
residual discharging current: I don’t understand, but the minimum voltage is 2.5V
Thanks @Barry0892 for the response. Much appreciated! da: Sofirn is looking like the kind of manufacturer I like to work with!
Perfect, the middle of that range is 3.50+3.95/2 = ~3.73V, I will use that.
Perfect, so 0.02C = 0.02*5000 = 100mA.
Perfect, so 45℃ it is.
Sure, but once reaching those 2.5V, there are two ways to proceed:
discharging stops at once, or
keep discharging but reducing current so as to keep voltage at 2.5V until said current reaches value X mA and then stop. In this case, X is what is called “reduced discharge current” and what I need to know is what its value is.
So, what I need to know is whether it’s 1 or 2, and if 2, I need to know what is the value of X.
Please, can you get back to the manufacturer and ask for this last remaining detail?
While waiting for a response from @Barry0892 or @Sofirn to that final question, I did a little test on my own for case 1 above, by using the following program on my MC3000:
This was obtained by feeding the data Sofirn already gave me (on the product page or in response to my questions above), and assuming that the discharge procedure should stop at once when 2.5V is reached (ie case 1 as described above).
The resulting measured capacity for the battery was only 4647 mAh, which is appreciably (353mAh or ~7.1%) less than the nominal 5000mAh this battery is rated at; this seems to indicate that case 1 is not how this battery should be discharged, and point towards case 2. Corroborating that, I have two more pieces of data:
Right after discharge stopped at 2.5V and the procedure was paused, voltage shot up all tjhe way to 2.88V in less than 1 minute, and then to 3.02V at the end of the 30min pause I programmed between discharge and recharge. Voltage recovery is normal after interrupting a discharge, but the magnitude and speed I saw here seems to indicate the battery still had available capacity to be drained.
At the end of the charge cycle that followed, total mAh supplied to the battery was just 4644mAh, which again falls quite short of the nominal 5000mAh even before discounting the charging (in)efficiency (some part of the energy supplied, around 5-10%, is always lost as heat). This seems to indicate the battery still had some charge in it when the discharge process finished.
Right now I’m discharging the battery to 3.73V for storage, let’s see whether and by how much the voltage shots up at the end of it; if it’s substantial, IMO this would also corroborate that the battery needs to be discharged according to case 2 pointed above in order to reach nominal capacity.
To be honest I don’t really care about charging parameters at this point. I just set a current and leave the rest as default nowadays, especially if the cell is a cheap one.
But my intention is to make the most of my batteries no matter how much they cost, otherwise I wouldn’t have spent $110 on a MC3000 to begin with (my previous charger, a Miboxer C8 costing less than half of that, already allowed me to set a charging current).
And the time I’m spending now is spent just once, when setting up the MC3000 program specific to each battery model – afterwards it’s just choosing the program and letting it do its thing.
. I believe data from anyone who can test batteries would be better.
Ok, ok, so from the “zippered mouth” emoticon you used, I gather it’s confidential or something.
da: Sofirn is looking like the kind of manufacturer I like to work with! 
