I'm here for a small review proposal or suggestion, DIY stuff gizmo. It is not a battery, but I think this thread is the closest related thing to (maybe some other generic or DIY review request thread could be nice).
It is an inexpensive “TC4056A” li-ion charging board with attached adjustable output boost converter. There is no protection circuitry for the battery but they're ;-) easy to find.
The board uses a schottky diode at the output (SS36, by the way), this means it could be possible to set it in parallel with others (but needs very tight output voltage adjustment).
That was maybe a hasty comment. The onboard output circutry is a boost engine, this means at some point it'll stop working due to too low battery voltage.
Mmm, looks like the SX1308/MT3608 will have to wait. :???:
A fellow from the far east who sometimes posts in this forum suggested me the above fake NCR18650B I spoke about is a BAK 18650-34T, with performance probably on par with NCR18650GA. This was sometime ago, but definitively I do not seem to find a way to obtain 18650-34T cells with their OEM wrap directly for sale in AliExpress:
I have a couple sales in my wishlist for what looks to be these cells, with what looks to be a pentagon top clearly distinguishable under small soldering tabs or cables. They are disguised as “green berets”, though.
yeah, it’s 1khz sine IR measurement, i measured the VTC5A with that meter, i got 9.8mOhm
i bought those from 1688.com ( wholesale website from China) so i guess it’s quite hard for HKJ to purchase these cells from there.
PM me the address then (a valid AliExpress' address), so I can submit it to the AliExpress seller I chose to buy from. This is the way I can afford it to be. Thanks.
I see metal shell case power resistors for sale in many places. Looks like the sort of thing but, how does the above and similar meters use them? Do they switch the load with variable PWM duty cycle to keep a constant current or a constant power?
Trying to determine what resistor values would cover a few low voltage li-ion tests.
I believe their OEM is Heter, meant for the electric vehicle market. I wonder if there's room for a review of them, they're technically a mid-power sub-2800mAh cell (EAIEP 2pcs “26F” sale link).
There's a small AliExpress sale in a few hours. I am not particularly interested in the 16340, but others may. In the meantime I may look for some co-funding for the other cell (because ;-) I'm rich). Anyone here?
Oh! Wellp, nevermind really. Found this Shop2097037 with slightly better pricing, interesting cells and cell packs.
They're selling this weird LiitoKala branded li-ion 7200mAh :???: 26800 cells with tabs, guess that is some electric vehicle market product (5C discharge rating). And I must also say, without a doubt, that 7200mAh in a 26800 is high energy density, beating PLB 5500mAh at least on paper.
Henrink, did you ever tested some electronic load like the following? (guess the answer is not yet)
Had a different, more display fancy electronic load in my wishlist but people were reporting failure to disconnect load after voltage cut-off in it. This one has good reports, guess I would only need a battery holder to complement with it.
I got and tested the Varicore batteries some time ago.
I started on in once, but it died on me. The problem is when they use a single mosfet transistor, standard mosfets are not good at analog regulation and cannot handle anything like the rated power when doing that.
That cell is a problem, it will not fit in my battery holders, 70mm long is about maximum I can test.
