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.
I bought some aaa batteries from ebay. The picture showed contour batteries. I think this is a good company which closed down or something…when they arrived they were Digimax. I discharged then charged them at 200mA in an Accupower IQ328 and two of them kept fluctuating between 1.41v and 1.42v. I ended up stopping the charge after 5 and a half hours! I know the current should be at least 0.3C but I wasn’t expecting this from brand new batteries. I always select the lowest current for new cells and when condition cells.
The balance board does not balance the cells, but that is no problem because charging and balancing the battery pack after taking it off the wall took only 4 minutes and 2 seconds
(The cells were charged and balanced before capacity test.)
If there would have been a large difference between the two cells, the charge/balancing time would have taken much longer than 4 minutes.
These cells are much better than the Original lead-acid battery that became useless after about one year.
A new 6V/4A lead acid battery is also more expensive than these cells + the protection board.
The LiFePo4 cells are still like new, it looks like they will last many years in that solar powered light.
I like the tests of new cells, but i am also interested in re-tests after they have been used in “real life conditions”.
I know it is very difficult to do that, but in this case i will continue testing these cells once a year