The 7000mAh s a bit optimistic, but it is definitely 6000mA and discharge current do not really matter. The cells do not matches perfectly.
Conclusion
As usual with LiFePO4 the output voltage is fairly stable during discharge and with 6000mAh there is a fair capacity in the battery and this is also the case at 30A.
Notes and links
The batteries was supplied by batteridoktorn.se for review.
Yes, but I find that you quickly forget the 141 grams of net weight and 7000mAh exaggerated or imaginary (your choice), it is not so good weight/performance ratio, I find that the INR26650-55A from PLB (which reaches him easily 6000mAh of capacity whereas only 5500mAh are promised initially on the paper) has a much better weight/performance ratio, after that is just my personal opinion.
I do not care about specs or claims. I believe in actual unbiased tests. Considering that, this LiFePO4 cell is amazing. Each cell has its applications, yes the PLB INR26650-55A whatever is much more energy dense, Sanyo NCR18650GA, LG MJ1/M36 or Samsung 35E even more. What's the point?
If I were to choose a cell for an UPS or automotive application this one fits way better than li-ion. Or, for example, as a MagCharger battery swap (2S cells).
If you don't like dishonesty just be trustworthy no matter what. As I believe, it always ends up being beneficial.
In my language there's a proverb which says Las mentiras tienen las patas muy cortas, which literally translates into Lies have very short legs. I think the meaning can ;-) be understood.
I am using 2 of these cells in a solar powered light to replace a lead-acid battery, and it works just fine.
(for about one month now, i hope they last longer than the lead-acid battery, that was only one year old and the capacity was only 150mAh instead of 4Ah)
The capacity test on my hobbycharger gave about 6500mAh, but my cheap hobbycharger is not professional measure equipment like HKJ is using.
I don’t have any 32650 light but I imagine the diameter would be very comfortable to hold. Energy density doesn’t match the top cells (unless you limit your search to only match the chemistry), neither volumetric nor gravimetric but 150W/cell pulse with 90W/cell continuos is quite good. Would be a nice choice for some hot rod.
Driver development needs to step up further. If you keep thinking in plain MOSFET switches controlled with ATtiny microcontrollers this is unlikely to happen. Regulation is good, full regulation even better. Keep improving it.
I love regulation! I love FET based linear drivers for their low cost and high power density. I love induction based drivers for their efficiency.
But boosting at 50A input is expensive.
And a 32700 light won’t be superb in lm*h/g or lm*h/mm³. Therefore here I value efficiency less than elsewhere.
But I view these cells as a good match for big toilet plungers. Cheap, probably better grip than N*26650 and 4N*18650, powerful.
Rust in cells can form in humid saline environments, near cold shores for example. A friend of me took a few cells in a trip to the northern lands of Spain and they came home with some serious rust crust, particularly in the more frequently used units. We were cleaning and rewrapping them the other day.
On the other hand a bit of rust is probably no issue for chinese factory quality control departments, and certainly not for their wholesalers/storekeepers. And given my knowledge in this regard, neither is for me.
I’m surprised that there’s not much discussion about these cheap cells. I have ordered many batches from Aliexpress and Ebay from different manufacturers. I have not tested all of them yet, but here’s some initial results:
Noname cells from Ebay: average capacity about 5800mAh
Varicore brand cells from Aliexpress: average capacity about 5850mAh
Liitokala brand cells from Aliexpress: only one tested so far. Capacity 6262mAh
All cells look pretty much the same, but Liitokala has slightly different looking positive pole. Capacity was tested by discharging to 2V using ZB2L3 module with 2 Ohm resistor.
For the price these cells perform great and have pretty consistent capacity. Liitokala might have little more capacity than others, but they cost slightly more. I’m really happy if these really last the 2000 cycles mentioned in the description.
Does anyone else have experience or measurements about these gray 32700 LiFePo4 cells?