Test/review of VBatty 32700 3.2V 7000mAh (Grey)

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.

https://nl.aliexpress.com/item/32650-3-2-v-7000-mah-lifepo4-oplaadbare-batterij-mobiele-LiFePO4-5C-ontlading-batterij-voor-Backup/32878468860.html?spm=a2g0s.9042311.0.0.27424c4dRNc10c

Rusty bottom means they are probably factory rejects.

The cells i got did not have rust, they were clean.

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.

Kłamstwo ma krótkie nogi. In polish this proverb translates exactly the same. More common than I thought.

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?

Let me just bump this thread.

I want to buy 4 of these cells, but i would like to know who sells the best ones, or the best value for the price.
Many many AliExpress stores sell them, but even though they all have a gray wrapper, there are different specifications, prizes and even sizes (between 32600 and 32700).
Soooo…. Any advice is welcome.

(i want to use them in a MAGLITE 3D)

Jerommel, I usually keep track of stuff like this so, according to what I have, the shop where Henrik got the cells for his review (#1874160 LiitokalaVariCoreFlagshipStore) is where you should look at, section 32700.

Okay, thanks Barkuti. :beer:

Hmmm… I’m still not sure, saw some discouraging reviews there, but these big cells are not popular here, so i’ll probably have to try my luck…

But if anyone else has a good suggestion for where to buy 4 of these, let us know.

And what is the value of a review written by someone who doesn't knows where his/her arse is? You know what this means, doesn't it?

The cells are good. Their consistency could be better, I know. But with LiFePO4 this is less important, at least with regards to battery pack assembly as I've already discovered the chemistry is self-balancing.

If you do care much about using them in series, buy twice or thrice the number of cells you need and, with the help of some battery capacity measuring device, sort/bin them low to high and make balanced packs. I recently bought this inexpensive EBD-M05 constant current capacity tester, discharges at up to 5A with 4-wire independent voltage monitoring and does discharge graphs. User HenrysCat has one, check:

It just occurred to me that 3S configuration of these cells can run perfectly on a 2S Li-Ion driver, because low voltage protection will kick in at 6 Volts. :slight_smile:

Since the consistency of those 32700 LiFePO4 cells is not the best at least one could drop a bit below 2 V. I see no reason for this to be a problem, though.

Mmm, just noticed I already pinpointed you to the EBD-M05 device.

Yeah, you did. :slight_smile:
It’s on my wishlist. :wink:

The grey VBatty 32700 LiFePo4 cells i use in a solar powered outdoor light are 2 years old now, time for a new capacitytest.
Now i have a much better capacity tester (Hidance DL24/P).
Two years ago i built a 2S battery pack with these cells to replace the original 12V 4Ah lead-acid battery that was dead after only one year.
These cells + the protection board were about the same price as a new 12V 4Ah lead-acid battery, but these LiFePo4 cells have a higher capacity (at least 50% more real capacity).

I tested the 2S battery pack at 2A with a 5,0V cutoff voltage, and these are the results:

5985mAh or 37,2Wh (=18,6Wh/cell) after 2 years of “outdoor temperatures” (cold in the winter, and 2 hot summers) is a very good result.
These cells will last many years, much longer than a lead-acid battery.

I will try to remember testing these cells every year, i hope they will last for many more years.
The next test will be at the end of 2021 :wink: .

Thanks for the update Hobbyfotograaf. Those are some impressive results.

I know it’s an older thread but it’s very useful… I’m quite interested in combining 4 of these in series for a project. Are these too big to fit into commercial hobby chargers that would be used for 18650s ? I’d quite like to get a 4 cell holder if possible but will consider connecting them together permanently (solder?) and finding a suitable charger…

You wouldn’t want to use an 18650 charger for LFP cells since the voltage is different. There is another type of hobby charger with wire leads, that can often be configured for different voltages. But, you want to have some kind of cell balancing when charging. You really should know what you are doing before attempting something like a series battery pack (parallel is simpler). If you just want a 6 volt LFP pack, Bioenno is a popular brand among ham radio types. They aren’t the cheapest but they are well made. They have 6 volt packs in 3ah and 12ah and come with optional plug-in chargers:

The ones I’ve seen people using were 12 volt, which is more popular.