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

So, where did you get your cells?

I’d love to build a car starter with some of these cells.

Would be dope. Or maybe I should just be using LiFePO4 pouch cells instead for easier connections.

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. :slight_smile:

Given the discharge curves of this cell, it would require a buck/boost driver for proper emitter handling when 1S/1S cells/emitters.

^:)

Or 3s cell / 2s LED…High Vf LED. Nice 4.2V at 30A. :slight_smile:

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: