Another Vapcell review. On a holiday? Happy Fourth of July!! I have a bunch of non-flashlight items, so my Tuesday/Thursday are full for a while! Cell reviews are fairly dry though, so maybe something else interesting today too?
As always, click for bigger images!!!
The most official site I know of for these is aliexpress, and they’re $13.99 each there. Here’s a link.
This is a solid medium (to low) capacity cell with a high current capability. IR is low, and even on the 20A discharge, the bounce back is minimal, indicating very good performance.
Like other Vapcells, these ship in a zipper pouch.
The individual cells have a plastic wrapper, too. This should be removed before use.
The blue wrapper is fetching with gold letters, and is perfectly fit. It’s thin too, which is something rewraps often get wrong.
The cell is a flat top of course, and unprotected.
I’ve tried to keep the scales similar, so over time the charts will be generally comparable.
“Bounce back” is what the cell voltage does when the cell rests after a discharge. After heavy discharge rates, the cell voltage bounces back higher when discharge is stopped. This corresponds to a discharge amount of less energy, and does mean that there’s energy left in the cell. So if I selected the cell with the highest bounce back voltage (ie the cell that was discharged at the highest current), then discharged it to 2.8V at 0.2A, I’d still find that there was a lot of energy still in the cell.
Here is why I think it so interesting about “Bounce.” A poorly performing cell will bounce back higher after high discharges. That’s because the IR is higher, and because the cell performs much worse under high loads. So a good performing cell will bounce back much less because it’s much more capable of high discharge. At high discharge on a capable cell, more of the energy makes its way out of the cell! Hence less bounce.
I more or less figured this out on my own, so I welcome discourse about this topic. Until I hear it’s wrong, I propose this as a new metric for cell quality!
Most often (read: always), internal resistance is mentioned as a spot value. In truth, the IR changes over time. Due to cell age and cell heat among other things. A graph of IR is interesting because it can show, for example, when a cell begins to “die” – at which point the remaining energy will be “harder” to extract. This is when the IR spikes. In the graph below, that’s around 750-800mAh. These graphs are also useful for determining if a cell would be good for a hot-rod flashlight, for example.
Same thing as stated in the intro – low IR and low bounce at high discharge indicate that this is a nice cell. It would work great in hotrod flashlights!
- These cells were provided by Vapcell for review. I was not paid to write this review.
- This content originally appeared at zeroair.org. Please visit there for the best experience!
- Whether or not I have a coupon for this cell, I do have a bunch of coupons!! Have a look at my spreadsheet for BangGood and GearBest coupons. Please subscribe and get notifications when the sheet is edited!!