Got the last of four Vapcell tests for you today! This is the green Vapcell 18650, a 2000mAh, 28A continuous cell.
As always, click for bigger images!!!
Like the other Vapcells I’ve recently posted, I don’t see these in most of our usual places. They’re fairly new, I believe. Prices I did see look to be in the ~8 range per cell (which is high).
These are nice quality cells, which seem to handle high current well, and hit their capacity rating on much more than the standard 0.2A discharge.
These cells ship in a Vapcell branded padded zipper pouch.
And they come with a small spec sheet, too. The cells are individually wrapped with a plastic wrapper, which should be removed before use.
Nothing unusual about these cells. They’re the standard Vapcell green, which is sometimes a blue shade of green, and sometimes a red shade of green (ie, Vapcells are blue or green or red).
The positive end has the 4 prong terminal.
There’s also a scratch off proof of authenticity sticker.
These are flat top 18650s, so the dimensions are 18mm in diameter, and 65mm in length.
I’ve tried to keep the scales similar, so over time the charts will be generally comparable.
See how this cell has fairly consistent bounce on the higher discharges. That’s a sign that it performs well under load.
“Bounce back” is what the cell voltage does when the cell rests after a discharge. Interestingly, after heavy discharge rates, the cell bounces back higher. 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 (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. And I have finally figured out what I think it so interesting about “bounce.” A poorly performing cell will bounce back higher on high discharges. That’s because the IR is higher, and because the cell performs much worse under high loads. So a good performing cell (like this one) will bounce back much less because it’s much more capable of high discharge. And we can see that here. This cell is capable well past the tested 20A, and so at 20A much more of the energy is used from the cell. Hence less bounce. I don’t really have anyone else telling me that, so I could be grossly wrong. Or maybe I just proposed a new metric for cell quality. ¯\_(ツ)_/¯
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.
As I said in the short review: These are good cells, capable at high current, and easily hitting their rated capacity. Recommended!
- 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 these cells, I do have a bunch of coupons!! Have a look at my spreadsheet for those coupons. It’s possible to subscribe and get notifications when the sheet is edited!!