Today’s the last of my Vapcell liion cell reviews! Well technically I have an IFR review coming up, which is also liion but not really something we’ll all use much.
This is an INR 14500 button top, with 650mAh capacity. Read on for testing!
As always, click for bigger images!!!
These are $3.75 each at Illumn.com, which is a good place to buy this type thing.
The cell seems to meet specs, and perform adequately. This is a good mix of low cost, and good drain (at the sacrifice of capacity).
I’ve tried to keep the scales similar, so over time the charts will be generally comparable. I don’t review a bunch of 14500 cells, so this is on the scale of my last 16340 cell.
The cell takes a big hit at 8A, which is past specification. Even at 7A, the cell seems to struggle a bit. Fortunately (?) the capacity is low enough that the cell never heats up that badly.
“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. These graphs are also useful for determining if a cell would be good for a hot-rod flashlight, for example.
This is a good cell if you need a high drain 14500. Don’t buy it for the capacity. It’s also fairly inexpensive, so that’s a bonus.
- These cells were provided by Vapcell for review. I was not paid to write this review.
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