While most smartphones, tablets, and laptops don't have batteries that are easily replaceable, many devices do indeed come with batteries that can be swapped out. But as good as modern batteries are, they can still die and refuse to be recharged
I find that the newer IMR batteries -- lithium manganese rechargeable -- cells are particularly prone to being completely discharged by some devices. And once discharged, need persuasion to come back to life.
So I have a few dead rechargeable batteries from random devices -- flashlights and tools primarily -- and looked into getting a charger that could resuscitate them.
I've been a long-time user of Nitecore chargers, so I was excited when I came across the "new" Intellicharger New i2. It's not all that new -- launched in 2016 -- but I thought I'd give is a go since it made some bold claims.
And since it was only a little more than $10, I didn't have much to lose.
This charger is small, lightweight, and not much to look at, but it can recharge a bewildering array of batteries (Li-ion/IMR/LiFePO4: 10340, 10350, 10440, 10500, 12340, 12500, 12650, 13450, 13500, 13650, 14350, 14430, 14500, 14650, 16500, 16340(RCR123), 16650, 17350, 17500, 17650, 17670, 18350, 18490, 18500,18650, 18700, 20700, 21700, 22500, 22650, 25500, 26500, 26650; Ni-MH/NiCd: AA, AAA, AAAA, C, D... that's a lot!), so it's the perfect one-stop solution for recharging.
This model can only take two cells at a time, so if I have more recharging to do, I'd get the four-cell i4 version instead, which you can pick up for about $20.
The New i2 features an array of safety features, including overcharge protection and thermal cut-outs, which offer peace of mind.
Most of the time you just put a battery into the charger and away it goes, but you can play with the charging currents if you want to optimize charging. The device comes with an easy to read display that shows what's going on during the charging process.
I'd read some reviews about the New i2 having poor solder joints, but I took mine apart to take a look and everything looked fine to me. Maybe there's been an increase in quality control, or maybe it was a bad batch. Either way, the one I bought was fine.
As for performance, it's great. It recharges every battery I can lay my hands on, and even brought to life the dead ones I had.
Within a few days it has more than paid for itself in recovered batteries (which have since been through a few recharge cycles with no issues whatsoever).
One note worth making -- keep the instruction manual (or download a copy) because some of the features aren't all that intuitive, and after a few months of just popping cells in to recharge, you'll forget how to access the more in-depth features.
If you need a battery charger, the Nitecore Intellicharger New i2 is worth a look, because you get so much for a low price.