I have these two batteries, 18350 form factor, without any label. As far as I know they are rechargeable because I've salvaged them and put in my salvaged "li-ion to be cecked" box. Now I've completely forgot where I took them and they doesn't seem to be li-ion.
They were at 2.7V more or less, then not too low to be used if li-ion,but then I've tried to charge them with my li-ion charger at 0.1A and the charger blocked the charge because no current were delivered. I thought they were already fully charged (quite strange, since they were in this box since january) and in fact after 24h they show 2.85V.
There's a way to understand which kind of batteries are them? PS: I can charge/discharge under constant load/voltage and log the current/tension. (in a safe container, of course)