Just got portable radio Ambient Weather WR-111B. It is using CR123A 3.7V/800 mAh rechargeable lithium ion battery.
On ebay I see CR123A 3.7V for a different capacity than 800mAh: 1200mAh or 2200mAh.
My question: is it safe to use for this radio (or any other hardware) a battery with right voltage but with a higher capacity (800 mAh vs 1200mAh or 2200mAh)
Yes, it is safe.
What is important in supplying power in batteries is the voltage. As long as you can supply the same voltage, then different capacity batteries will work, the only difference being different run times.
A similar basic logic applies to power supplies as well. If your laptop has a 19 volt 1.5 amp power supply that you plug into the wall, you could replace it with a 19 volt 5 amp power supply. The laptop would only pull or grab the 1.5 amps that it needs, the power supply does not push the current into your computer. The voltage however, should stay the same. You should not go with a 19 volt 0.5 amp power supply as the laptop would try to pull more current than the power supply is built to supply and it would overheat. I am getting a little of topic.
Go for the higher capacity battery if you want to spend the money.
PROBABLY the difference does not matter.
There is very little chance that the very high capacities claimed will be genuine in a cell / battery that size.
2200 mAh is more capacity than you'd expect in a LiIon CR123xx battery.
They may just be lying about capacity - which is common - and it may be an OKISH LiIon battery.
But it may be higher capacity but not rechargeable as it is a Lithium "primary" cell.
And often enough when people claim VERY high capacities they are liars selling junk and the products are LOWER than usual capacity.
Trying to recharge a Lithium primary battery will not produce recharging but also PROBABLY will not cause major damage. It is possible that it could cause fire or damage the charger in some cases - so do be sure that the batteries you use are rechargeable ones.
A fully charge LiIon battery will measure about 4.2V open circuit and should never be discharged below about 3V minimum.
There is a small chance that if you has a charger designed for a 800 mAh LiIon cell and you tried to charge a GENUINE 2200 mAh LiIOn cell with it that you could have problems - but in most cases the battery would at worst take longer to charge. It would also terminate charging at a lower percentage of its rated max charge current (as the charger was charging at 800/200 of fullcharge and shutting down at say 25% of this). The effect of this would be to charge the battery to slightly more capacity than a proper 2200 mAh charger would, but this wou;ld be unlikely to be a major problem.
