Ask HN: Should I charge my electronic devices with 5W, 10W or 12W power adapter?
Time doesn't matter, what is best for the battery? Like, iPads support 12W at most.
What this means for your question is this: all other things being equal, the power rating of the adapter makes no difference to the charging process. So long as the device does not draw more current than the adapter is capable of supplying the charge process will proceed at the same rate.
Basically, your device is designed to charge at a specific rate and it will draw only up to a specific amount of current (amps). Having a device that is capable of delivering more current doesn't mean your device will draw that current. A cell phone for example will have a varying charge rate, something that generally is between .5 amps and 1amp, with some devices capable of drawing 2 amps. But if you plug your phone into a 5 amp charger when the phones maximum rate of charge is 1amp, it will only draw 1 amp.
So in the end, bigger does not equal better, except to say that your highest charge rate should be equal to or less than the charging device, which helps keep heat to a minimum.
Beware: cold->heat too quickly often leads to internal condensation in humid weather and extreme temperature changes, shorting out a device if ionic impurities are on internals, when bringing a cold device into a much hotter or humid room too quickly. Instead, give it enough time to warm gradually, so condensation doesn't form (say limit temperature change to 10 •F / 4 •C per 30 minutes). Most devices still power some components while "off," so a condensation short is a still a remote but plausible possibility, which is why avoiding condensation is a good idea. BTW a "perfect" gadget would be waterproof, float AND either include a hygrotherm to evaporate thermal transition condensation or not have internal air pockets to prevent condensation.