[trimble-alum]

Likely the smallest wattage will limit the maximum amount of waste heat the batteries experience, which means less wear (physical, chemical, etc. thermal/electrical damage). Also, opt to charge the device at the lowest device operating temperature and with the most available cooling (battery side up or standing near vertical, not in a sleeve under a blanket). And from previous articles, charge from 50% up to about 70%, discharge, rinse-lather-repeat. Store device for extended times at about 60% charge at the lowest possible non-operating temperature (probably 40-50 •F, 4-10 •C)

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.