And I'm saying that this particular issue is completely inconsequential. Based on worst case scenario assumptions (fully discharging a 15 Wh battery down to 0% every day, waste heat equal to 100% of the charge, all electricity from coal), you're only using a 5.4 kWh per year, or about 2.5 kg of coal, about 4.6 kg of CO2 emissions.

That's about 170g/6 oz of beef (27 kg CO2/kg beef). Commit to eating (or wasting) one less burger per year and you've made up for the worst case scenario, calculated using unrealistically large assumptions.

Or that's 1.9 L/0.5 gallon of gasoline. Drive 25 km/15 miles less per year.

More realistically, we're probably talking 80% charge per night, 80% efficiency, and an electricity mix that generates the US average CO2 emissions of 0.384 kg/kWh. That cuts it down to 3 Wh/day, 1.1 kWh/year, and about 0.42 kg of CO2.

That's 16g of beef, or 0.17 L of gasoline.

The real impact comes from changes around the bigger uses of energy. Focus on the things using many orders of magnitude more energy, within your control: transportation, climate control, food choices. Consumer electronics are less than a rounding error.