Friday, April 9, 2011: Update 5/2/2016

The Real Cost of Rechargeable Batteries and Electronics

I seems like we hear a lot these days about how much our consumer devices are wasting electricity. “Don't leave your phone charger plugged in! Turn off the TV when not in use! TV's, stereos and cell phones are contributing to air pollution and global warming”. Doom! Scare!! Warning!!

Is this really true?

Some of this stuff makes sense and some just seems kind of off-the-wall to me. In the last few years, the electronics industry has made great advancements in reducing stand-by power consumption of battery chargers and power supplies. A cell phone charger 10 years ago might draw 6-10 watts while one today draws less than 1 watt.

I took it upon myself to calculate and/or measure the energy consumption of some of these devices.

If I may error on the side of overkill, let's assume you re-charge your device's batteries every day and that the battery was completely dead each time you charged it. Also assume 10 cents/KWH electricity rate.

Surprisingly, battery operated electronic devises don't cost that much to recharge.



Although insignificant, the cost of just having a AA battery charger plugged not doing anything is $4.30/year. The cost of charging four NiMH AA batteries 365 times is 81 cents.




You will always save energy and money by unplugging an unused charger. Whether that is too large of an inconvenience or not is up to you.

While charging batteries, my X8 AA/AAA battery charger sits on the counter top in the kitchen. It looks too cluttered to leave plugged in and sitting there all the time so it gets unplugged and put away after each charge. 

My cell phone charger is plugged in by my night-stand. It is too inconvenient to unplug it every morning. At the electricity cost of 44 cents/ year, who cares.  

To charge an itouch every day for a year will set you back 13 cents.

An ipad comes in at a whopping 91 cents/year. In other words, don't worry about it.  


However, leaving your PC on just so it can charge an itouch off of one of its USB ports will cost you nearly $88/year. Set your PC to sleep when not in use and charge your i-touch use a wall charger. You can buy Chinese knockoff chargers for about $3 at Deals Extreme. They work just as well as the $29 ones at the mac store.


Update 3/12/2012:  Computer motherboards (as January 2012) are now on the market that allow USB charging capability while the PC is in stand-by.  


For hi-drain devices, using re-chargeable batteries vs buying alkaline batteries is a no brain-er.

Charging four AA batteries 365 times will set you back $0.81. The same number of alkaline batteries, even when bought in a super inexpensive Harbor Freight 24-pack would still cost you $364.


Update 5/2/2016: 

I recently purchased a high-end battery charger. It makes all the rechargeable batteries perform so much better. It is a night and day difference. Not only does it recondition batteries, it also measures the energy capacity of AA and AAA batteries. Way cool.