Have you ever wondered which kind of charger is more efficient? Are wall 
chargers we use to charge our devices just as efficient as 12v car chargers? In this blog post, you’ll find out!
I grabbed 3 quality wall chargers and 3 quality car chargers with the intent to see how many watts each consumed, and how many they actually put into an [easyazon_link identifier=”B016PUQWMI” locale=”US” nw=”y” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]Apple iPad Mini[/easyazon_link]. To find these measurements, I used a wall [easyazon_link identifier=”B00E945SJG” locale=”US” nw=”y” tag=”genesgreenm0f-20″ popups=”n”]AC meter[/easyazon_link], a [easyazon_link identifier=”B00C1BZSYO” locale=”US” nw=”y” tag=”genesgreenm0f-20″ popups=”n”]DC power meter[/easyazon_link], a [easyazon_link identifier=”B01D9Y6ZFW” locale=”US” nw=”y” tag=”genesgreenm0f-20″ popups=”n”]USB dongle meter[/easyazon_link] and an [easyazon_link identifier=”B01MXLEVR7″ locale=”US” nw=”y” tag=”genesgreenm0f-20″ popups=”n”]Anker 1 ft Powerline cable[/easyazon_link]. Here are the results.
| Charger | Watts In | Watts Out | Percent Loss |
| [easyazon_link identifier=”B01BHE3EPU” locale=”US” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]Apple 5 watt[/easyazon_link] | 6.6 watts | 4.6 watts | 30.3% |
| [easyazon_link identifier=”B00A83I8G2″ locale=”US” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]Apple 12 watt[/easyazon_link] | 11.6 watts | 9.2 watts | 20.7% |
| [easyazon_link identifier=”B075L2SXVJ” locale=”US” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]RAVPower iSmart[/easyazon_link] | 11.0 watts | 9.1 watts | 17.3% |
| [easyazon_link identifier=”B0088U4YAG” locale=”US” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]PowerGen 20w car[/easyazon_link] | 8.9 watts | 8.8 watts | 1.1% |
| [easyazon_link identifier=”B01A4ZGLZ8″ locale=”US” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]Anker 42w car[/easyazon_link] | 10.7 watts | 9.9 watts | 7.5% |
| [easyazon_link identifier=”B00VH84L5E” locale=”US” tag=”genesgreenm0f-20″ cart=”n” popups=”n”]Anker 24w car[/easyazon_link] | 8.2 watts | 8.1 watts | 1.2% |
Wow! I didn’t expect to see such a difference in efficiency between the wall chargers and the car chargers. After a little digging, it makes sense – the wall chargers need to convert AC (alternating current) into DC (direct current), whereas the car chargers are just changing 12 volt direct current into 5 volt direct current that is the standard for USB. Even the worst car charger was 10% more efficient than the best wall charger – crazy, right?
I suspected AC wall chargers were less efficient from my experience using my 
pedal generator. I could see the wattage used by the wall chargers put more of a load than the DC car chargers, but it was great to quantify the real difference. I had no idea how much more inefficient wall chargers were! I will definitely be using car chargers whenever possible for the most efficient charging of my devices. On the other hand, if I need more of a challenge on my pedal generator, I can always substitute in the AC chargers!
If you’re living off grid, you may find this information very helpful in deciding how you should charge your mobile devices. Directly charging with solar or a pedal generator would be the most efficient way to go, rather than dumping all power to a battery bank, then converting to AC and charging with a wall wart (thoughts of all the efficiency losses in this cycle is making my head spin!).
I have an off grid barn with solar panels and batteries and of course an inverter(s). Conversion efficiency data is hard to come by. Biggest issue is trying to support cameras, mifi charging, and cell booster on a 24/7 basis. It mounts up. Im using a mixture of 12 and 120v lighting in a one or the other normal operation with manual switches for specific locations on the 12v side and motion sensors on the 120v locations. I have but dont use a 200w inverter that i tried on the cameras but have switched to DC. Have no idea about the difference in losses between the 200w and the 3500w i use when real power is needed. Looks like in the absence of mfg data ill have to get in the business of taking my own measurements. 7KW propane generator for real needs but dont have to run it much. Its all a fun science project anyway and is working out. Thanks for the info.