[Isaac Zachary]

Originally Posted by Drifter

Why does level 1 take so much longer? For example on the Ford Escape Plug-in level 1 (110v 20a) takes 11 hours to charge while level 2 (220v 40a) takes 3.3 hours.

So using 1/2 the power takes 3 times longer? I thought faster charging created more heat/waste?

1. First of all Level 2 @ 40A is four times the power of level 1 @ 20A. 220V is actually 240V. 40A is actually 32A. 240V x 32A = 7,680W. 20A is actually 16A, but most level 1 EVSE's only draw a maximum of 12A. 120V x 16A = 1,920W, and at 12A is 1,440W
   1,920W is one quarter of 7,680W. 1,440W is three sixteenths of 7,680W.
   
2. The more you have to change the voltage the less efficient charging is. Going from 120V to 400V (or whatever your battery is) is less efficient than going from 240V to the battery's voltage.
   So Level 1 charging actually creates more heat waste due to the charger's efficiency than Level 2. At much higher charging levels, like DCQC, is where you can get a lot more heat. But heat is also the product of not having enough time to dissipate.