chris1howell
Well-known member
Problem: Deploying an EVSE is expensive. Deploying several is very expensive and requires lots of electrical lines, panel space, etc...
Scenario: a place like LAX where lots of EVs park for an extended time. Let’s say we are going to install 16 30A J1772 EVSEs. That would take 16 EVSEs, 16 40A breakers, 16 Electrical runs, and 640A in the panel.
Experiment: 4 Open EVSE boards stacked… The latest boards have a communications bus I2c plus power pins on the top of each board. The boards are given a maximum group current to share, let’s say 60A on a 75A breaker. Each of the 4 hypothetical EVSEs are built to support up to 30A. So the minimum current for each EVSE is 15A. The EVSE stack communicates its status via the i2c bus. So if there is only 1 car actively charging it is offered 30A, 2 cars charging each gets 30A, 3 cars and each is offered 20A, and 4 would offer each the 15A minimum.
***The numbers can be changed to whatever… 2/4/8 EVSE stack… 16A/30A/75A EVSEs… 50/75/80/100A/more breaker. Lots of possibilities.
So now 16 EVSEs would require 4 breakers, 4 electrical runs, and 300A on the panel.
2011-12-16_18-19-47_762 by chris1howell, on Flickr
Thoughts…/?
Scenario: a place like LAX where lots of EVs park for an extended time. Let’s say we are going to install 16 30A J1772 EVSEs. That would take 16 EVSEs, 16 40A breakers, 16 Electrical runs, and 640A in the panel.
Experiment: 4 Open EVSE boards stacked… The latest boards have a communications bus I2c plus power pins on the top of each board. The boards are given a maximum group current to share, let’s say 60A on a 75A breaker. Each of the 4 hypothetical EVSEs are built to support up to 30A. So the minimum current for each EVSE is 15A. The EVSE stack communicates its status via the i2c bus. So if there is only 1 car actively charging it is offered 30A, 2 cars charging each gets 30A, 3 cars and each is offered 20A, and 4 would offer each the 15A minimum.
***The numbers can be changed to whatever… 2/4/8 EVSE stack… 16A/30A/75A EVSEs… 50/75/80/100A/more breaker. Lots of possibilities.
So now 16 EVSEs would require 4 breakers, 4 electrical runs, and 300A on the panel.
2011-12-16_18-19-47_762 by chris1howell, on Flickr
Thoughts…/?