AviatorMan said:
Ultraturtle,
your state" charging at the maximum rate available when possible saves you money, and saves us all CO2 emissions", can you elaborate?
We had planned on installing a level 2 charger but we find that the very basic charger is enough for us. Given that our power is Hydro generated and thus don't involve carbon emissions, I am trying to get a handle on the exact fallout from not installing that level 2 charger. What do you think?
What Bill said.
240 Volt 30 amp charging takes place at five times the rate of 120 Volt 12 amp charging, so spends roughly 1/5 the time powering ancillary loads. EV owners on other forums have measured efficiency differences of several percent between L1 and L2 charging.
As for where your power comes from, we are talking about the marginal, not total case. That is, where the next electron is coming from to power an additional load you are considering, not the ones you already use regularly. Grid power consists of hydroelectric generation already running at full capacity, supplemented by natural gas, coal, nuclear and other sources. Unless you have your own micro hydro generator operating at excess capacity, your next electron could well be coming from natural gas or coal. Charging off peak has the potential to lessen the impact, but the additional draw of less efficient charging makes less clean energy available for other users, forcing them to draw from dirtier sources.
All that said, if L1 charging works for you, stick with it. It is only a few percentage points less efficient and doesn't matter in the grand scheme of things, as there is embedded energy and carbon costs in the manufacture and transport of that L2 EVSE.