LeftieBiker said:
I seem to remember someone in our EV group posting a quote from GM saying the next Volt will have *slightly* faster charging. Between 3.3 and 6.6, for some reason, but closer to the low end.
I assume all the 3.3 KW chargers are so common because of 20 amp breakers being so common.
from http://www.mynissanleaf.com/viewtopic.php?f=6&t=13008" onclick="window.open(this.href);return false; we have a post saying the Leaf chargers at 240v are
3.3 KW to battery and 3.8 KW from wall and
6.0 KW to battery and 6.6 KW from wall but they allow used on a 30a curcuit (only 91.7% derate)
following the 80% derate rule
20 a * .8 for continuous load = 16a usable for the EVSE. 16*240 = 3.8 KW charger input, something like 3.3 KW to the battery.
30 a * .8 for continuous load = 24a usable for the EVSE. 24*240 = 5.7 KW charger input, something like 5.2 KW to the battery.
40 a * .8 for continuous load = 32a usable for the EVSE. 32*240 = 7.7 KW charger input, something like 7.2 KW to the battery.
50 a * .8 for continuous load = 40a usable for the EVSE. 40*240 = 9.6 KW charger input, something like 9.1 KW to the battery.
Since the Leaf 3.3/3.8KW charger fits the 80% derating rule for a 20a breaker but the Leaf 6.0/6.6KW charger doesn't I'm assuming they are counting on 30a amp circuits to be wired better or the car is requesting less than the full charge rate after the EVSE or charger gets warm.
Also worth noting that Tesla calls their charger 10KW and allows it's use on a 50a circuit so they seem to be willing to push the 80% derated rule as well.
If we go by 83.3% derate above 20a like Tesla does we get
20 a * .8 for continuous load = 16a usable for the EVSE. 16*240 = 3.8 KW charger input, something like 3.3 KW to the battery.
30 a * .833 for continuous load = 25a usable for the EVSE. 25*240 = 6.0 KW charger input, something like 5.5 KW to the battery.
40 a * .833 for continuous load = 33.3a usable for the EVSE. 33.3*240 = 8.0 KW charger input, something like 7.5 KW to the battery.
50 a * .833 for continuous load = 41.7a usable for the EVSE. 40*240 = 10.0 KW charger input, something like 9.5 KW to the battery.
so after all that why pick a charger closer to the 20a limit than the 30a limit? Gotta be a cost/weight/size thing. Doesn't make sense to focus on the bottom of the barrel charge rate.
Or heaven forbid they keep the same charger they used to call 3.3KW and start calling it 3.8KW with no physical change.