Home Charging Speed

[electruck]

^ your 60amp rated circuit is allowed to supply 48 continuous amps, which happens to be the exact amperage the Rivian Wall Charger supplies. So, regardless of being connected via a direct run from your main panel/split breaker or from a sub-panel.. as long as the EVSE can get 48amps.. you'll charge at ~25 m/hr.

Well, yes but no.

Since power = volts x current, you would be down approximately 1.5 kW @ 208V (or down roughly 3 mi/hr if we insist on factoring in driving efficiency which is highly variable).

240V x 48A = 11.5 kW
208V x 48A = 10.0 kW

That's not a huge difference but similar to the difference between 48A vs 40A charging at 240V. If there is a significant installation cost advantage to the split-breaker vs sub-panel, one should seriously weigh whether it's worth paying more to save a few minutes of charging over night.

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[ajdelange]

Hi, so I am in the process of having a wall charger put in the garage for the truck. However, I am not sure what the big difference is between one electricians way of installing the unit with a split breaker (208v@60A) vs. another electricians way of putting another sub-panel (240v@60A) and how this may or may not effects the rate of charge.
So am I still going to get the maximum rated juice to the truck ~25mi/hr of charge?

The choice between 208 and 240 V isn't made at the whim of the electrician. It is imposed on him by the nature of the service to the building. Residences are usually served by a single center tapped 240 V winding on a transformer whose primary is connected to a single phase of the distribution system. In addition to the 240V available from the ends of this winding 120V is available from the center tap. Office buildings, appartment complexes etc. may be served with 3 phase power at 120V (for the usual 120V circuits). In such cases 208 Volts can be derived by connecting across 2 phases (instead of just one in the normal case). If you are stuck with such service you are stuck with it and will only be able to charge at (208/240) times the rate you can get st 240V. There is nothing your electrician can do in this case except install an expensive step-up transformer to get you 240 V from the 208. Certainly not worth it IMO.

"Split breakers" and sub panels have nothing to do with any of this. If you have 240V service it doesn't matter whether the EVSE is wired through the main panel or a sub panel (as long as the breaker is the same capacity).

 

[electruck]

The choice between 208 and 240 V isn't made at the whim of the electrician. It is imposed on him by the nature of the service to the building. Residences are usually served by a single center tapped 240 V winding on a transformer whose primary is connected to a single phase of the distribution system. In addition to the 240V available from the ends of this winding 120V is available from the center tap. Office buildings, appartment complexes etc. may be served with 3 phase power at 120V (for the usual 120V circuits). In such cases 208 Volts can be derived by connecting across 2 phases (instead of just one in the normal case). If you are stuck with such service you are stuck with it and will only be able to charge at (208/240) times the rate you can get st 240V. There is nothing your electrician can do in this case except install an expensive step-up transformer to get you 240 V from the 208. Certainly not worth it IMO.

"Split breakers" and sub panels have nothing to do with any of this. If you have 240V service it doesn't matter whether the EVSE is wired through the main panel or a sub panel (as long as the breaker is the same capacity).

This would suggest that one of the electricians consulted was either incompetent or did not visit the installation site to assess the situation before providing guidance (one could argue those are one and the same). Either way, I would be inclined to avoid doing business with that electrician.

 

[Acoustic71]

I don't know. Something seems to be missing here. I just can't seem to put my finger on what it is.....

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