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Charging Rate

11K views 5 replies 5 participants last post by  Loboc 
#1 ·
Not sure if this is the right forum, and hope that it is at least still read since its been a while since anyone posted.

The electrician was out last week to do the site survey for my L2 charger install. He said the Bosch Power Xpress was installed on a 40A breaker but selectable at various charging rates. He then made the comment that "All EVs" only pull 20A for charging anyway. Anyone want to confirm or refute? I am superficially curious about the "All EVs" comment, but mostly wondering about the ELR...
I suppose it works out. 220V @ 20A is going to feed 4.4kw, which should charge the battery in the 4 hours advertised. Just curious about the details.
 
#2 ·
He then made the comment that "All EVs" only pull 20A for charging anyway. Anyone want to confirm or refute? I am superficially curious about the "All EVs" comment, but mostly wondering about the ELR...
ELR pulls the same as the Volt. Toyota Rav4 EV pulls up to 40A (requiring a 50-amp circuit). Tesla Model S pulls up to 80A I think... maybe more. There are more examples of your electrician being completely wrong about "all EVs" only pulling 20A.
 
#3 ·
He did mention the Tesla at 80a.
But I just saw the answer to my own question. From the product info on the cadillaccharging.com page:
The ELR is equipped with a 3.3kW on-board charger, a 30A charging station will not charge your ELR faster than a 16A charging station.

So, since 16A @ 220V is 3.3kW (3.5kW actually) it still works out that in a 4 hour period it will do the 13.2kWh to mostly fill the battery (i cant recall the exact amount of usable power in the battery)...
 
#4 ·
Maybe you should find another electrician. He's wrong: all EVSE don't pull 20 amps - depends on the vehicle.

The Volt and the ELR have a 3.3 kW OBC (onboard charger) so you'll only pull about 15 amps on a 240 volt charger regardless of the EVSE capabilities.

I'm running a Siemens VC30BLKB 30-Amp EVSE (set internally to 15 amps) connected to 30 amp breakers (old electric dryer socket).

You can buy a higher rated EVSE now for future proof and run the appropriate gauge wire & bigger circuit breakers.
 
#5 ·
The electrician gave you some wrong information. The EVSE supplies raw 240 volts to the car. The actual charger is located onboard the vehicle. (Just behind the right front bumper on the Volt.) The actual charge rate is set by the vehicle's onboard charger system and they vary from car model to car model. (They are NOT all 20 amps.) Many battery electric vehicles like the Leaf can draw up to 6.6 kw. (About 30 amps max.) The Volt has a 3.3 kw charger. (About 15 amps.) It will vary depending on what car you buy.

Some EV's even have a high speed DC port that can allow over 100 amps at high DC voltages. (Tesla Model S and Chevy Spark EV's have this feature.)

The rating of the EVSE it the maximum power it will deliver. If your car is capable of charging at a rate higher than the EVSE is rated for the car all automatically limit it's current draw to be within the EVSE's safe limit automatically. It is all handled automatically. The only issue will be how long it takes to charge.

On a Volt... Any EVSE that is capable of supplying 240 VAC at 15 amps or more will allow the Volt to charge in a little over 4 hours. Having higher capacity on your EVSE will not make the Volt charge faster... But it may allow your next vehicle to charge faster if that vehicle has a higher capacity onboard charger.

Hope that helps explain it.
 
#6 · (Edited)
All forum posts are visible in the 'what's new' area where most of us hang out. Also, they appear briefly on the home page until they scroll off. So, we see them all. No worries.

All EVs 'can' charge at 20amps and probably would have enough overnight charge for most people. Pretty much everything but GM can charge at a higher rate depending on what onboard charger they have and the handshake between the EVSE and the car.

I bought a GE that can charge up to 7.4Kw rate. I did this specifically so that it would not be at it's max all the time and theoretically last a long, long time. It is hanging off of a sub-panel fused at 50amps with a 40-amp breaker in the panel as per the GE install instructions.

With my circa 1951 house, going above 50amps would be an expensive proposition. I can't see ever needing to do this since my per-charge driving is usually less than 50 miles.
 
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