Difference in installing a 32 or 40 amp level 2 charger?

[Ride_the_lightning]

Oy, this thread!

Ask an electrician. Not the internet.

You should see the Reddit threads. People running 100’ extension cords out apartment windows to charge their teslas. It’s amazing there aren’t more self inflicted fires with that kind of stupidity.

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[Maquis]

Correct, 48amps, which is 11.52KW. My house varies on the V, seen as high as 248 or 249, so closer to 11.9KW.

I just ran it at 48amps, and it maxed out at 11.27Kw.

Correct - I’ll update my post.

 

[JmanMachE]

I installed the ChargePoint Flex hardwired which can deliver up to 48 amps (60 amp circuit). It works very well. The car will charge as quickly as it can with this, but a few things I learned afterwards.

At the higher rates (48 or 40 amps out), the MME will run more cooling and that can be very noisy. I was shocked the first time and researched it, but at least it keeps the batteries from overheating. I also believe I'm losing some additional power due to this. In hot weather, it was taking much longer to charge than expected at these higher rates.

For the most part, I keep the charger set at 40 amps (32 amps output) - same as the Ford charger. This seems to be the sweet spot - fast enough for me, still quiet and not wasting energy cooling the batteries. I can always increase it if I need the speed, simple to do from the app.

I wouldn't recommend anyone use 110 simply because the energy loss through the wiring is significant, and of course that is magnified over time since it will take days to reach full charge.

Hope this is helpful.

 

[RickMachE]

I installed the ChargePoint Flex hardwired which can deliver up to 48 amps (60 amp circuit). It works very well. The car will charge as quickly as it can with this, but a few things I learned afterwards.

At the higher rates (48 or 40 amps out), the MME will run more cooling and that can be very noisy. I was shocked the first time and researched it, but at least it keeps the batteries from overheating. I also believe I'm losing some additional power due to this. In hot weather, it was taking much longer to charge than expected at these higher rates.

For the most part, I keep the charger set at 40 amps (32 amps output) - same as the Ford charger. This seems to be the sweet spot - fast enough for me, still quiet and not wasting energy cooling the batteries. I can always increase it if I need the speed, simple to do from the app.

I wouldn't recommend anyone use 110 simply because the energy loss through the wiring is significant, and of course that is magnified over time since it will take days to reach full charge.

Hope this is helpful.

The charging noise at 48amps was fixed by an update, I had it done last September(?). There is no noise now.

 

[dtbaker61]

Correct, 48amps, which is 11.52KW. My house varies on the V, seen as high as 248 or 249, so closer to 11.9KW.

I just ran it at 48amps, and it maxed out at 11.27Kw.

thanks for the verification.... you and @delacruz.c5d clearly show the MME can take 48amps

I was going by the docs; which as we've seen are not always 'accurate'.

the standard 32amp mobile is fine for me at home, my average day is 20-50miles, and we don't have time-of-use rates in NM, so I don't have to hit any particular window when charging....

 

[dtbaker61]

...snip

For the most part, I keep the charger set at 40 amps (32 amps output) - same as the Ford charger. This seems to be the sweet spot - fast enough for me, still quiet and not wasting energy cooling the batteries. ...snip

so..... if the OP doesn't NEED faster charging, the mobile at 32amps is just dandy.

I wouldn't recommend anyone use 110 simply because the energy loss through the wiring is significant, and of course that is magnified over time since it will take days to reach full charge.

Hope this is helpful.

I object to your statement that 'loss through wiring is significant' charging from 120v. If the wiring between breaker and outlet is standard 12ga copper, and less than 25feet, the loss from wire is TINY. If you have a long extension cord that is 14ga or 16ga from outlet to mobile charger it might get pretty warm and be a problem.

Of you must use an extension cord, get a 10ga cord, and make sure it is as short as possible.

 

[walla2]

Difference between 32 or 40 amp L2 charger?

To my mind it's about 8 amps.

(Tip your waiters, try the veal, it's delicious...)

 

[YFD_233]

40 or 50 only for a nema 14-50 socket


correct about the 125%, but you are allowed to put a 14-50 on a 40A circuit


yes, with 6 ga copper you can use a 40A or 50A breaker.

6 ga for 40A?

 

[timbop]

6 ga for 40A?

#8 copper is the MINIMUM for a 40 amp circuit - but you can use heavier wire than you need so #6 will work for either 40A or 50A. The only reason to use heavier wire is "just in case": you never know what the future will bring and as I mentioned before running heavier wire prevents you from having to "do it over". You can run #6 on a 40A breaker with a 32A or lower EVSE. Then, at some point in the future when you have 2 EV's in the house you can replace the single EVSE with a dual-port one that can charge 2 cars at a time.

If you'd rather save the $50 and use #8 for your 40A line it will work just fine. I used #8 off of a 40A breaker to my 32A EVSE because I had leftover #8 wire and the panel is only 15 feet from the EVSE. So for me if I can talk my wife into getting a BEV I will run a second 40A line for her car (we have 200A service with plenty of headroom). If my run was long and/or difficult or my panel was on the verge of being maxed out I would have run #6 on a 50A breaker with the plan to get a tandem EVSE in the future.

In place of a tandem EVSE you can get one that can circuit-share with another of the same model.

 

[SMann40544]

 

[SMann40544]

Above is my MME GT charging off of a charge point hardwired to a 50 amp circuit breaker.
V=IR, Amp=Power/Volts

This is 9.674 KW and about 44 amps at 220 Volts.

 

[EELinneman]

Ok guys. What’s the difference in installing a 32 or 40 amp level 2 charger? And what’s a good cheaper one to get, so many to choose from?

Keep in mind that the circuit has to be derated by 20%, so a 32 amp EVSE needs a 40 am circuit breaker, a 40 amp EVSE needs a 50 amp breaker. Make sure your electrician wires this correctly.

As far as chargers go, the go to review is Tom Mologny (sp?) on You Tube. His channel is titled "State of Charge". I got a Juicebox via Costco and am very happy with it.

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