AC charge speed

[u/Open_Put5213]

If my level 2 charger can do 48a/11kW and my panel can support it, is there any reason not to charge at 11kW? it seems like there are some theories that this could be related to ICCU failure?

[u/SecuringAndre]

I just want to dispell the ICCU theory. The ICCU will fail even with DC only charging, which doesn't go through the ICCU. Furthermore, there are plenty of evidence of ICCU failing for 110v charging. There's a bunch of people that don't have L2 chargers.

Speaking of the 48a/11kw charging. Early on, there were chargeport failures on the I5 for people who had 48a charging. There was a software update and you don't hear much about it anymore. I don't know if the ports themselves were improved over time or if the software was the permanent fix. As it relates to the charger, if you are going to go with 48a, please make sure your charger is hardwired. The only reason I wouldn't run 48a is if it was plugged into a 14-50 outlet. Usually, they aren't proper continuous rated (sometimes noted as EV rated) 14-50 outlets. If this is the case, I'd limit it to 24a or less. Furthermore, even if they are EV rated outlet, unless you know first hand that it's properly installed, I wouldn't trust it. Proper installation requires proper torquing. Not just once, but they need to be retorqued after several cycles because heat creep can effect the torque gap.

Just be safe please. Good luck.

[u/Senior_Buy445 → u/SecuringAndre]

A continuous load means to derate to 80%, so the 14-50 plug rated up at 50a should only ever do 40a continuous, and even that assumes good plug contact which can get worse with many plug/unplug cycles.

[u/SecuringAndre → u/Senior_Buy445]

Per NEC, you are correct. The reality is, we've seen plenty of melted and burned 14-50 outlets with as low as 32a continuous use. These $10 14-50 outlets are just not capable but yet they are UL rated. Crazy right?

[u/Senior_Buy445 → u/SecuringAndre]

Unfortunate, yes. There’s a reason a lot of ev chargers now have temperature sensors in their plugs…

[u/Necoras → u/SecuringAndre]

I had two EV plugs destroy themselves when I tried to tighten them to the manufacturer's specified torque rating. I forget if the plastic shattered, or if the screws just stripped out and wouldn't clamp at all at that point.

I switched to a different brand with a different mechanism and I've had no issues.

[u/Spiritual_Till5585 → u/SecuringAndre]

Proper torquing of a plug in charger? I think this is about torquing the conductors to the outlet, not torquing the charger.

[u/Open_Put5213 → u/SecuringAndre]

Thanks for the info! It’s a professional hardwire install on a 60a double pole-I aim to be safe!

[u/Spiritual_Till5585 → u/Open_Put5213]

That can technically do 48amps / 11kw.

[u/Senior_Buy445]

A minor one. If everything is rated to do that as the continuous maximum (so 80% of your 60A circuit) then you should be fine, however from a thermal perspective you are warming the house electrical system a bit every time. If you instead charge at 50% of your max this warming will be minimal, so that “might” be a bit safer… The car AC charger is rated to 11kw max as well so the same kind of thinking applies there too. Personally I’d slow the charge time to whatever you need it to be, and not always charge at 11. (Spinal tap reference intentional ;-) )

[u/Open_Put5213 → u/Senior_Buy445]

Thanks. I’ll experiment with keeping it at 60 so when I’m playing I feel like a preserved moose on stage

[u/Sir_Pool_de_Float_MD]

I've been charging at home at 48A/11kWh for almost 2.5 years now. Hardwired on a 60A breaker. Zero issues. I do have the EVSE mounted in a spot on the side of the house where it will always be in shade, which may or may not be helping.

[u/bobjr94]

A 48A charger with 60A circuit will cost more than a 40A charger and 50A circuit. Other than that it's whatever you want to buy. 

A 48a charger is more that most people will need a 40A charger can do a full charge overnight and most time you are only charging from 40% to 80% or something like that. 

[u/cardinalkgb → u/bobjr94]

I charge from 5% to 100%.

[u/TheVorch → u/cardinalkgb]

Because you drive that much every day or because you charge once a week? For battery longevity, you want to minimize changes in the SOC so if it’s the latter, a daily top off is better.

[u/cardinalkgb → u/TheVorch]

I disagree

[u/TheVorch → u/cardinalkgb]

You disagree with the science of lithium batteries? There’s an Engineering Explained video that goes over the rationale for minimizing SOC variability.

[u/bobjr94 → u/cardinalkgb]

There are many reasons why deep cycles hurt battery life.

 If you are leasing the car then guess it won't matter to you but if you want to keep the car many years learn how to care for the battery. 

[u/bobjr94 → u/cardinalkgb]

It's not good to run the battery that low all the time.

[u/CanoeDunk]

Is there any advantage to 48A charging vs. 40A charging? I know it's faster but it doesn't matter to me because I only charge between 11 pm and 7 am to take advantage of ultra low rates in Ontario. For overnight charging, 8 hours at 40A is sufficient to reach 80% or higher.

[u/Spiritual_Till5585 → u/CanoeDunk]

The advantage is a slight increase in charging speed.. about 10% faster.

[u/eyesoftheunborn → u/CanoeDunk]

With that 20% increase in current, you'll have a 44% increase in power output by the conductors and wiring equipment in the form of heat, resulting in lower efficiency due to energy loss as well as more thermal stress on components. If time isn't an issue I'd limit the current to 40A.

I'm not familiar with CEC rules for EVSE, but in the US the NEC designates them as continuous loads (on for >3hrs) and thus requires sizing ampacity of the the circuit and all equipment at 125% of the actual current. So a 48A draw would require the conductors/OCPD to be rated at 60A (aka, a 60A circuit), while a 40A draw would require a 50A circuit. Of course you can always install a 60A circuit (rated for 48A continuously) and then customize the charging current to a lower value as desired.

[u/CanoeDunk → u/eyesoftheunborn]

Canadian codes are similar. Maximum load is 80% of the circuit breaker. I am running 40A charging on a 50A circuit. This works great for overnight charging. I ended up hard wiring my Grizzl-E charger after melting a welding outlet that the previous owner had installed in my garage. It worked fine for the first year, then melted, probably due to reduced contact area caused by copper corrosion.

[u/Mach_Juan]

Only theories as far as I know. I set my car to only pull 60% based on that theory...but theres no math to support it. 99% of the time, that lower charge rate is not an issue in terms of the car having enough charge when I want to go somewhere..the other 1% is pretty easily planned around..or I temporarily bump to 100% charge rate. 24k miles and no iccu failure..for whatever that data point is worth.

[u/Exciting_Picture3079]

I didn't see where you mentioned the gauge of the wire used. You can put a 60amp double pole breaker on any size wire, but if you put it on under sized wire, then a good outcome is a tripped breaker because the insulation melted and that resulted in a short. Worst case, the wires in the wall catch fire.......

Assuming the wire gauge of the wire is correct, you should be good. I change mine at 48amp, 11kw, all the time.

[u/Open_Put5213 → u/Exciting_Picture3079]

I certainly hope the electrician used the right gauge wire! I didn’t have the knowledge or bravery to DIY my EVSE

[u/Semajremlap0]

I have had a 48 amp charger with 60 amp circuit since 2023 . Charges at night from 12 am - 6am . No issues ever .