[RichardInCA]

Originally Posted by mjr24

So I don’t have to worry about the car trying to charge at 48 if my wall box only does 40? Will my car sense that and automatically change the charge rate to 40 or will I have to do that myself? I guess that’s my what could happen if I forget to do that? Obviously it’s moot if the car indeed senses it….

No, your car can’t demand more current than the wallbox will supply. I leave my car’s current limit on “unlimited”. Rather if you want to regulate the supply then you can throttle back from the car - like closing a tap.

[mjr24]

Originally Posted by Kennethjk

You might want to check your local utility to see if they are offering any rebates on a particular unit. There are many good ones out there.

I got $450 off my Juicebox, a 40 amp unit that was a plug in. Direct wiring is safer as 1 less point of failure and yes if you do go the plug in route, get a Hubble unit, industrial strength. I understand there is another company that makes one as strong. I went with plug in, in case the unit broke. I wouldn’t need an electrician to take off the old unit and or install the new unit and if the old one was bad I could just plug in the BMW unit until I get a replacement. As it turned out I had to replace 2 Juicebox units since they went bad within the warranty.

Unfortunately they are closing down their support and the unit will most likely be a dumb unit shortly. The only thing I ever did with the juicebox was down rate the amp charge. I normally charge at 32 amp. Less heat and less stress on battery and equipment.

Going forward I will adjust amp thru the car itself. I only charge at 40 amp if time is of the essence.

Dumb units, no adjustments thru the phone and are cheaper than smart units which have apps that coonect to the EVSE and you can measure various things

Enjoy

Just got my Gen 3 BMW wallbox installed today so I can finally really talk shop with you guys. Obviously, a lot of what you guys have explained makes way more sense now.

The electrician did a 50 amp breaker.

So my curiosity now is about some of you who obviously can charge at 40 amps but only choose to charge at 32 amps. You say it obviously puts less stress on everything. Is this a common knowledge thing?

I mean, is there any data that shows charging at 32 amps really causes a measurable less amount of stress than charging at 40 amps? Are you measuring "stress" by how warm the wiring gets? Obviously...the car can take fast charges of 140-150 kwh when at a fast charger so I know 32/40 isn't going to stress the car....so I'm assuming you are talking about more so stressing the wiring or breaker or EV charger/wallbox itself?

Now, I am assuming outside temp plays a part. It's 60 degrees here....maybe it would be different if it were 95 degrees and humid in terms of stressing the system and how hot the wiring gets.....

[RichardInCA]

I think at this point it’s all personal preference. I AC charge either at home (40A, 9.6kW) or at the office (~6kW, which translates to ~25A) and I’ve seen no change in my battery health per EFlow over several thousand miles.

[SkykingUSA]

Originally Posted by mjr24

Just got my Gen 3 BMW wallbox installed today so I can finally really talk shop with you guys. Obviously, a lot of what you guys have explained makes way more sense now.

The electrician did a 50 amp breaker.

So my curiosity now is about some of you who obviously can charge at 40 amps but only choose to charge at 32 amps. You say it obviously puts less stress on everything. Is this a common knowledge thing?

I mean, is there any data that shows charging at 32 amps really causes a measurable less amount of stress than charging at 40 amps? Are you measuring "stress" by how warm the wiring gets? Obviously...the car can take fast charges of 140-150 kwh when at a fast charger so I know 32/40 isn't going to stress the car....so I'm assuming you are talking about more so stressing the wiring or breaker or EV charger/wallbox itself?

Now, I am assuming outside temp plays a part. It's 60 degrees here....maybe it would be different if it were 95 degrees and humid in terms of stressing the system and how hot the wiring gets.....

It's more about long-term health. If you're leasing for 3 years and then giving the car back, it's not really a concern for you (would be for the next owner). However, if you're planning to keep your car for a long time (maybe 10 years let's say), then charging more slowly and keeping the charge between about 40% and 60% will help your battery degrade less over the long term.

There are various videos about it in the forums. I'll try to find a link or two and you can read about it.

EDIT: Here are some links.

[AiredaleDad]

I still think it's like filling your gas tank 80% instead of full. Or for you pilots out there, who have to calculate distance to where you are going, and figure how much fuel you need for the weight etc. and then put in just enough fuel (Plus required reserve) to get there instead of filling up. But I am an ICE guy. I just fill up and go until I need to fill up again.

[mjr24]

Originally Posted by SkykingUSA

It's more about long-term health. If you're leasing for 3 years and then giving the car back, it's not really a concern for you (would be for the next owner). However, if you're planning to keep your car for a long time (maybe 10 years let's say), then charging more slowly and keeping the charge between about 40% and 60% will help your battery degrade less over the long term.

There are various videos about it in the forums. I'll try to find a link or two and you can read about it.

EDIT: Here are some links.

No no…I’m not talking about stressing the battery. I am talking about the wiring, etc….charging cord, etc.

Some people on here say they charge at 32 or lower (even though they have the ability to charge at 40 or 48 amps on their chargers) because it places less stress on the wiring of the charger.

For instance, KennethJK’s post from October 4 says he charges only at 32 amp….

[AiredaleDad]

Originally Posted by mjr24

No no…I’m not talking about stressing the battery. I am talking about the wiring, etc….charging cord, etc.

Some people on here say they charge at 32 or lower (even though they have the ability to charge at 40 or 48 amps on their chargers) because it places less stress on the wiring of the charger.

For instance, KennethJK’s post from October 4 says he charges only at 32 amp….

Are talking about the wiring of the house to the charger, the internal wiring of the charger, or the Charging cable from the charger to the car? As someone who has worked in the Electrical/Electronics industry for 37 years, I know that if you have a qualified electrician install the wiring from the charger to the house, the wiring he installed should be able to handle about 150-200% of the rated load. So a 48 Amp Charger should have wiring that can handle well over 48 amps continuous load. The wall charger internals should be rated the same. And the charging cable to the car should also be rated well over the amperage subjected to it. If you look at the cables there should be printed information on it showing a part number that can be cross referenced to the rating of the cable. The reference will have information such as materials used, resistance between the conductor and insulation, capacity, working temperature range, etc. While cables can degrade over time, it's usually because of exposure to moisture, extreme temperature, and other environmental issues, (Especially if used regularly outdoors) and not protected. So clean the cables with a light coating of silicone grease on a rag to protect outdoor use cables. They should outlast the life of your car. But if the charger is rated at 48 amps, charging at 30 Amps is not going to prolong the life of the cables. It's like saying turning your home faucet only 3/4 open is going to prolong the life of a fire hose.

[RichardInCA]

Agree with AiredaleDad - if your charger was installed by a qualified electrician and you’re within specs for the wallbox, I don’t think there’s anything to worry about. That’s why all the replies have been about battery health as it’s the most common concern new EV drivers have.

[Scrapula]

I have an 80amp charger on 100amp circuit. I charge at 48amps. I believe more problems with batteries are charging above 90%.

[SkykingUSA]

Originally Posted by mjr24

No no…I’m not talking about stressing the battery. I am talking about the wiring, etc….charging cord, etc.

Some people on here say they charge at 32 or lower (even though they have the ability to charge at 40 or 48 amps on their chargers) because it places less stress on the wiring of the charger.

For instance, KennethJK’s post from October 4 says he charges only at 32 amp….

I didn't realize that. I didn't realize people were doing it to put less stress on their wiring. Like others have indicated, the wiring should be fine if installed correctly.