[Squidward]

I am considering a JuiceBox L2 charger and will probably install a 40 A plug for it as my house only has 100 A service and my electrical pane probably does not have the capacity for a 50 A circuit. The difference in price between the JuiceBox 32 and 40 is only about $50 and I was wondering if the JuiceBox 40 can be used with the 40 A circuit (32 A max current) in case I move or otherwise upgrade to a 50 A plug. There has to be a way to limit the power of the charger right?

I installed a Juicebox 40 last weekend in my garage. I have it on a 30 amp dedicated circuit, so will be limiting it to 24 amp max in the app. I called them (Enel X) before I bought it and they assured me that what I was doing was legit. I went with the 40 in case I want to upgrade to a 50 amp circuit down the line, though I doubt I will need it.

I can’t tell you how it works because I don’t have the car yet, but I asked about this subject in this forum a couple weeks ago and a lot of people convinced me that L2 charging at 24 amps will be plenty for a home with 2 EV’s with our level of driving.

 

[Squidward]

I am surprised the manufacturer told you this.

Some EVSEs have a hardware jumper or DIP switch that hard-locks a derated amperage setting -- the case would need to be opened and the setting manually reconfigured to make any changes. But I don't see any such setting in the Juicebox installation manual.

To rely on setting it in software... that's concerning.

In this example you're using a 40 amp box, connecting it to a 40 amp circuit, and limiting it to 32A in software. If that software setting gets reset -- by accident, due to power outage, software update, new phone, whatever, you could potentially have a scenario where the car is pulling 40 amps, on a 40 amp breaker, and the breaker won't trip because it's within limits.

Maybe that's just me being overly cautious, but it doesn't sound safe. I guess the fallback argument is that, per their instructions, both the 32A and 40A units require the same 8 gauge wire, so from that standpoint there's no difference.

After reading your reply, I think I will call them again and talk them through what I did just to be extra sure. That said, I just went and looked at their website and found this.

“Can I adjust the output power (amperage) of my JuiceBox. How can I do this?:

Yes, you can adjust the charging power limit in the JuiceNet app or dashboard settings. Use this, for instance, if you have a lower power circuit breaker that you want to ensure is not tripped during charging.”

 

[Squidward]

If it were me, I'd probably pull 6 Gauge cable (good for 55 Amps) no for any Level 2 EVSE above 16 Amps. 1) The incremental cost of the cable is pretty small compared to the cost or hassle of the installation 2) With #6 cable, even if a charger decided to change from 32 A to 40 A, you'd not really be at any fire risk, and 3) If you ever decided to put in a 50 Amp EVSE, you'd be all set cable-wise.

Yeah, the 30 amp line was already installed. I seriously considered pulling a new 6 gauge cable, but it would be a beast pulling it in my house. Once I saw that the charger could be adjusted up or down, I thought I would give it a try and then upgrade the cable and breaker later if it didn’t charge fast enough. They didn’t make it out to be a safety issue since the charger was built to do it. I think, and this is just the way I am thinking about it, the difference between the Juicebox 32 and 40 is the ability of it to handle the extra amperage but the way they explained it to me is that you set the system up to what you need it at. But, you all have me thinking hard enough that I will definitely call them again, and will let you know what they say.

 

[Squidward]

Of course you really need that car to see how it is going to work. Hopefully it arrives soon for you.

Agreed…and I hope it arrives soon too! I am looking forward to it. It’s all been a fun adventure. Installing solar panels, adding the charger, and now I just need the car!