multi point question. I have a nema outlet and I’m using the tesla mobile charger. Works great.
I have a 40amp breaker on my panel.
I’m looking at the juicebox charger to charge the car. I like the juicebox because of the app. It tracks electricity used per charge which is ideal for tracking my charging and paying for my electricity.
I own a Clipper Creek HCS-40 with JuiceNet board installed, so it's the same as what you're considering from a software perspective. I bought this for a Chevy Volt that I leased, but I recently replaced that car with a Model 3. Using any non-Tesla EVSE has some minor drawbacks because you need Tesla's J1772 adapter and the button on the plug's handle won't open the Tesla's charge port door. I also often have to wake up the car in one way or another to unplug the EVSE, but I don't know if the same would be true with Tesla's EVSE. (When a charge is still in progress, interrupting it by pushing the button on the J1772 handle while I've got my cell phone on me usually unlocks the charge port, but after the charge has finished and the car goes to sleep, this no longer works.)
(If anyone has a different charger they recommended with electricity tracking let me know).
You can get the same data out of
TeslaFi, just measured on the car's side rather than the EVSE side. I've compared the two, and they're virtually identical in what they say the car is consuming. TeslaFi also gives you access to charge data away from home, if that's important to you. Of course, TeslaFi is a subscription service (currently $5/month or $50/year), and using it requires giving a third party access to your car's data, so it's got its downsides, but it's worth considering as an alternative. I'm pretty sure some other third-party apps provide similar data, but I don't have specific suggestions. You can also access the data yourself using Tesla's API, but you'd need to be able to write a program to do it, unless somebody's written something already. (That's what the various apps are, really, although some of them are services that involve a third-party server.)
Two other J1772 EVSEs that might do the trick are the
ChargePoint Home and
OpenEVSE. A friend of mine has a ChargePoint Home, but I don't know precisely what sort of data it provides. I'm pretty sure that the ChargePoint Home gives you access to data from both your home EVSE and any public ChargePoint EVSEs you might use, which would be an advantage if you want to track such charges. You can also get the JuiceNet board installed in Clipper Creek or Aerovironment devices; see
this page of the eMotorWerks site. (I bought the Clipper Creek version because, at the time I bought my EVSE, the JuiceBox was not yet UL or ETL certified. It's since earned that certification.)
Now with the 40 amp breaker on my panel. Should I get the 40amp juicebox or the 32amp juicebox charger?
For continuous use (as in an EVSE), you should pull only 80% of the rated breaker (and wiring) amperage, which is 32A for a 40A breaker. If the wiring is capable of handling more amperage, you could replace the breaker (it's cheap) and get the 40A JuiceBox, but if the breaker is 40A, chances are the wiring is rated for the same. As I understand it (I'm not an expert), the difference between the official rating and what you can draw continuously is largely to do with the difference between momentary and continuous loads -- a brief burst of 40A draw on a 40A circuit won't cause a lot of excess heat, but a continuous load, over hours, may heat it up beyond what it can take. This is especially true if there's a weak connection or if the wires degrade a bit because they've been bent or otherwise stressed.
