MINI app vs “Smart” Chargers with WiFi

Smart EV chargers are for those who have solar. Some brands connect to the inverter directly for 100% solar only and to save breaker space.

 

I would guess that a very small percentage of people with smart EVSEs have solar. Besides having the ability to program their charging schedules, many choose smart EVSEs so they can record and track charging statistics.

 

Between the app and the Emporia home energy monitor I had installed into my main circuit panel, I personally don’t see any reason to get a smart charger. The emporia system was $150 on Amazon, plus $100 to be installed by an electrician. The price difference between a smart charger and a standard cable is greater than that $250, and I also can see the energy consumption in real time of not just the EV charger, but every circuit in my house.

I’m about to get solar panels because the energy prices here in texas are going up by 20% in 2022. Maybe I’ll re-assess at that point but I still think a smart charger will be unnecessary.

 

I can't take credit for this because someone else highlighted this point in another thread, but one benefit of a smart EVSE that's been cited is that it would allow you to keep your car set to "Charge immediately" since you could use your EVSE to manage charge timing to take advantage of time-of-use rates.

This could be particularly useful if you use public chargers with any frequency, as you wouldn't have to remember to manually over-ride your in-car charge settings every time you use a charger away from home. I've seen a couple of people note that they had plugged in at a public EVSE and, on returning some time later, found that their car hadn't initiated charging because it was set to charge only within a specific time window. But, if you don't expect to ever use public chargers, this wouldn't be an issue.

Sidenote: One potential downside of using a smart EVSE to manage time-of-use rate charging is that things could get complicated if you also want to use the Mini's pre-set departure time feature. In other words, what happens if I set a departure time in the car/app that's outside of the charge window set via my EVSE? My assumption is that the car would go ahead and pre-condition for departure using its high-voltage battery since it wouldn't have access to mains power outside of the charge window, but, if anyone has experience with this, I'd love to know what actually happens (I do have a smart EVSE, but I've only had my SE for a week and haven't had a chance to test this).

One other reason a person might opt for a smart EVSE is to take advantage of rebates offered by some municipalities for smart chargers that are demand-response-enabled. For example, here in the States, my state of Oregon offered a rebate of up to $500 towards the purchase of a qualifying smart, level-2 EVSE. I wouldn't be surprised if, down the road, some utilities also offer ongoing rate rebates for customers with qualifying smart EVSEs who opt-in to demand-response programs. Our local utility here in Oregon already offers ongoing rebates for homeowners with smart thermostats who opt-in to their demand-response program, and extending this to EVSEs seems likely. But this is very much municipality/utility dependent and may not be relevant where you are.

One last reason I could think of to go for a smart EVSE is if you have multiple electric cars and want to be able to charge them simultaneously without installing additional electrical circuits. A smart EVSE with load sharing would allow you to "daisy chain" multiple EVSEs and would manage power delivery across each of those EVSEs to minimize charge time for each of your vehicles, while staying within the max load of your one circuit. One example of an EVSE with this feature is Tesla's Gen 3 Wall Connector, and I believe JuiceBox offers at least one model that offers load sharing as well.

Those are the potential reasons for a smart EVSE that come to mind for me, but I'm still very much a newbie to this world, so it'll be great to see the responses from folks with more experiences with EVs.

 

Great summay; I concur with all of it.

One small correction: The current Gen3 Tesla connectors *do* allow load sharing, but they also each require their own circuit (breaker). In other words, you can program, say, your two boxes to draw 24A each or 48A alone, but each would need to be on a 60A breaker.

 

This starts to get really complicated with 100A main panels and maximum loads. A service upgrade to 200A with underground wires is $$$$$.

 

That was my observation, based on experience.

I use climatization when not plugged in, and it will indeed use the high voltage batteries to warm/cool the cabin as necessary. I use it in subzero temperatures when not plugged in at work, and I lose about 10% SoC to make the cabin nice and warm before I go home.

 

It does (I rely on this to warm the car in the mornings), but with a smart EVSE it will be unable to because the EVSE won't allow any electricity to flow. The car should be able to see this as "plugged in, no power".

 

If you want to really deep dive into battery charging curves and charging losses, it might be more efficient to use the battery to precondition the car and recharge completely at night. Charging from 99% to 100% can take upwards of 3kWh. I haven't spent the time to determine the final 1% at 32A vs 16A either! Have to factor in that 12V accessory battery too.

 

I have my SE start charging immediately once my low-cost window starts at 21:00, and it usually gets to 100% by about 00:00-01:00 (using the trick of having the departure time set to at least 30 minutes after the low-cost window). I then have the climatize happen so it's ready for departure at 07:30, so my SE is already at 100% SoC before climatizing but still plugged in to Level 2 so climatizing doesn't drop the SoC.

 

Right now I am using "reduced" level 2 charging instead of maximum to see if there is any difference. While plugged into a level 2 EVSE, high voltage battery is cycling between 99% and 100% and energy would flow EVSE -> high voltage battery -> heat pump. Long story short, the climatizing process could theoretically draw up to twice as much energy in Level 2 maximum as opposed to reduced charging to maintain SoC at 100%.

This is probably insignificant for most people but it's -18F here and the preconditioning was still running after 35 minutes before cutting it off. Overall it amounted to 2.2kWh of climatization, and 0.95kWh of recharging 99%->100% or 3.15kWh total. If it was under maximum 7,400W it could be upwards of 4.6-5.0kWh if the EVSE is running continuously in FRIGID weather where heat pumps are inefficient below -4F!

 

The mini app has certainly got better than the previous one we were stuck with this spring.
It depends what your definition of smart is, but I wouldn’t buy one unless I had multiple electric cars on a 100A service house. At that point for peace of mind it may be worth upgrading to 150A / 200A and a second full power EVSE over spending the money on a smart EVSE if you have big battery cars. Not an issue for a mini SE on a mini SE commute.
@Puppethead ’s observation was very smart though. If you public charge and select delay in app it’ll catch you one day. It’s really pestering the car can’t remember the charge settings of my home EVSE when I put the EVSE in the mini application on the car for “range monitoring.” I don’t know if mini ever pushes updates to the car like Tesla, but this would make me happy.

 

It does not. I've been caught by this. Plugged in to a ChargePoint, started charging, and went into store. 15 minutes later I got a notification from ChargePoint that my car wasn't drawing any electricity. Sure enough, I had left the SE on low-cost charging.

 

@F14Scott Thanks so much for this correction! As far as you know, is there a version of the Tesla connector that allows load sharing from a single circuit? Load sharing from a single circuit seems like a killer EVSE feature at this point in EV adoption, where first-timers recognize how fantastic EVs are and decide to replace a second ICE-vehicle with an EV as well, but it seems like very few EVSE manufacturers offer it.

I'd think, too, that condo and rental building owners would be keen on EVSEs with load sharing to enable more EVSEs with fewer circuits. Any thoughts on why this isn't a more widely available feature?

 

I agree with all your points!

Good news and bad news on the single circuit load sharing: Tesla's Gen2 wall connectors (aka HPWC) do it. But, they are no longer offered for sale. You can find them on eBay, however.

I, myself, have a set of two of the Gen2s on a single 60A breaker, connected to each other with a communication cable. They give up to 24A each when both are in use, or 48A alone.

I think the reason Teslas Gen3s changed is because they no longer use a physical cable to communicate the sharing nor a physical switch to dictate the maximum power draw; they do both via WiFi. As such, my guess is that if the WiFi connection goes down, each must operate as a stand alone connector at full power.