Recommend EV Level 2 Charger for home (US)

Hi, new guy here, thought I'd chime in on this thread because I'm having problems with mine. Had my MINI since Feb, but just had a dedicated circuit with a 35A breaker installed, charger is a Lefanev 32A portable chargebox, have set both Level 1 and Level 2 to "Max" in the MINI's Settings -> Charging Current menu, but it throws 2 errors when I plug it in. Tried to get a video today, but it took longer than expected to get the errors so I stopped recording thinking they weren't going to show up, but they did. :-( Anyway, the chargebox ramps up to about 7A and it's fine, then it goes up to about 14-15A and the MINI pops up with a "Charging has been reduced to prevent harm to components" type of message (didn't get a pic of that one, unfortunately), and then a "Drivetrain: Contact MINI...Please go to the nearest service center to prevent further damage" message. I thought the MINI was supposed to control the charging, and it could handle pretty close to what the 32A chargebox can put out, and they would handshake and sync and give the proper level 2 charging power. Anybody know what's happening? Also, if there's a troubleshooting thread this should be in, let me know and I'll go there. Thanks....

 

The first thing the stands out to me - which may have nothing to do with the issue - is the maximum current draw on a circuit should never exceed 80% of the breaker size. So for 32A draw it needs at least a 40A breaker. The wire gauge also needs to be appropriate for the correct breaker size.

 

There's no handshaking for power draw. The SE will try to draw the maximum it can, and the EVSE will only provide the maximum it can, and your circuit breaker will trip if the draw is too high. So essentially the "lowest" power in that chain is what you will get. There's no harm having the SE set to a higher value than what your EVSE will provide, but there is definitely a problem if your EVSE is set to a higher output than your circuit can handle. It sounds like that's what might be happening.

As @tesrivmini stated, you can't go higher than 80%. So on a 35 A circuit you safely can draw a maximum of 28 A. You also need to be mindful of the wire gauge —charging EVs is a constant high-amp power draw which is more stressful than other uses for power.

 

The SE has some way to control the incoming current because when your SE first arrives at the dealer, it's set to charge at half it's maximum capacity. Also, some EVSEs have a way to set the maximum current they will draw.

 

That was my point. The car and EVSE have maximum values. But if the car is set higher than the EVSE the smaller amount is delivered. They just don't "negotiate" a rate: the car says "give me 32 kW!" and the EVSE says "here's all I've got, 24 kW!"

Or, the car says "give me 16 kW!" and the EVSE says "Hah, that's only half of what I can do, here's all you want!"

(Of course I'm anthropomorphizing, they don't actually talk to each other. Think of it like water flowing, and each step is a different size of pipe.)

 

Thanks for the replies, but I don't think the problem is at the breaker or wire or outlet, the charger never draws above 14A or so, according to the display on the charger. The electricians that installed the circuit also replaced my meter and whole panel, been around for decades, so they know what they're doing. Wire is 10/3, outlet is a NEMA 14-50. They decided on a 35A breaker, and since the charger doesn't even get close to that, I don't think that's the problem, the MINI tries to get to MAX (which I understand is about 28A-30A or so, can't remember exactly, but somebody somewhere on here calculated it, I believe), and the charger starts delivering, then the MINI freaks out and throws errors and reduces charging to level 1/granny charging, circuit breaker never trips.

 

The SE will charge from single phase 240V at a maximum of 7.4KW 32A - due to some losses in the system, it doesn't quite all reach the battery, but that's what it can draw.

However, the max the SE can draw isn't the issue. Is this your chargebox? : https://www.lefunev.com/products/portable-ev-charger-level-2-with-nema-14-50-plug-ev-charging-box-ev-charging-cable-station-electric-vehicle-charger-compatible-with-sae-j1772-type-1-cars-32a25ft?spm=..index.products_1.3

If it is, then it definitely does draw 32A at maximum output. They do make a 16A chargebox, but you listed it as "Lefanev 32A portable chargebox" in your OP - if it's only the 16A version then the rest of this post is moot.

But, if there is an intention to connect a device that can draw 32A (a chargebox in this case, but it could be a welder, etc), then it needs to be on at least a 40A circuit. The 80% (i.e. 32 = 80% of 40) calculation isn't a suggestion, it's required as part of the National Electric Code (NEC 220-2). In addition, 10 gauge wire is too small for 35A, in fact it's actually too small for 30A: https://learnmetrics.com/30-amp-wire-size/

Now, I am not an electrician - though I am an electrician's son - I would urge you to get a second opinion, even over the phone. Because as far as I can tell, that circuit is under breaker-ed and under wired. Especially as @Puppethead says, for charging purposes, where there is constant high current draw for relatively long periods of time. It's both a safety and reliability issue. Would hate for any one to be injured or any property loss to occur, that's all.

 

I says pardon?? A receptacle should never be rated higher than the circuit can handle; for example, it is against code to install a 5-20 receptacle (a common 20 Amp outlet found in all modern kitchens) on a circuit wired with 14 AWG wire and a 15 Amp breaker. A NEMA 14-50 is designed for loads up to 50 Amps, but 10/3 is rated to 30. What’s the breaker rating?

 

Yeah that’s problematic.

 

Yes, that is my charger, 32A. Interesting they didn't use the proper gauge wire, the guy that spec-ed it out after I told him the requirements has been doing this for decades, surely he knows about the 80% rule. I thought it was odd that the charger used a 14-50 plug too, if it can only go up to 32A, but maybe it's the same one they use on their more powerful models. Electricians also thought it was odd that they used it, but figured that it wouldn't really matter since the charger is 32A and breaker is 35A and it's just in the middle.

So even if the wire gauge is a problem, I don't think it's causing the MINI to get up to 14-15A, then drop back down to ~7A since it's never getting anywhere close to the wire/breaker/charger/outlet limits, seems like that's a separate issue. I'll check on the wiring with another electrician and see what they say. Not sure if I can get the original ones out to re-run the wire and replace the breaker for free, but I'll have to talk to them and mention the 80% rule, etc. They seemed to be pretty knowledgeable and strict about code when they were doing the other work (I asked questions about why they were doing things a certain way), not sure why they didn't pay attention when they were doing this. :-(

Thanks again...

 

Have you tried to lower the setting in the car? I think for 240V it has two setting, max and restricted and the restricted is 16A. That would be better than 7A.

 

So wiring issues aside, from a problem determination perspective, there's three elements: breaker/wiring/plug, chargebox, MINI.

Ideally, if you can alter only one of the first two at a time, that will narrow down where the charging issue lies.

Obviously in the real world that's easier said than done though.

 

Have not, it's fully charged now and I don't drive much, so I'll have to try that in a few days when it's down a bit, I'll report back. If it gets to 14-15A and then chokes, not sure if changing it to 16A will make much difference, but I'll give it a shot.

Right, and since I don't think the wiring is part of the charging problem since it never reaches the limits of the breaker, wire, or plug, I can probably rule that out. I'm not sure if it's the chargebox because it seems willing to put out however much the MINI will accept. So that leaves the MINI as stopping the ramp-up of charging to what it should be, then going back down to level 1.

Thanks to all for the info, I'm guessing I'll just have to take it in to the dealer and hope they have a clue (mine is only the second MINI SE in OKC, so I'm guessing they don't have much real-world experience with them). If they have a level 2 charger that can go up to 32A, then it will be pretty easy to narrow it down at that point.

 

Actually that will allow you to confirm/deny it's the Mini with the problem, but it still leaves wiring or chargebox as the problem - you're changing two variables there - the Mini being the constant. Like I said, hard to test by only changing on variable at a time in the real world!

Does the basic level 1, 120V charger that comes with the Mini work properly when plugged into it? Yes it's level 1, not 2, but if it works as expected or not might help Mini diagnose the issue.

 

Oh, I know about changing only one thing at a time, I've been a mainframe/UNIX sys admin for a few decades now. I'm actually hoping that the dealer has a 14-50 outlet there somewhere I could also plug *my* charger in to in addition to the level 2 charger they (might) have (I have no idea if they have one, but I'd hope they would).

And yes, the basic charger works perfectly.

 

You have my sympathies - LOL

No worries, problem determination can be a new concept for many people!

 

Even though the MINI can only draw 32A I wanted to future proof as best as possible, especially as I had the EVSE installed in the garage, and hope it will last a while. So I went with the ChargePoint Home Flex and had it hardwired to an 80A circuit. I had an opportunity to test it out with my parent's Model 3 over the weekend and the Tesla took the full 48A it is capable of taking (2A short of the 50A the ChargePoint can put out in this configuration).




As an aside, I realized after install that I qualify for Connecticut's rebate for both the charger ($500) and the install ($500). You just need to have a qualifying smart charger installed this year, and allow them to manage/throttle/block your charging between 3 and 9 PM 15 times a month for June-Sept. If you don't "opt out" of more than 2 of those "events" per month, you get $50 for each of those summer months. Seems fair to me, and until they get a separate meter for my EVSE, probably better than trying to play around with some type of variable rate plan. Anyway; look to see if your state has any rebates.

 

Unfortunately, I can only get federal rebates/credits - OK has no EV rebates/credits/anything, they'd probably like to charge us for using EVs since they're so fossil-fuel oriented, lol...

 

Ha, I actually like UNIX more than MVS or z/OS (moved over to UNIX gradually for a few years starting in 1995), and my job will most likely last longer now that I'm a UNIX guy. I'm just hoping that I can definitively state it's the MINI or not after talking to/taking it in to the dealer. I'm not an electrician, but I understand enough to wonder how it could be the circuit or any part of it, since the charger seems to be willing to do all it can, which would be 30-ish A (and the circuit seems capable of putting all that out, albeit not ideally), but the MINI says "lower your rate, I can't handle it".