Level 2 Charging Approach

[dohearne]

Now that I have decided to purchase a new BEV i3, I have entered into the fog of Level 2 charging. The location of my electrical box relative to my garage could make running a 240V line to the garage expensive. However, the door from the garage is directly to the laundry room with a 30A-240v dryer outlet. I am considering adding a RV type wall pass through to get at the outlet (rather than using just the door ajar). I will then either plug/unplug dryer/EVSE or use something like Splitvolt. Has anyone to anything like this or have other solutions.?

 

[3pete]

First, most obvious answer that doesn't answer your specific question is to ask yourself if you need 240v charging or is 120v enough (assuming you do already have a 120v outlet in your garage)? What are your typical daily driving habits vs. how long your car spends in the garage at night and on the weekends? It's pretty easy to find 10hrs a day to charge which is easily 30-40 miles of range.

Are you getting a NEW i3 (with the 120ah battery)? If so, you'll have a bigger buffer to go into a 'battery deficit' even if you can't fully charge overnight, maybe you can catch up on weekends.

Are there convenient L2/ DC fast charge stations around you? This would also make it convenient to top-up if needed.

But to the point of using 240v: I did something similar using my dryer outlet until I had an electrician install a dedicated circuit but it was a very temporary thing and I routed the EVSE cable out a glass block window/vent. From what I found, electrical code frowns upon any non-permanent wiring going through walls.

The location of my electrical box relative to my garage could make running a 240V line to the garage expensive. However, the door from the garage is directly to the laundry room with a 30A-240v dryer outlet.

If the distance between Dryer and breaker box is a major roadblock, one thought to run by an electrician would be whether you can add an outlet onto the dryer circuit rather than running all the way back to the breaker box. You would need to manage the load on the circuit between the dryer and EVSE somehow either with something like a physical switch that only powers one outlet at a time.

 

[dohearne]

First, most obvious answer that doesn't answer your specific question is to ask yourself if you need 240v charging or is 120v enough (assuming you do already have a 120v outlet in your garage)? What are your typical daily driving habits vs. how long your car spends in the garage at night and on the weekends? It's pretty easy to find 10hrs a day to charge which is easily 30-40 miles of range.

Are you getting a NEW i3 (with the 120ah battery)? If so, you'll have a bigger buffer to go into a 'battery deficit' even if you can't fully charge overnight, maybe you can catch up on weekends.

Yes, I am getting an i3 with 120ah battery. Most days my driving will be under 30 miles of range, so your question regarding just using 120v is a good one. I am retired and at home the majority of the time, so I might get by with a L1 charge. However, somewhere I read that long term use of standard 110V outlet is not recommended for EV charging. Also, I was uncertain as to using L1 charging for pre-conditioning/pre-climatizing.

 

[dohearne]

“If the distance between Dryer and breaker box is a major roadblock, one thought to run by an electrician would be whether you can add an outlet onto the dryer circuit rather than running all the way back to the breaker box”

That is why one consideration was https://www.splitvolt.com/ which allows a dryer and a L2 EVSE to access the same outlet while preventing the dryer or EV to pull power at the same time.

 

[eXodus]

On l1 precondition will draw down the battery. Not enough power, needs about 3kw - so 240v

Do not use the dryer outlet. Those outlets are not designed for being unplugged/replugged all the time.

I like the idea of adding a second outlet to the dryer circuit. Most circuits in the house of more outlets then the maximum of the circuit can take if you would run them all at the same time.

In any room there are usually 6-10x 15a outlets on ONE 20A breaker. If you plugin like 2 space heaters - you trip the breaker.

The same for running the car and the EVSE charger at the same time. But the splitphase even takes out this user error. I like this solution. A bit price but good to keep habits the same.

 

[jadnashuanh]

Electrical code only allows you to use a max of 80% of the rated circuit with something like an EVSE, so on a 30A circuit, you could put a max of a 24A EVSE, which may limit your choices some.

If you were going to share that circuit with your dryer, you may want to install a transfer switch so that only one device at a time could be active. You could do that with either a plug-in EVSE, or a hard-wired one. Physically, they're identical, it's just that they put a cord with a plug on it versus just a pigtail you can wire into a box. IOW, you can swap between hardwired and a plug-in with no physical change to the box...take the old wiring off, change it to the new, desired configuration. A cord with a plug on it is readily available, should you want to go that route.

You could also verify what actual gauge wire is being used on that circuit, and if you're lucky, you may be able to safely just install a larger breaker, but you cannot do that if the wiring gauge is not sufficient.

The supplied EVSE with the i3 is probably a 10A device. If you have a 20A circuit in the garage, (you might need to swap a receptacle from a 15A one to a 20A one), you could improve that to a 16A EVSE on 120vac that would give you 60% more. That may be simply just swapping out a receptacle if the wiring is 12g. It's not uncommon to have a 20A circuit in a garage, but it may have 15A receptacles rather than 20A ones (one blade slot is T-shaped to accept a 20A plug).

 

[3pete]

somewhere I read that long term use of standard 110V outlet is not recommended for EV charging. Also, I was uncertain as to using L1 charging for pre-conditioning/pre-climatizing.

As mentioned: it is true that L1 can't keep up with pre-conditioning so you may leave with less than 100% charge. This is likely to be a < 5 mile impact on your range though.

I would chalk the "110v charging is not recommended long-term" to be a myth. It's definitely slower, it's less flexible (if you get home with 2 miles of range and need to go somewhere unexpectedly) and it will not fully keep up with the i3's pre-conditioning which means you may leave with less than 100% battery sometimes even when it's been plugged in for many hours.

The only other thing is that it's slightly less efficient than L2 charging. This is on the scale of a probably a few dollars a year though so not really enough to justify any sort of hardware to remedy.

There are rumors that L1 EVSEs (including BMW's """Occasional Use Cable""") are not up to the challenge of daily use but I have yet to see any evidence to support this. More likely, it's just that BMW wants people to install L2 so they don't get mad that their i3 is less than 100% when they leave after preconditioning, or they wear out their garage electrical outlet plugging/unplugging their EVSE every day, or to avoid people watching the miles of range slowly trickle up at 3mph in the first week they have the car.

That is why one consideration was https://www.splitvolt.com/ which allows a dryer and a L2 EVSE to access the same outlet while preventing the dryer or EV to pull power at the same time.

Something like SplitVolt would work but is probably designed such that the Dryer and EV are in the same room. If your dryer isn't in your garage, it might not be a solution an electrician would endorse. A "dumb" switch would seem to check all the boxes of *probably* meeting electrical code while allowing you to charge your EV at L2 OR use your dryer with the only downside that you would have to manually pick between the two. You *may* not even need a switch and can rely on remembering to not use both at the same time with the fallback that the breaker *should* trip if there's an issue.

Just my $0.02 from your description, I'd bet you'd be just fine charging off of L1 for the life of the car but I'm even more confident in saying you'd be good to try it for a month and then decide if you need something faster.

 

[jadnashuanh]

Places where 220-240vac is standard have it better when it comes to plugging in their EV...people also tend to want bigger batteries, and charging them will take longer when you let it get down. If you don't drive much on a daily basis, and can get back to full in between uses, you may not need to do anything. Double the voltage, double the power at the same amps.

The difference in efficiency between level 1 and level 2 is in the order of 5%, give or take a little. Say your electricity is about $0.20/Kw (about what mine costs), to put a Kw into your vehicle, you'd be spending $0.21. Over time, it adds up. Some places, their electric rates are considerably higher, and if you're lucky, yours is much lower.

I've seen my i3 pulling over 20A/240vac during a preconditioning/departure time cycle. That's quadruple the power the 10A/120vac EVSE can supply. So, the vehicle will limit some of what would be the most efficient for maximum range.

 

[dohearne]

All of the replies have been quite helpful and represent to me sound advice. As suggested, I will begin just using L1 charging and learn my needs. If I find I need L2 charging, I can park the car close enough to the utility room to easily access the dryer outlet while I determine the best way to put in a permanent solution. I am learning that owning an EV requires a different mindset, but I am enjoying adjusting my thinking.

 

[eNate]

Another consideration is increasing L1 amperage.

For my needs the stock 12A unit was barely cutting it (trying to charge mainly at work, where I plug in for free).

I switched to a dual voltage 16A unit, and that 33% increase in electrons made all the difference.

For the most part, my charge-at-work sessions are adequate, and when I do plug in at home, I rarely use the EVSE's L2 capability.

I have a 40A Clipper Creek box during on the sidelines. I'll eventually install it, but just haven't had the need to make it a priority.

 

[Pepeborja]

When I decided to get an i3 I knew I would need L2 charging because I wanted to be able to have a reliable way to replenish the vehicle battery overnight for my 94AH model. The only question left to ponder was what L2 size to get. I opted for the low end 240V/16A charger unit from Amazon using 12/3 wire in a 20A circuit.

Since my requirement is to have a full battery by next day (overnight~10hrs), having a bigger L2 charger would have only increased the costs by a factor of 3 and yet come morning either system would have got the job done, only one is faster than the other.

If you are DIY you can go with the lower end option to match the needs but if you are paying an electrician you may wish to go big since the labor cost will be the same for pulling cable and installation.

If L1 is your preferred option you can always get a “dryer splitter” https://www.amazon.com/Parkworld-88...MHX2WCX0GQF&psc=1&refRID=10T5ANX6MMHX2WCX0GQF for around $60 for those few occasions when you wish to go L2, so consider a dual voltage system if you can. Not a bad option if you don’t mind having a cable out the door a few times a year.

 

[dohearne]

When I decided to get an i3 I knew I would need L2 charging because I wanted to be able to have a reliable way to replenish the vehicle battery overnight for my 94AH model. The only question left to ponder was what L2 size to get. I opted for the low end 240V/16A charger unit from Amazon using 12/3 wire in a 20A circuit.

Since my requirement is to have a full battery by next day (overnight~10hrs), having a bigger L2 charger would have only increased the costs by a factor of 3 and yet come morning either system would have got the job done, only one is faster than the other.

Thank-you for this response but I only partially understand your approach. I do have 20A/110 V circuits in my garage which I assume you did also. To get the 240V, did you convert a pair of 110V outlets?

 

[eNate]

I do have 20A/110 V circuits in my garage which I assume you did also. To get the 240V, did you convert a pair of 110V outlets?

That is essentially how you wire up a 240v receptacle.

You'll need to make sure each side comes from a different leg from your load center (so one red and one black).

You'll also want to make sure the two breakers feeding these two legs are ganged together, so if one trips they both shut off. This can be accomplished with a simple breaker tie that could over each handle, or through installation of a tandem breaker.

It should be a dedicated circuit when in use because the EVSE will be maximizing the circuit. You wouldn't want an appliance or a power saw running off this same circuit while charging.

And of course you'd want to ensure you have 12 wire making the circuit, which is probably a given but worth confirming.

 

[Pepeborja]

Thank-you for this response but I only partially understand your approach. I do have 20A/110 V circuits in my garage which I assume you did also. To get the 240V, did you convert a pair of 110V outlets?

The circuits in my garage are all 15A and are already busy with 3 door openers, fridge, and air compressor.

I ran a brand new 50 foot spool of 12/3 wire from my basement panel to the garage on a new 20A double breaker.

I installed a dual voltage outlet supporting 120/240V @ 20A. It's a weird looking outlet because on plug is for 120V and another one for 240V appliances. I wanted to have a juiced up 120V outlet in the garage for those occasions when I run power tools that draw lots of juice tripping the 15A breaker when my compressor is running too. Here is a link to a similar outlet https://www.homedepot.com/p/Leviton...Vl-SzCh2vZww8EAQYAiABEgKbZvD_BwE&gclsrc=aw.ds

The reason for 12/3 wire is that the 120V outlet uses the BLACK and WHITE leads while the 240V use the RED and BLACK leads. I think I spent $70 on the wire, breaker, and outlet + 2 hours cursing and running wire.

Converting a 120V circuit to 240V requires a dedicated circuit and that was not an option for me.