Level 1 Living at 16 Amps

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eNate

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Since purchasing my BEV four months ago, I'd been for the most part charging at Level 1 using the stock, 12A BMW "occasional use charger." 

I should preface this post by saying I don't suffer range "anxiety" per se, but I do monitor my state of charge closely and loosely plan a day ahead. Saturday mornings can be a killer! I'm infrequently at 100%, and am OK with that, living the life in the middle-percentiles. FWIW, I've run the SOC down to zero once, which I've posted about previously (https://www.mybmwi3.com/forum/viewtopic.php?f=10&t=16492).

I charge for free at work, where my car is parked 8 hours a day, 5 days a week. I also charge at "the house", where it's parked 5 days a week for 7 hours. (*note that I'm renovating "the house" and I'm not staying there overnight, and I don't purposely charge where we're temporarily living because it's a duplex with a shared utility meter and on-street parking.)

chargeatwork1.jpg


My typical day is 40 miles -- 16 miles (11 freeway) + 10 miles (4 freeway) + 11 miles (4 freeway). But my work days and house days are offset, so some days I charge at the house only, and others at work only.

Anyhow, maybe a month ago I purchased a Duosida D25 16A EVSE from Brad at BSA Electronics, and my experience has much improved.

BEFORE, stock charger: Gaining about 25% charge over 8 hours, I was recouping roughly 45% per day (7 hours house + 8 hours work). With my 94Ah battery, 1% is roughly 1 mile** (a little more). This was riding on the margin, near net zero charge at the end of the day. An unexpected trip could throw me off. I found weekly (maybe a little less frequently) I'd visit a nearby Level 3 EVGo to bring my i3 up to 80%, or a nearby Level 2 Blink charger for a modest boost. Very typically I found myself running below 50% SOC most of the time.

(Photo: my EVSE lives in the frunk, even while charging)
chargeatwork2.jpg


 ** regardless of your battery size, the stock 120v 12A EVSE will get you roughly 4 miles of range per hour, and a 120v 16A EVSE 5 miles, depending on your miles/kWh driving efficiency

AFTER, Duosida charger: The 16 Amps of current is only a 33% increase over the stock charger, but it's completely changed my routine. By the end of a typical day, I end with about 15% more "in the tank" than what I began with. This also represents 15 to 20 additional miles "extra" I can drive without going into a charge deficit. My state of charge is generally greater than 50%, although I still dip into the low numbers, depending on the day.

chargeatwork3.jpg


But more importantly, the Duosida is a dual voltage charger. So I wired up a 240v circuit in the garage and occasionally Level 2 charge (@ 16A) when I'm in need of a greater boost. This is recouping about 10% per hour. But I am still being a cheapskate, and I pull the plug at 75% if I know I can top up to 100% later at work (75% allows 10% for the drive, and then +35% during my time at work).

Charging @ home, 240v using the same cord, same EVSE, running to a special receptacle I wired up in the garage:
chargeathome1.jpg


My stops at the Level 3 charger have all but disappeared -- I'll use one if I'm off schedule or on a longer errand, for a quick fix, but I don't think I've needed one since the switch-over.

Eventually I'll install a "real" level 2 charger at the house -- it's simply a lower priority project for me at the moment, and involves a small amount of concrete and drywall work. 

chargeatwork4.jpg
 
eNate said:
Since purchasing my BEV four months ago, I'd been for the most part charging at Level 1 using the stock, 12A BMW "occasional use charger."
Is the 2017 OUC rated at 12 A? I ask because the 2014 version is rated at 12 A, but BMW changed to a 10 A OUC in 2015.

eNate said:
Anyhow, maybe a month ago I purchased a Duosida D25 16A EVSE from Brad at BSA Electronics, and my experience has much improved.

eNate said:
 ** regardless of your battery size, the stock 120v 12A EVSE will get you roughly 4 miles of range per hour, and a 120v 16A EVSE 5 miles, depending on your miles/kWh driving efficiency
To clarify, most residential 120 V outlets are rated at only 15 A, so a Duosida 16 A EVSE would offer no charging speed advantage compared with a 12 A OUC when plugged into a 15 A outlet. Those with a 10 A OUC would be able to charge a bit faster assuming that the Duosida's Level 1 (120 V) output can be decreased to 12 A to prevent tripping a 15 A circuit breaker.

eNate said:
Eventually I'll install a "real" level 2 charger at the house -- it's simply a lower priority project for me at the moment, and involves a small amount of concrete and drywall work.
I charge at even lower power with our JuiceBox AC Level 2 EVSE, 16 A @ 208 V, compared with your 16 A @ 240 V Duosida EVSE, so your Duosida is certain a real AC Level 2 EVSE when plugged into a 208 V or 240 V charging circuit.
 
alohart said:
Is the 2017 OUC rated at 12 A? I ask because the 2014 version is rated at 12 A, but BMW changed to a 10 A OUC in 2015.


I can't say for certain. My 2017 was used and the dealership included a bubble-wrapped, I'd guess brand new, 12A EVSE. I don't know if it was the unit originally included with the car.

alohart said:
To clarify, most residential 120 V outlets are rated at only 15 A, so a Duosida 16 A EVSE would offer no charging speed advantage compared with a 12 A OUC when plugged into a 15 A outlet. Those with a 10 A OUC would be able to charge a bit faster assuming that the Duosida's Level 1 (120 V) output can be decreased to 12 A to prevent tripping a 15 A circuit breaker.


Good point, a 20A receptacle is needed to use this EVSE. Per code, new residential garages will have 20A, as will outdoor commercial spaces.

But to answer your question, no, the Duosida itself isn't multi-amperage selectable. A lower charge setting will have to be selected in the i3 via iDrive, as this EVSE will advertise 16A available to the car and will likely (hopefully) blow a 15A circuit.

The unit can be ordered with a NEMA 5-20 plug with the funny sideways prong so that it can't be accidentally plugged into a 15A receptacle.

alohart said:
I charge at even lower power with our JuiceBox AC Level 2 EVSE, 16 A @ 208 V, compared with your 16 A @ 240 V Duosida EVSE, so your Duosida is certain a real AC Level 2 EVSE when plugged into a 208 V or 240 V charging circuit.

I haven't actually checked my phase alignment to see if I'm 220 or 208, but there's a good chance I'm in the same boat as you.

By "real" what I really mean is a wall-mounted EVSE that doesn't live in my frunk, that I can pull up to and plug in.
 
We bought a used 2015 BMW i3 Rex, the charging cord is came with say 12A on it, but we also bought for very cheep a brand new BMW dual charger it say 120V / 240V and 12A / 16A on it. So far we only charge at home and have not used the BMW dual charger, Im guessing that if we did use the BMW dual charger on a normal 110 outlet we would not see any faster charging times ?

We dont have a 220 plug in our garage but plan to add one at one point.
 
KarlC said:
We bought a used 2015 BMW i3 Rex, the charging cord is came with say 12A on it, but we also bought for very cheep a brand new BMW dual charger it say 120V / 240V and 12A / 16A on it. So far we only charge at home and have not used the BMW dual charger, Im guessing that if we did use the BMW dual charger on a normal 110 outlet we would not see any faster charging times ?

No, almost for certain that EVSE you have gives you 12A at 120, and 16A at 240. Unless you see a selector switch on it,. But for sure it's 12A if it is outfitted with a standard NEMA 5-15 plug (standard household wall plug).

The EVSE can't detect what amperage is available on the circuit. If a 16A EVSE is plugged in to a 15A receptacle, here's how it goes down:
- The EVSE communicates to the vehicle that 16A are available
- The car's internal charger then begins pulling current at 16A (the EVSE acts as a pass-thru)
- The circuit you're connected to provides 16A until the circuit breaker trips, or the receptacle melts, or the wires in your house overheat, catch fire, and burn down the house
 
Disclaimer: I know absolutely nothing about things electrical. Nothing. Nada.

However, I am baffled by this whole external EVSE thing. Why is this function not built into the car? I doubt that it is a cost issue. Space? Portable EVSE's aren't that big, so I doubt it's a space issue. Why not build dual voltage EVSE function directly into the car?
 
Because the EVSE functions as an agent of the host .

So even though we carry the portable EVSE around in our frunk, it's set for the lowest common denominator -- a 120V, 15A circuit (here in North America -- Europeans on 220V get different EVSEs ).

When you pull up to an EVGo or Blink, same -- the EVSE communicates to the vehicle's charger exactly what is available at that point of connection.

The car's charger, on the other hand, can adapt to different voltages and currents, and will tailor its intake to only what is available.

Your question may poke at the reason BMW calls theirs an "occasional use charger," they could build it in, but then it would be different for each region, and you would need a separate household-style cord to plug in, with a plug that also varies by region, because the J1772 connector needs an EVSE as a go-between to connect to a power source. They recognize it's one less step to have a box on the wall in the garage than to have this extra piece of equipment to deal with.
 
Still doesn't make sense to me. If an external box (the EVSE) can communicate the appropriate information to the car's charger, a box built into the car could do the same thing. It doesn't seem that there's any reason that it has to be an external box. Then all we'd need is a cord with the J-1772 on one end and a plug for the wall outlet on the other end.
 
Ah, gotcha.

If the EVSE was built in to the car, how would it know what type of supply it was connected to? I suppose the car could detect voltage, but it can't detect available amperage. So if everybody was ok with charging at 12A, the external EVSE maybe could be eliminated.

The EVSE also provides some line monitoring to protect the car against damage, but that could be internalized, too.

Also, the EVSE cuts power before the connector is pulled out of the car, preventing arcing and premature wear and damage to the charging port (or harming the user).

I believe what it comes down to is safety and ease of use. If we were all left to manually select a charge rate based on a sign posted by the outlet, there'd be room for error. Similarly, some commercial charging locations actively change the amount of current available based on the number of vehicles plugged in at the neighboring stations.

This seems sensible since most users just have the EVSE mounted to the garage wall, and forget about it.
 
eNate said:
Ah, gotcha.

If the EVSE was built in to the car, how would it know what type of supply it was connected to?
[snip]

Again, I know absolutely nothing about things electrical, but I would assume that an EVSE that is built into the car would figure this out in the same way that an EVSE that sits outside the car does?

CURRENTLY: The EVSE is an external box with 2 cords. A short cord plugs into a wall outlet (110 or 220) and a long plug with a J-1772 connector plugs into the car. The EVSE figures out the amps/volts/whatever that is available and communicates that to the charger.

IN-CAR EVSE: A long cord plugs into a wall outlet (110 or 220) on one end and into the car on the other end. The EVSE is built into the car and sits between the car's electrical connector and the charger. In the same manner as with the external EVSE scenario, the EVSE figures out the amps/volts/whatever that is available and communicates that to the charger. Of course the EVSE could be built into the charger rather than being a separate box, but it makes the illustration simpler.

Again, I'm not seeing why there is a need for the EVSE to be an external box?
 
The EVSE can't determine the amps available.

An EVSE is built for a specific amperage draw, and must be wired per electrical code to support that current. I could buy a 30A EVSE and wire it on to a 15A circuit, and it would never "know." It can't tell the difference between a 15A circuit and a 50A circuit. The car would be told by the EVSE that 30A are available, the car would pull 30A, and the 15A breaker would immediately trip.

This is the same with any other electrical appliance. They draw what they draw. Most household appliances are deigned to work within the limits of 15A. All consumer space heaters max out at the same wattage because of the 12A continuous draw limit on a 15A circuit. Electrical water heaters are sold in a variety of amperages and will specify what gauge wire and what capacity breaker are necessary for compliant installation. 20A industrial tools will come with the funny sideways plug so they can only be plugged into 20A receptacles.

This is why all EVSEs include the disclaimer "must be installed by a licensed electrician." Once wired up correctly, the EVSE eliminates most possibilities for error. Clipper Creek won't even sell their 16A EVSE with a plug ("hardwire only"), probably to reduce their liability for someone plugging it in to an underrated circuit.
 
I'm talking about plug-in EVSE's like my TurboCord. Other vendors, including Clipper Creek, make and sell plug-in EVSE's. The EVSE sits inline, between the wall outlet and the charger. I'm just not understanding why it has to sit external to the vehicle, rather than internal to the vehicle. It would provide exactly the same function and work in exactly the same way. How does the location (external to the vehicle or integral with the vehicle) change anything?

You seem way more intelligent regarding chargers, EVSE's, and things electrical in general, so I have to assume that my electrical incompetence is preventing me from grasping some basic facts here.
 
I think I'm understanding your point.

To do it the way you suggest -- internal, dual-voltage, auto-detecting -- is of course possible. I think Chevy or Toyota did this, where you could just plug in an extension cord.

But there remains the need to identify the available current. If we're talking a miserly 12A, that would be it -- the owner would be stuck at that slow rate of charge, even if 30A were available.

Of course, you could get around this by including a selector switch or a settings menu where the owner could select the amperage rating of the circuit being used. But this does introduce the likelihood of user error, tripped breakers, damaged receptacles, and fires.

The other route would be to have the internal 12A EVSE, but allow it to be bypassed for an external EVSE for charging points with higher outputs.

And the manufacturer would at the very least have to provide the correct adapter for the electrical connection to work with whatever standard is in place where the car is being sold.

None of that is impossible. But my guess is the manufacturers expect that the majority of their buyers aren't going to tolerate charging at 12A, and find it more economical / practical / simple to include the "OUC" EVSE as a port add-on accessory that gets popped in the frunk and never sees the light of day.
 
The external EVSE is a semi-smart power switch. All of the real smarts and the ACV to DCV conversion is done in the car. The EVSE announces to the vehicle how much current it has. It does not say how much voltage. The car, as long as you don't provide power outside of what it can handle, doesn't really care. The EVSE sends a signal that says - I can provide up to X amps. The car then dutifully never tries to draw more current than the source says it has. Amps*Volts=POWER. So, the higher the voltage OR amps will provide more power.

You can think of the car as a big power user that can adjust so that it doesn't pull more power than what is actually available. The EVSE tells it, and does some interlock safety stuff, but basically is just a smart power switch.

It's possible for an EVSE to sense the power available and potentially say it has more amps, but it would require an adapter based on the plug attached to it. In the USA, a plug with the standard 15A configuration will fit into a 15 or 20A receptacle, and it has no easy way to tell whether it's plugged into a 15A or 20A one. If it has the 20A plug, it assumes things were wired properly, and it's in a 20A receptacle. Doing this manually with a switch is dangerous, as you could have it set for a 20A circuit, and plug it into a 15A one (assuming it had the 15A plug), and you'd overload the source. So, there's no way for the EVSE to really know what it's plugged into.

Those that are 120/240 v compatible (that requires an internal multivoltage power supply), so that it can generate and process the right interlock signals, not to handle more current. There's more power on a 240vac device at the same amperage...remember, power=volts*amps, so if you double the voltage, you'll get double the power, but the amps stays the same. The only way the car will try to draw more amps, is if the EVSE announces it has more.

Some EVSEs can be internally adjusted to announce they have more, but you must be fastidious to ensure the wiring can handle how you're setting it.
 
You guys are getting way beyond my pay grade. It's all interesting, but I don't see how it is actually relevant to my point which is simply that whatever a plug-in external EVSE does, it should be able to do if it was built into the car rather than sitting outside of the car. I can see no reason that the physical location of the EVSE should change how it operates.
 
Fisher99 said:
It's all interesting, but I don't see how it is actually relevant to my point which is simply that whatever a plug-in external EVSE does, it should be able to do if it was built into the car rather than sitting outside of the car. I can see no reason that the physical location of the EVSE should change how it operates.
The design of an EVSE that protects its user from electrocution would not apply if the EVSE were internal to an EV. If an EVSE were internal, the user would have to plug one end of a power cable into the EV and the other end into an electrical outlet. If plugged into an electrical outlet first, the cable would be hot when plugging it into the EV. In rainy weather, deadly electrocution by up to 240 V could occur. Smarts in an EVSE prevents this from occurring because the end that plugs into the EV can't be hot until the handshake between the EVSE and EV completes which can't occur until the plug has been plugged into the charging port.

Even plugging into the EV first could result in potentially dangerous electrical arcing when the other end of the cable is plugged into the outlet.

Also, repeated plugging/unplugging of 120 V or 240 V outlets can lead to worn or loose contacts in the outlet resulting in higher electrical resistance and potentially dangerous heat generation.

An EVSE is external to an EV for several very good reasons.
 
alohart said:
Fisher99 said:
It's all interesting, but I don't see how it is actually relevant to my point which is simply that whatever a plug-in external EVSE does, it should be able to do if it was built into the car rather than sitting outside of the car. I can see no reason that the physical location of the EVSE should change how it operates.
The design of an EVSE that protects its user from electrocution would not apply if the EVSE were internal to an EV. If an EVSE were internal, the user would have to plug one end of a power cable into the EV and the other end into an electrical outlet. If plugged into an electrical outlet first, the cable would be hot when plugging it into the EV. In rainy weather, deadly electrocution by up to 240 V could occur. Smarts in an EVSE prevents this from occurring because the end that plugs into the EV can't be hot until the handshake between the EVSE and EV completes which can't occur until the plug has been plugged into the charging port.

Even plugging into the EV first could result in potentially dangerous electrical arcing when the other end of the cable is plugged into the outlet.

Also, repeated plugging/unplugging of 120 V or 240 V outlets can lead to worn or loose contacts in the outlet resulting in higher electrical resistance and potentially dangerous heat generation.

An EVSE is external to an EV for several very good reasons.

Ok! That actually makes sense! Three cheers for external EVSE's! :D
 
Oops, downside to the 16A EVSE.

On Friday I got lazy at home and plugged in to my (nearer) 15A receptacle -- I didn't need the boosted current because I was going to hit 100% at work later that afternoon -- so I set the i3's charge rate to "Reduced" so as not to blow my 15A breaker.

Well I forgot to reset my charge rate to "Maximum" and have been charging at essentially 12A for the past three days. I left work Friday at 100%, as planned, but shorted myself about 10% on Saturday and Sunday's charging sessions.

So today I left home with 35%. I had to drive my father in law 20 miles one direction before doubling back to go in to work, and I was right on the cusp of having enough SOC. So the two of us detoured to an EVGo and I dropped an extra 10% into the battery. While sitting there chatting, I noticed my error -- that the 120v charge rate remained set as "Reduced."

I rolled into my work parking lot with 12% in the battery. I think I would have been at 3 or 4% if I hadn't stopped to charge, which is cutting it a little too close. But I have new confidence in the i3's guess-o-meter as that's roughly what I would have expected based on what it indicated when I began this drive.

This was my first EVGo visit in awhile, confirming that the 16A EVSE is continuing to have a dramatic benefit vs. the stock 12A unit.
 
Ha, I'll routinely get home with <5%... as I generally drive as fast as I can while leaving a ~5 mile buffer to home, in case something goes unexpected.
 
The EVSE is only an interface and safety interlock to the 120/240VAC to DC battery charger in the EV.
The EVSE only limits current to what it is set to or limited to, once it confirms that it is plugged into the EV, power can be turned on and the EV can start a charging session.

The EV can handle up to its maximum AC-DC battery charger's rating, which in newer EVs is 7.6kW, 32A at 240V.
It is not practical to deliver 7.6kW at 120V due to the higher current required and much heavier wiring.
An EV will quite happily draw 16A at 120V from a 15A circuit until the circuit trips.
That is why a 120V 16A EVSE needs a 20A circuit.
Some EVs can be set for charging rate and some 16A EVSEs have a charging rate selector so they can work with 15A and 20A circuits.

That is why there is an EVSE for L1 and L2 charging.
 
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