eNate
Posts: 438
Joined: Mon Sep 09, 2019 5:33 pm

Level 1 Living at 16 Amps

Wed Jan 08, 2020 3:04 pm

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 (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.)

Image

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)
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 ** 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.

Image

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:
Image

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. 

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alohart
Posts: 2074
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Level 1 Living at 16 Amps

Wed Jan 08, 2020 9:06 pm

eNate wrote:
Wed Jan 08, 2020 3:04 pm
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 wrote:
Wed Jan 08, 2020 3:04 pm
Anyhow, maybe a month ago I purchased a Duosida D25 16A EVSE from Brad at BSA Electronics, and my experience has much improved.
eNate wrote:
Wed Jan 08, 2020 3:04 pm
 ** 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 wrote:
Wed Jan 08, 2020 3:04 pm
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.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

eNate
Posts: 438
Joined: Mon Sep 09, 2019 5:33 pm

Re: Level 1 Living at 16 Amps

Wed Jan 08, 2020 11:58 pm

alohart wrote:
Wed Jan 08, 2020 9:06 pm

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 wrote:
Wed Jan 08, 2020 9:06 pm

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 wrote:
Wed Jan 08, 2020 9:06 pm

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.
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KarlC
Posts: 44
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Location: San Diego Ca

Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 9:17 am

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.
2015 i3 Rex, Arravani Grey, Tera World, Technology, Driving & Parking Assistant, Harman Kardon Audio System, 19" wheels

eNate
Posts: 438
Joined: Mon Sep 09, 2019 5:33 pm

Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 11:02 am

KarlC wrote:
Thu Jan 09, 2020 9:17 am
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
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Fisher99
Posts: 283
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Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 11:45 am

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?

eNate
Posts: 438
Joined: Mon Sep 09, 2019 5:33 pm

Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 11:57 am

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.
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Fisher99
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Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 12:24 pm

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.

eNate
Posts: 438
Joined: Mon Sep 09, 2019 5:33 pm

Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 12:44 pm

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.
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Fisher99
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Re: Level 1 Living at 16 Amps

Thu Jan 09, 2020 1:27 pm

eNate wrote:
Thu Jan 09, 2020 12:44 pm
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?

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