bradleydavidgood777
Posts: 169
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Re: Why is 240V 3x faster than 120V

Tue Jul 31, 2018 4:48 pm

Don wrote:It doesn't - You can't 'measure' how fast the car charges by attempting to judge how 'many bars per hour' you *think* you're getting

Volts X amps = Watts. 120 volts @ 12 amps is exactly half of what 240 volts @ 12 amps is. The charger can draw a maximum of 3.3 Kw, which divided by 240 equals 13.75 amps max - No way that's 3X 120 @ 12 amps

Don


And by the way all of your scientific calculations above did not prove anything. I get 3x faster charging on 240V than 120V. Proven by observation. I really don't like science or scientists cocky attitudes. They always seem to think they are smarter than everyone else and poke fun. And don't like to admit they are wrong when proven wrong by observation. They say "but the numbers prove it!" Even when you observe something else in reality.

Science = trial and ERROR. Lots of times error.
2017 I-Miev

Don
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Re: Why is 240V 3x faster than 120V

Tue Jul 31, 2018 5:14 pm

I'll admit it - I'm super happy for you (and super envious too!) that your car can charge at 4.3Kw (3X the 1.44 Kw the stock EVSE does) Sure wish mine could do that. Empirical evidence is unbeatable . . . . when it's accurately documented

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

bradleydavidgood777
Posts: 169
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Re: Why is 240V 3x faster than 120V

Tue Jul 31, 2018 5:23 pm

Don wrote:I'll admit it - I'm super happy for you (and super envious too!) that your car can charge at 4.3Kw (3X the 1.44 Kw the stock EVSE does) Sure wish mine could do that. Empirical evidence is unbeatable . . . . when it's accurately documented

Don


Again with the numbers!

I didn't state any of that!

Just that I get 3.2 bars and hour gain on my meter...every time. Then I drive and use those bars to get places. It's much easier and simpler than your numbers and calculations.
2017 I-Miev

JoeS
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Re: Why is 240V 3x faster than 120V

Tue Jul 31, 2018 6:55 pm

bradleydavidgood777, WHOA! There is no place on this forum for such statements, especially those that attack the scientific method, and I ask for you to please tone down your rhetoric. This is not some subjective opinion we are dealing with, but very simple measurable voltages and currents, yielding power, and power times time yielding energy. Also, there is nothing "amazing" about the Amazing-E except its brand name.

The title of this thread is expressed in numbers and refers to 120vac vs. 240vac charging of the i-MiEV, but the thread has also wandered into a discussion of 240vac charging at two different charging locations.

Let me try to put things into perspective -

On the issue of 240vac being 3x faster to charge than 120vac, in addition to Don's patiently trying to educate you showing you how to calculate the power going into the car, PV1's explanation further elaborated and took into account losses in the charging system and this was close enough - you read and accepted it (so why bring it up again?). The definitive answer would be to use CaniOn with a time-lapse camera trained on both the i-MiEV fuel gauge and the CaniOn display showing voltages (both input and battery) and currents (input ac and dc going into the battery) and the State of Charge percentage, and, of course, time. This would pin down the exact factor instead of the coarse 3X. Nice grammar-school science project for someone's child.

Now, bradleydavidgood777, you subsequently brought up the new issue of your being able to charge faster at home (3.2-3.3 bars/hour) than on the Blink charger at work (~3 bars/hour), repeatedly.

First off, since you're throwing out the decimal number of the bar, how in the world do you measure it? I presume you set a timer for exactly three hours and see that at work the gauge goes up by 9 bars and at home it goes up by 10 bars.

Now, to answer this discrepancy, I speculated that perhaps the Blink is running off 208vac (what you get when you tap into a common three-phase system). I know you can't stand numbers, but bear with me: the ratio of 240/208 = 1.15 which means, if the current is constant, that the i-MiEV charges about 15% faster on your home's 240vac than on your work's 208vac. Put another way and relating to our fuel gauge, a 15% increase of three bars actually yields 3.45 bars, so perhaps there are other variables we should look for. Once again, the only definitive way is to make measurements of the exact voltages and currents, with CaniOn being the easiest way to do that.

If you still want to prove your point or resolve the conflict, for starters, you might measure your "240vac" at home and see if the Blink (at work) display or nametag tells you its input voltage.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

JoeS
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Re: Why is 240V 3x faster than 120V

Tue Jul 31, 2018 6:57 pm

rnlcarlov wrote:That's why I measure charging speeds using Canion and SOC. Some bars represent more SOC than others, so they're not that reliable. At 240V 14Amps, I charge 20% SOC per hour, except when I reach above 90%.
Of course, using CaniOn is a much more accurate means of determining battery State of Charge than the resolution of our fuel gauge's sixteen bars. I thought we had a table showing bars vs. SoC, with a SoC range for each of the sixteen bars, but I can't find it. Anyone care to create this and post it?

rnlcarlov, that 20% number is a good rule of thumb that I don't recall seeing before. The top (sixteenth) bar has variations for a number of reasons, and, when charging, let's not forget the additional (unspecified) time the car might take to balance the cells once in the 16th bar.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

Aerowhatt
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Re: Why is 240V 3x faster than 120V

Wed Aug 01, 2018 7:51 pm

rnlcarlov wrote:That's why I measure charging speeds using Canion and SOC. Some bars represent more SOC than others, so they're not that reliable. At 240V 14Amps, I charge 20% SOC per hour, except when I reach above 90%.


Yes, that's what I have used for the last two years. It's an accurate and nice round number. I judge when I will be topped up and ready to go by the 20% per hour calculation (easy to do in one's head). I just add 35 minutes for the last 10% because it tapers.

Aerowhatt
2014 cool silver ES, acquired new 4/2015 (42.7ah at ~26K miles)
2014 Labrador Black Pearl ES, acquired new 3/2016 (41.5ah at ~15k miles)

rnlcarlov
Posts: 80
Joined: Wed Apr 13, 2016 8:30 am

Re: Why is 240V 3x faster than 120V

Thu Aug 02, 2018 7:59 am

Just to add some more numbers, with Canion I see a maximum of 2.5kW going into the battery (7 Amps at 360V), and since it's already measured as DC, it's the value after losses in the internal charger and so on. This is at 13.5-14 Amp charging in a 240V outlet.
Since we do not have 120V outlets in Portugal, I can't really compare speeds.

The closest I ever got was in a rural lodging, when I charged with a long extension. AC voltage dropped to 188V, and I was charging at 1.8kW

Image

bradleydavidgood777
Posts: 169
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Location: Media, PA

Re: Why is 240V 3x faster than 120V

Thu Aug 02, 2018 9:35 am

My point about the numbers and scientific method is that they are useless if you are trying to use them to prove something that does not match what you are actually observing with simple repeated observation. Especially when you also write in a way that sounds condescending.

You asked how I calculated it. Very simply. Charged 20 times took note of times and bars and used a calculator. Every time was exactly 3.0 at work and 3.2 at home.

The blink charger is at:
815 Arch Street
Philadelphia, PA 19106

I don't see online any indication of voltage for that station. I will check the equipment on Monday.

At home my wire measures 245V with a volt meter.

I don't have anything to prove. I'm just trying to understand my simple observation. And got annoyed by someone trying to prove me wrong with numbers and sounding condescending.
2017 I-Miev

Phximiev
Posts: 1182
Joined: Thu Jan 15, 2015 7:25 pm
Location: Phoenix

Re: Why is 240V 3x faster than 120V

Thu Aug 02, 2018 10:38 am

bradleydavidgood777 wrote:My point about the numbers and scientific method is that they are useless if you are trying to use them to prove something that does not match what you are actually observing with simple repeated observation. Especially when you also write in a way that sounds condescending.

You asked how I calculated it. Very simply. Charged 20 times took note of times and bars and used a calculator. Every time was exactly 3.0 at work and 3.2 at home.

The blink charger is at:
815 Arch Street
Philadelphia, PA 19106

I don't see online any indication of voltage for that station. I will check the equipment on Monday.

At home my wire measures 245V with a volt meter.

I don't have anything to prove. I'm just trying to understand my simple observation. And got annoyed by someone trying to prove me wrong with numbers and sounding condescending.


Trying calling the Weights and Measures people and see if they, or the county, will do an inspection: https://www.agriculture.pa.gov/consumer ... fault.aspx
2012 iMIEV ES
2014 Chevy Volt

JoeS
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Location: Los Altos Hills, California

Re: Why is 240V 3x faster than 120V

Thu Aug 02, 2018 2:37 pm

Phximiev wrote:Trying calling the Weights and Measures people and see if they, or the county, will do an inspection...
Phximiev, you're kidding, right? (you forgot the smiley face), as I don't think there is any issue here at all. Blink charges 39¢/kWh (if you're a member) at this station, no matter what the voltage. Since the car's input is current limited, it's simply that the i-MiEV charges slower there than when using his (quite high) voltage at home.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

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