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### Why is 240V 3x faster than 120V

When I would charge 120V with the stock EVSE on 12A amps I would get around one bar per hour.

On 240V with the Amazing E I get over 3 bars an hour. I've heard that the car pulls 13-14 amps. So how does that translate to over 3 times faster?

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

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
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PV1
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### Re: Why is 240V 3x faster than 120V

It boils down mostly to less overhead losses. The car's systems pulls around 600 watts when the high voltage circuit is active. This is near half the power input of a level 1 charge, the other half actually making it into the pack. During a level 2 charge, you still have the 600 watt overhead, but instead of 600-700 watts going to the pack, you now have over 2 kW going in.

Charge times at various power levels:
120 volt, 6 amps - practically forever (near zero measured power at the pack)
120 volt, 8 amps - 22 hours
120 volt, 12 amps - 14 hours
240 volt, 12 amps - 4.5 hours

The faster the pack finishes its charge, the less time the overhead consumption is active, the less energy required to charge the pack. Both of my cars have always charged around 3 bars/hour on level 2 and around 1 bar/hour on level 1.

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Thanks.

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

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
Don

Yes Don, I can measure it, and I have. I've plugged each one in and set the timer and come back and then saw that there were more bars than before and how many more there were. It was easy!

And it was consistantly over 3 bars an hour with the Amazing-E. I don't know how, it's just amazing!

Not sure why you think I can't do it.
Last edited by bradleydavidgood777 on Wed Jun 27, 2018 11:27 am, edited 1 time in total.
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Posts: 193
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Location: Media, PA

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

PV1 wrote:It boils down mostly to less overhead losses. The car's systems pulls around 600 watts when the high voltage circuit is active. This is near half the power input of a level 1 charge, the other half actually making it into the pack. During a level 2 charge, you still have the 600 watt overhead, but instead of 600-700 watts going to the pack, you now have over 2 kW going in.

Charge times at various power levels:
120 volt, 6 amps - practically forever (near zero measured power at the pack)
120 volt, 8 amps - 22 hours
120 volt, 12 amps - 14 hours
240 volt, 12 amps - 4.5 hours

The faster the pack finishes its charge, the less time the overhead consumption is active, the less energy required to charge the pack. Both of my cars have always charged around 3 bars/hour on level 2 and around 1 bar/hour on level 1.

That makes so much sense! Thank you PV1
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### Re: Why is 240V 3x faster than 120V

At work on the Blink charger I get right around 3 bars per hour. At home on the Amazing-E I get about 3.2-3.3 bars an hour.
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JoeS
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### Re: Why is 240V 3x faster than 120V

bradleydavidgood777 wrote:At work on the Blink charger I get right around 3 bars per hour. At home on the Amazing-E I get about 3.2-3.3 bars an hour.
That Blink station is probably running off three-phase and provides 208vac and not 240vac. That's why it charges slower than your home 240vac circuit. The Amazing-E has nothing to do with it as it simply passes through the house voltage and you are drawing under it's current limit.

My own rules of thumb:
For 120vac 8A I figure four bars for five hours of charging.
For 120vac 12A I figure six bars for five hours of charging.
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Don
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### Re: Why is 240V 3x faster than 120V

bradleydavidgood777 wrote:At work on the Blink charger I get right around 3 bars per hour. At home on the Amazing-E I get about 3.2-3.3 bars an hour.
Scientific measurements if ever I heard any!

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

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%.

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

Don wrote:
bradleydavidgood777 wrote:At work on the Blink charger I get right around 3 bars per hour. At home on the Amazing-E I get about 3.2-3.3 bars an hour.
Scientific measurements if ever I heard any!

Don

I don't get your deal Don. Why do you not think my measurements are accurate? Repeating the same charge every day and measuring the time and bars is accurate as can be. And always comes up the same measure every time and I've done it 20 times at all points of bars remaining and bars charged up. Always with the exact same results. 3 at work, 3.2 at home. What's your point?
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