Ingineer
Well-known member
Generally no more than 16.5a.rawhog said:So, I charge at 208v at work, and 240v at home. I just sent my rev1 EVSE in to get the rev2 upgrade. What current will I be looking at now?
-Phil
Generally no more than 16.5a.rawhog said:So, I charge at 208v at work, and 240v at home. I just sent my rev1 EVSE in to get the rev2 upgrade. What current will I be looking at now?
Ingineer said:The accessory power meter is a "fake" meter. It simply adds on some pre-coded amount of power when it detects you have turned somehing on (via the CAN bus). So it will not show the actual power draw, nor will it show many accessories, such as anything drawing power from the 12v outlet. Do not depend on it for making any calculations.
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Ingineer said:The accessory power meter is a "fake" meter. It simply adds on some pre-coded amount of power when it detects you have turned somehing on (via the CAN bus). So it will not show the actual power draw, nor will it show many accessories, such as anything drawing power from the 12v outlet.
Ingineer said:Here are my charging measurements on the Leaf:
Charging using the original 120v EVSE: (112.5v recorded at EVSE input)
Standby Power: 4.9w
Charge Power in: 1.451kW
Power to Leaf Battery: 1.125kW
Total Power Lost: 326w
Total Charge Efficiency: 77.5%
These measurements are all using our Rev2 Upgraded EVSE:
120v: (112.6v recorded at EVSE input)
Standby Power: 1.7w
Charge Power in: 1.436kW
Power to Leaf Battery: 1.125kW
Total Power Lost: 311w
Total Charge Efficiency: 78.3%
240v: (239.8v recorded at EVSE input)
Standby Power: 3.4w
Charge Power in: 3.756kW
Power to Leaf Battery: 3.414kW
Total Power Lost: 342w
Total Charge Efficiency: 90.9%
All these measurements were with the Leaf pack at around 62 degrees F and ~65% SoC. Readings were allowed to stabilize before recording. The power to the Leaf battery was calculated by recording amperage at the cell interconnect level using a high-accuracy kelvin-connected current shunt, so the losses are a sum of all EVSE/Charger/Leaf systems. Charger input power was similarly recorded using lab-grade calibrated true RMS equipment, not a Kill-A-Watt.
These efficiency calculations do not take into account the coulombic loss in the Leaf's battery, and other Leaf systems during discharge, so this is only charging efficiency up to the battery pack itself but not including the pack, of which also has notable loss.
While I'm at it, someone asked me recently what the idle draw of the Leaf is. It bounces around a lot, but it's as low as 140w, typically around 160w with all accessories, lights, and CC off, and 230 watts for headlights and 360w with High-Beams on. (My Leaf will be slightly lower, as I've changed most of the incandescent bulbs to LED.) Again, these power measurements were derived by recording amperage at the cell interconnect level using a high-accuracy kelvin-connected current shunt.
If anyone wants to know any highly accurate information about the Leaf's systems, I might have already recorded it, feel free to ask!
-Phil
KillaWhat said:I Just LOVE this forum!!
Ingineer said:Here are my charging measurements on the Leaf:
Charging using the original 120v EVSE: (112.5v recorded at EVSE input)
Standby Power: 4.9w
Charge Power in: 1.451kW
Power to Leaf Battery: 1.125kW
Total Power Lost: 326w
Total Charge Efficiency: 77.5%
These measurements are all using our Rev2 Upgraded EVSE:
120v: (112.6v recorded at EVSE input)
Standby Power: 1.7w
Charge Power in: 1.436kW
Power to Leaf Battery: 1.125kW
Total Power Lost: 311w
Total Charge Efficiency: 78.3%
240v: (239.8v recorded at EVSE input)
Standby Power: 3.4w
Charge Power in: 3.756kW
Power to Leaf Battery: 3.414kW
Total Power Lost: 342w
Total Charge Efficiency: 90.9%
All these measurements were with the Leaf pack at around 62 degrees F and ~65% SoC. Readings were allowed to stabilize before recording. The power to the Leaf battery was calculated by recording amperage at the cell interconnect level using a high-accuracy kelvin-connected current shunt, so the losses are a sum of all EVSE/Charger/Leaf systems. Charger input power was similarly recorded using lab-grade calibrated true RMS equipment, not a Kill-A-Watt.
These efficiency calculations do not take into account the coulombic loss in the Leaf's battery, and other Leaf systems during discharge, so this is only charging efficiency up to the battery pack itself but not including the pack, of which also has notable loss.
While I'm at it, someone asked me recently what the idle draw of the Leaf is. It bounces around a lot, but it's as low as 140w, typically around 160w with all accessories, lights, and CC off, and 230 watts for headlights and 360w with High-Beams on. (My Leaf will be slightly lower, as I've changed most of the incandescent bulbs to LED.) Again, these power measurements were derived by recording amperage at the cell interconnect level using a high-accuracy kelvin-connected current shunt.
If anyone wants to know any highly accurate information about the Leaf's systems, I might have already recorded it, feel free to ask!
-Phil
Ingineer said:The coolant pumps (there are 2) run all the time while charging, pump one runs at 39% duty-cycle and pump two runs at 44%. The speed does not change regardless of charging power, which is why there is significant fixed overhead while charging. Why this was chosen by Nissan is a mystery.
The Power factor varies but is almost always above .96 and usually .99 or better.
Yes, the Battery ECU decides what the charge power limit should be and the charger obeys. So if you have higher line voltage, you'll have less amps, but you won't ever increase power.
-Phil
NREL LEAF Teardown and Detailed TestingDaveinOlyWA said:Phil; any thoughts of internal losses after power is delivered in the battery; heat, etc? what percentage? even a ballpark figure would be appreciated
Of the energy pumped in to the battery, you get 97% out.Energy from the wall from dead to 100%: 25.414 kWh
Energy from the onboard charger to battery: 22.031 kWh
Energy from the battery during discharge: 21.381 kWh
drees said:NREL LEAF Teardown and Detailed TestingDaveinOlyWA said:Phil; any thoughts of internal losses after power is delivered in the battery; heat, etc? what percentage? even a ballpark figure would be appreciated
Of the energy pumped in to the battery, you get 97% out.Energy from the wall from dead to 100%: 25.414 kWh
Energy from the onboard charger to battery: 22.031 kWh
Energy from the battery during discharge: 21.381 kWh
I trust this result of 97% for overall average battery efficiency, but it is an average, because how you drive affects the battery discharge loss. As I have posted several times, the discharge loss as measured by the voltage sag under load is approximately 1% per 10 kW of delivered power. 20 kW is 2% or 400W, 30 kW is 3% or 900W, etc.drees said:NREL LEAF Teardown and Detailed TestingDaveinOlyWA said:Phil; any thoughts of internal losses after power is delivered in the battery; heat, etc? what percentage? even a ballpark figure would be appreciated
Of the energy pumped in to the battery, you get 97% out.Energy from the wall from dead to 100%: 25.414 kWh
Energy from the onboard charger to battery: 22.031 kWh
Energy from the battery during discharge: 21.381 kWh
Sounds like a vicious circle. You're not using the car to it's potential because of L1, therefore, you're less likely to buy another EV next time, therefore you're reluctant to spend money on L2, therefore you're not using the car...jpa2825 said:... Without knowing what my next car will be, I am finding it hard to invest $1k + wiring (or even less via EVSE Upgrade) when the 120v existing outlet in my garage is meeting my needs (but restricting my flexibility).
jpa2825 said:If you are trying to make an argument to spend the $ to get an L2 charger / 240v outlet with EVSE Upgrade, can you very roughly & broadly assume a pickup of 15% efficiency of wall to wheel (90% v. 75%)?
If so, do you then simply run your calculations to show how many less kW you pull to charge the LEAF * the $/kW your energy provider is charging you to determine how valuable this efficiency is to you?
dglaser said:I am so happy to know about these findings! Based on the information that Phil collected, is it correct to assume that the 6.6 kW Level 2 charging on the 2013 Leaf would be closer to 95% efficiency (i.e. 6.3/6.6=.95)?
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