Leaf Charging Efficiency - Lab Test (and Idle power draw)

Does anyone know what the ac compressor actually draws power wise? I thought I read 1.5kw. Also what voltage does it run on? I would assume 300+ volts or is there some other off converter in there just for the compressor?

It can draw up to roughly 2kW from my experience, and down to almost nothing. This depends on the temperature delta (head pressure).

It runs directly off the pack voltage which varies but is usually around 300-400v.

-Phil

BrockWI said:

Does anyone know what the ac compressor actually draws power wise? I thought I read 1.5kw. Also what voltage does it run on? I would assume 300+ volts or is there some other off converter in there just for the compressor?

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Dear Phil

I'm working on a project of Analysis of Nissan Leaf performance in high altitude levels (in Ecuador), I'm working in this Analysis with my University ESPE in Quito, Ecuador. I have been searching power curves analysis graph or data of power analysis for this investigation if you have any idea where I can find this information this would be really help full. Thank you really much.

Sincerely

Michel Ochoa

Is there an efficiency difference between new and old battery packs?
In other words, for a given number of miles driven, does an older leaf end up using more electricity?

brycenesbitt said:

Is there an efficiency difference between new and old battery packs?
In other words, for a given number of miles driven, does an older leaf end up using more electricity?

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Yes, the resistance in the back increases as it ages. I don't think I've seen anyone test or estimate what kind of actual impact on efficiency that has though. This also means that more heat is added to the battery as it charges and discharges but again not sure if that impact is great enough to be significant.

QueenBee said:

brycenesbitt said:

Is there an efficiency difference between new and old battery packs?
In other words, for a given number of miles driven, does an older leaf end up using more electricity?

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Yes, the resistance in the back increases as it ages. I don't think I've seen anyone test or estimate what kind of actual impact on efficiency that has though. This also means that more heat is added to the battery as it charges and discharges but again not sure if that impact is great enough to be significant.

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Theoretically, there is a difference because the internal resistance increases as the traction battery pack ages. Since internal resistance is still small compared to other losses, I did not notice a difference in power from the wall (per mile driven) after the new battery was installed in the 2011 compared to the old battery with 8 capacity bars. The 2015 is slightly more efficient in power from the wall because charging at 6 kW reduces the charging time which reduces the overhead losses from cooling pumps and active system modules. Charging efficiency of the 2015 at 120 volts or at lower rates on 240 volts seems to be about the same as the 2011.

Edited to add: Since regeneration is greatly reduced with a deteriorated battery, the efficiency would be worse for stop and go driving with a deteriorated battery compared to a new battery. My commute is mostly freeway (carpool lane) driving so I saw very little difference in efficiency between the original battery at 8 bars and the replacement battery in the 2011.

Gerry

I am finding the 90% Plus efficiency figure of interest. I am assuming that there is an AC outlet feeding the charger in the Leaf, and it has a full wave rectifier. Such a rectifier configuration has an efficiency, ignoring the diodes as far as I recall, about 81%. The 78% efficiencies make some sense. But am at a loss to see how you can get 90%, if you have a full wave rectifier. If you supply DC in, then yes you'd easily get 90%.

http://analyseameter.com/2016/04/full-wave-rectifier-efficiency-equation-applications.html

My own analysis is slightly lower, but I am not fighting over a small percentage loss.

If you put a large cap on the output, you will get close to the max DC, but at the expense of very narrow current spikes, which some RMS meters will struggle to measure accurately.

Phil, any thoughts,before I pull my hair out on this one.

Switching power supplies have pretty much replaced full wave rectifiers.
Switching efficiency can be in the high 90%.
Doing a google search, I see there are many articles on this.
Particularly where voltage multiplication is used, a full wave may not precede
the switch.
The service manual only gives a block diagram of the charger, so hard to tell
what they do.

Yesterday arrived home with almost dead battery. Thought that I will run it down to turtle for calibration.
Ran down to turtle (0.5kWh left). Charged it to 100% (my 100% is 21,9kWh, 95% battery SOH left).
EVSE power meter showed 23.1kWh of consumption.

I should mention temperature was a bit below freezing. Water pump is not running at this temperature on 2014 Leaf.
Also there was a defrost cycle during that charge cycle, consumes 0,6kW for 5-12 minutes, therefore subtract up to 0,1kWh.
It appears to get 21.4kWh of battery charge it used 23.0kWh. Holy cow :shock: That is around 93% +/- 2% efficiency :shock:

Charging at 230V/16A.

LeafSpy stats:
https://goo.gl/photos/TKf1UNRDCvhbRpps8

So I am looking to use a 300w panel to charge my car. I am only expecting it to charge a few miles a day, but I am trying to figure out how best to do this. First I thought I could use a battery and an inverter to charge at 200 watts or so, but it sounds like that would not even cover the charging overhead? Maybe I can charge the battery and use a bigger inverter to charge closer to 1200 watts? Thoughts? Thanks for all the number crunching and sharing! It's been a big help!

Your best bet is to charge a 12v battery bank and then when that is full via solar, or close to it, start an inverter large enough to run the stock EVSE that came with the car. You could go with an open EVSE and set it down to 6 amps, but as you noted the overhead with pumps and such you wont get far. Even with our solar, 3000 watts, I sometimes set our EVSE to 240vac at 6 amps, which is the same wattage as 12 amps at 120v but with less loss and our inverter is 240vac as well.

300 watts of solar even at 5 hours of good sun a day is only 1500w, maybe enough to charge the car with the stock EVSE for 1 hour, which might get you 5 miles a day.

5 miles a day would be great if I could get it! Next I have to find a battery that does not weight to much. I was looking at a 1000 watt hour lead acid but it weighed about 70lbs.

With lead acid, the weight is proportional to the life and ah's it can store. Also if you going to pull 1500w for one hour you need at least 300 ah at 12v or three of the larger marine 12v batteries. Even with one of them, 100 amps at 12v you won't get more than 20 minutes out of it before the inverter drops off in low voltage.

BrockWI said:

I sometimes set our EVSE to 240vac at 6 amps

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The car errors out when I set my EVSE that low. My Leaf seems to require about 8A @240V minimum, or doesn't charge.

Mine does, I do it all the time, I just went and checked it again and it is set to 6 amps @ 240 volt.

BrockWI said:

Mine does, I do it all the time, I just went and checked it again and it is set to 6 amps @ 240 volt.

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Mine will also go down to 6a, I only did it once for a test but it was 6a, any lower and it wouldn't charge.

coolate said:

So I am looking to use a 300w panel to charge my car. I am only expecting it to charge a few miles a day, but I am trying to figure out how best to do this. First I thought I could use a battery and an inverter to charge at 200 watts or so, but it sounds like that would not even cover the charging overhead? Maybe I can charge the battery and use a bigger inverter to charge closer to 1200 watts? Thoughts? Thanks for all the number crunching and sharing! It's been a big help!

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Please don't. You can walk few miles a day. If you really want to be green.
You will have a system that costs at least 1000$ and it will give you less than 10 cents per day!
You need 10 000 days, or 27 years to somehow make it reasonable. Just buy grid electricity.
In some places you can opt to buy ONLY green power.

If you really want to do any reasonable amount of Leaf charging with solar (offline)
you need at least 20x250W panels with buffering pack (at least one Powerwall). This would give you
at least half of the battery on a good day. Without battery you have to keep your car home during mid-day.

It will not help if you go from one 300W panel to two, four, or even 10. It just doesn't work efficiently.
You could run your PC and speakers on 300W panel though. But with at least two big car batteries as a buffer.

Heh, walking 5 miles a day would be ideal, but weather and time don't allow. Also I get a real solar system would be better, but it's also not possible at the moment. Someday I hope where I live will be better for it. Cost wize I am looking to stay below $500. I have most the parts and found some good prices. The only time I see the sun is when the car is parked in a lot while I am at work, so I would love to get some range while it sits. Plus it is for experimental/fun. I could upgrade the stereo system for about the same money, but this would be more fun.
5 miles a day adds up to 1,300 miles weekdays and 1,800 with weekends a year. So it is an amount worth thinking about for me for fun! Granted 5 miles is a best case

You will never get 5 miles with 300W panel.
At max you could get 1kWh per day, in summer, sunny weather.
This translates to theoretical 1/22 of the total range of 24kWh Leaf.
Actually, due to losses, it will be very expensive to get over 1/30 of range.
Aka less than 2.5 miles per good day.
You will not be able to get that without battery pack+charging controller.
Because the slowest way to charge Leaf in US is around 1300W input (120V AC)
and 300W goes to waste. You charge your battery during the whole day and you
get an hour of charging in the evening, no more.
Also you might have problems with ground with cheap offline system, be prepared.
If you start fiddling around with "shortcuts" you might blow your Leaf's charger.

You will not be able to do that on 500$ by the way. You need to stay online with grid.
And that means a lot of other things. Also costing money.

Anyway, if you like to experiment on things that will definitely not be profitable, why not.
But it would be more reasonable to just buy electricity from grid and buy more efficient
tire set for the Leaf. Will have more "free range".

Again I have a different experience. I am not sure about Eroupe, but here in Wisconsin, I average about 3 sun hours a day in winter and 8+ in summer. Granted if it snows or is totally overcast your out of luck, maybe getting 1 sun hour a day on a overcast day. For example last week was our worst this winter only producing 17.7 kwh over the week with 3000w of solar. That turns in to just over 2 kwh a day. So divide that by 10 and that's roughly a 300w system.

I suggest if you have the panels go for it, I always encourage people to go that route if they are inclined.

I didn't get our PV setup for financial gain, the grid is less expensive, I got ours instead of a noisy loud genset that would only keep costing me $ down the road. At least the PV systems is slowly generating me $ instead of slowly costing me more $. And it is seamless, if the power goes out I don't notices and everything in our house keeps working with no noise.

Of course this doesn't take in to account the knowledge you learn by stepping in to this.