Time studies of charging?

[fsc]

Does anyone know where I might find a chart plotting the relationship of initial SOC and time to recharge (to 80% or to 100%), for either a 120 V or 240 V circuit? I recognize that charge duration will be affected to some extent by battery condition, EVSE model, circuit characteristics, and weather conditions.

 

[DaveEV]

Check surfingslovak's post in the Better (reverse) SOC meter already in the car? thread.

 

[garygid]

The 6-hour L2 charging Log at http://www.wwwsite.com/puzzles/cando/" onclick="window.open(this.href);return false;
can be read with my CAN-Do program there, and used
to show plots of "SOC" (GIDs), Pack voltage and current, etc.

Those with a Logging SOC-Meter can log their own car (driving
or charging) and share their results with others.

 

[aqn]

Does anyone know where I might find a chart plotting the relationship of initial SOC and time to recharge (to 80% or to 100%), for either a 120 V or 240 V circuit? I recognize that charge duration will be affected to some extent by battery condition, EVSE model, circuit characteristics, and weather conditions.

Every time I plug in, I record, among other things, temperature (per LEAF's display), remaining GOM miles, remaining bars, time, charging voltage, etc. I then record the time of the CARWINGS "charging stopped" or "charging complete" email. I currently have data from 239 charge events. The average charging time is 18.7 minutes/kWh. If you want, I can probably give you the whole set of data in a spreadsheet to figure out differences due to SOC, temperature, etc.

 

[fsc]

If you want, I can probably give you the whole set of data in a spreadsheet to figure out differences due to SOC, temperature, etc.

Thanks Andy! I'd definitely be interested to see your data; is there a link where I can find it?

 

[weylan]

I am curious as well if some one has rough estimates?

I currently know that with the standard EVSE 120VAC, it is about 6-7 miles/hr of charge.

I don't have an L2 charger yet but am waiting on the EV project and will have a L2 Blink charger at home.
I was wondering if someone has the rough estimate of miles per charge for the L2 chargers?

 

[Herm]

I was wondering if someone has the rough estimate of miles per charge for the L2 chargers?

aqn says "average charging time is 18.7 minutes/kWh"

so divide your Leaf's average miles/kWh by 18.7 and you will get miles per minute of charging... about a mile every 5 minutes, or 12 miles of range per hour.

 

[Stoaty]

The formula I use (for SOC between 20 and 80%, not for charging above 80%) is:

3% increase in Gids per 10 minutes of charge on L2

If I start at 30% charge (per Gid-meter) and charge for 2 hours 20 minutes I should be at 72%. I find this formula to be accurate to + or - 2% over a large charge interval. For example, after 2 hours 20 minutes charge starting from 30% my Gid-meter reading will always be between 70 and 74%. I have been using this method to keep my SOC a bit lower for the summer, charging to 72-75% in the morning, ending up with 32-35% when I get home depending on whether I drive anywhere for lunch.

 

[smkettner]

16 amp L2 takes about 1/3 the time of L1.

 

[planet4ever]

I currently know that with the standard EVSE 120VAC, it is about 6-7 miles/hr of charge.

Not unless you are a hypermiler!

The physical reality is that 120v * 12A * 75% efficiency = 1.08kW. Which means that to within 10% accuracy you can look at miles/kWh as reported on your dash, and that is how far you can go on 1 hour of 120v charging.

So sure, if your dash shows something between 6.0 and 7.0 m/kWh, then you can go as far as weylan says. Most of the rest of us won't go nearly that far. My lifetime average is at 4.1 m/Kwh, and I think that is rather typical.

Ray

 

[weylan]

I agree, sometimes I hypermile, but I think I average about the same, 3.8m/kwh to 4.4m/kwh.
To work it is 3.8m/kwh and to home it can be 5m/kwh. And while I know that I am not a hyper miler all the time, I find that I am am going by what the range meter tells me how much charge I have.

So this is really useful.

aqn says "average charging time is 18.7 minutes/kWh"

so divide your Leaf's average miles/kWh by 18.7 and you will get miles per minute of charging... about a mile every 5 minutes, or 12 miles of range per hour.

16 amp L2 about 3x faster then the time of L1?

NEW DATA POINT:
I have a tendency now to use the L2 at IKEA in emeryville for about 30 minutes for lunch. So that seems to be about 2hrs of L1 charge. Is that seem to be right? If I use the formula above I get 35 /5 = 6 miles of charge. But I don't yet know if this seems right.

 

[planet4ever]

16 amp L2 about 3x faster then the time of L1?

Well, back when I was taking math, "3x faster than" meant "4x as fast as", but that was a very long time ago. Maybe they changed the rules.

But, to your real question, yes, L2 for the LEAF is (or at least can be) about three times as fast as L1. Of course 240v will pump energy twice as fast as 120v, at the same amperage, so there's 2:1. But the LEAF is limited to 12A at 120v, while able to pull 16A at 240v. That gives you another 1/3 faster, so you are up to 2/1 x 4/3 = 8/3. That's still not quite three times as fast, but the other hidden factor is that the LEAF has a cooling system that runs all the time while the battery is charging. Since it has to run a lot longer when charging at 120v, it ends up stealing more energy from the charging process.

Or, if you want the simple answer, I could point you at the Owners Manual which says that "Normal charge" (L2) takes approximately 7 hours from Low Battery Warning, while "Trickle charge" (L1) takes approximately 21 hours from the same point.

Ray