Imiev and Leaf charging

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acmotor
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Imiev and Leaf charging

Post by acmotor » Sat, 07 Jul 2012, 04:23

I've charged imiev and leaf from 'empty battery' point as indicated on instrument panel. (loan vehicles...)
Image

In both cases charge via the slow (trickle) charge cable supplied with EVs and its inline control box from a 15A mains socket.

Imiev draws 9.8A with pf 0.99 at ~235VAC ~2.24kW (on arlec power meter). Current ramps up gently over some 20 seconds.
Standby power after battery fully charged ~5W
Charge time was just over 6 hours to charger auto shut off at 100%. Arlec power meter indicated 14.1kWh from power point.
Imiev battery pack is quoted at 16kWh. Charger efficiency needs to be allowed for but is hopefully 95%+

Leaf draws 10.3A with pf 0.97 at ~235VAC ~2.35kW (for bulk of charge time). Current ramps up as with Imiev. Standby power after battery fully charged ~25W.
Charge time was ~ 11 hours to charger auto shut off at 100%.
Arlec power meter indicated 23.0kWh from power point.
Leaf battery pack is quoted at 24kWh. Charger efficiency needs to be allowed for but is hopefully 95%+

Both vehicles can then travel around 100km of real world driving with freeways, city and some 110k travel, As I tried this week (aircon and heating off). Not complaining with that.
If you can get the 160+km suggested by various tests then your are probably being a traffic hazard ! (I don't want to start a debate here)


Thoughts...

Now if I had a Leaf, a 'charging station' allowing full 15A charge would be advisable so that EV could be charged within the 10 hour off peak electricity window. (Leaf can be user programmed for charge start/stop times).
The vehicle manufacturers are probably justifiably conservative with charge currents e.g. they specify a 15A socket for the 10A trickle chargers as the current may exist for many hours and 'tired' wiring or connectors or non exclusive circuits may present a fire risk.

Whilst the imiev is a smaller vehicle, so is its power consumption, no different to ICEs.

So... A question. How does the trickle charging cable / charge station control the current draw of the EV charger ? What actual range of current is available ?
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coulomb
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Imiev and Leaf charging

Post by coulomb » Sat, 07 Jul 2012, 05:50

acmotor wrote: I've charged imiev and leaf from 'empty battery' point as indicated on instrument panel. (loan vehicles...)
Wow. Nice research.
So... A question. How does the trickle charging cable / charge station control the current draw of the EV charger ?
The other end of the charging "cable" (there is some electronics there) is a J1772 connector, right? My guess would be that it "tells" the charger that it's a charging station with 10 A capacity. My understanding is that the capacity of the charging facility is one of the parameters communicated (by the duty cycle of a control tone). Per the Wikipedia J1772 article, a 10% PWM indicates a 10 A supply. (It would be tempting to supply a 25% PWM indicating 16 A supply, but I understand why they would be reluctant to do that.) The circuitry for making your own J1772 adapter (apart from the connector itself) is quite easy, and most of what you need is in the Wikipedia article. So it looks like you could make a version of the "charger box" (mains plug to J1772 interface) that would get the charger to limit itself to 16 A (in the case of a 6.6 kW charger; the 3.3 kW charger probably draws less than 15 A already).
What actual range of current is available ?

The Wikipedia article seems to indicate 4 possible supply capacities (10 A, 16 A, 32 A, and "fast charge") for a J1772 setup. Maybe you can supply intermediate PWM ratios to get intermediate capabilities).

The Leaf comes with a 3.3 kW charger, though new vehicles (at least in the USA) are supposedly coming out with 6.6 kW chargers. There was a promise at one point that owners of Leafs (Leaves? :-) with 3.3 kW chargers could upgrade to 6.6 kW about now, but according to this article, that may not happen:

Green Car Reports: Want to Upgrade Your Leaf to 6.6 kW? It Might Not Happen.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

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Imiev and Leaf charging

Post by coulomb » Sat, 07 Jul 2012, 06:28

acmotor wrote: Now if I had a Leaf, a 'charging station' allowing full 15A charge would be advisable so that EV could be charged within the 10 hour off peak electricity window.

It's not clear to me, but I suspect that at least for now, if you don't agree to have a proper EVSE installed in your house, you may not qualify for the privilege of purchasing a Leaf.

I was one of the "all you need is a 15 A outlet" crowd, but recently I've come to see the value of a plug (like the J1772) that is designed for supplying decent charge currents on a continuous basis. It seems that ordinary 15 A outlets and plugs won't last long if used regularly at higher currents (around 10 A or more). (Of course, 10 A plugs and outlets have the same issues.) The blades discolour over time, the plug and leads get warm, the cable softens noticeably, that sort of thing. So that's why you get the 15 A cable with the leaf, "for emergency charging only", and they want you do do your regular charging with a commercial EVSE in your garage. I hope that one day they won't cost the current $2600 (? from poor memory) installed, more like $600 would be my guess.

We had two Leafs at a recent Brisbane AEVA meeting, where these issues were discussed.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

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Imiev and Leaf charging

Post by Simon » Sat, 07 Jul 2012, 06:42

When you say empty battery is this with just the "---" (for Leaf) showing on the range estimate or till turtle?
http://www.mynissanleaf.com/viewtopic.php?f=31&t=6876 Here is some data from 100% to turtle. From memory the Leaf has a useable capacity of 19kwh.


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Imiev and Leaf charging

Post by acmotor » Sat, 07 Jul 2012, 10:59

Both to power cutback turtle. Both recharge around 15 deg C ambient, in garage. About 4000km on imiev odo and 300km on leaf.
This was not meant as any form of definitive test, just some real world data.

Ah, good info on the J1772, thanks coulomb.

A feeling I get from the leaf manual is that you are being prepared for serious degradation of the battery pack capacity. Not only are you warned off fast charging or discharging, 100% charging, 100% discharging, operating hot etc., you are presented with a battery temperature meter and battery health meter as part of instrumentation and a 'battery report card' upon servicing where the user is rated for their charging, driving and storage habits.
Now this is all good for battery care, however with only a 3 year warranty on the battery as standard (extendable to 5 year by paying another $1,995) an uncertainty creeps in as to nissan's own expectancy of battery life.    Image

Last edited by acmotor on Sun, 08 Jul 2012, 13:51, edited 1 time in total.
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Imiev and Leaf charging

Post by Simon » Sat, 07 Jul 2012, 17:40

Some owners on the mynissanleaf forums are reporting losing 2 capacity bars already!
http://www.mynissanleaf.com/viewtopic.php?f=30&t=8802
I thought battery warranty was standard at 8years? But a battery warranty is not really much good when it doesn't cover capacity loss anyway.

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acmotor
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Imiev and Leaf charging

Post by acmotor » Sat, 07 Jul 2012, 18:30

What I am seeing on websites, glossies and dealer comment is..

imiev has 5yr/100,000km general warranty including battery and 10yr/100,000km warranty on powertrain (not battery)

As mentioned, leaf has 3yr standard warranty that can be extended for $1995 by 2 years to a total of 5 year warranty.

Prius offers an 8 year warranty on battery but then a hybrid battery is not really a comparison to a real EV battery. Image

As far as I can accertain, the battery warranty is for 80% of original capacity, though I see scope for voiding the warrany if user "actually uses" the battery. Image

Back to the charging.... So it would be practical to have the EV charge start from 9pm (start of off peak) at a programable current between say 5 and 15A so that it was charged before 7am.
This would be the kindest on battery and grid infrastructure ?

We had the origin energy vist to establish feed in and switch board capacity for a 32A 'nissan' charge station (though would buy from a local charge station specialist). Passed as it happens, however in discussion with the sparky that called in, there are many houses (mostly older) that would not pass.
This could be expensive to upgrade, many thousands $ + a few more thousand $ for the charge station itself.
Seems extreme given the charger is only going to 15A (and can be programmed for less).

Perhaps some switching intelligence may be required e.g. EV and HWS (booster) could be mutually exclusive ?
iMiEV MY12     105,131km in pure Electric and loving it !

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