Intelligent battery charging???

[Dsinned]

This morning I did an "extended" charge using my Leviton 32A, 7.7kW, L2 EVSE. I started with an existing charge range of 70 miles and ended with 112 miles, for a net increase of 42 miles. The charge took 2 hrs 33 mins for a charging rate in terms of range of 16.8 miles per hour.

During the last hour of charging I monitored and recorded my Leviton charging station's power consumption using a home energy monitoring device that senses my whole house electric power consumption. While charging the RAV4 the energy monitor reading was about 7.8kW, so I think my monitoring system must be fairly accurate. Early in the morning only ~100W (excluding the charging station's full power consumption) sounds reasonable for the total electricity used in my home, plus ~150W periodically when my refrigerator cycles every so often. It is obvious when it turns on, because I can see the reading increase by about 150W at the same time I here the refrigerant compressor running.

Here's what I found really interesting after I thought my EV was already finished recharging. I observed something akin to a trickle charge during an additional 30 minutes of undisturbed plug-in time. This seems to indicate the RAV4's battery management system automatically does some sort of cell balancing and/or top off charge after the point of a fully (bulk) charged battery.

 

[HD172]

What whole home energy monitor do you have?

 

[Dsinned]

What whole home energy monitor do you have?

I have a EnviR Home Energy Monitor made by Current Cost in the UK. You can buy it from Amazon.com, or from an online distributor in Florida at "Powersave.com". I getting their EnviR kit + Netsmart Gateway tp have a complete wireless solution for realtime data logging. Here's a link to a YouTube demo of their recently released ENERATI DASHBOARD software app.

http://www.youtube.com/watch?feature=player_embedded&v=TzLa8P9Mq5U

There is another product called "TED" (The Energy Detector) that does essentially the same thing as the EnviR. It is also available from Amazon.com but slightly more expensive perhaps it has more in-house software support.

Both monitors work on the principle of sensing incoming AC current from your power company's mains connection to your utility breaker box, but you do not have to disconnect or modify any existing AC circuits. These energy monitors are essentially an upscaled version of the widely used "Kill-a-Watt" handheld meters, but for single phase, 240Vac power connections commonly used in residential electric power applications.

My EnviR is very handy to monitor the high power load contribution to my household's electric power consumption while charging my EVs. The graph of energy consumption during the time my car is charging, usually around 3 to 7am when electric rates are lowest, shows fairly obviously how much power is being provided via the charging station. However, keep in mind the accuracy of a typical home energy monitor such as either the EnviR or TED is probably no better than +/-10%; close enough to see a big surge in the overall load used at your residence compared to the rest of the household when most everything else is turned off.

Btw, a home energy monitor has helped me tremendously to find ways to conserve more energy by measuring the electrical appliances scattered throughout my home, and how much they contribute to overall electric power consumption.

 

[TonyWilliams]

This
I observed something very interesting during the last 30 minutes of charging my RAV4 just before completion. The real time electric consumption reading on my whole house energy monitor began to slowly decrease. This demonstrates that the RAV4's battery management system automatically "scales back" the onboard charging rate as it nears the point of a fully charged battery.

Not too surprisingly, my Chevy Volt does the same thing. This leads me to the conclusion that big auto manufactuers of EVs must realize that "overcharging" a Li-ion battery is detrimental to its longevity. Does that sound like a logical conclusion to everyone else as well?

Very normal, and more important with fast charging. A Nissan LEAF can pull 120 amps at 394 volts (47.3kW, or 2C charge rate of a 24kWh battery) until about 50% SOC, when it starts dramatically reducing amps all the way to sub 10 amps as it approaches 100%.

This is programmed in to both ensure no cell overcharges, and mitigate heating of the cells. The cells get much, much hotter at the top of the charge.

For a 41.8 kWh pack at 9.6kW (40 amps * 240v max in USA) is only 1/4C, so the charge rate taper down will happen far later in the charge than 50% SOC.

 

[Dsinned]

Tony, please post more about your 120 to 240V OEM charger conversion. Does it work at BOTH voltages, or just 240V now? Can you get it with some sort of AC plug adapter for either voltage? What 240Vac outlet receptacles does it support? The type(s) for an electric clothes drier? How much does it cost?

 

[TonyWilliams]

Tony, please post more about your 120 to 240V OEM charger conversion. Does it work at BOTH voltages, or just 240V now? Can you get it with some sort of AC plug adapter for either voltage? What 240Vac outlet receptacles does it support? The type(s) for an electric clothes drier? How much does it cost?

http://www.EVSEupgrade.com

Works on 100 volts to about 265.

Comes with L6-20P locking connector so that you can put on any plug you want with a pigtail to an L6-20R and one of these (there are many more). YOU must supply the pigtail, or have it built

NOTE: many commercial areas do not offer 120/240 volt service, but instead 208 single/three phase, or 277/480v service. Don't ever use 277 or 480 volt. 208 volt single phase will reduce your power output accordingly (208 * 12 = 2.5kW charge rate).

These guys may still be in business to build these pigtails:

http://www.evseadapters.com/

Any extension cords you use need to be 12 gauge / 3 conductor (referred to as 12/3) with L6-20 connectors. Try:

http://www.stayonline.com/nema-20-amp-locking-plug-208v.aspx

NEMA 5-15 - Normal household plugs in USA / Canada at 120v (1.44 kW rate)

"Quick220" - connects two 120v circuits that are out of phase to make 240v (2.88kW)
http://www.quick220.com/220_volt.htm

"30 Amp RV plug" (not NEMA) - 120v in RV parks (1.44kW rate)

NEMA 6-20 - 240 volt at motels for the room air conditioner (2.5kW or 2.88 kW rate)

NEMA 6-50 - Welding shops 240v (2.88kW)

NEMA 10-30 / 10-50 - Electric dryers at 240v (2.88kW)

NEMA 14-50 - RV parks with "50 amp" service. Don't ask an RV park for 240v, because you will likely stump them. Just ask for 50 amp service. (2.88kW). If you get 20 or 30 amp service, you will only have 120v (1.44kW)

NEMA L5-20/30 - usually 120v (1.44kW)

NEMA L6-30 - some generators at 120/240v (1.44/2.88kW)

NEMA L14-30 - generators 240v (2.88kW)

CS6365 - Industrial grade generators and commercial grade extension cords for heavy industry (2.88kW)

 

[Dsinned]

Tony, thanks for the detailed info. What is your opinion of the workmanship of this conversion? Do they return exactly the same unit you started with, i.e. the Toyota OEM charge cord that came with your RAV4 EV? Is there a possibility they will come up with a future firmware upgrade, so we can charge the RAV4 EV at 3.84kW (240V @ 16A) instead of 2.88kW (240V @ 12A)?

 

[TonyWilliams]

Tony, thanks for the detailed info. What is your opinion of the workmanship of this conversion? Do they return exactly the same unit you started with, i.e. the Toyota OEM charge cord that came with your RAV4 EV? Is there a possibility they will come up with a future firmware upgrade, so we can charge the RAV4 EV at 3.84kW (240V @ 16A) instead of 2.88kW (240V @ 12A)?

High quality, respected service. They do about 1/3 of all Nissan LEAF units sold in the USA (14,000).

You get the same unit back, unless you buy a different one. The only physical difference externally is the L6-20 connector.

The 12 amp limit is a material one, not firmware. The Nissan LEAF's Panasonic EVSE can be bumped to 16 amps (I owned two of them) and now, for 2013, I see that Nissan is going with this cheaper Panasonic EVSE that we have in the Rav4 and is also used in the Plug In Prius.

Progress?

 

[HD172]

I'll second the recommendation for the upgrade. I received my unit 2 days after I sent it in. I highly recommend it.

 

[Dsinned]

Noted. Thanks. So, the limitation of the Toyota (Panasonic) charge cord is the wire gauge can only safely handle 12A, thus the 16A "rev2" upgrade cannot be done unless you have an OEM 2012 Nissan Leaf charge cord to update?

 

[HD172]

Yes but even an upgraded leaf evse will not work with our rav4s. That is what I was told by evseupgrade. I have a leaf too and I wanted to get the rev 2 upgrade to allow 3.8kwh charging. The upgraded rav evse is what the leaf is using while I use the blink.

 

[TonyWilliams]

Noted. Thanks. So, the limitation of the Toyota (Panasonic) charge cord is the wire gauge can only safely handle 12A, thus the 16A "rev2" upgrade cannot be done unless you have an OEM 2012 Nissan Leaf charge cord to update?

True, EXCEPT the 16amp Nissan / Panasonic will not work with Rav4 (neither will SPX).

Nissan will switch to the cheaper Panasonic that we have for 2013 on the LEAF. Also, note that the cheap Panasonic is life limited for number of charges (I don't know the specific number of charges).

Then, if you can't code break it, you get to buy another one.

 

[sam]

Toyota's approved electric vehicle equipment provider, Leviton, offers multiple options for charging your RAV4 EV. For the shortest charge time, Leviton [5] offers a custom Level-2 (240-volt), 40A, 9.6-kW output charging station that can have you up and running in as little as five to six hours

 

[Khaihon]

Also, note that the cheap Panasonic is life limited for number of charges (I don't know the specific number of charges).

Then, if you can't code break it, you get to buy another one.

Hi Tony,

Congratulations on finishing the BC2BC! My family and I came out on Sunday, but we missed you. Actually, we didn't see anyone except DNF #2. Still had a good time.

Regarding the stock charger for our Rav4ev... Do you have any reference for the artificial charge limit??? Has someone ran into this limit? Will this limit exist even after an upgrade via Phil? Sounds like I'll need to pick up a less limited charger one sooner than I was planning (hopefully that number is somewhere in the 4-5 digit range).

 

[TonyWilliams]

Also, note that the cheap Panasonic is life limited for number of charges (I don't know the specific number of charges).

Then, if you can't code break it, you get to buy another one.

Hi Tony,

Congratulations on finishing the BC2BC! My family and I came out on Sunday, but we missed you. Actually, we didn't see anyone except DNF #2. Still had a good time.

Regarding the stock charger for our Rav4ev... Do you have any reference for the artificial charge limit??? Has someone ran into this limit? Will this limit exist even after an upgrade via Phil? Sounds like I'll need to pick up a less limited charger one sooner than I was planning (hopefully that number is somewhere in the 4-5 digit range).

Sorry to miss you!!! All the rally cars except the two LEAFs were present by 8pm, when we awarded the Teslaccessories Center Console Insert and trophy to the winners of Georg Kuhnke and Jack Bowers in Jack's Signature Tesla Model S (both of those guys also have Roadsters).

Phil is the guy to talk to about the charge limitations of the Panasonic EVSE. My modified unit is still for sale.