Toyota Rav4EV Upgrade project
This opportunity came my way because of the approx 50% capacity Ni-MH battery array.
It was no longer sufficient range for for original owner to make a complete round trip commute, which had been successfully done for many years prior. But lacking pack replacement opportunities, the original owners reluctantly decided to sell.
The plan is to upgrade to Li Ion cell design which will result in the following improvements:
1. Increased range - 30.7kWhr pack capacity, for greater than 130 miles
2. Pack weight reduced by 390 pounds (but adding
3. Increased current capacity - better for climbing and acceleration without battery stress
4. Increased cycle life
5. Incorporate on board charging, needing only a cord adaptor to plug into 120V or 240V
Here is the factory electric 2003 Rav4ev at 85k Miles:
The only service this vehicle has needed since 2003, other than tires, is replacement of the 12 Volt Lead Acid accessory power battery! There is no wear in the brushless drive motor which is connected directly to front wheels through individual half shafts. Very long life expectancy without loss of performance or efficiency along the way.
It is currently being used for trips under 55 miles while preparations for upgrade are made.
I logged a 55 mile day, starting with driving through a heavy snow flurry in the morning, with near freezing temperatures continuing throughout the day and climbing the hill at the end of the commute w/ side trip. So, despite the capacity reduction, it is still quite capable.
A 40 mile trip costs $1.10 (@11 cents/kWh)
It will drop to 77 cents/40 miles when we switch to time of use metering and set the Rav4EV's built in timer to charge during off peak time.
This new EV implies another increment in the solar panel array (eventually) to reach net zero power use for our driving.
Update July 2009
The lithium Ion cells have been ordered. It will take a couple months for delivery.
I was able to fit the CRF into the Rav4 by removing the front seat and replacing the bike's front wheel with a small one that lowers the handlebars and allows driving it in, literally.
This is what I drove to the John Wayland Invitational Drags at PIR. I made the round trip at 62.5 miles, with 1/8 charge remaining.
I included the charger just in case (just right of the bike rear wheel)
Here is a shot of some of the competition on the track that evening:
The Tesla vs. the Tango. This was a close race.
Update October 2009
The batteries for this Rav4ev upgrade have arrived:
There are 96 cells in these 5 boxes.
96 of these cells will allow for 130 mile range, and drops the weight of the current pack by 390 pounds.
They are rated for a peak of 1200 Amps (5 ms impulse), 400 Amps for 30 seconds, and 30 Amps continiously. This is a big improvement over the factory NiMH cells.
The electrical load travelling down a level freeway at 60MPH is ~10kW, which implies ~30Amps continious current load, which is the discharge current specified for the 3000 cycle life rating.
They are officially tested/rated to greater than 3000 cycles at 70% depth of discharge, but will only be discharged regularly to less than 50% of full capacity with a 40 mile commute, extending the life even more.
An inside view of the vehicle:
(click to enlarge)
