Transport Evolved 2002 Toyota RAV4 EV Battery Replacement 15

Staff Car Update: Sparkie The 2002 Toyota RAV4 EV Goes On Vacation — And We Learn How Close To Death She Really Was

As regular readers to Transport Evolved will know, we not only believe in covering the latest in cleaner, greener, safer and smarter transportation but also living by example wherever possible, filling our own personal garages with cleaner, greener, safer and smarter cars.

And while income levels preclude us from affording the latest and greatest Tesla to put through its paces, our staff fleet has included an eclectic selection of cars over the years, most of which are some form of battery electric vehicle. And while we’re representing modern electric cars that you can buy today with the two Nissan LEAFs present on our fleet — not to mention numerous other modern electric cars owned by regular contributors and contacts — we also happen to own two (now vintage) 2002 Toyota RAV4 EVs.

Sparkie is getting a new 9old) battery pack.

Sparkie is getting a new (old) battery pack.

Why? Well, aside from our desire to own an affordable electric vehicle, we’re curious as to exactly what owning a previous-generation electric car like the 2002 Toyota RAV4 EV really entails. Can you really rely on a 15-year old electric vehicle as a daily driver for example? Are parts and repairs a challenge in a super-rare car no-longer officially supported by its creator? And what happens when the vintage NiMH battery pack dies and you need a new one?

While our Washingtonian Toyota RAV4 EV — belonging to the Walton-Elliott household — came with a recently-replaced battery pack, ‘Sparkie,’ the Oregonian Transport Evolved Toyota RAV4 EV hasn’t been particularly healthy since we adopted he back in March this year. Gifted to us as a non-runner, we promised her former owners that we’d bring her back to life and get her back on the road for another 15 years of fun.

We were extremely lucky...

We were extremely lucky…

As we explained back in March, Sparkie’s original owners had her original battery pack replaced after 60,00 miles or so, replacing the factory original NiMH battery pack with a reconditioned battery pack of identical cells when her range started to drop. After replacing the pack, Sparkie was then used as a light-duty vehicle until she became temperamental some time last year, finally being retired some time last fall. When we rescued Sparkie in March this year, her original 12-volt accessory battery was dead, she wouldn’t’ charge, and things looked decidedly grim.

By April, we’d coaxed Sparkie to life with the help of a brand-new accessory battery and had even convinced her to cover short distance trips without any issue, paying careful attention to not let the weakest battery (which was sitting 2 volts below the rest of the pack) from getting too low. At the time, we learned that we could gently accelerate and keep a constant speed as long as the battery pack was not too cold, since the average estimated 25 mOhm resistance of each cell in the 26 kilowatt-hour NiMh battery pack was well beyond Toyota’s original definition of a ‘dead battery pack.’

Towing our heavy RAV4 EV with a Ford F250 was an experience in itself.

Towing our heavy RAV4 EV with a Ford F250 was an experience in itself.

Our goal was to keep Sparkie running for local trips until we’d sourced a new battery pack, possibly with a more modern cell chemistry that we could use to replace the original pack. But by the end of May, Sparkie was having none of it, finally giving up on her battery pack and letting out some ceremonious ‘magic smoke‘ one day after pulling out of the garage. Electric or gasoline, smoke is generally not a good sign, so we parked Sparkie up and waited, still intending to do the work ourselves. But a family crisis in the Gordon-Bloomfield family made it painfully apparent that we not only needed Sparkie on the road as soon as possible but in as healthy a condition as possible.

Cleaned and ready to install, our new battery pack is far healthier than its predecessor.

Cleaned and ready to install, our new battery pack is far healthier than its predecessor.

The one official specialist to replace NiMh battery packs on the first-generation Toyota RAV4 EV (remember, NiMh battery packs are no-longer made in the sizes used by these cars due to a patent owned by Chevron) is in Southern California, a good day’s drive away. The other option as we saw it, was to keep our eyes out for a replacement pack from a salvaged vehicle and then put it in ourselves.

Luckily, such an opportunity presented itself locally to Transport Evolved’s headquarters. What’s more, for a not-too-unreasonable fee, we were told the battery pack could be swapped out and a new, salvage one from a 2002 RAV4 EV (or Ford Ranger EV from the same period) could be fitted. With the replacement pack showing decent capacity and internal resistances of less than 5 mOhms per module, we jumped at the chance  — and took the financial hit.

As part of the deal, we agreed to tow Sparkie’s lifeless body down to the specialist in question (who asked us not to mention them by name), a fun day of trucking that involved using a Ford F250 pickup capable of travelling 14.4 miles per gallon of gasoline. Or to put it another way, 14.4 miles on 33 kilowatt-hours-equivalent of energy.

The next day, we discovered just how close Sparkie was to death — and how lucky we were.

The new pack was given a full service before installation.

The new pack was given a full service before installation.

The 15-year old battery pack in Sparkie had apparently suffered a internal short circuit after being used long after its internal cell resistance had become too high, causing the cells in question to weld themselves together in a permanent short circuit. Had we continued to use the car at this point, she most certainly would have ended up less complete.

But after removing the dead pack, our contact was able to clean the entire battery tray (removing excess sand from Sparkie’s former desert home) and fit a nicely-matched set of 24x EV-95 NiMH modules made up of ten NiMH cells each. Then, the new pack was fitted.

Given the age of the battery pack, and the fact that the cells have remained dormant for several years (NiMH is the only chemistry that can safely be left for years without cell degradation), the next few weeks will consist of the battery pack undergoing full charge and discharge cycles to condition it and bring back its optimum range. According to the math, we’re hoping that a real-world 70 miles will be possible, assuming we treat the battery pack carefully and with respect. Abuse it too much or fail to care for it by over discharging it, and we’ll be looking at a very expensive repair bill.

Of course, a modern electric car with Lithium-ion battery pack has none of these issues. Moreover, modern battery management systems are far more advanced than they were fifteen years ago. But we’re hopeful that in just under a month we’ll get to see Sparkie again — and give her a real range test.

Naturally, you’ll be invited along for the ride.


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  • CDspeed

    Nikki, it would be interesting to find out if you could replace the cells with new lithium batteries. It would I’m sure be expensive, but you could find out if it’s feasible, and what the range gain would be. Being on the west coast, you could probably find out a lot from EV West.

    • Long term, that would be awesome. Sadly, with this year taken up pretty much by family medical emergencies (and TE bringing in only a modest income) we’re not quite able to afford anything more fancy right now.

      We can hope!

      • CDspeed

        I wasn’t suggesting you try to do it, yes the cost would be high. But in keeping this future classic on the road, and other late model EVs, it would be interesting to see that an upgrade is possible in a future TE piece.
        P.S. Sorry to hear about the medical emergencies, I hope all goes well, Chris

      • Thalass

        Hopefully things improve for you guys, and before these new cells start to fade you can upgrade the old girl! 🙂

  • tomsax

    Our 2002 RAV4 EV is still on the original battery pack at 75,000 miles. We get about one mile per percent SOC in moderate weather, so a practical range of about 80 miles while staying out of the bottom 20% to be nice to a 14-year-old battery pack.

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