Our NiCD Force Conversion

When we bought our 1997 Solectria Force sedan, we had the option of equipping it with advanced batteries but the price tag was beyond what we had budgeted. I made a promise to my wife, Elizabeth, that when the time came to change out the battery pack, we'd install a set of advanced batteries that would provide longer range.

Well, the car is now almost 3 1/2 years old and the lead-acid pack is ready to be retired. We had a couple of warning signs show up last fall, when the car's power started to sag at less than the normal range, and we replaced two batteries out of the original 13. We knew this was just a temporary measure because eventually all the batteries would start showing their age. That time came late in March 2001, when a short trip to the local bakery resulted in a loss of power and our first tow.

Fortunately, I had been in contact with Solectria about the battery pack situation for some time and had a plan in place. Solectria has agreed to help me in the conversion of the car from lead-acid batteries to nickel-cadmium (NiCD) batteries, which I will buy from Saft, a manufacturer of various battery types located in France. I had thought about using nickel-metal hydride (NiMH) batteries but they are still extremely expensive, don't provide much more range than the NiCDs and are finicky about temperature.

The first thing to do was talk to Solectria in detail about the changes necessary to turn our lead-acid Force into a NiCD vehicle:

Solectria was kind enough to send diagrams of the NiCD battery box layouts with plumbing details and Saft battery part numbers. I relayed the information to Saft, who provided me with a detailed parts list. I placed the order for the batteries and their watering components on March 21, 2001, and Saft is hoping for a 9-11 week delivery. In the meantime, the Force is garaged and I'll start making the various changes necessary to install the new batteries when they arrive (hopefully, sometime in June)!

As the project moves along, I'll be adding photos, commentary and probably some spleen-venting to this page. Stay tuned, because when we're done, we'll have an EV that will satisfy over 95% of our driving needs!

Well, I received notice on May 15 that the NiCD modules have been shipped from France, where they're manufactured. According to the US representative, Lou Magnarella, that means I should have them in my hot little hands around mid-June. I'd better get busy!

I shipped the Solectria motor controller back to the factory on May 21. This will allow the Solectria technicians to reprogram the controller's computer with the proper voltage levels for the new batteries. NiCD batteries have a higher "top end" voltage and a lower "low end" voltage than the lead-acid batteries that the controller was programmed for. Reprogramming it makes sure that it will allow regenerative braking all the way up to the new battery limits, and won't go into the battery-saving "limp home" mode until the batteries are at a lower voltage.

I'm still looking into a way to fix the DC-DC converter so that it can take the higher input voltage of the NiCDs. And talks continue with Saft to see if they'll uphold the warranty with my current battery charger. I should start hearing more from them the week of May 28 -- One of their technicians has been out of the office and will be back then!

On June 19, without warning, the doorbell rang. A semi-truck was sitting out front on the street with a couple of crates full of "ACCUMULATEURS ELECTRIQUES ALKALINS" (that's French for alkaline batteries). Not wanting to carry several hundred pounds of batteries 150 feet from the street to the garage, I hopped into our Solectria E-10 pickup and drove down to the street, backing up to the rear of the semi trailer. The driver helped me unload the individual batteries into the back of the E-10, then I signed for them and he headed out. I drove the truck to the garage, and since I wasn't going to be able to use the batteries anytime soon, I set their crates up in the garage and transferred the battery modules back into them.

I was amazed the batteries showed up so soon. It was right when Saft had estimated, but I'm used to things taking a lot longer than they're supposed to. Well, I was busy with other things around the house and I had no front battery box from Solectria yet, so the batteries are sitting in their crate waiting to be installed.

1) Solectria finished reprogramming my AMC325 motor controller in record time, and returned it to me in just a few days! I was really impressed by their quick turnaround.

2) After a big go-around with Saft and Brusa, the maker of the Solectria BC3300 charger, I decided to have Brusa upgrade my charger to the NLG412-Saft version. This is a special configuration that allows for several charging profiles, including the "commissioning" charge profile needed for the first charge of the pack. It will also tie the charger to the car's amp-hour counter, allowing the charger to monitor the actual amount of energy put into the batteries and adjust the charge accordingly. Saft's engineers expressed concern about the NLG412's output waveform having too much ripple current, but Brusa agreed to add a special filter stage that will clean up the charger output. The charger was shipped to Brusa (in Switzerland!) on July 19. Expected turnaround is 6 weeks, which I hope is plenty of time to get the rest of the work on the car completed.

3) I finally gave up and ordered a special NiCD version of Solectria's DC-DC converter. I spoke to several people about reworking the existing converter so that it would deal properly with the higher finishing charge voltage of the NiCD pack, but nobody had any workable solutions. What the heck, I may be able to use the old one as a backup unit for the truck. Spare parts are good.

4) I located a spare NLG412 charger and mailed the check out for it. Have you noticed how much I like having spare parts?

A little aside

If you've never had the pleasure of removing a car's instrument cluster, don't worry -- you're not missing a lot of fun or anything. I found this out first-hand when I took the amp-hour counter out of my Force to ship back to Brusa! In the Force, the Brusa amp-hour counter box is located under the steering column, behind the bolster panel. The display is up in the instrument cluster, left of the speedometer. I have a Geo Metro service manual and looked at the instructions for removing the cluster the night before:

Remove or Disconnect:
1) Negative battery cable (check!)
2) Two screws and instrument cluster lower covers (check!)
3) Four screws and instrument cluster bezel (WHAT?!!)

At this stage, there are two screws visible. The other two are hidden under the upper steering column cover, which you have to remove first. No problem, I took those out and removed the upper cover, exposing the other two screws. I removed them, pulled the bezel, then looked at step 4:

4) Speedometer cable by pushing on plastic tab

Uh, ok. You don't even SEE the speedometer cable at this point. It turns out that to reach it, you have to remove the knee bolster and several other pieces under the steering column, then reach up behind the instrument cluster, fumble around and attempt to disconnect the speedometer cable. Heaven help you if you have big hands.

5) Four screws, three electrical connectors and instrument cluster

Let me tell you, these guys don't believe in providing any kind of slack cable on those three connectors, and disconnecting them by getting both hands in the tiny space inside the instrument cluster area is no easy task. But I was able to get it out, despite the fact it took about three times as long as I had expected.

I now have a spare Brusa NLG412 charger on my parts shelf, thanks to another EV owner selling some of his surplus parts. I like having spares of critical EV components sitting around because it isn't like I can run down to the local auto parts store and pick up a motor controller or 240V battery charger!

While discussing some details of the NiCD Force with one of Solectria's technicians, he mentioned that they had one of the NiCD vehicles they had built sitting in their shop waiting for some work to be done. When I heard this, a little voice inside my head said, "you need to get up there and see this vehicle!" and I quickly asked if it was possible to come up and see it. I would have to talk to the tech's manager to arrange it, but he said it was probably doable! I had a small window of opportunity in my schedule as an alderman here in Port Washington, so I pitched the idea and they agreed! I had frequent flyer miles available for the trip to Boston and there were seats available; the next Wednesday I arrived at Boston's Logan Airport, grabbed my rental car and headed to Solectria's Wilmington facility.

I can't say much about my visit to the Solectria offices/workshop (I had to sign a non-disclosure agreement), but there is no doubt that actually going over the NiCD force from top to bottom and front to back was incredibly valuable! I took about two hours to get the details down in my sketchbook (they wouldn't allow me to take photos because it wasn't their car!) but I found out a number of interesting bits of information about how the batteries were mounted, how their cooling system was plumbed, and how some of the major components, such as the motor controller, were mounted. The front battery box in the NiCD Force is a two-level affair, with three batteries mounted in the front/top and seven mounted below and to the rear.

The NiCD batteries require a special liquid cooling system with a radiator to dissipate heat generated while charging or driving. It turns out the radiator is mounted where the Metro's gas tank used to be, just ahead of the rear wheels. Looks like they just use a spare Metro radiator leftover from when they used to strip out the engines from the stock cars.

While at Solectria, I asked what the status of my battery box order was. This was August 15, and the battery box had been promised by mid-July! It turns out that they quoted me that delivery date in error, and the box wasn't due from the fabricator for another week. Oh, well...

I received a box from Solectria the last week of August -- Yeah! It was my new DC-DC converter! I took it out to the car to see how I could mount it (it had different mounting brackets than the one on the car), and noticed that it has an extra connector on it. Hmmm. I then looked closely at the nameplate -- It was rated for 200-400VDC input, 312V nominal! Arrggh -- It was the wrong part, made for a much higher voltage! It's been sent back to Solectria, where they can figure out what went wrong in the order processing and send me a new one for my 156V car..

It's September 1 and things look like things are starting to come together on this project. I got a call from Solectria yesterday, and they said my complete order, including battery box, box covers, radiator, cooling system parts, etc. will be shipped on September 4!

Add that to the fact that Brusa sent me an email a week ago saying that my charger would be sent back in two weeks, and it looks good for a completion of this project by the end of September!

Now that it looks like the critical components are coming from Solectria in the next week, I'm going to shift into high gear and start pulling out the lead-acid batteries this week. I'll also pull the front lead-acid battery box out (according to Solectria's Ed Trembly, this may be a bit of a challenge, because he says that in addition to the bolts holding them in place they use an adhesive used by railroads to bond steel rails together). Oh boy, this sounds like fun!

Well, as I write this, it's October 30. Here's what has transpired since the last entry:

Because of various other commitments in my life, and not having all the parts necessary on hand, the project is kind of stalled right now. On the positive side, I know what I have to do and just about everything is in place.

I'm hoping that next week will bring the time I need to get the front battery box in place and move ahead with the project. I'd really love to have the car running by the end of November...

Well, they can be if they aren't disposed of properly. Saft has an extensive recycling program for their batteries, which is smart because some of the components are pretty expensive. By recycling these materials, Saft reduces the need for raw materials, saves money and prevents toxic waste from entering the ecosystem.

Not the flooded types used in EVs. The "memory" effect was common in older NiCD batteries used in household appliances, and caused a loss of power over time when the batteries weren't cycled fully.