Our NiCD Force Conversion
Extending our Force's Range with Advanced Batteries
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The Story So Far...
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:
The front battery box will have to be replaced in order to accommodate the NiCD modules, which aren't the same size as the lead-acid batteries they are replacing. The rear battery box, luckily, remains the same!
The NiCD batteries will need to be "plumbed" for watering and a cooling system must be added. The lead-acid batteries didn't need any watering and were air-cooled, but the NiCDs need a bit more attention (not that much, as it turns out).
The motor controller will need to be reprogrammed so that it knows what the voltage limits are for the new battery pack.
The charger will need to be reprogrammed with a "profile" to fit the new battery pack.
The DC-DC converter, which converts the 156-volt main battery voltage into the 12-volt supply used for the car's headlights, radio, and other systems, will need to be changed because the NiCD system voltage may exceed its input limit. We may be able to avoid replacement by adding a voltage clamp to the converter's input.
We may need to replace the car's amp-hour counter with the newer generation unit, though we're not sure about this.
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!
The batteries are shipped!
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!
The batteries Arrive!
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.
Since the last report, here's what's happened:
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 Trip to Solectria; More Delays
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!
Things remaining to get:
EPDM (rubber) hose for the cooling system and watering system for the NiCD batteries. I need 7mm and 9.4mm ID hose for these systems, plus manifolds/connectors.
A couple of extra parts from Saft. They shipped some bags of rubber hose connectors for the watering and cooling systems, and I think I have enough of them. They also sent some rigid electrical connectors, but if I'm going to use them, I'll need a few extras.
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!
October Comes and Goes...
Well, as I write this, it's October 30. Here's what has transpired since the last entry:
I did get all the batteries pulled out of the Force, and they're currently stacked in my garage. I dismantled pretty much the entire engine compartment of the car, removing the fuel heat unit and its tank, disconnecting it from the heater core and draining the coolant.
I got the front battery box out. The adhesive Ed Trembly mentioned wasn't so bad -- It was very hard but no match for my trusty air-powered chisel. The stuff was pretty brittle and I'm glad I was wearing safety glasses because it shattered into little shards as it came off. With the adhesive out of the way, I started looking at how to get the box physically out of the car. Pulling it downward was out of the question: It had huge tabs used to bolt it to the frame. Pulling it up was out, too -- Obviously the box went in before the motor assembly, because there was no clearance to get it out. I decided to cut those mounting tabs off with a Sawzall and drop it out the bottom of the car, which worked perfectly.
Solectria made good on their promise and the battery box, box covers and cooling system stuff showed up. I had to get a radiator to use because they didn't supply it; I found one at radiator.com -- I kid you not! Of course, it came without a radiator cap (this whole project has been a cascade of "I need just one more part..." scenarios). Solectria's kit came with a ton of hose, fittings, a pump, electrical cable, terminals, a control box, and ABSOLUTELY NO INSTRUCTIONS. OK, I think I'm fairly smart, but when you get a control box with several unlabeled connectors coming out of it, you really should get some sort of errata sheet that tells you what the heck the connections are for! A call to Solectria resulted in me having to fax over a form authorizing them to change my credit card for consultation time. Since then I received an email detailing the connectors and their use.
I got the charger and filter box back from Brusa on September 20. Suffice it to say I hope I never have to ship anything abroad again. Getting my charger back from the clutches of the shipping company and the US government was loads of laughs (NOT!). Customs wanted to treat it as if I was buying the entire charger from Switzerland, instead of just upgrading it. Well, the bottom line is, I got it back and it looks pretty straightforward. They gave me a new filter box, which will take the ripple current out of the charger output, making Saft's engineers happy (I hope). They also provided a new interface unit so that the charger can talk to the amp-hour counter and know how much energy to put back into the batteries, and count the total so the charger knows when the batteries will need watering. The charger itself has new logic that will provide four different charging profiles (Commissioning, Maintenance, Fast and Normal).
Getting the charger upgraded means that the interface to the car needs to be changed, something I had spaced out on. Another call to Solectria reveals that the change to the LED box in the trunk isn't simple, so I had to ship that to them for modification. As of October 30, it's still there, though I got an email today indicating that it's close to being finished. This box will have a new connector on it that will allow me to select the desired charging profile.
As part of the cooling system, I got the radiator I needed, but it was just the radiator. I also needed the electric cooling fan and shroud. I found this online as well, at an auto salvage outfit called autoandparts.com. You tell them what you're looking for, and they email all their salvage yards. You then get emails directly from the salvage yards which have your part. Cool.
Looking at Brusa's specification sheet for the Saft charger, it turns out I need special temperature sensors so the charger can monitor the battery temperatures. The car already has two sensors but apparently they aren't the same as the ones Saft makes. Time for another email to Saft to get these ("I need just one more part!")
I dropped a couple of NiCD modules into the rear battery compartment to check their fit and so on; I'll need to rig a hold-down mechanism like I saw on the car at Solectria to keep the batteries from moving vertically when the car hits bumps and so on. I have all the parts for this but haven't started the mods.
I ordered a ton of little spring hose clamps (104 of them) from the hardware store. These will be used to keep the batteries' cooling system hoses in place. They were ordered weeks ago but haven't shown up yet. Time for a follow-up call to the hardware store to find out what the heck's keeping them.
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.
||The engine compartment of my Force,
as it stands today. Note missing battery
box, motor junction box has been
dismantled, fuel heat removed.
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...
NiCad Conversion, Part 2
Aren't NiCD batteries bad for the environment?
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.
Don't NiCD batteries suffer from the "memory" problem?
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.
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This page last edited August 06, 2002