I have a Corbin Motors Sparrow Electric Car, I drive it everywhere, and I love it. I kept this diary of everything that I did with the car until the end of 2003. Here is the continuing story. Newest Entry - Mon Aug 11 19:27:59 PDT 2008 Sat Jan 24 17:20:52 PST 2004 - 6463 Miles It's cold today by California standards. Maybe 45 degrees. The battery pack is even colder. The pack is finally to the point where I can't make the local trips I need to. Today I drove to the hardware store, 6.3 miles, and the finishing voltage on the pack while driving at 35 MPH was 153 volts. That is just too low. I also noticed that at 5 miles the voltage plummeted from 160 to 154 volts. I think one of the batteries must only have a capacity of 5 amp hours or so. It is time to set aside a weekend and switch out the packs. The second pack is still happily simmering away on the solar battery charger in the garage, just waiting to be installed. I expect to go from 5 miles of good range to perhaps 20 or more, a huge leap, and have better driveability besides. Of course, there will be more news here when the switch takes place. Sat May 8 22:21:36 PDT 2004 - 6463 Miles Almost there. 10 of 13 batteries are installed. I have been unable to work on the car because of a heavy workload, but I finally found a few spare weekends to swap the batteries. Tomorrow I may ride again! Mon Jul 5 17:53:58 PDT 2004 - 6494 Miles I'm Back! The battery swap is complete! When I said "tomorrow" above, it turned out to be almost two months. I have been too busy at work to complete the job. But I finally got the last battery in, and I have taken several test drives. The used pack is roughly twice as good as the one I replaced, and that one is now happily serving as the garage solar system battery bank. Oh by the way, that solar system is used to change my new (Happy Birthday from my wife!) eGO Electric bicycle! Yes, I have two electric vehicles now, and they are both solar-charged, and I now have a choice of vehicles for short trips. Of course the Sparrow is the vehicle I use for higher speeds. The eGO is limited to 25 MPH to preserve it's "bicycle" classification. Both vehicles now have similar range, roughly 15-20 miles. The eGO draws only 180 Watts when charging compared to the Sparrow at 1,800 Watts (I have the 110v charger) and the lesson learned is that as efficient as the Sparrow is at moving a single person around, a motorized "bicycle" is more than five times as efficient. Food for thought. By the way, now that Corbin Motors is effectively gone from the face of the earth, you may wish to visit Myers Motors for all things Sparrow. They have purchased the assets of Corbin Motors and they appear to be continuing the Sparrow dream. It sure is good to have the Sparrow back on the road again! Sat Dec 4 18:39:24 PST 2004 - 6548 Miles What fun! I have been working at home a lot. Tonight I took the Sparrow to Trader Joes - a popular "alternative" supermarket in the Bay Area - and did some serious shopping. The trip used 9 Amp Hours from a cold pack, and the Sparrow was still happy at 55 MPH speeds at the end of the trip. This pack is the used pack I purchased for roughly 1/4 the cost of a new pack. It is completely different than the pack it replaced. The old previous pack had low resistance and low capacity. That means it showed excellent voltage until the energy was drained, which happened within 8 miles, and then the voltage would plummet. This pack shows high resistance and high capacity. It starts off with significantly lower voltage (5 volts lower on the average) than the old pack, but then it holds that voltage - so far I have driven further than the old pack could go and the voltage is still up to what I would expect for less than half of the energy drawn from the pack. New batteries start off with high capacity and low resistance. I wonder what was different between the use of two packs to make them end up so different in behavior?? The more I drive, the more I learn. Sat Jan 29 14:30:22 PST 2005 - 6562 Miles It's been a long time since I took the Sparrow out for a ride. The Sparrow has been on the the trickle charger (which is in turn controlled by the X10 socket to avoid charging during peak energy use times) and the voltage today was a satisfying 187 volts. The trickle charger can clearly keep the bird in "ready-to-roll" condition. The trip today was to OSH (Orchard Supply Hardware) for some parts to complete the wiring between the house and garage. This wiring will allow the old (used) Sparrow battery pack to become a huge "backup battery" for the house. There is a 1000 Watt inverter waiting in the Garage for an electrical pathway to the house, and the Sparrow was dispatched to buy the last few pieces of underground conduit. The Sparrow performed well, but the used battery pack is showing it's age. Resting voltage was excellent at 165 volts after the trip, which consumed 6.5 Amp Hours. However, during the 35 MPH trip home, especially when accelerating, the battery voltage drew down as low as 150 volts. There is too much internal resistance in the batteries to permit the capacity in the batteries to hold the voltage up. Still, for short trips like this one, there is no problem using the Sparrow instead of the petroleum-fueled vehicles. With crude oil near $50/barrel, daily deaths in Iraq, and the grand experiment of dropping democracy on an entire nation in the form of a war beginning with the Iraq vote today, I felt pretty good leaving the gas cars right where they were. They are definitely part of the problem, not part of the solution. I suppose we will all be happy if Iraq becomes a friendly democracy and continues to supply us with oil. I am certain I am not the first person to have made that connection. But even that will come to an end someday. Sun May 1 20:47:12 PDT 2005 - 6617 Miles It was a beautiful day today. I had two reasons to drive today, and the Sparrow handled them both without difficulty. I am building a solar-powered (of course!) pump/fountain combination for our backyard pond, and I needed some plumbing parts from Orchard Supply Hardware. It was also time for the evening meal, so I ordered Oriental take-out before I left to get the parts. The Sparrow performed very well. I had "topped it up" just before the drive, by plugging in the Zivan charger for 15 minutes. The Sparrow had been on the trickle charger for a few days, (I took a drive to Orchard Supply Hardware on Thursday, and plugged it back into the trickler after I got home) and it jumped to 194 volts "instantly", and then shifted to the 2 amp finishing charge. That trickler seems to be able to replace about 3 AH each day. That is in spite of being turned off automatically every weekday between 12 noon and 6:00 PM to avoid charging during the high-cost rate of my TOU (Time Of Use) electric metering. The Sparrow pulled out of the driveway with 170 volts showing on the E-Meter, and within a few blocks the "surface charge" was off the batteries and the voltage had settled to 165. That is excellent, all things considered. Remember, this is a used battery pack I bought back in August of 2003, and I have been doing my best to stretch it while battery technology advances... The trip was 8 miles long, and the Amp-Hours used read 8.6 when I arrived back home. During the trip, while parked, the pack would gradually "recover" voltage and when I came out of the Hardware store it read 169 volts - that is much better than the old pack it replaced. The pack has higher internal resistance than a new pack, so it still "sags" under acceleration to 158 volts or so, but I can keep up with the flow of traffic just fine. I try to drive with a "light foot" and never let the voltage go below 160 volts it I can help it. As I drove I kept my eye on gas prices. The lowest price I passed was for regular at $2.57. I have been working at home a LOT for the past year, and I rarely use anything but the Sparrow (and the eGO, but that is another story...). I personally use less than 10 gallons of gasoline each month now, thanks to a job that does not require a commute, and adequate short-range electric transportation. I would not care if gasoline was $5.00/gallon, or even $10.00/gallon (well, that would hurt, I admit) because I just would not spend that much money each month on it. BUT - If I had to start commuting again, I would be just as unhappy with the prices as everyone else. I would be writing to Toshiba about those batteries, that's for sure! There is a new company (http://www.calcars.org) that is expanding the battery capacity of Toyota's Prius - and adding a charger - and presto, essentially, you have an electric car with a gasoline generator backup. Clever. Not to criticize the effort, but much of the benefit comes from "recharging at night" - plugging the car in every night. When people ask me how often I have to charge the Sparrow - and I say "I plug it in every night" - many of them kind of shake their heads. I think the Plug-in Prius will face the same resistance. It's a great idea, though. I wonder why the automobile manufacturers didn't think of it? Oh, that's right, they probably DID and decided NOT to create anything that would interfere with the stability of our petroleum-fueled economy... Is there a better explanation? Anyway, form a line, because there won't be many of these Helectric Cars (Hybrectic?) for a while, and the Sparrow waiting list was more than two years at one point, so I know the interest will be high. It's interesting that Hybrids are so close to being a successful electric car - that adding a bit more battery capacity "tips the balance" and instead of a gasoline car with electric assist, it becomes an electric car with gasoline assist ... perhaps commercial electric cars are not as far away as we have all been repeated told by automobile manufacturers. While I wait for Toshiba to come through with a 200 pound/200 mile/5000+ cycles battery pack, I have my sights on these interesting Lead-Acid (Lead-Non-Acid?) batteries being made in China. These batteries seem to be incrementally better than the Optima batteries in the Sparrow. Not the quantum leap the Toshiba batteries might offer, but better than "state-of-the-art" for Lead-Acid. Sadly, there is no way to get a sample. Note: Today I had to buy 150 lbs of crushed rock for the rim of the pond in our backyard. You can't put that kind of weight in the Sparrow. Amazingly, the eGO pulls a trailer with that load with ease. Round trip to the rock quarry took 20 minutes. Charged from the old Sparrow battery pack in 1 hour. Beautiful. Sun Jun 12 16:00:10 PDT 2005 - 6653 miles The sparrow was off the trickler for a while due to an X10 conflict with someone else on the same house number. All better now. I took it for a ride to OSH for some gardening supplies, and I noticed the voltage was abnormally low. Hmm. Resting voltage was 163. The pack was really low, though, on the way home, like 153 cruise, so I left the Sparrow turned on after I got back home and measured the voltage on the batteries: # front 12.60 12.63 12.61 12.58 12.56 12.59 # back 12.37 <-- 12.59 12.54 12.58 12.56 12.30 <<-- 12.52 Looks like a couple of batteries were weak... The trickler is working perfectly again, so I am looking forward to the next ride to see if the pack is back to normal. Tue Sep 13 20:23:32 PDT 2005 - 6700 Miles The Sparrow has been "resting" in the garage while my wife and I have been pretty much doing nothing but working. I drove it to the Dentist yesterday, 8.5 miles, and it was no different than the last time I drove it. Performance was fine. Voltage was 168 at rest at the Dentist, and 165 volts resting at home. Today I drove the Sparrow downtown and back, about 4 miles. According to the E-meter, the trickle charger had only put about half the Amp Hours back from the trip to the Dentist. Surprisingly, the battery voltage was BETTER today than it was yesterday! It was 170 volts resting in town, after driving the first 2 miles, and 168 volts at home, after driving the full 4 miles. An interesting result, to say the least. I wish I had better tools for testing batteries. I was surfing the Web last night and discovered this: An internal resistance tester for lead acid batteries. Very interesting! I may build one and see if there is anything to be learned from my pack by measuring the batteries this way. Thu Apr 20 18:27:20 PDT 2006 - 6744 Miles Gas around here just topped $3.00/gallon. Time to fix the Sparrow! Luckily I have been able to use the eGO for many trips, but I miss having the weather protection and higher speed of the Sparrow. Before I can get the Sparrow back on the road for "real" trips, however, I need to increase the range. I bought this Computerized Battery Analyzer and I have been testing batteries like a madman. I hope to find the weak ones, swap them out, and get the Sparrow back to work! So far I have found one battery that only registered 6 Amp Hours! I'll be switching it with one of the Pedal Generator batteries once all the tests are done. The tester is excellent - I highly recommend it. Tue Apr 3 21:44:22 PDT 2007 - 6849 Miles And now, almost a year later, gas just hit $3.24 a gallon. While I have been too busy to write much on the Sparrow, I still have it, and it still runs! I expect to dive back into it this summer and locate the one bad battery that remains. Meanwhile, 5-10 miles trips on the ancient, used battery pack are still possible. I have been considering purchasing a new pack. Every vehicle needs maintenance, and the Sparrow has been relatively inexpensive to maintain. We just replaced the clutch in our Saturn Wagon - $580! The Saturn dealer quoted $1,900 - so a new battery pack for the Sparrow does not sound that bad. Let me see - at $3.24/gallon, a $1500 battery pack would be equivalent to only 460 gallons of gas. At the 26 MPG average the Saturn makes, that would take the car 11,960 miles. Add in a few oil changes, and let's say the cost equivalent would be 10,000 miles. Well, batteries are starting to appear that are going to easily outperform the Optimas. If I do buy another set of Optimas, that will probably be the last time I buy old-fashioned lead-acid batteries for the Sparrow. Right now, the cheapest source of those batteries is DeWalt 36 Volt Power Tool battery packs. The cells work out to about $5 each, with a capacity of 7 Watt-hours. There is still a long way to go to equal the Optima cost of roughly $0.33/Watt-hour - but the MUCH longer lifetime of the lithium cells makes them cheaper in the long run. Better batteries are ALMOST here. Sat Aug 25 20:35:33 PDT 2007 - 7000 Miles Today was a big day for Sparrow #95. 7000 Miles! Original drive belt. The eGO continues to be my first choice for short trips on city streets, but for roads with 35-40 MPH limits, and longer (but still short!) trips, I take the Sparrow. Every month or so I hear about some new battery that would likely be compatible with the Sparrow (and the eGO!) so I am hopeful that when the time comes, battery replacement will result in better-than-new performance for both of them. In the meantime, I'm doing just fine with what I have. Sat Dec 22 10:16:39 PST 2007 - 7116 Miles News! I am testing a theory I have about a new LiFePO4 battery pack. This pack is rated for 14 Amps at 12 Volts. LiFePO4 is the latest technology for Lithium-Ion batteries, and it is safer than older LI-Ion technologies. It also features a working voltage range that more closely matches Lead Acid batteries. The pack is about the size of a small paperback book and weighs about the same too. Of course, it's not powerful enough to directly run the Sparrow, but that's not my goal. During my most recent shopping trip, the Sparrow voltage dropped down to 153 Volts during acceleration, and then stayed at 159 Volts during steady driving. I think one of the batteries has reached its limit. I measured all the batteries, and I found one under the seat that is about three tenths of a volt lower than the rest of the pack. I think that battery is nearing the end of its life. Today, I'll hook the LiFePO4 pack up in parallel with that battery and see if the pair can perform well enough to make the drive to the grocery store and back. Before connecting the two batteries together and heading for the road, I tested the concept with an older Optima from the previous pack. It's OLD! I tested it in 2003, and it had a capacity of 10.0 Amp Hours. I have been using it in a large Solar/Pedal battery bank ever since. On November 20 of 2007 I measured it again, and it is now down to 3.76 Amp Hours. I attached all my measuring equipment to it last night, and also attached the new LiFePO4 battery pack in parallel. AND IT WORKED! Using a regular charger, I was able to charge the pair. The charger behaved as if it was connected only to a standard Lead Acid battery. It charged up the twin batteries and shut off. I then started the Powerwerx Computerized Battery Analyzer and tested the capacity of the twin batteries. The first pleasant discovery was that the LiFePO4 battery discharged FIRST, before the Lead-Acid Optima was significantly drawn down. That means the Optima in the Sparrow will be relieved of the first 2.4 Amp Hours of discharge on the trip. As you can see from the battery specs above, it can take an Optima years to gradually lose capacity. The new twin pack may keep me driving short distances for months, or even years. The LiFePO4 battery is rated at 500 Cycles, but I have seen others rated at more than 2,000 cycles, so I have high hopes that this little pack will last for years. I'll add an entry after the trip to the store this morning. My goals now is to limp along and AVOID buying a completely new set of Optima batteries, which have climbed in price over the years to roughly $175 each. The Sparrow pack would cost $2,275 at those prices. The new LiFePO4 batteries are the BEST available alternatives to Lead-Acid, but the technology is so new it is still too expensive to completely replace the Optima pack. And if I can hang on a little longer, there was a recent breakthrough in battery technology that might eventually result in a battery pack for the Sparrow that would be incredible - a range of hundreds of miles and a virtually infinite lifetime. Well, I can dream, can't I? Sun Dec 30 12:23:27 PST 2007 The LiFePO4 battery is still attached. The Sparrow is on my home-made trickle charger, and the voltage of the "hybrid" Optima + LiFePO4 battery is 13.06 Volts. Every other battery in the pack is over 14 Volts. While the charge current is less than 200 mA, amazingly I can hear one of the Optimas hissing. Obviously the "seal" in that battery is leaking, which means the battery is slowly cooking out. That is not supposed to happen, but clearly it does. I am going to turn on the Zivan to see what happens to the individual battery voltages, and then take a ride to the hardware store. Sat Jan 12 18:46:22 PST 2008 - 7147 Miles Success! But not without a little more effort. After the trip to the hardware store, I was poking around with the voltmeter, and I noticed that one of the battery terminals was CAKED with green corrosion! Horrors! My heart sank at the sight. I need to explain that it was also good news, because two things turned up on the hardware store trip that made me unhappy. First. the voltage would sag down to 155 Volts on acceleration on the way home. Second, there was a new, annoying sag-and-surge when I tried to drive at a steady speed. I thought it might be the Polyswitch in the LiFePO4 battery pack cutting in and out. Well, I have news. Today I decided to test those batteries once and for all and see which ones were not pulling their weight. I used zip ties to mount my voltmeter to the hood support, and with the hood open, and the voltmeter probes attached to each battery in turn, I accelerated down the driveway. Why did I never think of this before? Within 15 minutes I had determined that the voltage of the battery with the corroded terminal fell as low as 7 Volts under acceleration! It had to be either a poor contact, or a dying battery. There was one easy way to find out. Fix the contact! I took off the corroded terminal and cleaned it as well as I could. I sprayed contact cleaner on it and I put a green felt "battery terminal washer" on the battery post (it's the negative post) under the cable clamp. I tightened everything back up, and headed off into the sunset. Really, I did. It was 4:30 and the sun was just setting. And the Sparrow is BACK! I drove to Trader Joes to do my week of shopping, which the Sparrow was just barely, painfully able to do last time I tried (with no LiFePO4 booster battery) and THIS time at the red light that is halfway there, the voltage was 170.5!! The voltage never dropped below 160 Volts for the entire trip, and is was at 163 when I was cruising steadily at 30 MPH on the final stretch to my house. There is no doubt in my mind that the combination of the lead acid battery and the LiFePO4 battery is working as I expected. It's working SO well, in fact, I may buy a second LiFePO4 battery for the only other weak Optima in the pack, and postpone buying a complete new pack as long as possible. Meanwhile, LiFePO4 battery prices will continue to drop, and I'll start saving for a 100% LiFePO4 battery pack replacement. Depending on what I am willing to spend, I could get a 100 Mile pack with 2,000 cycles of life - do the math - that's a two hundred thousand mile battery pack! Sat Mar 15 19:01:19 PST 2008 - 7240 Miles And the experiments continue! Last week I received a new Watt's Up meter. These little meters just keep getting better. This one has new firmware that allows the readings to be reset (older models had to be unplugged to "reset" them). I added Anderson PowerPoles to it, and plugged it in between the LiFEPO4 battery and the Optima it was boosting. Then I went for a ride! My hope was that the LiFEPO4 battery would contribute to powering the Sparrow, and the Watt's Up meter confirmed it did. Here are the readings from a 7 mile trip: Starting Volts: 13.65 Ending Volts: 12.64 Lowest Voltage: 11.83 Amps MAX: 4.24 Watts MAX: 51.9 Watt-Hours Delivered: 5.6 Amp Hours Delivered: 0.46 Awesome! Finally, some real data! Generated in real time, on a ride too! That's what I needed to know whether my idea was working. Here is my analysis: 1. I almost always charge the Sparrow with the Trickle Charger I designed. The trickle charger never puts out enough current to push the Optimas to the point where they start to vent gas. It charges them up until their Oxygen recombination cycle begins, and then the whole system stabilizes at that point. Since the LiFEPO4 battery is in parallel with one of the Optimas, it "sees" the same voltage the Optima does during charge (and discharge for that matter). 2. I have Ed Ang's "Angulators" on 12 of the 13 batteries (the Angulator failed on #13 so I took it off), and they never blink (indicating overvoltage) when the Sparrow is on the Trickle Charger. 3. Before every ride these days, I plug in the Zivan for a few minutes to equalize the batteries and also to verify that all the Angulators start blinking, indicating that the Optimas are all fully charged. The Angulators usually start blinking within 60 seconds. 4. The Optima with the LiFEPO4 never blinks. Interesting. The LiFEPO4 battery is holding the voltage down - I believe it is charging during that short period that the Zivan is running! I briefly stopped the charge, unhooked the LiFEPO4 battery, and started the charge again, and the Angulator started blinking immediately! That proves the Optima was charged, but I suspect the LiFEPO4 battery was not fully charged. I think the Optima is absorbing too much of the power the Trickle Charger is producing to allow the LiFEPO4 battery to completely charge. It may also be charging very slowly. I drive/charge 1-3 times a week, and the Trickle Charger can take several days to recharge the Sparrow completely. 5. The Trickle Charger never drives the pack voltage above 185 Volts (approximately). The Zivan will reach as high as 216 Volts (that's as high as I have ever seen on my pack). I believe the Zivan WOULD completely charge the LiFEPO4 battery pack! I'll test the theory by using a regular Automotive battery charger to charge the Optima/LiFEPO4 pair, which will drive the voltage to 15 Volts on that set without needlessly over-charging the entire pack. THEN I'll take another ride, and see if the LiFEPO4 battery contributes more power to the Optima it is supporting. 6. The peak readings from the Watt's Up meter were recorded on the way to my destination. Very little power was added to the readings on the way back. That PROVES the LiFEPO4 battery pack was discharged first - before the Optima! The Lowest Voltage reading is well below the LiFEPO4 battery pack nominal Voltage - which tells me it was totally discharged early in the trip. That is exactly what I wanted to see. My plan was to have the LiFEPO4 battery pack work harder than the Optimas, and it certainly did. I have more tests to run, but so far the idea of pairing a long-life LiFEPO4 battery pack with a Lead Acid battery capable of high-Amperage "burst" discharges looks like it will work! One more interesting possibility it to use the LiFEPO4 battery pack as the "Voltage Regulator" for reach Optima instead of an Angulator. LiFEPO4 battery packs tolerate overcharge very well, and simply begin to heat up - which is exactly what the Angulators do! The LiFEPO4 battery pack costs roughly the same as a 12 Volt battery Voltage regulator, so battery #13 may serve as the test bed of that theory. More tests are planned. Sun Jul 13 20:32:39 PDT 2008 - 7353 Miles Another 100+ miles and all is well. Keep in mind this battery pack is a USED pack I installed in July of 2004! It has been trickle-charged this whole time, and it gradually loses capacity, but I can still make the trip to Trader Joes every weekend for food, and the Sparrow performs well on the trip. During the last 4 years I have been tempted many times to replace the pack again, but I think I am finally calmed down :-) enough to live with it until LiFePO4 replacements are available that can simple be switched in for the Optimas. And yes, that kind of LiFePO4 is coming fast. They will replace automotive starting batteries at 1/4 the weight and 2-4 times the lifetime, giving better gas mileage and easier cold weather starting. And I will be able to buy 13 and simply load them into the Sparrow for a state-of-the-art battery pack. That is the long-term goal, as long as the Sparrow continues to run reliably. David Butcher Mon Aug 11 19:28:14 PDT 2008 - 7384 Miles On a total whim, I purchased 8 Headway 38128L 10Ah LiFePO4 cells. They arrived today. Enough to make a 12 Volt, 20 Ah battery. All of them, together, weigh 2 pounds amd seven ounces. Wow. This weekend I'll rig them up as a replacement for one of the Optimas and start testing. Sun Aug 31 00:36:03 PDT 2008 - 7404 Miles Well, it took longer than I thought to free up time to work on the LiFePO4 cells but tonight I made progress. I have four of the cells assembled into a battery. They are almost fully charged, which I discovered by attaching them to my pedal generator and pedaling in 6 amps or so. The voltage quickly rose to 15 volts and then as I held it there, the amperage tapered down to less than an amp after only ten minutes of pedaling. I'll finish the other four cells tomorrow and then I'll be able to run some serious tests. I have a 1,000 watt Inverter that would happily draw 83 amps at 12 volts if I tried to run a hair dryer, for example. That will be enough to simulate typical current draws while accelerating in the Sparrow. Since the LiFePO4 cells are arranged as two sets of four cells in parallel, each set would only be delivering a little over 40 amps during that test, which is supposed to be well within their capabilities. If they pass that test, they will go into the Sparrow for some serious experimentation! David Butcher