This blog is the story of taking a 10 year old Twike that has been setting idle in a backyard in Portland, Oregon and restoring it to is former glory and getting it back on the road. It is Twike number 434.
I'm at 664 miles mostly commuting from work to home and back. Some of the trips have been to downtown Portland in the evening to attend a OEVA meeting which makes for about 36 miles a day (with two charges since my range about 20 miles). Yesterday, I went for a hike in Forest Park with my son Paul. We picked out a nice starting point, drove the Twike there, did a nice 2.5 hr hike and drove the Twike home (10 miles round trip and lots of elevation gain). A true green activity since I charge with 100% renewable electricity from PGE at home. On a more technical note, last weekend I replaced the differential oil with a synthetic brand. This seems to have fixed a lot of the noise problems I was having at 40-50 mph. There is still some noise but much less. I may still need to look at the motor mounts and see that they are lined up and tight. I think next on my list is to fix the canopy from opening so far that it hits the plastic windshield. Over time I think this contributed to is loosing its grip/glue on one half. I still on occasion have problems with the speed sensor going out, mostly when its hot and usually after lots of regen (like on my trips into Portland). Pulling over for 2 minutes and restarting seem to fix it for now. I have email from a friend in England who suggests the speed sensor needs adjusting and gave me details on how to do it, but it is involved and may involve dropping the motor/differential. Not a 5 min job. I have driven every day to work since July 1 except for 3 days when we had 106 or near 106 (really high temps mess with the charging), when I went to Boy Scout Summer Camp (drove my gas car, ugh), and went to Florida on vacation (took a plane!). Every day it gets more and more natural to drive and a gas car feels more and more foreign when do I drive one. My Lexus needs a 90k service and it may be its last ;-)
Today was the OEVA EV Awareness day in Portland, Oregon. We had vehicles of many types from conversions, to factory production vehicles, to motorized bikes. I was there all day with my Twike since I can now drive from my house to downtown and back and I'm also part of the OEVA group. What made my day though was when a Tesla showed up. The owner is David Stiers who you may remember as the actor who played Charles Winchester on MASH! It turns out his is retired and lives just south of Newport Oregon. He heard indirectly that there was something happening today in Portland around Electric Vehicles and thought it would be great fun to show up. He found our web site and just took it upon himself to drive the 130 miles from Newport to Portland (good to have a Tesla with 240 mile range). Thus this afforded me several things. One, I got to meet him and a fine gentleman and in good humor he was. Secondly, I got to see my first Tesla in person after reading about them for ages. And thirdly, probably not the first but one of the few shots of a Twike and Tesla together. I have a 2kwh pack in the Twike and can go 20 miles, the Tesla has a 50kwh pack and can go 240 miles (and of course top speed is 150 miles per hour). I have him in efficiency but he has me in every other category (except luggage space, I think I win there). Thanks to David for just showing up as he is one of only 3 Telsa vehicles in Oregon (so I hear). In regards to the Twike, it is doing great and it getting regular use as I drive it to/from work everyday.
Today I put on 36 miles (a new 1 day record). I drove the 8 miles to/from work and worked out at Bally's during a late lunch. I zipped home and did a quick top off charge so I could drive all the way to downtown Portland for the monthly OEVA (Oregon Electric Vehicle Association) meeting. Coming home was kind of a challenge in that it is 10 miles, climbs over 1000 feet in elevation and I had it do it with my lights on which suck more power. No problems and I made it with about 30% battery power remaining. With 12 year old NiCad cells, I am not quite sure how much capacity I can rely on. BTW, the picture is of my license plate "Oregon TWIKE". It is a motorcycle plate because in the state of Oregon, a Twike is licensed as a motorcycle.
Starting yesterday, I am doing my daily work commute via the Twike. The missing piece was getting a second battery pack working well. I drove yesterday and today to and from work which for me is just under 8 miles. I don't yet have a good feeling for how much power it is taking to do my commute but today it only took 1.2Kw to charge it when I got to work (and that was after it ran the fans for a while to cool the batteries). The NiCads can deliver lots of power but they do heat up in doing so and right now we are having a heat wave in Portland which does not help. I got lots of thumbs up and waves today. One guy was keeping next to me and yelling out his open windows. "hey! really cool. Where did you get it? Did you build it?" that kind of stuff. Kind of hard to drive and answer questions in traffic. Work is cool about letting me charge there (used 12 cents of power today). I'm not sure, but I might have enough charge to go roundtrip without charging at work. Tomorrow I'm going to try a trip to someone's house that is 13 miles away so we will start to test the range a little more. Currently, my longest single trip is the 8 miles to work. Since I brought it home, I bought 3 new tires, had them mounted and balanced, and I installed them on the vehicle. I also did a lot of cleaning up in the battery compartment and on all the removeable panels (bottom and sides). With two reasonable battery packs, the car is pretty snappy on acceleration. I can keep up with traffic no problem and can even hill climb at a reasonable rate (not as fast as a car but at least I *can* accelerate uphill now). I have been taking a less direct route home to minimize the hill climb time (I climb the hill by winding through a neighborhood as this allows me to drive slower without annoying anyone). On the way to work however, I go straight down the hill with regen on full sucking amps back into the batteries. Tonight my odometer read 204 miles. Expect a lot more miles in the weeks ahead.
Last night I drove the TWIKE 8 miles from Northwest Portland to my house for the first time. It had to climb over 1000 feet in elevation. This was a real test of the 2nd battery I got working and only the second charge cycle on that battery. I know from experience from the other batteries that it takes several charge cycles to wake up the 10 year old NiCad cells. I expect the range now with two batteries is around 15-20 miles on level ground. I am working on a third pack that should extend that to nearly 30 miles. I have lots of other small things to work on and some larger ones. I need to replace all three tires. I noticed that one has large cracks (not surprising for a 10 year old tire). This must be fixed before I can consider much serious driving. It was amazingly stable at speed and at one point I think I was exceeding the speed limit without realizing it. EV grin here I come!
Today, I found an Insurance agent that would insure my TWIKE and not just for liability, but for collision and comprehensive as well (all at motorcycle rates which is far cheaper than any of my cars). Once I had insurance proof in hand, I stopped by the DMV and applied for a title (including vanity plate). One big smile later, I had a 3 month temporary sticker in hand ready to apply to the back window. Look out, I'm fully street legal with no inspection required.
Last night I put in the second battery pack I put together with the old Ni Cad cells and one of the 5 tested BMS boards. I was able to set the controller to 2 batteries, download new BMS software from the controller (it did not like seeing 5.24 BMS software when it is 5.1), and do a normal charge to top off the batteries. I put air in the tires, cleaned the outside of dust, and took it for a spin. I gave rides for the better part of 2 hours until I felt I should charge it up again. The odometer read 5.1 miles! I noticed that one pack is stronger than the other as one was supplying more of the current and took more current on the recharge. I'm thrilled that the charging system works as well as it does. I have so much more technical understanding of the entire BMS/BATTERY/CONTROLLER system now that I have debugged all the problems bringing up these old battery packs. I estimate each pack is about 2Ah (2.8 originally) and that puts me at about 16 mile range for the two packs. I should be able to build up the third pack in the next couple of weeks which should get me close to 25 miles of range per charge. This should be enough for my daily commute while I work on getting my lithium battery built (expected range 40+ miles). I'm thrilled! I still have a long list of little things that need attention including the seat belts (retractors are sticking .... may replace seat belts), wood steering handle is split (patch for now), one of the plastic panels under your feet is broken (someone stepped on it while it was out of the car), etc. Also, I need to start the DMV/Insurance stuff now so I can get the vehicle home from Northwest Portland. If all goes well, I will be able to *drive* it home.
On Monday night on March 16th 2009 I put my partially charged reconditioned battery pack in the car with the intent of having the car charge it. Even though with level 2 access I could tell it it only had 1 battery, I could not get it to charge the battery. Then I tried just powering the car. It worked. I was able to put the car in reverse and move the car a few feet! I am working hard on getting the second battery pack reconditioned enough to get about 2Ah out of it which should be good for about 15 miles between the two packs. This is assuming the car will charge them full up. I should know in another week or two if this is possible but it was great to see the car move under its own power. I continue to work on my lithium based design which will eventually replace the Ni-Cad pack.
I have not posted since November, 2008. Sorry about that. Here is a summary of what has happened on this project since then. I purchased the rest of the A123 M1 cells I needed for $5.50/cell. I have 450+ cells now. I have been looking at BMS designs so I can protect these cells (they need to stay between 2.5 and 3.7 volts for best life and safety). Apparently, this is an area that is lacking in good off the shelf solutions. I will either need to pay lots of $$ for a solution (i.e. more than the cells themselves cost) or build my own so I can customize it to my specifics. As part of this effort, I have a demo board of the Linear Technologies LTC6802 chip. It seems to function with my testing so far but I will have to add up the cost of the parts to build a functioning BMS (shunt based design) to see the true cost. In the meantime, I started to do a serious attack on the TWIKE battery BMS setup. At this time, I am not pursuing the software based BMS any further as it became too difficult to see what was going on to try to emulate it correctly without any working real BMS boards. I turned my focus to the hardware itself and will the help of a friend at work, we got 5 working BMS boards to talk to the service program. I also located a disassembler for the BMS software to get a better understanding of how it works. That was fun as I looked at 3800 lines of assembly code! Over the last 30 days, I have been doing charge/discharge cycles on one of the best looking old NiCd packs. I was able to restore about 60% capacity by cycling the old cells. Last night at Synkromotive I carefully soldered back in a working BMS board (14 temp sensors, 7 voltage monitor wires, 14 cell to cell connections, 1 power connection, 1 RS485 4 wire communication connection). As I wired up the last connection, the board red led started blinking! After connecting it to the car and putting the car in charge mode, the car downloaded BMS software to it and began to read out the battery pack voltage! This proves the car charge/controller system is working properly and the other battery pack I was trying to charge has a bad BMS. I also discovered how to get into service mode on the controller (TWIKE Access Level 2). This lets you set all kinds of good stuff on the controller including the number of batteries. I tried setting it to 1 battery (which I did not know was even supported) and it seems to be working happily with 1 battery. When I tried to charge the battery, it complained that the battery was too hot (77 deg C). Clearly, I messed up one of the temp sensor solder joints. I'll have to run the service program to find out which one and fix it before trying to charge it for real. Next steps are to put another working BMS into another candidate battery after I do the battery testing to make sure the cells are good. With two old tired batteries, I should get 10 to 20 miles of range (for testing) while I work on my Lithium solution. I'm thinking 112s4p would be a good starting setup. Even with LION cells and my own BMS for Low Voltage Cutoff and Shunt Based overcharge protection, I may integrate 1 or 2 old BMS boards to make it trivial to keep the onboard controller happy (Both on charge and discharge). A hybrid solution may be the path of least resistance. We'll see. Stay tuned for more.