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EV Maintenance Log

This page covers maintenance and modifications I have made to the car since getting it running.

Sept 7th, 2007Replace BatteriesReplaced original, exhausted pack (was 10 years old, as it turns out) with a brand new pack of seventeen T-105s. See EV Traction Battery page for details.
Sept 16th, 2007Replace Vacuum Pump RelayAfter investigation, turns out that the relay originally supplied with the SSBC vacuum pump kit in my EV Braking System contained a hysteresis circuit, so that the pump would not rapidly turn on and off. I had installed a different relay because it was smaller. I replaced this relay with the original one, and now the vaccuum pump switches on and off less frequently, and without any problems caused by the proximity of the vacuum switch to the pump. (I originally theorized that that was the problem on my EV First Impressions page)
Sept 21st, 2007Replace DC-DC converterThe original Intelipower 9160 DC-DC converter I installed would not produce enough power to run the EV Automotive Electronics when running off of 102vdc. I took it out, and after playing with it on the bench using a variac, my oscilliscope and a dummy load, I decided that it was not possible to adjust it to work on the lower voltage. I replaced it with a Sevcon DC-DC converter that is designed for a nominal input voltage of 60-100vdc. This required making a new combination heat sink/bracket to support it and adapt it to attach to the mounting brackets I designed for the intellipower unit. Fortunately the new converter and heat sink assembly is smaller than the original intellipower so no redesign work on the chassis was necessary. The new converter works fine, putting out 13.5v consistently. I will keep the intellipower unit because I will need it once I move back to my originally planned 136v traction battery. The sevcon unit cost about $280 delivered.
Sept 29th, 2007Repair fuse bracketI melted down a fuse bracket today after one of my longest drives to date (26 miles, mostly at 50+mph). I determined that what happened is that an extra long steel nut (usually used in suspended ceiling instllations) which I had used as a standoff and electrical conductor in the EV Traction Circuit got too hot. Likely this is becuase the electrical resistance of steel is higher than the welding cable and copper lugs used for the remainder of the wiring. The heat melted down one side of the front compartment fuse holder. I knew something was wrong because I could smell it, so I stayed very light on the throttle for the last few miles and got home OK with no damage except for the melted piece of plastic. This also explains the hot smell I would detect every time I dumped more than about 150 amps to the motor I had been attributing the smell to ozone generated by the motor brushes.

Redesigned the fuse bracket to not use the steel standoff. I was probably losing about 100 watts of power or more due to this steel nut's additional resistance so this fix should help my range and performance slightly.
Oct 14th, 2007Replace rear windowSome fine example of humanity put a rock through my rear window today. Theft didn't seem to be the motive as the car was unlocked, and the interior did not appear to have been rifled through. No damage (fortunately) to any of the expensive EV bits. New window found via craigslist same day. On the bright side, I've saved enough on gas at this point to cover the $40 for the new window.
Nov 2nd, 2007Undercarriage inspectionI jacked up the back of the car and looked underneath today for the first time since getting the car going. It looks good, the controller, motor, cabling and (of most concern) all the electrical connections appear to be fine. Despite my having driven in the rain a few times, there is no sign of any water splashing up and getting into either the motor or controller. Nonetheless, still a TODO to fabricate some cowlings and find a brush cover for the motor housing. Also replaced the straight 30wt mineral oil in the transmission with synthetic 10w30.
Jan 4th, 2008Battery wateringFlooded lead acid batteries such as mine require periodic watering to replenish electrolyte that has been lost to evaporation and electrolysis due to the charging process. I added about 1.25 gallons of water across the 42 cells of my 17 Trojan T-105 golf cart batteries. All cells were down an even amount of water (probably about 1/4 inch from full) which is a good sign. If a given cell is much higher or lower than all the others, that can indicate a problem with it. Total cost of this maintenance: $1.88 for two gallons of distilled water.
March 16th, 2008Installed motor brush cover and missing underbody cowlingThe motor brush cover is just a stainless steel strap with ventilation holes cut in it that clamps around the back of the motor to reduce the likelyhood of anything (like a rock) getting into the motor brushes and causing serious damage. I had gotten one with the motor but it was in very bad shape so I just left it off, and have been driving without it. I finally got a usable one as a freebie from the same guy I bought the four extra Trojan T-105s from for my Range and Peformance upgrade. I also installed a factory underbody engine cowl I got off of a parts MR2. The one from my car was missing. This cowl won't do much for aerodynamics but will help keep road spray and debris off the controller and motor.
March 16th, 2008Reroute 12v Battery CablingWhile re-installing the Intellipower 9160 DC-DC converter for my Range and Performance Upgrade, I decided to take the opportunity to reroute the battery cables that hook my 12v garden tractor accessory battery to the DC-DC converter. Originally, I had wired it such that all the loads (headlights, wipers, contactors, etc) were all BETWEEN the DC-DC converter and the battery. This meant that the voltage drop was enough across the distance that the battery would never charge correctly. Since everything was torn apart anyway, I rerouted the wiring such that the DC-DC converter is now Between the battery and all the loads of the car, which should help keep the battery charged more reliably.
April 13th, 2008Upgrade fusesWhen I performed my Range and Performance Upgrade, I also decided to upgrade the fuses in my car. I had originally installed three 48vdc, 500A fuses (which had been sold as 96vdc fuses) and these fuses have always made me nervous, due to their low voltage rating and very spindly construction. I replaced the rearmost of the three fuses of this type in the car when I added the additional batteries, and on this date I removed the other two 48vdc, 500A fuses and redesigned my frontmost fuse holder to take the new type of fuse. The car now has two 130vdc, 600A Ferraz-Shamut semiconductor fuses, both easily replaceable. (one of the three original fuses was very difficult to reach. Guess which one would have blown first..)
April 22th, 2008Build front air damI spent a whopping 2 hours this evening to convert a rear plastic bumper cover from some kind of a subaru into a front air dam as the latest of my attempts at EV Efficiency Improvements. Follow the link for details.
April 30th, 2008Rework vacuum pump mounting positionThe vacuum pump for my EV Braking System is mounted in a fairly tight spot above the right front wheel of the car under the front compartment. It came with a set of rubber shock mounts to isolate vibration, but I did not install these because of clearance issues. I instead bolted the pump directly to the car body. This made it quite loud inside the car. While it was not too noticeable when driving, it was very annoying at a stop. I finally got around to modifying the pump to fit better in that spot, and remounting it using some rubber shock mounts that I salvaged from the MR2 during the initial conversion. I did not use the shock mounts that came with it because they turned to be very fragile. Anyhow the vacuum pump is much quieter now.
May 5th, 2008Paint Job!At long last, I have gotten around to taking the car into Maaco to get the bodywork finished and have the whole car repainted. The job took about a week (though they initially said two days) and it came out about as I expected for a $1000 worth of body work and paint. Once they rework a few minor issues with the paint under warrantee (a couple runs and an area with some dirt that got into the paint) I will be satisfied with the job. The rework needs to wait until the current paint is fully cured which will take a couple of weeks. Still, it looks way better than it did before. I will shortly be taking some new pictures for the main page of my Toyota MR2 EV project log.