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Post by rdlb on Oct 31, 2015 13:57:07 GMT -6
My secular employment has included for forty some years electric drive control systems. I have seen material handling equipment go from carbon pile resistor, brushed series wound motors and wet cell batteries to transistorized drive controllers with AC brushless motors and gel celled batteries. Soon lithium-ion to be debuted as a battery source. www.yale.com/north-america/en-us/announcements/press-releases/first-commercially-available-lithium-ium-ion-battery/ Battery chargers with mechanical timers to smart charging systems to on demand charging systems. Batteries that have computers that communicate with the chargers to charge according to the needs of a specific battery. Electric vehicle batteries to be replaced are not cheap. Improper care during the cycling of the battery through usage, charging and cool down can and does shorten the life of any deep cycle battery. Battery technology has greatly improved and life of the newer batteries has increased. Yet, currently most consumers are not fully educated on the use and application of electric vehicle maintenance. I do see that the hybrid vehicles are a step in the right direction, on demand charging stations for certain vehicles a step as well.
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Post by lowell on Oct 31, 2015 16:04:13 GMT -6
Batteries are continually evolving, another thing to consider is the continued evolution of the super capacitor. It can provide power for the initial phase of electrical demand and allow gradual increases in lithium ion battery power consumption. www.sciencedaily.com/releases/2015/10/151024092537.htm
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Post by rdlb on Oct 31, 2015 18:11:05 GMT -6
Batteries are continually evolving, another thing to consider is the continued evolution of the super capacitor. It can provide power for the initial phase of electrical demand and allow gradual increases in lithium ion battery power consumption. www.sciencedaily.com/releases/2015/10/151024092537.htmAll of our electric drive control systems use capacitors in many ways, to shut down the main SCR by reversing the polarity and having a high positive current going against a lower positive current thereby shutting off the main SCR. Another way is to smooth out the three phase DC or AC current spikes for smoother operation within the traction motors. I have found that the older caps can burn by high current stored through a hand. I use a resistor to dissipate the energy stored in a controlled way. I am interested in what they consider "high" temps created in EVs. All of our units have protective circuits with thermal cutbacks to allow cooling of parts of the system. However with AC drive control and motors this rarely occurs. Interesting commentary above as all of our DC power controllers which convert DC current to three phase AC current internal temperature sensors are set at 60F to turn on fans to force air through a vented heat sink. The fans rarely come on yet, the heat sinks are made of aluminum and are usually mounted to a large thick steel plate. With that said, during R&D of our three phase AC traction motor and controller. The AC brushless motor was purposely stalled for 72 hours, the controller did heat up and lost some internal parts of the which were replaced with stronger components. The motor however suffered no damage. A brushed motor would have burned up through the brushes, brush holders and pulled and distorted the commutator bars. The heat damage that i have had to repair has usually been loose connections at the main power cable lugs, either the controller or at the motor. Most of the heat is at the batteries during use or charging as current flow has a certain amount of resistance through the battery. Resistance=heat, heat=resistance. Brushed motors thermal cutback around 160F and if the current limit is set too high for short trip operation. AC motor thermal cutback is lower and we have not seen any issues there.
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Post by lowell on Nov 1, 2015 2:07:52 GMT -6
"HITECA, can operate at temperatures of up to 200 degrees Celsius. " 200 degrees Celsius = 392 degrees Fahrenheit Another article about the same breakthrough is found at: www.industrytap.com/electric-cars-travel-further-on-new-ceramic-battery-technology/12742"Britain’s National Physical Laboratory has designed and developed a new high temperature ceramic capacitor in hopes of improving the use of electric and hybrid vehicles, which could mean that the vehicles can travel much greater distances on one battery charge. Electric or hybrid vehicles all need the necessary cooling equipment because of limitations in the temperature rating in many components like capacitors that store electrical energy. As a result, additional cooling systems are required in the vehicle, which all add weight and hamper its power and efficiency.
In response to this, the NPL has developed a ceramic capacitor dielectric material that has a high energy density. The material, HITECA, can operate at temperatures of up to 200 degrees Celsius. Tatiana Correia is a Higher Research Scientist in Functional Materials at NPL and was the leader behind the research. “Industrial electronics need to be able to perform in the harsh environments in which they operate,” she says. “The ability of HITECA capacitors to function at higher temperatures than existing capacitors will help make electronic systems more robust and remove barriers for technologies such as electric vehicles that rely on them.”
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Post by matador on Nov 4, 2015 20:02:01 GMT -6
When they build a truck that can haul a trailer 8-12 a day at a speed of at least 65mph, I'd buy one in a heart beat.
Electric vehicles have a long way to go to be a complete viable answer to everybody. Back in the 80s or maybe the 70s there was talk about electric vehicles on a wired highway, where the vehicle had contacts similar to electric trolleys. Back then there was no way that would happen, the cost and how to charge for the electricity was beyond our knowledge but that doesn't mean it won't come to reality in the future.
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Post by lowell on Nov 4, 2015 22:43:00 GMT -6
The hydrogen fuel cell can power an electric truck hauling a trailer for 8 to 12 hours a day, providing you stop at future service stations that refill the hydrogen. Jelly like mediums have been developed that make the hydrogen fuel tank safer than a gasoline fuel tank. The jell has been shown to be effective at absorbing the hydrogen and releasing it to the fuel cell as needed.
Toyota uses an extremely strong tank. "Toyota reached back to its roots as a loom manufacturer in the early 20th century to create triple-layer hydrogen tanks made of woven carbon fiber.
The tanks, which are lined internally with plastic, underwent "extreme" crash and ballistics testing, Hartline said, noting that they were "shot with bullets that actually bounced off."
"They had to move to high-caliber armor-piercing rounds to pierce the tank, and even then it had to be shot in the exact same spot twice with an armor-piercing bullet," Hartline said.
The Mirai has other safeguards, including structural integrity to protect the tanks and electronic systems that are programmed to shut down any hydrogen lines in the car if a leak is detected. "So there are redundancies upon redundancies," Hartline said. "We're not going to put anything on the road that doesn't meet our safety, quality and durability standards.""
"The advantage of hydrogen fueling stations is that there's really a global standard that doesn't require specific tooling. Cars will be able to refuel anywhere, all the nozzles will be the same," said IHS analyst Devin Lindsay.
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