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builds:mcqueen
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builds:mcqueen [2016/11/24 13:16] thejerm [Datalogging and display] |
builds:mcqueen [2016/11/24 20:55] (current) thejerm |
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| {{:builds:mcqueen:pforile.jpg?direct&600|}}\\ | {{:builds:mcqueen:pforile.jpg?direct&600|}}\\ | ||
| - | //"LiPo turned Baltimore's car - a good vehicle that was designed to run just behind the speed leaders - into an absolute, adrenaline-charged beast that could now out-pull and out-run nearly every car since the beginning of the fused era."// | + | //"LiPo turned Baltimore's car - a good vehicle that was designed to run just behind the speed leaders - into an adrenaline-charged beast that could now out-pull and out-run nearly every car since the beginning of the fused era."// |
| Built By: [[http://baltimorehackerspace.com/|Baltimore Burners]]\\ | Built By: [[http://baltimorehackerspace.com/|Baltimore Burners]]\\ | ||
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| Qualifying third in its debut race weekend was quite inspiring, and Baltimore knew they had a winning formula on their hands. When the 2016 rules came out and allowed the use of LiPo batteries, the Baltimore team bought 8x 5Ah 14.4V LiPo battery packs to replace one of their LiFe packs which had been driven negative during some testing. Since an 8S LiFe can use a 60A fuse but an 8s LiPo can only use 50A, the ECU switched its current limits out based on the voltage of the battery pack at controller boot. | Qualifying third in its debut race weekend was quite inspiring, and Baltimore knew they had a winning formula on their hands. When the 2016 rules came out and allowed the use of LiPo batteries, the Baltimore team bought 8x 5Ah 14.4V LiPo battery packs to replace one of their LiFe packs which had been driven negative during some testing. Since an 8S LiFe can use a 60A fuse but an 8s LiPo can only use 50A, the ECU switched its current limits out based on the voltage of the battery pack at controller boot. | ||
| - | Despite the reduced current limit, LiPo turned Baltimore's car - a good vehicle that was designed to run just behind the speed leaders - into an absolute, adrenaline-charged beast that could now out-pull and out-run nearly every car since the beginning of the fused era. | + | Despite the reduced current limit, LiPo turned Baltimore's car - a good vehicle that was designed to run just behind the speed leaders - into an adrenaline-charged beast that could now out-pull and out-run nearly every car since the beginning of the fused era. |
| The switch to LiPo was a clear, immediate, unexpected, and unbeatable performance gain for this vehicle. Though the current limit went down 17%, the voltage increased by nearly 13% so net power out of the battery could remain fairly unchanged. Additionally, battery impedance went down on the LiPo pack so the voltage did not sag under load. This meant that net power to the motor actually increased substantially under heavy acceleration. The creation of McQueen's first LiPo pack was paired with a change in system wiring from 10AWG to 6AWG, which also contributed to the decreased system impedance and increased power. Finally, the higher voltage of LiPo coupled with its lower impedance meant that the car could now hit 23mph on a fully charged LiPo pack, much higher than the 19mph that it was capable of on LiFes. Remember what your KV rating means, folks! | The switch to LiPo was a clear, immediate, unexpected, and unbeatable performance gain for this vehicle. Though the current limit went down 17%, the voltage increased by nearly 13% so net power out of the battery could remain fairly unchanged. Additionally, battery impedance went down on the LiPo pack so the voltage did not sag under load. This meant that net power to the motor actually increased substantially under heavy acceleration. The creation of McQueen's first LiPo pack was paired with a change in system wiring from 10AWG to 6AWG, which also contributed to the decreased system impedance and increased power. Finally, the higher voltage of LiPo coupled with its lower impedance meant that the car could now hit 23mph on a fully charged LiPo pack, much higher than the 19mph that it was capable of on LiFes. Remember what your KV rating means, folks! | ||
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| When McQueen was rebuilt into the sensorless-brushless-driven, lithium-powered vehicle it is today, Baltimore kept with the idea of a quick-change battery pack but moved the location of the pack to under the front hood. this would make extraction during a race easier (since it would be vertically extracted) as well as slightly improving the weight distribution since the battery pack is now forward of the front axle instead of behind it. The battery is lifted out of the car by pulling on a rope strap, and a new battery is dropped into placed, allowed to latch, and plugged in. During an endurance race, a well-executed battery change will not increase driver change pitstop times more than a couple seconds. | When McQueen was rebuilt into the sensorless-brushless-driven, lithium-powered vehicle it is today, Baltimore kept with the idea of a quick-change battery pack but moved the location of the pack to under the front hood. this would make extraction during a race easier (since it would be vertically extracted) as well as slightly improving the weight distribution since the battery pack is now forward of the front axle instead of behind it. The battery is lifted out of the car by pulling on a rope strap, and a new battery is dropped into placed, allowed to latch, and plugged in. During an endurance race, a well-executed battery change will not increase driver change pitstop times more than a couple seconds. | ||
| ==== Detachable Trailer ==== | ==== Detachable Trailer ==== | ||
| - | After observing the utility of TrainRex and the fun of towing people around, Baltimore decided to expand their trailer lineup by building a themed 1-seater trailer for Lightning McQueen as well. The seat is a standard folding chair, painted in Lightning McQueen's red, with yellow racing stripes. Towing around cargo or a person does significantly impact McQueen's acceleration but due to the current-limiting ECU, full-throttle performance is still possible (provided a passenger can hold on). | + | After observing the utility and fun of TrainRex's boxcar and caboose, Baltimore decided to expand their trailer lineup by building a themed 1-seater trailer for Lightning McQueen. The seat is a standard folding chair, painted red with yellow racing stripes. Towing around cargo or a person does significantly impact McQueen's acceleration but due to the current-limiting ECU, full-throttle performance is still possible and overall top speed is unaffected (provided a passenger can hold on). |
| {{ :builds:mcqueen:2015-10-29_19.48.50_2.jpg?direct&300 |}} | {{ :builds:mcqueen:2015-10-29_19.48.50_2.jpg?direct&300 |}} | ||
builds/mcqueen.1480015016.txt.gz ยท Last modified: 2016/11/24 13:16 by thejerm
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