Electric Vehicle C

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Re: Electric Vehicle C

Postby HandsFreeCookieDunk » February 28th, 2016, 7:15 am

Sorry to whine on here, but I'm a little confused.

Why is the voltage limit for battery packs 7.2V when the two cell LiPo battery packs that are recommended for pretty much every motor are labeled 7.4V? I mean, I guess it's not that big of an issue since I can switch to regular 9V batteries, but I was wondering if anyone knew if the intent of this rule was to ban the two cell LiPos.

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Re: Electric Vehicle C

Postby finagle29 » February 28th, 2016, 7:23 am

Banning two cell LiPos was probably a safety thing
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Re: Electric Vehicle C

Postby Ed63 » February 28th, 2016, 7:44 am

Brushless motors are great, but a brushed motor is just fine for this event. We're using a brushed motor and battery directly connected and getting times in the 1.75 to 1.80 sec range. We have been the fasted car at both invitationals so far this year. Sometimes simpler is better.

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Re: Electric Vehicle C

Postby windu34 » February 28th, 2016, 7:51 am

Ed63 wrote:Brushless motors are great, but a brushed motor is just fine for this event. We're using a brushed motor and battery directly connected and getting times in the 1.75 to 1.80 sec range. We have been the fasted car at both invitationals so far this year. Sometimes simpler is better.

What how?? I am barely getting those times with my brushless setup
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Re: Electric Vehicle C

Postby Ed63 » February 28th, 2016, 8:48 am

3000mah 7.2V NiMH battery, DC brushed motor, belt driven gear set. We originally had a faster motor but didn't have enough traction to use it. Kept spinning out.

You can definitely get enough speed with a brushed motor setup.

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Re: Electric Vehicle C

Postby windu34 » February 28th, 2016, 9:12 am

Ed63 wrote:3000mah 7.2V NiMH battery, DC brushed motor, belt driven gear set. We originally had a faster motor but didn't have enough traction to use it. Kept spinning out.

You can definitely get enough speed with a brushed motor setup.

motor specs? brand?
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Re: Electric Vehicle C

Postby gh » March 2nd, 2016, 8:47 pm

LiFePO4 cells are 3.3V nominal and charge to 3.6V.
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Re: Electric Vehicle C

Postby Bazinga+ » March 3rd, 2016, 3:35 pm

Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.
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Re: Electric Vehicle C

Postby chalker » March 3rd, 2016, 4:31 pm

Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.


I think this FAQ relates: https://www.soinc.org/node/1664

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Re: Electric Vehicle C

Postby windu34 » March 3rd, 2016, 5:31 pm

chalker wrote:
Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.


I think this FAQ relates: https://www.soinc.org/node/1664

No, I believe what Bazinga+ is referring to is not crossing the first photogate at the beginning and instead of moving forward, back the vehicle up a bit (for example 2 meters backwards from the starting line) and then accelerating so that he has more room to accelerate rather than the given 0.5 meters to the first photogate.
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Re: Electric Vehicle C

Postby chalker » March 3rd, 2016, 6:54 pm

windu34 wrote:
chalker wrote:
Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.


I think this FAQ relates: https://www.soinc.org/node/1664

No, I believe what Bazinga+ is referring to is not crossing the first photogate at the beginning and instead of moving forward, back the vehicle up a bit (for example 2 meters backwards from the starting line) and then accelerating so that he has more room to accelerate rather than the given 0.5 meters to the first photogate.


I understand exactly what the question was, hence my statement that that FAQ 'relates' to it. The FAQ says it's ok to stop and reverse at the end of the run, thus some assumptions could be made that same applies at the beginning of a run.

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Re: Electric Vehicle C

Postby GoldenKnight1 » March 4th, 2016, 3:24 am

Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.


First, I love the idea.

4.d. States "No part of the vehicle can be further than 1.00m behind the start line." Now I might make the argument that the intention of that rule was only to be at the moment of activation but that was not how it was written and there is no FAQ addressing it.

If it was allowed though be careful in your planning as you won't necessarily know how much space you will have behind the start line to do this.

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Re: Electric Vehicle C

Postby JonB » March 4th, 2016, 4:29 am

Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.



This exact idea has been a hot topic of debate within our team. Some would read the rules and say "okay" and others "no" (some might state "spirit of the games" rule...). At the regional and state level I feel that you could get a run violation or something of the like because ES would not expect to see something like that. You could arbitrate but the outcome of that is such a variable. It is a gamble that might not be safe at many levels of competition. Honestly, I feel the safest place to do something like this is actually nationals being that they are expecting teams to find creative solutions to problems.

Of course, this is all just my opinion.

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Re: Electric Vehicle C

Postby Bazinga+ » March 4th, 2016, 5:44 am

JonB wrote:
Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.



This exact idea has been a hot topic of debate within our team. Some would read the rules and say "okay" and others "no" (some might state "spirit of the games" rule...). At the regional and state level I feel that you could get a run violation or something of the like because ES would not expect to see something like that. You could arbitrate but the outcome of that is such a variable. It is a gamble that might not be safe at many levels of competition. Honestly, I feel the safest place to do something like this is actually nationals being that they are expecting teams to find creative solutions to problems.

Of course, this is all just my opinion.


Yeah that's what i was thinking. Do you think the track length for nationals will be announced? Like the furthest distance the car can go and the furthest back it can go.
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Re: Electric Vehicle C

Postby JonB » March 4th, 2016, 9:37 am

Bazinga+ wrote:
JonB wrote:
Bazinga+ wrote:Are we allowed to have the car go backwards right when it is activated and then start going forward like 2 meters behind the starting line? I don't see any rule against it but not sure if that would be 'in the spirit of the competition'.



This exact idea has been a hot topic of debate within our team. Some would read the rules and say "okay" and others "no" (some might state "spirit of the games" rule...). At the regional and state level I feel that you could get a run violation or something of the like because ES would not expect to see something like that. You could arbitrate but the outcome of that is such a variable. It is a gamble that might not be safe at many levels of competition. Honestly, I feel the safest place to do something like this is actually nationals being that they are expecting teams to find creative solutions to problems.

Of course, this is all just my opinion.


Yeah that's what i was thinking. Do you think the track length for nationals will be announced? Like the furthest distance the car can go and the furthest back it can go.



I do not think it will- especially after this conversation. haha


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