Electric Vehicle C

[HandsFreeCookieDunk]

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.

[finagle29]

Banning two cell LiPos was probably a safety thing

[Ed63]

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.

[windu34]

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

[Ed63]

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.

[windu34]

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?

[gh]

LiFePO4 cells are 3.3V nominal and charge to 3.6V.

[Bazinga+]

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'.

[chalker]

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

[windu34]

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.