Hobbyist Forums banner

Capacitor Banks

10K views 59 replies 27 participants last post by  geitz2003 
#1 ·
All our racing classes are based on using 1 cell Lipo power (a maximum of 4.220 volts) to power the motor and an optional receiver pack of limited capacity to power the electronics. In 3 of our classes we specify the use of the SMC 4000 MAH battery with the specific intent of limiting the availability of battery or power capacity.

Recently we've become aware of the use of so called ultra or hybrid capacitors of very high capacities (for instance, 750,000 microfarads). A capacitor is an energy storage device similar to a battery and we consider the use of these "super" capacitors as providing an additional power source other than the batteries allowed by rule.

As a result, effective with the Spektrum 300 at Hobbyplex this weekend, we are prohibiting the use of these auxiliary capacitor banks in all classes. Vehicles will be limited to those capacitors typically supplied by the ESC manufacturer or the equivalent.

We suspect some may argue that these high capacity capacitors don't really make a difference. If they don't make a difference, then removing them causes no problems or loss of performance. If they do make even a small difference, then removing them brings things back into balance with the intent to use only the batteries permitted by the rules as a power source. As we don't allow even one thousandth of a volt of extra battery capacity at tech inspection for battery voltage, allowing the unlimited use of an alternate energy storage device such as these super capacitors doesn't make sense.
 
See less See more
#52 ·
The tighter the spec the more rules needed. Simple classes need more rules unless you add the following statement. Unless stated as allowed in the rules its prohibited.

I can even see issues with the mud boss rules they simply say you have to use stock parts, but different versions of the kits come with different parts. so far all I see is different body mounts, but who is to say at some point they won't have other parts different. I think the rules should say use traxxas pn xxxx instead of use the kit parts. Much more clear.
 
#56 ·
My point was to clarify rules before it becomes an issue. Since the springs in the lcg kit are not legal, what is to stop traxxas from releasing a kit that includes the lcg chassis and those springs stock. I think the rules could be changed to simply state the only legal springs are pn xxxx. Legal shocks are pn xxxx. Much like they did with the little bumper. I would also like to see the body template in the rules. They are flat parts, so why not release the spec for the panels so they can be checked as well. I am sure people will copy them since they are not hard to make and a bit expensive to import. All this should make the class grow and keep it one design.

This class seems to be taking off and my local shop says they are having a hard time getting kits. They can get the Gordon body kit which has different body mounts, had to buy the "stock" ones so the body would fit without drilling more holes.
 
#59 ·
This is just my $0.02 worth. TOUR says in the rules that battery voltage can be checked before the battery is plugged in to the speedo and AFTER it is plugged in.

DIRECT from the TOUR rule book.

Voltage Limits:
1s Li-Po batteries may be charged to a maximum of 4.22v. Batteries presented to Tech over the 4.22 max voltage will have to be drawn down to 4.20 before they will be allowed to race. This should prevent the problem with voltage creep back up over the legal limit.

Voltage verification do be done as part of standard pre-tech race procedure

4.22V per cell is not only the maximum voltage per cell that Li-Po batteries may be charged to......it is the maximum voltage per cell allowed to be presented to the motor drive circuitry for the purpose of powering your car.............period.
Any attempt to use a secondary source of power (receiver pack battery or booster) to drive the motor at a higher voltage than 4.22V per cell is prohibited. No sneak circuits, no gray areas. This is blatant cheating.

If any violation of this rule is suspected, the race director has the right to perform an “in-line test” of the car’s operating voltage on the starting grid. A connector wired in the configuration below will detect all voltage influences on the motor drive circuitry.

On page 8 of the rule book there is a diagram showing the type of connection that will be used to validate that there is no back feeding or other influences on the supplied voltage to the Speedo.

I have NEVER seen anyone do such a check.
And when I do see guys show a pack at 4.23 or more volts, most of the time they just run the motor until it shows 4.22 on the meter and they let them go out and run.

TOUR has the rules, I don't know the BRL rules well enough to comment on them, so I can't comment on that.

If someone is suspected of cheating, via sneak circuit or what not, all the race director has to do is pull the car, prior to the start, and check the voltage at the battery or at the motor.

Forcing everyone to buy more speed controllers, motors, batteries, etc only chases away drivers.

When you have a rule in place, use it.
In my opinion BRL did just this. NO CAP BANKS other than stock per mfg.
Any questions.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top