Cap packs?

[FatCatRC]

What are cap packs for? And are they used for normal bashing not just speed demons?

 

[The Donut Man]

When an ESC tells a brushless motor to spin up, the motor draws power from the battery in a stream of very short "pulses" rather than a constant supply; this is one way brushless motors differ from brushed DC motors. These pulses create what we call "ripple voltage" which fluctuates above and below the actual voltage of the battery pack. In high powered systems where a lot is being asked of the motor (like in speed-run or drag cars), this ripple voltage can spike high enough to fry the ESC if it's not kept in check. Because capacitors can charge and discharge much, much faster than a battery (because batteries take time to release power), a bank of capacitors can act as a filter and smooth out the ripple voltage to a safer level. It's insurance for your power system and some speed-runners have reported that their ESCs run cooler when using a cap pack.

As for if a cap pack is needed for bashing, the best bet is checking your data logs if your ESC is capable of logging. Ripple voltage is considered safe if it's under 10% of your max. battery voltage, and I can't imagine (unless a basher is way over-geared) that a basher setup would get close to that. But I honestly don't know!

 

[LibertyMKiii]

When an ESC tells a brushless motor to spin up, the motor draws power from the battery in a stream of very short "pulses" rather than a constant supply; this is one way brushless motors differ from brushed DC motors. These pulses create what we call "ripple voltage" which fluctuates above and below the actual voltage of the battery pack. In high powered systems where a lot is being asked of the motor (like in speed-run or drag cars), this ripple voltage can spike high enough to fry the ESC if it's not kept in check. Because capacitors can charge and discharge much, much faster than a battery (because batteries take time to release power), a bank of capacitors can act as a filter and smooth out the ripple voltage to a safer level. It's insurance for your power system and some speed-runners have reported that their ESCs run cooler when using a cap pack.

As for if a cap pack is needed for bashing, the best bet is checking your data logs if your ESC is capable of logging. Ripple voltage is considered safe if it's under 10% of your max. battery voltage, and I can't imagine (unless a basher is way over-geared) that a basher setup would get close to that. But I honestly don't know!

This is a great answer.
I'll add that if you are using a factory Arrma ESC or any of the Hobbywing ESCs it is probably not needed. Same for the Castle MMX8s.
Other Castle ESCs were lacking capacitance and need capacitors. (MM2, XLX, MMX6s)

A cap pack does not add any measurable amperage or power to the system. As doughnut man wrote up, the cap pack acts as a filter to smooth out those oscillations in the power going into the ESC. This reduces stress on the ESC.

 

[LMC]

I was curious about this as well, I’ve seen plenty of capacitors used in high end car audio but didn’t get why RC’s neeed them, now I know.

 

[FatCatRC]

When an ESC tells a brushless motor to spin up, the motor draws power from the battery in a stream of very short "pulses" rather than a constant supply; this is one way brushless motors differ from brushed DC motors. These pulses create what we call "ripple voltage" which fluctuates above and below the actual voltage of the battery pack. In high powered systems where a lot is being asked of the motor (like in speed-run or drag cars), this ripple voltage can spike high enough to fry the ESC if it's not kept in check. Because capacitors can charge and discharge much, much faster than a battery (because batteries take time to release power), a bank of capacitors can act as a filter and smooth out the ripple voltage to a safer level. It's insurance for your power system and some speed-runners have reported that their ESCs run cooler when using a cap pack.

As for if a cap pack is needed for bashing, the best bet is checking your data logs if your ESC is capable of logging. Ripple voltage is considered safe if it's under 10% of your max. battery voltage, and I can't imagine (unless a basher is way over-geared) that a basher setup would get close to that. But I honestly don't know!

Okay thank you! ya I run a Max 6 v3 and just field runs and a lil bashing but no speed runs or drag races.