Quote:
Originally Posted by Gallagher
Will the setup of 6s cells with a lower kv motor generates more spike volts compared with the setup of 4s cells with higher kv motor?
I thought since the current requirement is less in the 6s setup, the spike volt will not higher than that of 4s setup. Is that right?
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If all else is equal, the spike on 6s will most likely be higher than on 4s. A lot depends on
how you apply the brake (jamming it on vs smooth gradual application).
Quote:
Originally Posted by Nick
I've been thinking...
The problem is when you brake/reverse, the motor generates additional voltage.
So, the capacitors need to be inbetween the ESC and motor? The problem is, when you reverse the motor, won't the voltage also reverse down the pos/neg wires? Which means the capacitors have to be non-polarised or they'll go bang.
And which of the 3 wires would I have to connect capacitors too?
I don't understand how putting capacitors on the battery side of the ESC will reduce the spike...?
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The motor is not reversed when braking. Basically the ESC pulse-shorts the motor windings (ever feel the turning resistance if you take a raw motor and connect the phases together?) The spikes come between the PWM pulses.
Do NOT put caps on the motor wires!
Quote:
Originally Posted by Unsullied_Spy
Putting caps on the battery side gives that voltage somewhere to go, since the internal resistance of your lipos is higher than the internal resistance of the ESC (energy follows the path of least resistance) a lot of energy is contained within the ESC causing serious heat issues as well as a lot of wattage running through circuits and components not built to handle it. By adding caps you are giving some of that ESC-killing wattage somewhere to go and they will also help protect against ripple current (a major killer of ESCs). $5ish worth of components can save you hundreds worth of ESCs!
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As I said before, caps won't do a whole lot to reduce the spike amplitude except the fact they take a hair longer to charge does reduce the peaks somewhat.