Dead capacitors
 

Hey guys, did something a bit dumb today. I accidently connected the the battery around the wrong way which caused a lot smoke and maybe a little flame from the capacitors of my Pico ESC. I'm hoping only caps have died. I'm going to order a new capacitor module but the only supplier here in Australia has the 3 capacitor module that's on the MMax Pro, where the Pico only has two caps. Will this work with the Pico?

It will work, a capacitor bank is just acting as a buffer and a high frequency filter.

But why searching for a specific RC capacitor bank, go to an electronic component shop and you can find the capacitors in all sizes and values.

But you have to fear the ESC is toasted, you can still try it w/o the capacitor bank.

There's a good chance it will be toasted, but I will check it. It will run without the capacitors?! What do they do exactly?

They smooth out the voltage when the current flow changes abruptly, which helps protect the ESC and can potentially give you a bit more punch.

Don't run the ESC normally without them, but it's fine to test if the ESC is functional without them.

stuff so you reversed the polarity on the esc and poof caps went.. esc is toast..caps on esc don't work as a high freq filter .not wired in that way.. they do help voltage sags only when wired like they are on your esc.

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good thing the 'caps' did not explode... they can.. when powered backwards..but they do have a pressure release body
electrolytic capacitors ... they store and release power...
they are not high frequency filter capacitors..

test the ESC.. but the 'fet's' hate that.. big time.

I reckon it's probably dead but how should I test it? Cut the capacitor module off and connect the battery and see if it runs?

yes,,, see if it drives a motor.. and check and see if bec works a servo.

You could always go to your local electronics store and buy a 4700uf 16v capacitor for cheap then wire it in place of your existing cap bank and see if the esc still works.

Will the ESC still power on without a capacitor?

YES, its main function is to prevent a low voltage issue at Full power starts...
like a run-away.. or shudder..

for testing it is fine..

Yes, the capacitors are parallel connected to the battery wires, they only provide a more stable voltage, not only as a voltage buffer but also as an high frequency filter to damp the high frequency ripple on the power lines.

Without them a normal ESC will still work but the ESC can become hotter if you still want to use it to drive a car.

Thanks guys. Will give it a test tonight and see what happens. If it's dead I'll send it in for repair. Probably going to be a costly mistake!

Have you ever had a high power car stereo? It's easy to see at night when stereo is cranked up and the bass booms, the car headlights will dim. That's because the amplifier is pulling more amps then the battery can deliver. One solution is to add a capacitor inline to the amp. That's the same thing these capacitors are doing. When you pull full throttle from a dead stop the motor will pull a lot of current causing ripples in the battery voltage which can cause problems for the esc's fets.
You can still test the esc though to see if it's fried simply by disconnecting the pinion connecting the battery and squeezing the trigger once. If it turns the esc is good if not it's fried. CAUTION you don't want to do a lot of free spinning of the motor it's not good for it, but one quick test won't hurt anything.

If you fried it a manufacturer won't cover it. They don't cover esc's that were hooked up reverse polarity. And it's possible that it's not fried I accidentally hooked one up backwards once and got lucky.

Test the brakes too. Brakes are often the first to go when reversing polarity.

Thanks I learned something new.

I'm not expecting them to cover my stupidity!

Got some interesting results! I cut the capacitor module off, plugged in a battery and turned the ESC on. It boots up as normal, the steering works, the lights show throttle and brake movement, but the motor doesn't turn. Will the motor turn without capacitors installed, or is the ESC stuffed?

You don't need the caps to turn the motor. The esc is a goner.

Your Pico has a damaged Mosfet board. Maclan will be able to identify a reverse polarity situation visually.

Yep, I am an idiot!

You made a mistake...... big difference....

now if you did 3 like this... WELL maybe.. :)