Added some caps.
I finally got around to adding a capacitor to each of my two stock Spartans. They both now have brand new ESC's.
I may try testing on 6s just to see what kind of temps arise.
And still cannot locate my water proof GPS to do some speed runs with the 2 new CNC props.
What does a capacitor do on a boat?
In as simple as I know how to explain it, the use of the additional power capacitor is necessary to dissipate noise and smooth voltage spikes, and will also improve the performance of speed controls in boats or cars/trucks by reducing the operating temperature by 10-15 degrees F.
You do need to add capacitors with low ESR (equivalent series resistant) such as the ones I used by Rubycon, 35v @1000 mfd ZLH series.
The stock ESC has 2 capacitors already right?
So you added additional ones?
Yes I added just one capacitor to each speed control.
Depending on the results after I do some test runs, I may add one more to each ESC.
I ordered 10 of these capacitors and will be adding them to my rc trucks as well.
Whats RC Trucks are you looking to add Caps to? What ESCs? Curious if I should add one, or something similar to my MMM2 ESC I'll be putting into my Traxxas 1/10 Rally. Also what size props are you going to be testing?
Originally Posted by orca44
For starters I'm going to add one to my E Revo and to my mmp ESC that is in my 4x4 lcg slash. I'll most likely add them to my 2wd Slash's that have Castle SV2 ESC's.
I'm going to be testing a CNC x442 and a CNC x443 prop. They work good but since I can't find my GPS I don't know what sort of speeds I'm running.
I have been using 2 1000uF caps 35v but they are axial. One lead on each end not both on one end. If you bend them into a u shape the leads line up with the posts and leave a clean install with the can of the caps sitting between the original caps and the wires for the motor and touching the top of the esc case. They were from radio shack and only a few bucks. I will try to post a pic later. And while running hard on 6s the caps are all cooler than the motor. Telemetry data says 135 on motor. ( dual pic up and separate cooling lines) it seems like a good and cheap insurance policy for the esc as it definetly runs much cooler now.
Just by chance, do you know if the capacitors that you got from Radio Shack were/are low ESR caps?
The axial lead caps work good for soldering right on to the ESC battery connections.
Can someone post a link for what caps I should buy for my boat?
This is where I got mine.. There are a lot of suppliers of low resistance capacitors, some are counterfeit so choose a reliable source.
http://www.thecapking.com/whatwestock.html Go down to 35v caps and locate the Rubycon 35v 1000 mfd ZLH cap. I think I paid .60 each.
http://site.thecapking.com/Files/ZLH.pdf This is PDF of the capacitor
Where and how are these new caps connected? Do you have a picture?
I don't have a picture of mine, but here is a Traxxas link and go to post #14 for the picture..
In the meantime I guess I should take some pics of mine.
Can you add more than 1 additional cap?
I don't understand why Castle wouldn't install bigger caps, if it makes such a big difference. If we can get them for a few bucks, then it's pennies on the dollar for them. I feel that there has to be a loss somewhere. Maybe a shorter run time, because the capacitors are consuming some voltage that could be going to the motor? Just wondering...
Yes. A capacitor is only storing energy in itself, which is then used when a device, in this case the ESC, is requiring a large amount of current or voltage.
Originally Posted by RobF353
In the use of capacitors installed on/in a ESC, they are there to absorb spikes in supplying voltage from the batteries to the motor.
I have copied this from another source and added my own information.
First and explanation/theory...
First a watery analogy, water running in a pipe and through a tap. Now turn off the tap quickly. You'll hear a loud knock/shock sound in the pipe. The water wants to continue flowing but it can't, for a moment the water pressure is much higher than the static water pressure. It's the same for a current that's switched off, because of the inductance it wants to keep on flowing, voltage gets higher.
The speed controller is like a water tap that's switched off (and on) very fast (8,16, 32kHz PWM) to get the desired current. Turning off the current, in combination with the battery wire inductance, causes voltage spikes because the current wants to continue on its course (ref. inertia of the moving water column). Those voltages are higher than the battery voltage. The input capacitors (the one's on the ESC) takes care of these spikes (they reduce the wire inductance). The longer the battery wires, the higher the voltage spikes induced in the wires, the harder on the input capacitors. They will get warmer, heat up and explode. This is caused by the wire inductance, not by wire resistance. So adding extra capacitors are the solution, thus reducing/compensating the wire inductance. Longer motor wires instead of long battery wires will reduce inductance.
So I repeat, in the case of Capacitors used in/on an ESC, they are used to absorb SPIKES!!!!
You may want to know that according to Castle, running partial throttle makes your ESC work harder than at full throttle. But full throttle will stress the batteries when their rating does not meet the current demands of the motor/load of the system.
Hope this clears the air a little!!!!
Does Castle recommend adding capacitors? I understand them helping with the voltage spikes, but that's why caps are already on the ESC. If I'm understanding you, it's beneficial to add a capacitor if you have longer battery wires? So if we have our stock battery setup, then there's no need for extra caps?
According to Traxxas and Castle, if you don't have a capacitor pack installed, your total ESC to battery wire length should be no more than 5 inches. If you have a capacitor pack installed you can have 8 inches. I don't know about you guyz, but when I bought my boat and Lipo's, I had 5 inches of wires just on my batteries alone. Now, I have a total wire length of 5 inches with a CC Cap Pack installed.
Awhile back I called and spoke with a tech at Castle as to adding capacitors to the Spartan ESC, and the tech I spoke with said to contact Traxxas, although Castle did say I could use one of their cap packs. But did not want to say that I could add one of my own.
Originally Posted by Carnes99
If there was no need to add caps to the stock ESC we would not be having this discussion. The manufacture is not going to admit it is needed, if so, they would do a recall and fix them themselves or provide us with the part to do the modification. They will as in my case and others, replace/repair under warranty the defective part until the warranty has expired.
Smaller capacitors have lower ESR, (Equivalent Series Resistance) hence the use of smaller caps and the area to install them. When Caps are installed in a parallel circuit, the capacitance increases and the ESR decreases.