we have the same equipment exact problem

Dump my Q2 that works:weird: just to make work with the Spectrum that should have been re-called:eek:

It was my understanding that those ESC's don't put out enough power for the receiver to run the servo, hence why you need to install the cap to get it to work. Everything I read thus far about this issue is related to that speed control and certain servos. If it were me I would be on LRP rather the Spektrum, but this is just my opinion.

I have been running the Spektrum since they were available. My unit is from the first batch!
I run a Q2 and an Airtronics digital servo. I have had absolutly zero problems with the unit. Maybe the difference is that I run the LRP World's kit on the ESC!!

The reson why the cap did not work on the LRP ESC was becuase it was a Novak cap!! For a capaciter to work at all, they are to be matched to the MOSFET's that the ESC use. Since Novak and LRP ESC's use different MOSFET's they require different capaciters!
MOSFET's in the ESC's open and close at specific intervals. The cap has to be designed accept power in the same interval the the MOSFET open's and closes. If the MOSFET is open when the cap is closed, the cap will not store any power and it will not do anything to help your problem. You need a cap that will work with the LRP MOSFET's. Or, to make it easier to understand, you need a cap that will accept and store power when the MOSFET releases it!!
Your best choice is to run the LRP World's Kit. Your problem will be solved!

Matching Cap ????????
 

Trying to figure out if your being serious ? A cap charges when power is input to it. You really think novak or lrp design and manufacture their own caps........ What you just said makes absolutly no sense

Re: Matching Cap ????????
 

I'm with you on that one. It does not make any sense to me either. I would think a cap is a cap. All they are doing is buying them from a supplier and sticking their lable on it. I'm not an electrical engineer, but that just does not sound right.

A cap is a device consisting of 2 or more conductive plates seperated from one another by a dielectric nonconductor such as glass , mica , plastic , or dry air , used for storing an electric charge. Now tell me what component allows a cap to open or close at a specific or any given time for that matter ?

Re: Matching Cap ????????
 

I am 100% serious. My terminology may not be 100% correct but caps are designed to work within a certain range. If the MOSFET's in the ESC do not operate within that range, the cap will not be as effective as the correct one or will not offer anything at all. Even on the Novak website you will see that, vist the LRP website as well. All caps are not the same. Not all caps will work with all ESC's.
Look at the Novak website where thyey offer 3-4 different caps. All the caps they offer are to be used with specific Novak ESC's. They, the manufacture call this out in bold, red type. They say do not use this cap with any other ESC than those listed!!
Novak says that not all their caps will work with all their ESC's. So what makes you think that any Novak cap will work with an LRP ESC????

Never said that a cap open and cloeses...I said the MOSFET opens and closes. But if cap is not designed to accept the strengh of current the MOSFET puts out or for the same duration that the MOSFET remains open, the cap is not effective or as effective ias it could be in storing the power.

Yes given a caps rating or size.... If you install a cap that is too small it will not work. We are not using the cap for the speedo....... We are simply storing power for the reciever/servo to utilize when the bec doesnt produce enough. 4700mf is plenty for this application. I am not looking to argue i am willing to learn , but the info needs to be correct.

Re read your post................ " If the mosfet is open when the cap is closed"

Re: Re: Matching Cap ????????
 

what the site says is that a 680 micro farad cap will not work on speedo's that require a 4700micro farad cap. Basically the only difference in cap is the composition and the size. different materials behave differently and basically have different caracterisitics. one such characteristic is the speed at which the cap will charge. think of a cap as a small battery. the material it is made of and the size will dictate how fast it will chager. the microfarad rating is basically the capacity of the cap. so you see that there is no such thing as a "Novak" cap or "LRP" cap.

what may make a difference is the material the cap is made of and the size. with these 2 differences, the transition time between when the extra power is needed by the receiver and servo may make the cap not very effective. think of it like this if it take one second to charge the cap, but the receiver and servo combo needs the extra juice every .5 seconds then the cap is not effective. at that point you have 2 options reduce the size of the cap or the makeup of the cap. so that it will charge faster. the problem with going smaller in terms of micro farads is that the amount of "charge" may not be enough to help the receiver\servo combination.

The important thing is to balance the power requirement with teh size and rating of the cap. not the make and model.

this is also true on the speedo thing.

Now what theisgroup stated makes sense.