Futaba 2.4ghz system - Cap required?

[Chris Green]

Hello all,

I'm having a bit of a problem with my 2.4ghz futaba system, and my matrix speed controller.

Basically, off the start line, sometimes I get a bit of a stutter, where the power cuts out. This is typically on the first time I apply full throttle. It doesn't happen every time, and it is not linked to one particular set of cells.

Also, sometimes if I put my car down on the track for the first time, if I apply full throttle, down a straight, and then apply full brakes, the brakes don't work at all, and the car accellerates at full speed, until it hits something. (Only minor breakages so far! :woot:).

What I think is happening, is that the radio system is losing power, when the maximum current draw is being applied to the motor? Does that make sense?

The Nosram matrix I have, does not have a power cap on it.

Would it be advisable to fit a spektrum capacitor? would this help?

Thanks,

Chris.

[markwilliamson2001]

Hi Chris,

I was thinking about what you said on Friday about this. I don't remember seeing a capacitor on Neil Craggs B4 attached to his receiver, but I am sure he had one attached to the power wires on his Speedo. This maybe what is causing your problems, but it might be worth checking the manual. I know my novak said that you MUST always use one, and when I didn't on my old Novak Cyclone, I had terrible dumping problems for some reason (this was with 2000 cells mind), but once fitted the problems went away.

http://www.oople.com/rc/photos/worksop270108/OOP_7789.html

It is jus to the right of the speedo in the above pic.

HTH
Mark

[Chris Green]

Hi Mark,

The latest versions of the matrix speed controllers (as in your photo), include a capacitor. My version didn't, but the fact that they added one to the later models, tells me it would be a good idea.

However, I'm thinking the spektrum power capacitor that plugs into the receiver would be the best bet?

[markwilliamson2001]

Try both. I read that the spektrum one stops glitching, but not really the problem your having. I would say fit both, then you won't have a problem, or its with the setup on the speedo. Do you have it on NIMH or is it on auto battery detect.

Try that as well.

Mark

[Chris Green]

the version I have doesn't have a lipo mode, so I guess its on the right setting.

I'm having trouble finding a spectrum capacitor at the moment!

[markwilliamson2001]

I think you could make one up with an old receiver plug and some thin wire. Just get the matching cap from maplin!! I might have a receiver plug you can use of an old servo, so you could use that wire as well!

Just need to find out the spektrum cap rating.

I will try and find out for ya!

Mark

[strobe]

Hi Chris & Mark.
The details on my Spektrum cap is: 10V. 4700uf. 105 Deg c.
Hope this helps.
Mark

[Chris Green]

Cheers for that Mark.