The Old Capacitor Trick - and some background on why and when to use it.
The problem
Bought a Novak GTB 4.5R Brushless "Current sucking hog" and had tons of glitching.
So I slapped that brushless system in the Ultra-Pede yesterday and glitching problems galore. Geared 13/87 - which from the online threads seems to be a little under-geared. Just like a Lady Gaga sound... Da..da..da..da..daaaaaaaaaaaa.. Like it's attempting to send Morris code.
I get zero glitching and non-existent cogging (as advertised) when running with the wheels off the ground, however the moment the Pede hit the ground I get glitching when attempting a full throttle take off. If I do a slow start no glitching then I can punch it full throttle without glitching. I also get some glitching at extended 20+ foot ranges. I also seem to only get a feel of the full power and speed when the wheels are off the ground otherwise when on ground it only seems to only have about twice the power of the old Titanite.
Batteries are standard PowerMax Pros, GP3300s and similar style stick/shotgun packs with Deans Wet Noodle and plugs added. Even after resolving the glitching issue, to get the full power of the brushless system and I had to do a high current battery pack conversion - see this.
Attempting to move the antenna around to see if it was a antenna/power wire related issue, but did nothing. Tranny is packed with plenty of Lithium Grease to minimize radio interference. Dropped a new battery in and thought for a second that cured the issue but started glitching just as before. The ESC was set at factory default, with the exception of running Drive Profile 2 (100% F/R mode). But have tired other profiles with the some glitching results. Drive frequency is fixed in brush-less mode on the GTB.
The esc is mounted in standard placement with the power wire side of the ESC on the left (antenna side of the Pede) and the receiver and wire harness bundle is on the right. This points the blinky ESC lights forward and allows the two separate groups of wires to go around each side of the rear shock tower. I also twisted each group of wires to shorten them and hopefully cancel out any potential other interference problems. That process in itself did not relieve the major glitching issue but may reduce any other issue that may have occurred - i.e., still needed a capacitor. Just covering all the bases in advance.
The Solution from the conversation with Novak
Talked with Novak tech support. Their recommendation was two fold.
A. Separate the power and signal wires, currently my are all zip tied together in a 1/2" bundle. That did nothing.
B. Purchase a capacitor to plug into the battery pack slot on the receiver or use a battery pack. That should provide enough juice to the receiver to get through the initial current hit on the battery during hard acceleration.
What they say occasionally happens is that there is such a huge initial current draw that the receiver current drops low enough (a brown out of sorts) that you momentarily loose signal because there is not enough power to run the receiver, then of course everything rebounds and the process starts over again and then the voltage pogos until you let off the trigger. To you it looks like glitching.
Novak was correct in diagnosing my issue. Moving the cable did nothing, although I left them separated as it seemed like a good idea.
The receiver was in fact experiencing a "brown out" during full acceleration and with the addition of a simple 1000uf (1000mf) 35V polarized capacitor from Radio Shack the glitching issue was resolved although everything worked even better after going to the Novak 5700mF Cap.
The glitching issue was history after this very minor "The Old Capacitor Trick" upgrade and will take longer to explain than do.
What Capacitors do for your RC car
Caps store energy, like a battery, so think of a capacitor as very short term battery backup for your receiver or ESC. They can be used on the ESC or the Receiver whichever needs it. I found one article which indicated that your should have a cap on both your ESC and receiver as a standard piece of equipment to prolong the life of each which is typically shortened from continuous voltage fluctuations. Think of it also as a power conditioner for your electronics.
What to Buy
If you can go buy the Novak 5700mF cap ($5), you will be most happy with it when used in connection with a high current brushless system. That said I initially used a 1000uf 35V Axial-Lead (polarized) Electrolytic Capacitor from Radio Shack that worked and killed the big glitching issues. The key when looking for a cap at Radio Shack is that it needs to have arrows on the label of the cap (a polarized capacitor), be of decent quality, 10+ volts (35V is the norm and is overkill since you BEC and receiver or only 6V max) and be at least 1000uf (same as 1000mf), but preferably 4000-6000mF. The bigger the number the more current it stores, but keep in mind there is a point where bigger is just bigger.
The 5700mF is all you need up to doing timed high speed runs where the motor is pulling so much current continuously that the cap doesn't have a chance to recharge. In that situation you really are better going to a receiver battery pack and disconnecting the BEC. Although I originally thought a 4700uf (4700mf) was plenty, the 5700mF makes every setup run with no glitching, so my recommendation to everyone is to use the Novak 5700mF capacitor.
The Radio Shack ones are rated for 35V whereas the Novak are for 10V and are therefore about 1/2-1/3 the size and are more easily mounted and still deliver the same power. Your BEC and receiver only kick out 5-6V so, anything over 10V really is overkill and adding weight.
How do I make one of these things: It took some digging on how to hook it up.
The arrow on the cap. points in the direction of current flow (from + to -) so the tip of the arrow is - and
Scrounge a spare receiver jack and solder the red (+) lead to the + end of the capacitor and the Black (-) lead to the - end of the capacitor. Remove the third lead. I also picked up the variety grab bag of Radio Shack shrink wraps and shrink wrapped everything up so no sparking could occur. I also put a nice big shrink wrap over the whole cap for protection - gee looks just like the Novak on the ESC. Then plug it into the spare battery slot on receiver, the same one you would use if you were using a battery pack on your receiver and tucked the cap around the front of the receiver. That's it - super simple. The capacitor will charge from the power supplied from the ESC as needed and will discharge when current drops suddenly.
Crude picture but you get the idea of how to solder it together. Make sure you shrink wrap everything well. Capacitors can spark. Capacitors generally can last a very long time but don't last forever, so if you get a year or two with heavy use you are doing great.
I also want to re-stress that even after resolving the glitching issue, the potential of your brushless system is almost solely dependant on the quality and build of the battery pack. 3000Mh batteries are an absolute minimum, GP3300 are better, and 4200Mh are preferred. You spent the cash on the brushless system, don't get all cheap on the power source. To get the full power of the brushless system either buy your packs already set up in a side-by-side configuration or do a high current battery pack conversion yourself - see this. As a brushless system will melt stock Tamiya connectors and overheat stock power wire, I am assuming you already know that you should be using either PowerPoles or deans as connectors and something like Deans Wet Noodle power wires.
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