This voltage protector offers 3,300,000 uF of energy storage in a small and lightweight package.
.
more powerful multicopters bring us the opportunity to use bigger cameras, very big and complex gimbals, and of course big and powerful servos.
a servo, being a motor, needs a big available "immediate" energy, which means high current, when it starts moving.
capacitors are used to store energy for fast discharge application, and most of us know the "voltage protector" devices for RC, which are usually about 10,000uF capacitors that are plugging in the RC receiver and will give more stability and stored energy,
with the latest developments of EDLC (electric double layer capacitors) and high energy capacitor,
the ability to use them in the RC field is now possible.
.
Comments
I hope you dont mind a bit of input from a 'newbie' on the site?
As an electronics engineer whose experience dates back to before the days when computers ran on gas, i have to agree with the comments made by Bernard and others above, but would like to add the following comments from experience.
Its true that there will be lots of low value caps, dotted around the circuits at many points. Generally in electronics, that employ IC's and the like, a large value capacitor is used to add stability to the voltage rail, its value depending on the current within that circuit, and its frequency response, is generally very low, and in the order of a few tens/hundreds of Hz. Smaller capacitors, are employed to filter out the higher frequencies, often extending up into the radio spectrum, with values ranging from 0.1uf right the way down to a few pf.
Looking at the scope graph above, some of the spikes are 10ms apart, so the external noise is in the order of about 100Hz which a capacitor of this size would struggle to filter out completely, a smaller value of 10 to 100uf across the measuring point would certainly reduce that.
Generally, the higher the frequency you want to protect against noise, the more often a low voltage capacitor is used, especially around IC's where 1 cap per chip is usual. Wires and PCB tracks act as 'aerials' in picking up noise, so on longer runs of wire, more caps are preferred, especially where brushed DC motors are used, because these are very effective 'transmitters' of RF noise.
I dont think in reality, the flight time would be much reduced, a capacitor of this variety is VERY efficient. If the capacitor has 'X' amount of energy stored, that came from the battery in the first place, at the end of the run, when both battery and cap are discharged, you will have used the same amount of energy, as if just the battery was used. It would be different however, if the cap was fully charged, and then a freshly charged battery was fitted.
This capacitor is effectively reducing the impedance of the supply source, allowing higher instantaneous peak currents to flow when demanded, and helps to keep the voltage at a constant level, but however, its no real solution for a poor installation that has undersized battery supply cables, allowing a greater voltage drop during peaks of high current..
Anthony, that's not it at all.
The idea is to use the cap as a storage reservoir to keep up the voltage going to the servos during transients. When servos get a command to move fast, they take a lot of power, which can cause a dip in the voltage supply. The Cap helps supply power during the transient, holding up the voltage.
ultracapacitors or vanadium plating?
I am not sure how this discussion will grow. :-)
Placing 3.3 M uf is huge:-)
I would try 10 uf Tantalum Capacitors near a servo power source to help the pulse drains.
Tantalum capacitors weigh less and can do almost the same. http://www.engineersedge.com/instrumentation/tantalum_capacitors.htm
A large capacitor is generally known as an all round panacea for noise problems. If you are using a huge electrolytic capacitor, for example, just after a ubec, the power on time for the electronics can be considerably slowed. Voltage regulators can fail to reach their designed initial condition, and microprocessors in the autopilot and in digital servos can fail to initialise, seemingly randomly. Some of these super caps have a fairly high internal resistance, so the massive advertised capacitance is just not as effective in reducing noise spikes as the lable might lead you to believe. Now ARHEXA makes some pretty impressive claims, and I do not doubt that in this particular case they are quite genuine. If the reader tries this and does not have the same success, then I suggest he takes careful note of the particular capacitor chosen, and places it in the circuit in exactly the same way ARHEXA has. Otherwise he may be bighting off more than he can chew.
Remember; bigger is not always better.
Two of these in series would give you 10 Million uF of capacitance, at only $10 (plus a bit of heat shrink and an extra servo lead) for $10 USD. You should realize however that these will put a LARGE load on your BEC when it is trying to come up to voltage when you first turn it on. The energy to run your servos and such after you loose power has to come from somewhere, and it will flow from your BEC limited only by the resistance of the wire connecting it and the internal resistance of your caps, essentially shorting your BEC for a period of time (just like when you plug in your lipo you get the pop from the spark). This large load could cause booting problems its self. For the $21 USD the author wants I would install a small receiver pack as a redundancy measure. Also note that your equipment will continue to run after your plane is switched off.
yeahhhh i have a 1 farad, 500gr capacitor in my car stereo .
I will put on my drone hahahahaha
If ur trying to sqweese more battery/flight time out of ur aircraft by using huge storage capacsitors, this is not gonna help...
A Capacity works like a shock absorber, and a storage place for current.
But it sucks every amp from ur battery that the cap. can hold so your not extending battery life, you storing it and then releasin it.
Now if ur just tring to give ur servos more accurate voltage, then this should help, but i think it will cost u in flight time because of shortened battery life
-
1
-
2
-
3
of 3 Next