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tamiya wrc

Receiver power capacitor

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Hello!

I am writing regarding receiver power capacitor, I did not have any problem with glitching I was just curious what is actually the difference with or without it. I have Futaba 3PV transmitter with 314SB receiver, so I have the telemetry information about voltage of the receiver on my transmitter. When I make fast steering moves with Savox servo motor I noticed that the voltage on receiver start droping from 6V to 4,8V in the worst case. So I decided to install the power capacitor on my receiver and I thought that with installation the voltage will be constant 6V, but there is actually no any difference?
How is work power capacitor and it is OK that is power capacitor connected into S.BUS2 port on receiver? Maybe any ideas or thoughts about topic? See attached electrical scheme.

Thank you.

Power capacitor 30.3.2018.PNG

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did you DIY the cap?

2200uF isn't much... I think most stutter stoppers use 6800-8700uF single electros or there's some with a PCB of multiple smaller caps totalling around 8000 too.

my savox are very power hungry 

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I build a DIY capacitor, with a 2200uF 16v capacitor too.  

It was cheaper than one that's already made ($4.75 for 10 capacitors instead of $7 for a built one).  

Sadly, it didn't stop my Savox from twitching.  As WillyChang says, maybe 2200uF wasn't enough.  I think I'll try larger capacity.  

 

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3 hours ago, edeneen said:

it doesn't work, so you wasted $4.75 trying to save two bucks?  LOL

 

Oh yes, I am glad I didn't order 10 built-ones.  I would have wasted $70 (Savox sellers pair with the same 2200uF capacitors, and reviews were split on the effectiveness of them).  

I think I'll spend another $5 and order five 6800uF capacitors --twice as expensive as 2200uF.  I was going to upgrade my fleet's servos with Savox, I'm glad I didn't do that.  I've got a $5 Chinese metal gear servo works fine.  $35 Savox isn't working so well.  I'll spend another $5 for some capacitors, and see if they work.  If not, I'll never buy Savox again.  

EDIT: @tamiya wrc  DIY just means "Do-It-Yourself."   Since you bought a $10 LRP glitch buster, your's isn't DIY.   

 

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all my Savox are super thirsty... ok they're also very torquey and crazy fast, but they cause brownouts & glitching quite often even on proper good gear like Spektrum... they might even had a hand in smoking an RX.

Futaba servos of the same speed/specs aren't as crazy on current draw imho; both are the shorty/aileron types popularly used for touringcar steering few yrs back.

Perhaps they also want full 6.0V not lesser 5.0V so check your BEC output.

 

Hobbyking sells their cap for ~$2 :lol: cheaper than I can buy either cap or servo lead for. They go 3300uF, it's about half size of a AAA battery. Stock up each time I need to pad out any order.

If you've got many empty slots in your zillion-channel RX you can plug in multiples... or hack the lead to solder on more caps in parallel.

If you're into electrolytic physics supposedly smaller caps have "faster response" than larger, so it's worth using multiples. Get a scrap of breadboard and wire them up!

You can also pay premium for caps rated for faster response (ESR? ESD? dunno)... but I think these are more for high-frequency circuitry with repeated drain/recharge demands... not the one-off every-now&again service we're using them for - so no point paying extra for those. (but if you get them free yeah they'll work just the same)

 

 

 

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I ordered two 5800uF thumb sized glitch busters for $7 on ebay (built ones).  $3.50 a piece is one dollar more than the Hobbyking stuff.  But 5800uF is larger too.  I hope they can prevent me from hammering the Savox to save my sanity...

 

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