Servo current draw

[vvviivvv]

Hello gents,

Does anyone have any data on servo current draw? I'm unable to run boats for a few months so can't test it for myself (or have access to my boats)

I'm looking to optimize a racing setup that I have a specific amount of watthour to compete in,

There's no specifics on using a rx pack / bec my theory is, i can leave the main battery to power the motor, rather than using the BEC attached to the ESC to power the servo.

It's a oval course with very short straights so almost constant adjustment on the rudder for the faster boats (speeds aren't anything above 60mph / 100km/h)

Probably use a Savox 1258tg black edition or 2265 black edition these are fairly small hulls sub 900mm / 35"

Anyone have any data they'd care to share?

[Panther6834]

If you spend some time googling the info, I guarantee you'll find it...servo data IS there for the finding. You can also email manufacturers for the info...whatever you don't find via Google search, you can get that way.

Btw, Savox servos tend to be a bit on the "power hungry" side. Might be worth checking into Hitec, Power Hobby, PowerHD, AGFRC, NSDRC, and ProTek.


~ More peace, love, laughter, & kindness would make the world a MUCH better place

[vvviivvv]

I could probably google it like you say but then what's this forum for... Not trying to be a nag but i do like to use the search function on the forum and read old threads full of valuable info

If we all google everything and don't bother contributing, the forums will continue to decline

[NativePaul]

I haven't seen any servo testing here, all I have seen was from RC Review on youtube, it isn't 100% applicable to us as he uses mainly rock crawler cars and his testing is mainly about the stall torque and amp draw at stall, and mainly does full size servos, but while not the way I would test, you can infer some degree of efficiency information from his videos.

To me the most interesting thing to see was that like LiPo C rates servo specs are usually marketing BS with little basis in reality, that they can only get away with as there are so few people testing.

Those are some pretty heavy servos, personally I run a 9g servo in minis, a 20g micro servo in 1, and a 35g mini servo in 2, I only use full size servos in bigger boats than my race boats. I have always favoured torque gears with <.18s/60 degrees, but recent speed geared servos are claiming as much torque as my servos while being twice as fast so I am considering switching to speed servos, however I want to test whether it is actually servos improving, or just marketing BS improving.

I haven't done any testing as yet (I do plan to) to say how efficient they are for us, but I shy away from using Savox for classes 1 and 2 because they tend to be whiney, plenty of folks do so they work for sure and maybe they will test out to be the best, but until I see testing saying they are better than the competition I will take a quiet servo over a whiney one.

[Xrayted]

I can only guess based on many years of anecdotal observations with my RC helis. I had a few helis with opto ESCs over the years, so I used a separate 2S lipo for the electronics. I would burn 350-450 mAh per flight, getting about 4 flights on a 2200 mAh RX pack, but consider that is powering 4 HV servos at 8.4V plus the flight controller, and the flights were 5 minutes each, not the typical 2.5-3 minutes like a boat race.

I dont think there will be that much if any runtime gain by removing a single servo from the main battery on your boat, but it would be an interesting experiment. I'm sure its there on paper if lab testing, but at the currents our boats pull, a hundred extra mAh is gone within seconds, and I'm not sure if that would even rise above the noise floor vs the variability in mAh from one run to the next that occurs naturally on any boat?

[Panther6834]

I could probably google it like you say but then what's this forum for... Not trying to be a nag but i do like to use the search function on the forum and read old threads full of valuable info

If we all google everything and don't bother contributing, the forums will continue to decline

On one hand, I get what you're saying. Unfortunately, to be completely realistic, this can't be applied to every situation. For matters that are specific to RC boating, I can understand, and agree with, what you said. After all, this is an RC boating forum, and if one is looking specifically for RC boating information, an RC boating forum should be the perfect place to find such info. However, when it comes to RC matters that aren't specific to RC boating, that's when you need to expand your resources, which can include other RC forums, and using Google. That's what I, and many others, do. If you didn't find what you were looking for via the forum search function, and if people responding don't have the specific/exact info you're looking for, them using the Internet to find said info becomes your realistic option.

On the other hand, speaking of the forum search function, you say you use it...so, I can only assume you already did that, and didn't find the info you were looking for, thus you asked the question you did. If that's the case, and you didn't find the info, then the next logical step is to search where the actual answers might be found...in other words, googling, as already suggested.

Not "trying to be a nag" (to use your words), but, while you're waiting for others to answer, you could easily do what was suggested, see if you can find the info you're looking for...and, assuming (actually, I should say 'knowing') you'll find it, you could post the info as a reply, so that others don't have to do the same thing. Which leads me to part of why this forum (and other forums) are dying - because people ask questions that others don't have the answer to, then they Google the info, and find what they were looking for...but, they don't post the info to help others (ie. they only help themselves). When I've asked a question (on any forum), and don't find the answer from other forum members, if I end up googling, and finding said answers, I always reply to my thread, providing the answers, so that others might have use of them in the future.

Whatever you decide to do, I wish you the best of luck in finding your answers...and, should you find them by any means other than someone else responding to your thread with the answers, I might suggest you post the info, or links to where said info can be found, so as to help others, and to help keep this forum 'alive'.


~ More peace, love, laughter, & kindness would make the world a MUCH better place