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https://www.modelsport.co.uk/product/savox-hv-low-profile-digital-servo-15kg0085s74v-414545 just ordered one of these as I thought it would look nice in the TD4 when it arrives. Have just noted that it says it’s 7v but I thought BEC was only around 5v. Will it work ok with normal radio gear or do I need something specific?

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No it'll work fine. A lot of modern servos are now rated to 7.4v input so you can use all the voltage from a 2s lipo to increase torque and speed. As long as your receiver will also accept 7.4v. Otherwise, just plug it in as normal and it'll run with what ever voltage it gets (up to 7.4v of course).

 

**edit** - That'll be a lovely servo for the 4wd TD-4.

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If you use the TBLE-04S with a servo drawing more than 1.5A the BEC may cutout.

 

Edited by Sir Crashalot
ESC not included in kit
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2 hours ago, Busdriver said:

Have just noted that it says it’s 7v but I thought BEC was only around 5v. Will it work ok with normal radio gear or do I need something specific?

It is 15kg/0.085s@7.4v, so similar to the RPM rating for brushed motors, @7.2v. It can still work at slightly different voltage, usually! 

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It should work just fine with lower BEC voltages (normal is 6.0V nowadays, 5V would be quite low by modern standards) as well, but will be slower and less powerful than the given ratings (as these are for 7.4V). But if you don't have a 7.4V BEC-capable system, I would not buy a HV servo. Savöx 1251MG is a popular servo for standard BECs, even though Savöx servos were notorious for causing "brown-outs" (especially with Spectrum radio gear).

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2 hours ago, hIghQ said:

It should work just fine with lower BEC voltages (normal is 6.0V nowadays, 5V would be quite low by modern standards) as well, but will be slower and less powerful than the given ratings (as these are for 7.4V). But if you don't have a 7.4V BEC-capable system, I would not buy a HV servo. Savöx 1251MG is a popular servo for standard BECs, even though Savöx servos were notorious for causing "brown-outs" (especially with Spectrum radio gear).

Already bought it🤭

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I've always wondered why Savox servos continue to be highly regarded and oft-recommended despite their reputation for brown outs and their glitchiness. The latter being so pervasive that some places sell glitch-buster capacitors with Savoxes as a package deal.

Even a perfectly functional Savox is an assault on the ears due to its incessant whining.

Someone correct me if any of this is wildly inaccurate.

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I’m more concerned with the lack of steering in the super avante that was shown in the recent review. Kind of makes a high speed servo useless imo with little turning. I am considering canceling my preorder.  As for savox other than their whininess i think they are great as are all the protek servos i have had. No complaints from me, but they dont come cheap

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6 minutes ago, Rb4276 said:

I’m more concerned with the lack of steering in the super avante that was shown in the recent review. Kind of makes a high speed servo useless imo with little turning.

I believe there are steering stoppers (which are removable) on the arms that limit the swing because it has dogbones up front. Install CVDs, remove the stoppers, problem solved.

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3 hours ago, DeadMeat666 said:

I've always wondered why Savox servos continue to be highly regarded and oft-recommended despite their reputation for brown outs and their glitchiness. The latter being so pervasive that some places sell glitch-buster capacitors with Savoxes as a package deal.

Even a perfectly functional Savox is an assault on the ears due to its incessant whining.

Someone correct me if any of this is wildly inaccurate.

I have quite a few Savox servos, 1251MG and 1258TG and they are noisy (I thought thats difital servos constantly adjusting?) but they have never glitched or caused brownouts for me.

I have heard 2 reasons given for the glitching.

This was common on older Spektrum systems. I also heard that Flysky radios used near Spektrum ones caused Spektrum rc gear to glitch too. Never experienced this as have never used Spektrum but I do recall on the old racer forums some clubs banning Flysky because they thought that was the problem but it was actually Spektrums issue. I haven't heard about Savox causing glitches, or Flysky causing interference in a few years so I assume it was older radios, or all a big myth. 

Or it could be that more modern ESC have better BEC so don't have the same problem? I have used Trackstar 80a Turbo, Speed Passion Reventon which are both older and they were fine, so it must be really old ESC.

I also know a lot of people who use them in both 10th and 8th scale racing and they could buy anything else like Sanwa, Futaba etc as they aren't buying cheap, they're spending proper money on their servos (one even runs a 1251MG in his 21.5T stock TC and he owns a hobby shop and usually uses Muchmore for everything)

So I don't think that this is an issue anymore. I wouldn't hesitate to buy Savox servos and often recommend them. They have given me years of good service and suffered a lot of abuse in my (and my sons) race buggies.

The 1254 that @Busdriver has bought looks great. An updated 1251MG by the looks of it with the HV meaning its faster and stronger. I would definitely look at that when my onroad cars need new servos

 

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Can someone explain in simple words what brownouts are. Glitches I understand, in fact I have an anti glitch module in my spares box somewhere. Was used on multi esc operations in boats

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1 hour ago, Busdriver said:

Can someone explain in simple words what brownouts are. Glitches I understand, in fact I have an anti glitch module in my spares box somewhere. Was used on multi esc operations in boats

Brownouts are when an RC car temporarily stops responding to the transmittor's signal due to the receiver's internal BEC not being able to provide enough amperage to the servo. This usually happens with servos that are very powerful, or just very inefficient/powerhungry.

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1 hour ago, Busdriver said:

Can someone explain in simple words what brownouts are.

I understand it to be, the servo pulling that much power, the reciever cuts out of a second.

Savox are quite renowned for it, but similar to motor turn limits on the esc, the faster and more powerful the servo, the more power required to drive them.

Not had any issues running race escs, as they are designed for it, but with the cheaper 10bl120, my 1274MG did need a 'glitch buster' which is just a capacitor plugged into a spare RX port, you can make them for under a quid.

I've had issues running low profile servos in off road cars, I know some who don't (probably better drivers than me...) but I've found the gears are thinner, so don't take the knocks a full size servo can. Although with the TD4 coming with the high torque servo saver (51000), a low profile shouldn't be a problem.

 

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Great choice @Busdriver I’ve got a few of them attached to 51000 servo savers and never had a problem. I quite like the little digital noises they make 😃

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I've had so far good luck with a JX PDI-4409MG low profile servo, 9Kg, $12.99 USD. Running with a Quickrun 1060 ESC and a Super Stock TZ motor on a TT02. No glitches whatsoever.

Note that I am by no means a pro, just a parking lot casual racer on improvised layouts.

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One thing you'll need to do, is set the steering end points on the transmitter.

The servo will pull more amps, if the TD4's steering linkage only allows ,say 90% of the servos travel, as the servo will be pushing like mad to make its 100% stroke (against the servo saver, so that'll wear out quick too).

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I purchased the Saxov 1251 for my upcoming Super Avante build, and also use a Flysky tx/rx.  My first Savox servo actually, and when setting up the radio/receiver/esc I noticed noise others mention.   It won't bother me to be honest, and I have extra capacitors stocked as I've experienced frequent "brownouts" with my cars that run DSServo 25kg models and have full lights to operate as well.  A bag of 10 16v 4700uF cost around 10 bucks.  

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25 minutes ago, Killajb said:

I purchased the Saxov 1251 for my upcoming Super Avante build, and also use a Flysky tx/rx.  My first Savox servo actually, and when setting up the radio/receiver/esc I noticed noise others mention.   It won't bother me to be honest, and I have extra capacitors stocked as I've experienced frequent "brownouts" with my cars that run DSServo 25kg models and have full lights to operate as well.  A bag of 10 16v 4700uF cost around 10 bucks.  

I'm assuming the kg of a servo is only half the equation when it comes to figuring out if the servo will be drawing a lot of power. 

When it comes to amperage requirement:

"Slow" 25kg servo = "fast" 9kg servo

I believe the trade-off between speed and pulling strength is just down to internal gearing.

Does that sound about right?

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Savöx servos became popular in racing for their relatively low price for the performance they have (plus not being some no-name brand of dubious quality).

They are considered to be quite power-hungry, and with older, less powerful BECs that often lead to brown-outs - older Spectrum radios were most affected by this. Nowadays BECs have become more powerful and the radio equipment also got better, so brown-outs don't happen very often anymore - with decent quality gear. Could still happen with cheap ESC(BEC) / radios though.

Today there are other good (IMO also better) servos available in a similar or  close-enough price range, so I do not recommend Savöx any more. (Not saying they're bad, just don't recommend them)

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2 hours ago, DeadMeat666 said:

I'm assuming the kg of a servo is only half the equation when it comes to figuring out if the servo will be drawing a lot of power. 

When it comes to amperage requirement:

"Slow" 25kg servo = "fast" 9kg servo

I believe the trade-off between speed and pulling strength is just down to internal gearing.

Does that sound about right?

I'm sure a number of factors go into the amount of current a servo can demand.  The "lazy" fix (at least for me) has been to add a single 16v 4700uF capacitor. 

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3 hours ago, hIghQ said:

Today there are other good (IMO also better) servos available in a similar or  close-enough price range, so I do not recommend Savöx any more. (Not saying they're bad, just don't recommend them)

PowerHD? 

I've been more than impressed with their whole range TBH. I use them pretty much exclusively.

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5 hours ago, Wooders28 said:

I'm not sure I'd take the quoted specs as gospel, on paper, there wasn't much between these two. But in reality, there was..

 

https://youtube.com/shorts/cy9cGA3p3rc?feature=share

Yes my racing fleet is all Futaba and the BLS servos are absolute monsters... Although according to the specs they're not even on a par with a Chinese special 🤷‍♂️

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2 hours ago, DeadMeat666 said:

PowerHD? 

I've been more than impressed with their whole range TBH. I use them pretty much exclusively.

I've also been very impressed with PowerHD in my bashers and crawlers, their 1812MG is a bargain at only just over 20 quid. Wouldn't use it for racing, but I know that racers do use their higher end servos.

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Well it arrived today. Will now have to wait for the TD4. Will def look at end points so as not to over stress the gearsE0DFAE4E-2597-4C81-BC81-E377189307E5.jpeg.837a18b262b52a4cf4400cf8da150175.jpeg

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