RunRyder RC
 6  Topic Subscribe
WATCH
 1 page 3238 views POST REPLY
HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › question about jr ds8717 power consumption
03-08-2008 04:16 AM  10 years agoPost 1
xxcysxx

rrKey Veteran

Baltimore, MD - USA

My Posts: All  Forum  Topic

does anyone know what is the average power consumption for four jr ds8717 on a 90 size heli. and also a ds8900g for the tail as well. i couldn't find any spec on the unloaded and stall current draw for these servos.

also by the way, would the arizona regulator have the muscle to handle these power hungry servos. i know it would turn the servo on the bench, but i'm concern when a load is put on these servos, then the load will be put on the regulator.
from the fromeco website they mention it can handle a maximum of 17.8 watts. what would that look like in amp draw if i power from a 7.4v 2s lipo.

also another question. since a lipo battery can handle much higher amp draw than the arizona regulator can. if i run all the electronics directly from the 7.4v 2s lipo. would the servo electronics and other on board electronics wear out prematurely over time from feeding them too much volts.

thanks for any inputs

Tam

PM  EMAIL  Attn:RR  Quote
03-08-2008 04:54 AM  10 years agoPost 2
oysifly

rrVeteran

Bentonville, AR

My Posts: All  Forum  Topic

I have a friend running that set up and seems like he measured them running at 5 amps continuous. I may be wrong, but pretty sure on it.

Quick...here comes my wife....hide that new Heli !!!!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-08-2008 05:05 AM  10 years agoPost 3
xxcysxx

rrKey Veteran

Baltimore, MD - USA

My Posts: All  Forum  Topic

ah ha!!! look at what i found. it took a little diggin, and i've found it.

http://www.runryder.com/t409677p1/?highlight=current

Tam

PM  EMAIL  Attn:RR  Quote
03-08-2008 05:10 AM  10 years agoPost 4
Long Nguyen

rrVeteran

SoCal, US

My Posts: All  Forum  Topic

does anyone know what is the average power consumption for four jr ds8717 on a 90 size heli. and also a ds8900g for the tail as well. i couldn't find any spec on the unloaded and stall current draw for these servos.
http://runryder.com/t409677p1/?highlight=current

It seems like they are really amp-hungry...
also by the way, would the arizona regulator have the muscle to handle these power hungry servos. i know it would turn the servo on the bench, but i'm concern when a load is put on these servos, then the load will be put on the regulator.
from the fromeco website they mention it can handle a maximum of 17.8 watts. what would that look like in amp draw if i power from a 7.4v 2s lipo.
It depends on what voltage you are using. The higher voltage, the less work the regulator does so it can offer more amps. Here is a small graph from fromeco website

where: 6V (red), 5.5V (pink), and 5.0V (purple)

Here is the formula to calculate the current

Watts = Amps*(Vin-Vout)
also another question. since a lipo battery can handle much higher amp draw than the arizona regulator can. if i run all the electronics directly from the 7.4v 2s lipo. would the servo electronics and other on board electronics wear out prematurely over time from feeding them too much volts.
Yes a normal lipo can put out many amps but they don't go straight into your electronics after turning on. it depends how many amps your electronics draw. So basically, the voltage is constant, the amperage varies and depends on usage. If the amperage (current) exceed the limit current of the regulator, the regulator will have a hard time and maybe burn out.

Long Nguyen
My videos: http://vimeo.com/longnguyen/videos
Máy bay cắt cỏ!

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-08-2008 05:36 AM  10 years agoPost 5
xxcysxx

rrKey Veteran

Baltimore, MD - USA

My Posts: All  Forum  Topic

hey, the red line on that graph shows about 17 amps at 6.0v. that's for real?

so Watts = Amps*(Vin-Vout)

7.4v - 6.0v = 1.4v
1.4v * 17 Amps = 23.8 watts

oh i get it. so it measured in how much of the excess voltage it burn away.

Tam

PM  EMAIL  Attn:RR  Quote
03-08-2008 01:20 PM  10 years agoPost 6
bob00

rrVeteran

Toronto, ON

My Posts: All  Forum  Topic

4.5 - 5A sounds about right. I get just a little more than half the number of flights on the same rx pack from the same heli fitted with 8717's vs 9451's.

A few years ago we determined avg. current draw of a heli with 9252's to be about 2 - 2.5A, so its in the ballpark.

- Rob

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
03-10-2008 05:58 AM  10 years agoPost 7
xxcysxx

rrKey Veteran

Baltimore, MD - USA

My Posts: All  Forum  Topic

thanks guys for the help.

Tam

PM  EMAIL  Attn:RR  Quote
03-10-2008 07:05 PM  10 years agoPost 8
Hanson

rrNovice

Poland SILESIA

My Posts: All  Forum  Topic

is it safe to use those servos 8717 with ALIGN B6T 2in1 ?
anyone using 8717 with 2 in 1 - 600n?

PM  EMAIL  Attn:RR  Quote
03-10-2008 07:20 PM  10 years agoPost 9
helislider

rrNovice

Lake Arrowhead,CA -USA

My Posts: All  Forum  Topic

I just received three 8717 and after reading this post realize that I need to upgrade my power supply. Can anyone recommend a good power system for these servos. I was looking at going with the Arizona Reg. with the 3600 Iron corps Batteries. The heli has three 8717,s and two 9254,s. http://www.fromeco.org/Products/01-...27/Default.aspx

Do not follow where the path may lead. Go instead where there is no path and leave a trail.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-10-2008 10:27 PM  10 years agoPost 10
xxcysxx

rrKey Veteran

Baltimore, MD - USA

My Posts: All  Forum  Topic

becareful of over weight. check the manufacture spec sheet for the weight. i wanted to have a highest capacity battery pack to fly long without recharging, i was using a pack of elite 4500mah 4.8v sub-c pack and i was having a nose heavy problem. the pack was weighting 280 grams, but it can certainly handle the amp draw from these servos.
i just odered an arizona regulator and a pack of thunder power prolite 2100mah 7.4v 2s lipo to replace the sub-c pack.
the regulator weight 50 grams and prolite lipo weight 98 grams. almost half the weight saving. i hope it show a difference once mounted in the model.

Tam

PM  EMAIL  Attn:RR  Quote
03-10-2008 10:47 PM  10 years agoPost 11
Jeff polisena

rrElite Veteran

westpalmbeachflorida usa

My Posts: All  Forum  Topic

I have a raptor 50 and 90 with same setup
I run 4-8717's with GY 611 w/servo and TJ rev max limiter with VR 5203 spectrum duel regulator between receiver and gyro only all running off of 1 2000mah TP prolite lipo and get 5-9 min flights per charge flying hard collective (tictoc,kaos,hurricanes,etc.)

PM  EMAIL  GALLERY  Attn:RR  Quote
03-11-2008 05:21 AM  10 years agoPost 12
xxcysxx

rrKey Veteran

Baltimore, MD - USA

My Posts: All  Forum  Topic


Jeff polisen
I have a raptor 50 and 90 with same setup
I run 4-8717's with GY 611 w/servo and TJ rev max limiter with VR 5203 spectrum duel regulator between receiver and gyro only all running off of 1 2000mah TP prolite lipo and get 5-9 min flights per charge flying hard collective (tictoc,kaos,hurricanes,etc.)
wait a minute. you're using 2000mah prolite lipo and you're only getting 5-9 minute flight per charge. so you recharge the battery after each flight? that don't sound right.

anyway, so you're powering directly off the the lipo battery, feeding 7.4 volt into the electronics. does this wear out the electronics prematurely?
i know they can handle the higher voltage, but would they last as long. like over clocking a processor, you can get more for your money by over clocking, but you loose efficiency.

Tam

PM  EMAIL  Attn:RR  Quote
03-11-2008 05:31 AM  10 years agoPost 13
JKos

rrProfessor

Redondo Beach, CA

My Posts: All  Forum  Topic

I think he meant five 9-minute flights.

- John

RR rules!

PM  EMAIL  GALLERY  Attn:RR  Quote
03-11-2008 06:18 AM  10 years agoPost 14
MolokaiBoy

rrKey Veteran

Lahaina, Maui,Hawaii USA

My Posts: All  Forum  Topic

I'll be running 3X 8717's, Solid G w/9256, 9452 throttle, multigov, spectrum dual output reg, R921 DSM2 rx in my 600. Will a TP 2S 3400mAh rx pack be sufficient for atleast 5-6 flights per charge?

Les
Maui RC Modeler's, Big Island RC Helis, http://www.facebook.com/mauirc

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-11-2008 06:22 AM  10 years agoPost 15
Funky Trex

rrElite Veteran

Westerville, OH - USA

My Posts: All  Forum  Topic

Yes, I use a TP 3400 in my Stratus with 8717s. I easily get 5+ flights per day with plenty of mah left over.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-11-2008 06:35 AM  10 years agoPost 16
MolokaiBoy

rrKey Veteran

Lahaina, Maui,Hawaii USA

My Posts: All  Forum  Topic

Thanks alot Funky

Les
Maui RC Modeler's, Big Island RC Helis, http://www.facebook.com/mauirc

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-11-2008 10:16 AM  10 years agoPost 17
Jeff polisena

rrElite Veteran

westpalmbeachflorida usa

My Posts: All  Forum  Topic

I charge after 5 flights I have yet to lose any electronics and have put a lot of time on them so far . Yes I run directly off battery , fully charged 8.4 volts and dropping each flight, if I want to keep hitting hard I put 2 flights and re charge to keep voltage up to get speed and torque out of servos

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 3238 views POST REPLY
HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › question about jr ds8717 power consumption
 Print TOPIC  Make Suggestion 

 6  Topic Subscribe

Saturday, June 23 - 2:00 am - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online