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HelicopterRadio - Servo - Gyro - Gov - Batt › help needed with servo power
12-21-2015 02:24 AM  24 months agoPost 1
thtoyman

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Gone ,Flying.

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Hi I'm try to set up a new thing. but I want to use a 2 cell lipo. with no reg. so I would like the know if a servo like this could run a full charger a 2 cell lipo. or should I try a life battery.
Specifications:

• Torque at 6.0v: 187oz-in (13.5kg-cm)

• Torque at 7.4v: 208oz-in (15kg-cm)

• Speed at 6.0v: 0.16sec/60º

• Speed at 7.4v: 0.14sec/60º

I'm looking for troque and speed. So any ideas?

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12-21-2015 03:47 AM  24 months agoPost 2
dkshema

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Cedar Rapids, IA

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Which servos are those?

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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12-21-2015 03:49 AM  24 months agoPost 3
thtoyman

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just some I have looked at online.

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12-21-2015 06:27 AM  24 months agoPost 4
Pistol Pete

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Seffner, FL

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LiFe is a sure bet.

~~Enjoying the hobby one flight at a time~~

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12-21-2015 09:04 AM  24 months agoPost 5
thtoyman

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but a life not 7.4

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12-21-2015 11:56 AM  24 months agoPost 6
JuanRodriguez

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The Villages, Florida

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I would think that the ones that give a spec for 7.4 V would be OK but I would check with the manufacturer first....

Been there, done that and old enough to know better.....

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12-21-2015 01:32 PM  24 months agoPost 7
Pistol Pete

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Seffner, FL

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The Raw numbers...

but a life not 7.4
Yes, it is 7.4V when fully charged vs LiPo at 8.4V.

Given that excess voltage gets dissipated into heat, then;

V * A = W

(8.4-7.4) * 2A = 2W

Using 2A as an average.

Since we know that LiFe under load is always 6.6V, then;

(8.4V-6.6V) × 2A = 4.8W.

The reason I am NOT using 3.7 volts under load for LiPo is because it is not always exactly that voltage when under load and especially at 2A.

I would have used 3.7V IF the load was significant such as a battery used for powering a brushless motor, which quickly bring it down to that "nominal" voltage.

Besides, difference in torque-speed between these two voltages is unnoticeable to us mere mortals.

Unless the mystery servo is labeled HV (8.4V), I have doubts it was intended for LiPo voltages.

Bottom line...LiFe.

~~Enjoying the hobby one flight at a time~~

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12-21-2015 01:36 PM  24 months agoPost 8
doorman

rrProfessor

Sherwood, Arkansas

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Spec' s

If the servos you are looking at have an
HV after the model number, then they are High Voltage..
With that and a listing with 7.4 spec also tells me they are HV rated...
I run a 2s 5000 direct in my latest scale model and it is working just fine..
Good luck.. Stan

AMA 2918-Team JR, Spin Blades, East Coast Scale Helicopter,Castle Creations

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12-21-2015 11:09 PM  24 months agoPost 9
thtoyman

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Gone ,Flying.

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Just as I was checking the relpys I did get a phone call the them. I did find out, a 2 cells lipo will work.I did ask about a full charger 8.4 . He told me thats fine. Also said. that what these servos was make for.. So thanks you all who posted up.

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HelicopterRadio - Servo - Gyro - Gov - Batt › help needed with servo power
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