HOW MUCH POWER?
09-01-2007 | 11:53 PM
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From: FAIRFIELD ,
CA
HOW MUCH POWER?
how much battery power will i need when using two jr 8711 elevator , 2-jr 9411 aileron, 1-jr 4031 nose gear,2-jr 2721 flaps, 2-3021 retracks and brakes ,1-jr 3421 rudder i have two 1400mh 6v cell with 2 switches and a bat share. i also may be using a couple of match boxes. i know the 8711 take a lot of power . if this won't work please let me know what will . this is for the fei bao hawk.
thanks
Arden
thanks
Arden
09-02-2007 | 05:42 AM
#2
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RE: HOW MUCH POWER?
You may want to recharge after the 1st light. Based on what you put it, you know how much was consumed.
For the size, it also matters if you want to do 10 flights or 5 flights a day.
My boomerang had 11 servos, most of them digital. I used dual 2400 Nicads. I only recharged after the 5 flight (but measured voltage before every flight).
Good luck,
For the size, it also matters if you want to do 10 flights or 5 flights a day.
My boomerang had 11 servos, most of them digital. I used dual 2400 Nicads. I only recharged after the 5 flight (but measured voltage before every flight).
Good luck,
09-02-2007 | 11:15 AM
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From: Tomball,
TX
RE: HOW MUCH POWER?
Do yourself a favor and get an amp meter. I have seen several different kinds and all seem to work in the same manner.
1. you can connect it inline with each individual servo to see how much current draw it has with plane just turned on. Then while moving that surface or valve.
2. you can connect it inline with each battery to see how much total current draw the whole system affects each battery.
This will help you determine if you have a bad linkage setup or if you have to much travel causing a binding situation etc etc. I don't know how much power the 8711's will pull but I know it is alot. Would also help to know which type of battery you have. NIMH or NICAD etc. etc. NICADS can give a better "burst" of power then NIMH and are heavier and have a Memory Rentention. Long story short. Depending on your load would determine how many flight per charge you would get. The most import thing to think of here is, Can your airplane ask for more power than your system can handle at any one give amount of time. I would bet not. Basically the sytem sees the "battery" as a 2800 5 cell setup. Since you have the system split up you have opted for redundancy and added more equipment that could possibly fail.(MOST PEOPLE DO) The reason I mention this is because you should also think of the following. If a switch or battery fails, can my system run on one battery? the following is just an average. better cells can do a lil better.
The maximum discharge rate for a NiCd battery varies by size. For a common AA-size cell, the maximum discharge rate is approximately 18 amps; for a D size battery the discharge rate can be as high as 35 amps. Keep in mind at a discharge rate that high, the battery would not last long.
Hope this helps. [8D]
Digital Servo & Receiver Current Meter
Key Features
Easily plugs in between the receiver and a servo, or between the battery and receiver, to aid in setting up linkages
Accurately measures current, charge current, servo current draw, and discharge current
Precise digital LCD readout displays current or voltage
Allows you to locate binding and mismatched or defective servos
Monitors charge voltage for peak charging and cut-off point for discharging
Universal connector with 9" leads
1. you can connect it inline with each individual servo to see how much current draw it has with plane just turned on. Then while moving that surface or valve.
2. you can connect it inline with each battery to see how much total current draw the whole system affects each battery.
This will help you determine if you have a bad linkage setup or if you have to much travel causing a binding situation etc etc. I don't know how much power the 8711's will pull but I know it is alot. Would also help to know which type of battery you have. NIMH or NICAD etc. etc. NICADS can give a better "burst" of power then NIMH and are heavier and have a Memory Rentention. Long story short. Depending on your load would determine how many flight per charge you would get. The most import thing to think of here is, Can your airplane ask for more power than your system can handle at any one give amount of time. I would bet not. Basically the sytem sees the "battery" as a 2800 5 cell setup. Since you have the system split up you have opted for redundancy and added more equipment that could possibly fail.(MOST PEOPLE DO) The reason I mention this is because you should also think of the following. If a switch or battery fails, can my system run on one battery? the following is just an average. better cells can do a lil better.
The maximum discharge rate for a NiCd battery varies by size. For a common AA-size cell, the maximum discharge rate is approximately 18 amps; for a D size battery the discharge rate can be as high as 35 amps. Keep in mind at a discharge rate that high, the battery would not last long.
Hope this helps. [8D]
Digital Servo & Receiver Current Meter
Key Features
Easily plugs in between the receiver and a servo, or between the battery and receiver, to aid in setting up linkages
Accurately measures current, charge current, servo current draw, and discharge current
Precise digital LCD readout displays current or voltage
Allows you to locate binding and mismatched or defective servos
Monitors charge voltage for peak charging and cut-off point for discharging
Universal connector with 9" leads
