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Old 05-17-2005, 05:19 AM
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A.R.T.F.
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Default servos

What’s the difference between futaba 3001 and 3004 servos?

Also is it ok to use 6V with standard RX, switch etc? and will there be a greater drain on the batteries i.e. less flight time if compared to the same capacity batteries on 4.8V?

Thanks
Old 05-17-2005, 07:51 AM
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Default RE: servos

3004s are exactly the same except they have a ball bearing at the output shaft.

And yes, you can use a 6v pack just fine with your system. Flight times will be the same or a little longer, but your servos will move faster and have more torque - Just be advised that you cannot charge a 6v pack with the charger that comes with the radio!
Old 05-17-2005, 08:01 AM
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Default RE: servos

http://www.futaba-rc.com

It has a chart that will tell you everything you need to know about thier servo's and a FAQ that will give you advice on 6volt systems.
Old 05-17-2005, 10:06 AM
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Default RE: servos

i had a look on the futaba site but cant find any info on chargers. what do you suggest?
Old 05-17-2005, 10:28 AM
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Default RE: servos

I have a Hobbico Accucyle Elite. Charges near about anything that the average RC'r would ever use.
Old 05-17-2005, 01:50 PM
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Default RE: servos


ORIGINAL: MinnFlyer

3004s are exactly the same except they have a ball bearing at the output shaft.
What benefit or disadvantage is there to having the ball bearings in the 3004 servos?

Thanks
Old 05-17-2005, 02:17 PM
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Default RE: servos

No disadvantages at all, just a smoother servo
Old 05-17-2005, 11:46 PM
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efergie72
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Default RE: servos

Hey Minnflyer, I thought that with the 6v you got more power and speed but your flight time suffered for the same mah. Analogy being bigger diameter hose for the same amount of water? Please set me straight oh wise bearded one!!
Old 05-18-2005, 02:18 AM
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A.R.T.F.
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Default RE: servos

Also why can i not use the standard wall charger?

Thnaks
Old 05-18-2005, 08:10 AM
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Default RE: servos

ORIGINAL: A.R.T.F.

Also why can i not use the standard wall charger?
The short answer is it's not designed to bring the voltage high enough. For more details, I suggest Red's battery site: www.rcbatteryclinic.com. In particular, read through the topic titled "All about Wall Wart Chargers". If you're adventurous, you could probably cobble something together. My solution was to just buy the already recommended Accucycle Elite. I'm glad I did, it's proven to be useful for the variety of different packs I have.
Old 05-18-2005, 08:15 AM
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Default RE: servos

The components needed to regulate the current is based on the voltage of the battery pack. Going to a 6 volt pack from a 4.8 volt will cause more heating which the components may not be rated for and the charger may also not regulate the current properly. [8D]
Old 05-18-2005, 08:26 AM
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Default RE: servos

What Piper_chuck said was on the right path, but not a complete answer. Let me see if I can fill in what's missing. When we call our flight packs a 4.8v or a 6v pack we are actually referring to the minimum voltage of the pack. A normal battery cell (there are 4 cells in a 4.8v pack and 5 cells in a 6v pack) has a minimum normal voltage of 1.2 v. Do the math, 4 x 1.2=4.8v. And 5x1.2=6v. Now on the opposite side a cell has a max charged voltage of 1.5v. So if you do the math here, 4x1.5=6v, and 5x1.5=7.5. If you look at your wall wart you will see that it has a voltage at or a little above 6v. The charger has to be able to put out at least the maximum voltage of the pack, for a 4 cell pack that is 6v. You can now see that a 6v wall wart will not have enough power to charge a 5 cell pack fully (7.5v). To do that you will need a charger that puts out at least 7.5v. If you are going increase the size of your packs I would recommend to get rid of the wall wart chargers and get on of the "smart" chargers on the market. They are able to detect the number of cells you have and adjust the charge accordingly.

Hope this helps.
Old 05-18-2005, 10:38 AM
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Default RE: servos


ORIGINAL: efergie72

Please set me straight oh wise bearded one!!
As I understand it (And I could be wrong - It's been known to happen) You are sending more voltage to the servos, but they are not drawing any more amperage than they usually would.

Can any Electrogeeks out there confirm or reject this?

PS. RCKen is right on with his description
Old 05-18-2005, 01:46 PM
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Default RE: servos

MinnFlyer,

I humbly come crawling before you and ask forgiveness ahead of time, but a 6v flight pack provides less flight time than a 4.8v pack (unless you go for the higher mAh premium batteries). Even Futaba states this. The old "more holes in the bucket gives more water but for shorter time" analogy.

Old 05-18-2005, 02:02 PM
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Default RE: servos

Charlie P. is right if you don't incread the mah of the pack, like he said. Minn, they will draw more current. I=E/R, therefore thinking loosely of the servo as the R (or load) as a constant, if the voltage goes up so will the current. Where do you think the speed comes from? Nothing for free.

Please note this a very loose explaination and leaves many variables unaccounted for so don't tear it to death please.
Old 05-18-2005, 06:08 PM
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Default RE: servos

Pretty much that. The servo electical load (impedance) doesn't change, so with a higher Voltage, more current is pulled from the battery. That naturally drains the battery faster.

Also, a NiCad or NiMh battery (And some other batttery chemistries) needs approximately 0.2 Volts per cell above the nominal cell voltage applied to reasonably reach full charge. So a charger needs to put out somewhere between about 5.6 to maybe 6.0 V to charge a 4 cell/4.8 V pack, and about 7.0 to 7.5 for the 5 cell/6.0 V pack. This is under the load of the pack, not the open circuited Voltage, which may be a bit higher. Too high a Voltage for too long a time can cause the pack to make funny noises, smell funny, and release funny light and smoke. And maybe some schrapnel. Automatic Peak or Delta Peak detect chargers are the best to use, but sometimes to work right require a diode in the transmitter battery circuit to be bypassed.
Old 05-18-2005, 10:10 PM
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Default RE: servos

Ok, chalk up one more time I was wrong.

I hate the taste of crow [:'(]
Old 05-18-2005, 10:14 PM
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Default RE: servos


ORIGINAL: MinnFlyer

Ok, chalk up one more time I was wrong.

I hate the taste of crow [:'(]
Minn,
Dump enough ketchup on it and it's not too bad!!!!

Trust me, voice of experience here.
Old 05-18-2005, 10:37 PM
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Default RE: servos

Ok, chalk up one more time I was wrong.
Yea, I thought I was wrong once, but I was mistaken.
Old 05-19-2005, 07:06 AM
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Default RE: servos

Hate to count the number of times I've been wrong. Fortunately, my wife keeps track for me.
Old 05-19-2005, 07:45 AM
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Default RE: servos

Unless you really need the extra speed from the servos why bother? I have switched to higher capacity NiM battery packs for the planes so I can fly all day if I want to without changing planes. Thats worth while as long as you have a charger to match.[8D]
Old 05-19-2005, 08:22 AM
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Default RE: servos

Aren't wives great for tracking those things? Mine considers it a full time job!
Old 05-19-2005, 09:09 AM
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Amazing memories. Can't always remember to cook though.
Old 05-19-2005, 09:25 AM
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Mine wins awards as a back seat driver. I get evaluated periodically by corporate fleet safety people and occassionally by DOT because of the things I drive for work, but she always disagrees with their evaluations. She KNOWS I'm not as good as they say I am.
Old 05-19-2005, 09:36 AM
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Maybe she should evaluate them too.

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