which is best? 4.8v or 6v ?
02-02-2008, 11:29 AM
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RE: which is best? 4.8v or 6v ?
ORIGINAL: focusjohn55
which voltage is best for servos etc etc..?
which voltage is best for servos etc etc..?
02-02-2008, 12:18 PM
#4
RE: which is best? 4.8v or 6v ?
ORIGINAL: DMcQuinn
Use 6 volts. Servos work better. very little downside to this.
Use 6 volts. Servos work better. very little downside to this.
Mark
02-02-2008, 12:47 PM
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RE: which is best? 4.8v or 6v ?
Depends on what you're flying. If you're flying smaller models or warbirds and the servos are sized apropriately, then 4.8v works just fine. If you're flying larger planes with big surfaces and using high torque digital servos then 6v wins out. Many ignitions work perfectly at 4.8v and don't benefit from higher voltage. Always read what the manufacturer says about voltage before upping the voltage for products you have been runnung at 4.8v.
02-02-2008, 01:39 PM
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RE: which is best? 4.8v or 6v ?
ORIGINAL: mmattockx
About the only downside is that they will draw more current and you may need to use a larger capacity battery. That said, most people use WAY bigger batteries than they need anyway, so it may be a non-issue for you.
Mark
ORIGINAL: DMcQuinn
Use 6 volts. Servos work better. very little downside to this.
Use 6 volts. Servos work better. very little downside to this.
Mark
02-02-2008, 01:48 PM
#8
RE: which is best? 4.8v or 6v ?
ORIGINAL: dirtybird
In an electric motor the torque produced is proportional to E x I. If you increase E you need less current provided you are using them in the same airplane.
In an electric motor the torque produced is proportional to E x I. If you increase E you need less current provided you are using them in the same airplane.
Mark
02-02-2008, 03:31 PM
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RE: which is best? 4.8v or 6v ?
Mark
[/quote]
In an electric motor the torque produced is proportional to E x I. If you increase E you need less current provided you are using them in the same airplane.
[/quote]
That does not necessarily mean that because torque is proportional, it remains constant. After all, if the E goes up whilst the impedance remains the same, so I goes up. What we are seeing here is an increase in both E and I, resulting in increased torque.
02-02-2008, 08:02 PM
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RE: which is best? 4.8v or 6v ?
ORIGINAL: Ejiro
Mark
Mark
[/quote]
That does not necessarily mean that because torque is proportional, it remains constant. After all, if the E goes up whilst the impedance remains the same, so I goes up. What we are seeing here is an increase in both E and I, resulting in increased torque.
[/quote]
Not true. The servo produces the torque it needs to do the job. If the job remains the same the torque produced remains the same. With the greater voltage it needs less current. The impedance remains the same but the servo amp reduces the pulse width applied to the motor to compensate.
Get one of the electric calculator programs and keep the prop and RPM the same and increase the voltage. The current will go down.
The reason you go to higher voltage is to keep the current within reason.
02-02-2008, 08:06 PM
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RE: which is best? 4.8v or 6v ?
Another advantage to 6v is if you loose a cell you still have power, where with 4.8v if you loose a cell the voltage is too low to power the receiver and servos.
Austin
Austin
02-02-2008, 08:07 PM
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RE: which is best? 4.8v or 6v ?
ORIGINAL: mmattockx
Then why did the pattern guys start using bigger batteries when they went to 6v?
Mark
ORIGINAL: dirtybird
In an electric motor the torque produced is proportional to E x I. If you increase E you need less current provided you are using them in the same airplane.
In an electric motor the torque produced is proportional to E x I. If you increase E you need less current provided you are using them in the same airplane.
Mark
Gorden Banks, editor of RCR tested this a year or so ago and published the results in RCR. Check it out.
02-03-2008, 12:30 AM
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RE: which is best? 4.8v or 6v ?
First check the specs on the servos you are using.....Futaba 92xx series are designed to run 4.8v only. Some smaller 9g servos are also only designed for 4.8v. Otherwise 6v will always win hands down!
02-03-2008, 01:19 AM
#14
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RE: which is best? 4.8v or 6v ?
Actually, there are two or three downsides that spring to mind.
Operating at six volts instead of 4.8 volts will consume the power in your batteries faster when running the higher voltage. This assumes that the 6 volt and the 4.8 volt packs are using the same brand/model/capacity cells. Performance comes with a price.
Servos wear out faster on 6 volts than they do on 4.8 volts.
Most receivers become a bit twitchier when running the higher voltage without running a regulator.
And the list goes on.
For the average sport flyer, the advantages of running 6 volts are dubious at best, plus the one extra cel in the pack (nicad and nimh) weighs more than the traditional 4.8 VDC four-cell packs.
Of course, those looking for the fastest and the strongest performance of their servos will run 6 VDC. No argument from me on that particular point. Is it worth it? You decide.
Ed Cregger
Operating at six volts instead of 4.8 volts will consume the power in your batteries faster when running the higher voltage. This assumes that the 6 volt and the 4.8 volt packs are using the same brand/model/capacity cells. Performance comes with a price.
Servos wear out faster on 6 volts than they do on 4.8 volts.
Most receivers become a bit twitchier when running the higher voltage without running a regulator.
And the list goes on.
For the average sport flyer, the advantages of running 6 volts are dubious at best, plus the one extra cel in the pack (nicad and nimh) weighs more than the traditional 4.8 VDC four-cell packs.
Of course, those looking for the fastest and the strongest performance of their servos will run 6 VDC. No argument from me on that particular point. Is it worth it? You decide.
Ed Cregger
02-03-2008, 11:20 AM
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RE: which is best? 4.8v or 6v ?
ORIGINAL: Ed Cregger
Actually, there are two or three downsides that spring to mind.
Operating at six volts instead of 4.8 volts will consume the power in your batteries faster when running the higher voltage. This assumes that the 6 volt and the 4.8 volt packs are using the same brand/model/capacity cells. Performance comes with a price.
Servos wear out faster on 6 volts than they do on 4.8 volts.
Most receivers become a bit twitchier when running the higher voltage without running a regulator.
And the list goes on.
For the average sport flyer, the advantages of running 6 volts are dubious at best, plus the one extra cel in the pack (nicad and nimh) weighs more than the traditional 4.8 VDC four-cell packs.
Of course, those looking for the fastest and the strongest performance of their servos will run 6 VDC. No argument from me on that particular point. Is it worth it? You decide.
Ed Cregger
Actually, there are two or three downsides that spring to mind.
Operating at six volts instead of 4.8 volts will consume the power in your batteries faster when running the higher voltage. This assumes that the 6 volt and the 4.8 volt packs are using the same brand/model/capacity cells. Performance comes with a price.
Servos wear out faster on 6 volts than they do on 4.8 volts.
Most receivers become a bit twitchier when running the higher voltage without running a regulator.
And the list goes on.
For the average sport flyer, the advantages of running 6 volts are dubious at best, plus the one extra cel in the pack (nicad and nimh) weighs more than the traditional 4.8 VDC four-cell packs.
Of course, those looking for the fastest and the strongest performance of their servos will run 6 VDC. No argument from me on that particular point. Is it worth it? You decide.
Ed Cregger
The receiver has its own built in regulator. It doesn't need another one.
The greatest advantage of using 6.0 V is the voltage has further to go down before it affects the receiver. It will reduce unknown dropouts when using heavy drain servos.
02-03-2008, 03:18 PM
#18
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RE: which is best? 4.8v or 6v ?
I agree. Running higher voltage is always better than running higher current, as far as I square R losses are concerned.
What I am saying is that most sport flyers (non 3D or pattern) will not reap much of a benefit from running 6 VDC with its higher expense (new battery and charger).
Ed Cregger
What I am saying is that most sport flyers (non 3D or pattern) will not reap much of a benefit from running 6 VDC with its higher expense (new battery and charger).
Ed Cregger
02-03-2008, 05:27 PM
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RE: which is best? 4.8v or 6v ?
The "real" reason that 5 cell packs caught on in Pattern was the availability of good, adjustable regulators that were very precise in holding the source voltage to the servos constant, regardless of the charge condition of the battery. Most were set at 5.1, some at 5.4, but on the high-precision coreless digitals the constant voltage was pretty important for flight to flight consistency.
Now - the naysayers and skeptics will say "that's total b.s. NO ONE could tell the difference". My response would be "then clearly you have never done it"
Pattern has very specialized demands for very high precision servo responses.
My position on using the 6v systems is simply the benefit of greater speed and greater torque, and that's a fact. One may have an "opinion" that it is not true, but that doesn't change the facts very much.
I like how objective data withstands opinions. Makes it more fun on RCU, don't you think, Mark???
Now - the naysayers and skeptics will say "that's total b.s. NO ONE could tell the difference". My response would be "then clearly you have never done it"
Pattern has very specialized demands for very high precision servo responses.
My position on using the 6v systems is simply the benefit of greater speed and greater torque, and that's a fact. One may have an "opinion" that it is not true, but that doesn't change the facts very much.
I like how objective data withstands opinions. Makes it more fun on RCU, don't you think, Mark???
02-03-2008, 11:09 PM
#21
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RE: which is best? 4.8v or 6v ?
ORIGINAL: Bob Pastorello
The "real" reason that 5 cell packs caught on in Pattern was the availability of good, adjustable regulators that were very precise in holding the source voltage to the servos constant, regardless of the charge condition of the battery. Most were set at 5.1, some at 5.4, but on the high-precision coreless digitals the constant voltage was pretty important for flight to flight consistency.
Now - the naysayers and skeptics will say "that's total b.s. NO ONE could tell the difference". My response would be "then clearly you have never done it"
Pattern has very specialized demands for very high precision servo responses.
My position on using the 6v systems is simply the benefit of greater speed and greater torque, and that's a fact. One may have an "opinion" that it is not true, but that doesn't change the facts very much.
I like how objective data withstands opinions. Makes it more fun on RCU, don't you think, Mark???
The "real" reason that 5 cell packs caught on in Pattern was the availability of good, adjustable regulators that were very precise in holding the source voltage to the servos constant, regardless of the charge condition of the battery. Most were set at 5.1, some at 5.4, but on the high-precision coreless digitals the constant voltage was pretty important for flight to flight consistency.
Now - the naysayers and skeptics will say "that's total b.s. NO ONE could tell the difference". My response would be "then clearly you have never done it"
Pattern has very specialized demands for very high precision servo responses.
My position on using the 6v systems is simply the benefit of greater speed and greater torque, and that's a fact. One may have an "opinion" that it is not true, but that doesn't change the facts very much.
I like how objective data withstands opinions. Makes it more fun on RCU, don't you think, Mark???
------------
I agree with Bob on these points regarding high performance applications, such as pattern, 3D, maybe racing, etc.
In fact, I run 6 VDC systems on such aircraft myself.
What I'm trying to prevent is someone becoming flustered and upset because they just started in the hobby and they can't afford to go 6 VDC on their trainer. Yes, it happens. <G>
Ed Cregger
02-03-2008, 11:28 PM
#22
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RE: which is best? 4.8v or 6v ?
ORIGINAL: dtm360
First check the specs on the servos you are using.....Futaba 92xx series are designed to run 4.8v only. Some smaller 9g servos are also only designed for 4.8v. Otherwise 6v will always win hands down!
First check the specs on the servos you are using.....Futaba 92xx series are designed to run 4.8v only. Some smaller 9g servos are also only designed for 4.8v. Otherwise 6v will always win hands down!
02-04-2008, 05:41 AM
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RE: which is best? 4.8v or 6v ?
ORIGINAL: Ed Cregger
------------
I agree with Bob on these points regarding high performance applications, such as pattern, 3D, maybe racing, etc.
In fact, I run 6 VDC systems on such aircraft myself.
What I'm trying to prevent is someone becoming flustered and upset because they just started in the hobby and they can't afford to go 6 VDC on their trainer. Yes, it happens. <G>
Ed Cregger
ORIGINAL: Bob Pastorello
The "real" reason that 5 cell packs caught on in Pattern was the availability of good, adjustable regulators that were very precise in holding the source voltage to the servos constant, regardless of the charge condition of the battery. Most were set at 5.1, some at 5.4, but on the high-precision coreless digitals the constant voltage was pretty important for flight to flight consistency.
Now - the naysayers and skeptics will say "that's total b.s. NO ONE could tell the difference". My response would be "then clearly you have never done it"
Pattern has very specialized demands for very high precision servo responses.
My position on using the 6v systems is simply the benefit of greater speed and greater torque, and that's a fact. One may have an "opinion" that it is not true, but that doesn't change the facts very much.
I like how objective data withstands opinions. Makes it more fun on RCU, don't you think, Mark???
The "real" reason that 5 cell packs caught on in Pattern was the availability of good, adjustable regulators that were very precise in holding the source voltage to the servos constant, regardless of the charge condition of the battery. Most were set at 5.1, some at 5.4, but on the high-precision coreless digitals the constant voltage was pretty important for flight to flight consistency.
Now - the naysayers and skeptics will say "that's total b.s. NO ONE could tell the difference". My response would be "then clearly you have never done it"
Pattern has very specialized demands for very high precision servo responses.
My position on using the 6v systems is simply the benefit of greater speed and greater torque, and that's a fact. One may have an "opinion" that it is not true, but that doesn't change the facts very much.
I like how objective data withstands opinions. Makes it more fun on RCU, don't you think, Mark???
------------
I agree with Bob on these points regarding high performance applications, such as pattern, 3D, maybe racing, etc.
In fact, I run 6 VDC systems on such aircraft myself.
What I'm trying to prevent is someone becoming flustered and upset because they just started in the hobby and they can't afford to go 6 VDC on their trainer. Yes, it happens. <G>
Ed Cregger
02-04-2008, 09:45 AM
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RE: which is best? 4.8v or 6v ?
I ran NiMH 6.0 packs with Futaba recievers and Hitec servos for 3 years in multiple planes and never had servo glitch due to high voltage without a regulator. The only servos I have seen do that are JR.
I don't really see what the extra cost is to run 6 volt packs? I ran NoBS 1400s and 1500 low impediance packs and the only cost difference is like $3 or $4 for the cost of the cell.
That being said I ran 4.8 on my first few small planes... there is no point on using 6.0 on a high wing plane or really anything you are just flying circles with because you won't notice a difference.
I don't really see what the extra cost is to run 6 volt packs? I ran NoBS 1400s and 1500 low impediance packs and the only cost difference is like $3 or $4 for the cost of the cell.
That being said I ran 4.8 on my first few small planes... there is no point on using 6.0 on a high wing plane or really anything you are just flying circles with because you won't notice a difference.
02-04-2008, 10:10 AM
#25
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RE: which is best? 4.8v or 6v ?
It isn't the price of a single cell, Jake. Newbies will buy a new 5 cell pack. The real expense comes in when buying a charger to charge the 5 cell pack successfully.
To we old timers, the cost is insignificant. To someone married for a year and a half and with a child, it could represent more money than they have available, especially when the stock radio's 4.8 VDC flight pack is brand new and perfectly adequate. Peer pressure, or perceived peer pressure, can be a problem for young folks just trying to fit in.
Ed Cregger
To we old timers, the cost is insignificant. To someone married for a year and a half and with a child, it could represent more money than they have available, especially when the stock radio's 4.8 VDC flight pack is brand new and perfectly adequate. Peer pressure, or perceived peer pressure, can be a problem for young folks just trying to fit in.
Ed Cregger