Bozwth

My Feedback: (3)

Is it desirable to use a voltage regulator with Futaba PCM receiver driving 4 Hitec 5645's and a 5945 with a 2800ma 6v NiCd battery? I have an MPI switch with one and without one. I was just wondering if its needed or if it offers any advantage at all.

Bozwth

mglavin

My Feedback: (31)

What type of regulator, Switching or Linear?

What is the specification of the regulator and or the operating parameters? Or simply the regulated voltage output specification?

No, regulators are not needed IMO. The only advantage I'm aware of is the consistent voltage offered, which by most admissions is difficult to realize. As the battery pack voltage diminishes it will no longer regulate, it will pass voltage. In most cases with 6.0V sources the battery off charge will provide sufficient voltage to maintain the rated output for a very short period of time, thereafter its worthless.

The best scenario would be a LOW DROPOUT VOLTAGE, switching regulator rated to handle inputs up to 8.5V, regulating the output to 5.5V or so to take advantage of and realize the stable voltage output.

Geistware

My Feedback: (16)

I would not recommend a voltage regulator.

Bozwth

My Feedback: (3)

I have no idea what kind of regulator I have. Its the one that comes connected to the switch that MPI sells. I assume that it just limits the maximum voltage output of the battery. If I don't need it then I won't use it. The less weight the better.

Thanks again for all the help [8D]

dirtybird

My Feedback: (5)

Regulators work by putting a variable resistor between the battery and your system. Anyway you look at it they are energy wasters. All current receivers that I know of have a regulator built in. The energy they waste is very small. But the energy wasted by a voltage regulator for heavy servo draw would be very wasteful. Don't use them if you can get away without them.

hilleyja

My Feedback: (3)

Hitec is on record that there is never a need for a voltage regulator for their servos. They are all compatible with both 4 and 5 cell packs. I have seen advertisements that do say some of the Futaba servos are only compatible with 4-cell packs. I know Futaba has a servo/gyro combination that is definitely not compatible with 5-cell packs.

RJConnet

After years working in the field of industrial electronics I have come to the conclusion that I don't want a switching regulator anywhere near any of my planes. The only one I have around is the one in my computer and it has been replaced once. My previous computer also had a PS failure. A switching regulator is almost impossible to repair without a bin full of replacement parts and a test-bench full of expensive electronic test equipment. That being said I have run
5-cell packs in many of my planes with no regulator and never had a problem. [8D]

RJ

Geistware

My Feedback: (16)

I too would think that a switching resistor would cause electrical noise.

mglavin

My Feedback: (31)

They inherently do, BUT some have been tested and work quite well. Additionally they are advantageous in that they are much more efficient and some buck the voltage minimally.

GalenB

My Feedback: (18)

I use HS-5945MG servos with 5 cell packs without a regulator and have had great success . Nary a twitch has been seen... Some servos twitch when connected to an unregulated ad freshly charged 5 cell pack...

Lynx

I whole heartidly agree, switching regulators are just BAD karma to anything involving R/C equipment, you're asking for trouble if you use one. Although I'm sure one could (or has) been designed that has sufficiant filtering to get rid of the problems that might crop up. Linear regulators are VERY wastefull, I never relized how much untill I started using them in electronics. They should only be used if you absolutely require a standard voltage for some reason, maybe if you're using li-poly packs. But even then it achieves regulation through wasteing that extra voltage. No regulator built can equal the amount of current you can drain from the power source directly no matter HOW you build it, so you're losing high end power using one. It's best to design your system around the voltage range your battery produces. The most usefull power regulation feature for R/C equipement would be large value capacitors, as they can give you HUGE peak currents, problem is the size and weight they take up make them virtually useless. If you want to go through the trouble to create a capacitor array to buffer your battery you're looking at nearly 98% efficiancy and it almost eliminates problems from high pulse drain devices (like digital servos) Never seen anyone create anything like that before though.

Bozwth

My Feedback: (3)

I can't have any bad karma in my plane. The voltage regulator goes back on the shelf. [8D]

Lynx

I just picked up some aerogel capactors from, DigiKey to play with, I'll have to see how they work on an RC servo. I'm using them to just play around with hold up power on some micro controllers, but at 1 Farrad and 5 volts (6 peak) they should hold up fairly well if used to buffer the power to a servo on a 4.8 volt pack (couldn't be used on 6 volt packs) With something like that, even a full negative deflection under load to neutral to full positive deflection under load wouldn't cause even a hicup in the power line. They should filter out virtually all feedback too. Pulse current on these is something like 20+ amps, and can be raised by putting them in parrallel. They're only about 3/4's of an inch long 5/8's wide and 1/4 inch thick, they are 3.75 each though, so they're expensive if you want to add one (or more) to each servo. Weather or not they work, I'll be having fun spot welding things with them <smirk> 4 in series will provide 20volts at 1 farrad, and that's a HUGE amount of instant power. I'm actually hopeing it'll be usefull as a "Poor mans" stick welder, for quick tack welds on things like little nuts and bolts (thread lock eat your heart out) Anyways, that's more than anyone wanted to know, I'll shut up now.

hooker53

My Feedback: (106)

Nary a twitch has been seen... Some servos twitch when connected to an unregulated ad freshly charged 5 cell pack...

Galen----I think the twitch is what we are trying to beat here. If some servos twitch when not conn. to a regulator and it's indesirable to use a Reg. than how do you get rid of the twitch short of going back to a high Cap. 4.8 pack??? I'm having the same Prob here. Thanks Hooker53

Bozwth

My Feedback: (3)

OK here's a different scenario. This airplane has a 4.8 1300ma NiCD battery pack, a Hitec receiver and Hitec 645MG's. The switch with the voltage regulator that I was referring to above is a "MPI miracle switch". The unit is about $40 bucks so I assume its a pretty good unit. Since I'm not going to be using it with my 6v/digital system, would it hurt anything to use it on this 4.8v system? I think one of the benefits of this unit is that if the switch fails the circuitry keeps the circuit closed. Will the regulator rob energy from a 4.8v system or does this kind of regulator only rob energy when its above 6.0v?

Lynx

Using a regulator in a 4.8 volt system is just a waste of energy. It serve's no purpose.

GalenB

My Feedback: (18)

This was my attempt to say that my Hitec digitals do not twitch on a freshly charged 5 cell pack -- unlike some other brands... I guess I should have said "some other brands of servos..."

hooker53

My Feedback: (106)

Well GalenB. You are right there. I have not tried Hitec's on this plane that was twitching. I think this goes right back to the old adage, you get what you pay for!!! The servos that I'm getting a twitch on is FMA and MPI's Like I said though, when I went back to a 4.8 volt 1200 Mah pack they fell quite as a mouse. Now I have a Maxx prod. switch that has the voltage leds on it and don't know how much battery it's going to take to opperate all that, but will keep an eye on it. Thanks Hooker53