Jon Dahlgren

I have a JR 8103 8 channel PCM radio and i want to use a 6V receiver pack instead of 4.8V. Can i do this?

Primarily this is to solve some problems related to the hall effect RPM sensor in my turbine control unit. Apparently if the current draw gets too high due to the high number of servo's, the voltage gets unstable and/or drops causing the RPM sensor for the turbine to fail.
It will give me more servo power too.

I am running the radio in my turbine powered hotspot with the following servo's:

2 JR 8411's
2 Voltz thin line servo's
1 JR 3321 servo
3 JR 531 servo's


Any help would be appreciated


thanks


Jon Dahlgren

MO_Radio_Tech

Under every circumstance I have seen, JR receivers and servos work with 6 volts. At "Ask Danny at JR" Danny just answered this. He says to use a regulator.

Geistware

My Feedback: (16)

I have heard that some of the JR receivers don't do well on 6 volts. Ask Danny at JR and he should be able to help.

KJohn

Have you considered using a separate battery pack for the sensor. If you do that then drain in other parts of the flight system will not affect voltage at the sensor. In other words, you would no longer be sharing one battery between everything.

Lynx

Higher voltage will actually cause a higher strain of current on the battery and would more likely make the problem worse, you're better off getting larger capacity cells as that will truly help your problem. If you have the patience to do it, wiring up a large number of big electrolytic capacitors in parallel can reduce or eliminate voltage dips like that from quick servo hits, you just have to use a large number of high value caps. They use tiny little tantalum ones on electric motors to reduce noise. Bigger ones will reduce even bigger 'noise' IE voltage drops. You just have to be carefully because if you use enough and develop short on the live side of the capacitors you can generate enough heat to weld.

_kearney_

This is recomended by my club. With 4 cells if one cell fails you will not have enough power to run you reciver. with 5 cells if one cell fails you will be good to land and you will find you have a cell out because your pack will hold less charge. Even if you have no problems with your pack, this will give you more flight time and it will keep you safer while flying. However i have no idea if this is what your question is concerning but you may want to try it anyways...

strato911

Actually, your flight time is reduced if you are using the same capacity cells. According to Ohm's Law, higher voltage through the same load means higher current.

Therefore, if you use 4.8V 900mAh packs vs. 6.0V 900mAh packs you should experience longer flight times on the 4.8V packs. If you upgrade to 6.0V packs for the "cell redundancy", don't forget to increase the capacity accordingly.

_kearney_

I was told otherwise, oh well im a newb what do you expect. maby its the type of battery!

strato911

Lot's of mis-information is floating around, being spread by the less-informed:

Correction to annother common bit of mis-information:

Swapping transmitter crystals without re-tuning is illegal in North America (it's legal overseas). Receiver crystals may be swapped legally.

MO_Radio_Tech

What has been said about capacity by some of the previous posts is true. More mAh = more capacity, regardless of 5 cell or 4 cell.

More comments on 6V (assuming the equipment is designed for and compatible with 5 cells.)

Good side:

Receivers don't receive any better or worse.

Most servos have increased speed and torque.

May be more reliable due to higher voltage / extra cell.

Bad side:

On helicopters, seems to work gyro/high speed tail rotor servo combo to death. Must use a regulator or stay with 4.8V.

Some receiver/amplified "y" harness combos don't work at all at 6V. Must use a regulator in this case.

Some servos act quirky right after 6V pack has been charged. This does not seem to be a problem under a load in the air, and as volatge drops, phenomenon goes away quickly.

This tech does not beleive that a servo motors lifespan is reduced by using 6V. Jury is still out on that.

Conclusion,

6V helps many people get more out of thier servos and may add a degree of reliability, when used properly and with regulator when needed.

But, most people are happy with good old 4.8V four cell packs and never have problems.

The 6V is not for everybody, but I like them.