Moving to High Voltage

[TazmanianDevil]

Hi friends



From my experience it's never mind if you'll move to high voltage to get 1000 oz of power to the servos because no mater what battery you install they just can't give the amount of current the servo needs.

It's all about the way you fly and the throttle management.

Even for rifle rolls you don't need the surface to be 60 degrees that can cause a servo to stall no matter how strong it is.

Use a tradition high quality servo, work right with your throttle and I promise you you won't need this high voltage servos.



I run on my plane savox 2270 HV because I was thinking that they will stop the stall issue and will give endless power, and I was wrong. I even tried to give them direct 7.4 V which is actually 8.3 V and it didn't work friends, I could put the bran new Futaba or JR or Hitec.

You will stall the servos cause of the battery.

Now I'm using regulators to reduce the voltage to 6.6 and use throttle management and viola no problem.

I bet that guys that are using true A123 Brand doesn't have a problem.

My 2 cent friends.

 

[stangflyer]

ChickenBalls;19685 wrote: Not sure give it a try, report back to us, let us know what color the smoke was you get.

Magic smoke...kind of like an "SBD"...... Ya can'ts see it, but damn...ya know it's there. LOL

 

[mikeh]

Thinking about using lipo in my next bird. Where is the cut off voltage on lipo? Is it the same as a lion, 7.0 volts under a 1 amp load?

 

[stangflyer]

Thinking about using lipo in my next bird. Where is the cut off voltage on lipo? Is it the same as a lion, 7.0 volts under a 1 amp load?

I found this information regarding you question. Hopefully it helps.
http://www.rcuniverse.com/forum/rc-...0881201-what-should-my-lipo-cutoff-print.html
Also: http://www.rctech.net/forum/electric-off-road/461171-lipo-cutoff-voltage.html

 

[jaybird]

Thinking about using lipo in my next bird. Where is the cut off voltage on lipo? Is it the same as a lion, 7.0 volts under a 1 amp load?

I stop at 7.2 under a 1 amp load. I may be leaving a little on the table but I feel safe at that number.

 

[Capt.Roll]

LiPo's are fine but there are a couple of things to take under consideration.

Many LiPo's are discharge rated at 20C plus so putting them under 1 amp load won't tell you much as I doubt there is much voltage drop. On my electric ARF flight packs the motors can pull 90+ amps and I'll see a voltage sag to 3.6-3.7 under a wide open load.

LiPo chemistry can be volatile; a pack can puff and/or catch fire at any time. I would not charge your Lipo packs in your plane.

To help maximize the life of a LiPo, it's best not to discharge below 3.6 volts per cell; 3.7-3.75 is even better. Also it's best if you do not leave them in a fully charged state. 3.8 volts per cell is the recommended storage charge.

 

[Ohio AV8TOR]

LiPo's are fine but there are a couple of things to take under consideration.

To help maximize the life of a LiPo, it's best not to discharge below 3.6 volts per cell; 3.7-3.75 is even better. Also it's best if you do not leave them in a fully charged state. 3.8 volts per cell is the recommended storage charge.

For sure and a better way to look at it because IR affects your voltage ability is too look at how far you discharge your pack. Never consume more that 80% of your battery capacity in mAh. I would never go down to 3.6v. 3.7-3.75v are good numbers to shoot for.

 

[1932]

How to put balance leads on two cell lithium ion.
Want to charge with GT500 but it does not like cell count.
New to this, but working on it.
Been using A123 and now Lipo.

 

[camss69]

I've recently gone back to LiIon from LiPo because I like to be able to charge in the plane. I ran LiPo for several years for all the reasons mentioned but I hated not being able to leave them on charge and walk away. They also don't like to be left fully charged for long periods of time, and my balancer would continue balancing (draining the batteries) if I left it plugged in, the LiIons don't need to be balanced. Then there are times when I needed to mount the batteries where I couldn't easily see them or they weren't easily accessible. For my flying style LiIons put out plenty of power and are convenient to use.

 

[Surfer Dude]

To the original question my setup that I have come to like, uses two castle Bec pros set at 8.4 volts using two 3 cell lipos. I have been using this setup for the last 3 years with no issues.