Why do you use HV and / or why don't you?

[3D-Joy]

I only have a hand full of flights on my new 50% Yak and have noticed I am only using 480 - 500 mah per each 13 min flight. My FROMECO 7800's are feeding 14 8911HV and 2 savoxHV servos,,, I shudda went HV a long time ago.

Wow thats like soooo little.
My 40% extra 260 uses around 1000 mah total (500 per battery). And thats for 10 minute flights ! I charge every flight so I know exactly. I consistently do between 950 and 1050 depending how hard I fly and if I use smoke or not. Everything is driven from these 2 packs.

 

[Terryscustom]

Seems a little high, but not crazy. I know on my 176cc PAU extra I'm burning about 375mah per pack per flight.

 

[3D-Joy]

Seems a little high, but not crazy. I know on my 176cc PAU extra I'm burning about 375mah per pack per flight.

Yes it appears quite high to me too but like I said, everything runs from these 2 packs, engine and smoke pump included. Plane is equipped with 8711 servos which are known to require more power than other servos (less efficient?). Its relatively heavy at 42lbs which may also make a little difference.

Anyway its been like that for 7 seasons and well over 1000 flights (I wish I counted them it has to be closer to 1500) so I'm not changing anything !

 

[ChickenBalls]

@combat chicken good read. Weigh options, and honestly go with what works best for you, as you can see from this thread, all of em work. If @mulehead1969 or @emtp275 start telling you there Nicads are better, send em to me, I'll tell em to pound sand

 

[stangflyer]

Seems a little high, but not crazy. I know on my 176cc PAU extra I'm burning about 375mah per pack per flight.

I'm about where you are. The 176cc Sukhoi is about 350 per pack per flight...., the 260 a little less (2 less servos) at roughly 315 per pack per flight. But then I only run the radio off them. No smoke and no ignition.

 

[Xpress]

You guys need some brand new Hitec HSB-9380 servos in your airplanes. Fly all day without recharging, they draw almost nothing!

 

[3D-Joy]

Arent they the servos that to get full benefit of them you need to use no regulator or battery share circuit so you get the regenerative charge ?
I installed 2 of these servos in an 1/8 RC moncter truck but had to use their PAD thing because i was running off a BEC which can't allow regenerative charge. Servos are quick and precise.

 

[Xpress]

Arent they the servos that to get full benefit of them you need to use no regulator or battery share circuit so you get the regenerative charge ?
I installed 2 of these servos in an 1/8 RC moncter truck but had to use their PAD thing because i was running off a BEC which can't allow regenerative charge. Servos are quick and precise.

That's why we include the PAD with the HSB's, in the event you use a BEC/regulator. They're still ultra efficient, and they're HV compatible so you can plug a 2s lipo/ion directly into the receiver.

Whether you run them at 6 or 7.4 volts doesn't actually even matter because the brushless motor inside of them is so ultra efficient that they generate the same torque values throughout their voltage range, the only variable that changes with voltage is the speed.

 

[Reza]

I'm late to this discussion but what brand HV servos are we talking about, any?

As for A123, they are excellent batteries but with a descent charger and buying a descent lipo battery, one shouldn't worry too much about batteries catching on fire. I personally don't charge my batteries unattended. I charge them when I'm working in my shop or on the way back from flying field. When I know I'm not going to see them until the next day or so, I take them off the charger. Just got the habit doing so over the years.

 

[stangflyer]

You guys need some brand new Hitec HSB-9380 servos in your airplanes. Fly all day without recharging, they draw almost nothing!

A little pricy but good looking numbers on the servo. 472 ounces at both 6 and 7.4 volt.

HSB-9380TH
Operating Voltage Range: 6.0-7.4 Volts
Operating Temperature Range: -20° to +60° C (-4°F to +140°F)Operating Speed (6.0V): 0.17 sec/60° at no load
Operating Speed (7.4V): 0.14 sec/60° at no load
Stall Torque (6.0V): 472 oz/in. (34 kg.cm)
Stall Torque (7.4V): 472 oz/in. (34 kg.cm)Operating Angle: 45 Deg. one side pulse traveling 400usec