Six HS-5645mg Servos
 

I am building a 30cc spacewalker and using 6 hitec hs-5645mg servos and Im wondering what battery setup I should use. This is my first plane with all digital servos. Normally I would use a 2000mAh 5 cell NiMh battery, but would this be enough, or should I run twin battery packs.

Thanks
Brendan

RE: Six HS-5645mg Servos
 

Hi Brendan,
remember to keep the ignition batt and switch separate. (probably requires 4.8 volt anyhow).
I am running 4 5645, 2 5995 and 2 5945 on my 1/3 extra with 2 2400 mA batts. Its plenty for that plane.
here is the 5645 spec on 6v: Current Drain (6.0V): 9.1mA/idle and 500mA no load operating
Here is the 645analog: Current Drain (6.0V): 9.1mA/idle and 450mA no load operating
they dont give the loaded spec but im sure it gets up there. I would run dual batts and switches just to be safe. 250 mah of batt minimum per servo is what i was told. and either pack should be able to operate the aircraft 3 fueling cycles.
On the space walker wouldnt 4.8 volt to the servos be plenty? still have 143 oz/in torque and power demand is down 20%. It does make the servo a little slower and I have read certain new rx's dont much like 4.8V. If it works good it is a weight savings for you.

RE: Six HS-5645mg Servos
 

I thought that 5 cell would have given me longer flight time, not thinking that its making the servos draw more current. Even with 4.8v I would get plenty of torque. I am more concerned about the current draw from the 6 digital servos. I was already planning to power the ignition with a 2000mAh 4 cell NiMh, as it can't handle anymore voltage.

RE: Six HS-5645mg Servos
 

I use a 2500mah 2cell LiPo Rx battery in all my aircraft, with a 6v voltage regulator. Quick to charge and the charge lasts a long time. I have never had a problem. I use two FMA 10S chargers for all my Electric, Gas, and Glow batteries. I put two Enegerizer 6v Golf Cart batteries in the back of my van, in series. It powers both chargers. My motor batteries are 5S 5000mah packs. I can charge two at a time on each charger. A 5S 5000 pack, close to fully discharged, will charge in 45min. Some friends of mine have Honday 1000W generators and a 60a Power Supply. They can charge the same cells in half the time.

Just disconnect the batteries from the switch harness at the end of each flying day, to be sure they do not get accidentally over discharged.

I have no need for NiCad or NiMh ever again. Eneloop and A123 are also good. Eneloop is a NiMh format that holds it's charge like a LiPo, however, it does not charge as fast as a LiPo.

RE: Six HS-5645mg Servos
 

I would run the second pack. cheap insurance. 4000 mah total is more than enough.

RE: Six HS-5645mg Servos
 

Use an A123 4600ma pack. The A123 packs from ElectroDynamics are great!