I am setting up a 1/3 scale pitts and would like some advice on the reciever battery. Should I use a 5 cell pack or a 4 cell pack? I do not need extra speed on the servos and i believe the 5 cell pack will draw more current.
I'm using two four cell packs and two switches per the battery clinic. Only three more cells over a 5 cell pack and better protection. Oh, the cells are
700's which results in 1400 mah total capacity.
Dan Thompson (AMA 32873, EAA 60974, WB4GUK, GROL) remove POST in address for email
I've used 5 cell packs on everything from fun fly to sportsman to pylon to giant scale for many years. I love the 5 cells. Extra voltage is a good thing with long servo leads. I love the 20% torque increase, too. Be sure to use a sufficient mAh battery for that big, aerobatic plane. I'd go with 1500 or greater. Dr.1 Driver "There's a Hun in the sun!"
Stuart, First the answer is it depends.... What is your confort level with batterys? What kind of charger do you propose to use? etc etc....
See above...
Yes, it will draw more current
It depends mostly on the radio.. there is some discussion that certain servo's don't like the extra voltage and get jittery.
I have used both 5 cell with and without regulateors as well as the dual battery packs all work good in my chosen application and I have had no problems with any of them. Personnally I would go with a 5 cell pack of about 1800 Mah ratings no regulator.
Either voltage will work nicely. Others have pointed out some of the problems with five-cell packs, not the least of which is jittery servos when the pack is freshly charged.
A regulator would be nice, but not required.
What is required is increasing the current rating of the pack if you step up to five cells.
The change from four to five cells results in a voltage increase of
125%. Working against a fixed load, a higher voltage will cause a higher current flow, so you need to bump the current capacity by the same 125%.
Whatever the four cell current rating, multiply that by 1.25 to determine the current rating the five cell pack should have.
If for example you have a 4.8 volt 500 mAh pack now and swap in a 5 cell pack, the 6 volt current equivalent would be 625 mAh to maintain the same discharge period (flight time).
If you don't increase the current capacity by the same percentage as the voltage increase, the five cell pack will go flat faster than the four cell pack.
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