Here is an email exchange that answers the questions most people have when they’re considering a 5-cell (6 volt) pack:
Q: “Dave, one last question, then I will be sending you an order to upgrade my batteries. What is the difference between 4.8 and 6 volt receiver batteries besides weight?”
A: A 6 volt pack gives you some additional safety: one cell can short and you will still have enough voltage to keep flying. That is not to say that every type of cell failure is covered if you use 6 volts — a cell can always open up, and no amount of voltage is going to help you then. The extra voltage will give your servos more speed and more torque, and the increased speed will give your airplane a feeling of crisper roll damping. Flying time is slightly reduced with a 6V pack compared to a 4.8V pack of the same capacity, but the reduction is minor and shouldn’t enter into a typical battery choice.
Q: “My Futaba manual says that the receiver will use both voltages.”
A: Yes — it is made to accept 4 alkaline cells, which is 6 volts.
Q: “What performance increase, if any, will the 6 volt battery give? What specifically will improve — better reception (whatever that means)? Less interference? Faster servo travel? Thanks, David H.”
A: More torque and more holding power. Torque typically increases by more than 25%, and of course rotation speed is faster. The quicker return to center is the part you will probably notice most in your flying. I have also heard it argued (by those more knowledgeable than I) that many receivers have more range and are slightly narrower-band with more voltage.
You will occasionally see jittery servos when you first switch on a freshly charged 6V pack. This usually goes away in just a few seconds — the peak voltage of a fully charged 6V pack is well over 7 volts, but it settles down quickly.
For most of my smaller and normal-sized ships I am chasing weight savings, so I use 4.8V. I do use 6V on a combat model, and I would use it on any large model (or a twin-pack / twin-switch-harness setup), as I like redundancy in ships that are more important to me. There are many different views on this subject — ask 5 different people and you will probably get 5 different answers.
About 90% of all packs in use are 4.8V, and 4.8V is fine. If you are after extra torque, more speed, or some redundancy, 6V is a good choice.
Happy Flying!
Dave Thacker
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