Leslie Ward

I can't recall anyone ever mentioning what voltages recievers can operate on. I am assuming anywhere in the 4.8----11.4 area.
Is this correct? I will eventually go to elect. power and beginning to make up a shopping list. Slope / thermal and maybe something to fly at the soccer fld.
Aloha, Les
Kauai, HI

3dd

My Feedback: (6)

most receivers don't like over 6 volts

Sir Raleigh

4.8 - 6 volts

Leslie Ward

OK!
So how is the voltage reduced/handled, with a higher volt system. Two batteries? Sorry for the seemingly basic questions, I feel as I should know the answers.
Aloha, Les

Sir Raleigh

If your ESC has a BEC (Battery Eliminator Circuit). indicated by the presence of a 3 wire cable with a plug on the end that will fit your receiver, then the ESC will supply the correct voltage to your receiver.

If the ESC does not have this 3 wire cable, then you will need another battery box for the receiver. This battery box will hold 4 AA batteries to supply the correct voltage to the receiver.

jooNorway

All receivers work good a bit below 4,8 volt. Some work at low voltages as 3,6 volt. Some receivers don`t like to get much above 6 volt, others (high end) work well on 7,5 volt.
Usually the BEC delivers 4,8 - 5,5 volt for the system.

jdetray

Hi Leslie -

A correction to the good information others have provided:

An ESC (electronic speed controller) will always have a 3-wire cable that plugs into the receiver, whether the ESC contains a BEC (battery eliminator circuit) or not. It's through this cable that the receiver controls the speed of the motor. If the ESC has a BEC, the center wire (usually red) provides power to the receiver. If the ESC does not have a BEC, the center wire does nothing, and you'll provide receiver power by means of a separate battery or an external BEC.

Below is a hookup diagram for the electronics in a typical electric plane where the ESC has a BEC.

Further Explanation:
The ESC (electronic speed controller) connects to the battery, the motor, and the receiver. The ESC serves three main functions.

Controls motor speed
The details of this function differ depending on whether the motor is a brushed or a brushless motor. But in any case, the ESC takes the battery voltage and applies it to the motor in a manner that varies when you move the throttle control on your transmitter.

Battery Eliminator Circuit (BEC)
In electric planes, keeping the weight low is often very important. Since a battery is usually the heaviest component in a plane, it is helpful if you can use just one battery to provide power for both the motor and for the receiver and servos. So most ESCs contain a Battery Eliminator Circuit (BEC). The BEC regulates the battery voltage down to a lower voltage that is appropriate for the receiver and servos. This eliminates the need for a separate, second battery for the receiver and servos. Hence, the term Battery Eliminator Circuit. The ESC connects to the throttle channel on the receiver and sends power to the receiver through that connection.

In larger electric planes where low weight is less important, it is common practice NOT to use the BEC and to instead use a separate battery for the receiver and servos. Obviously, a separate battery for the receiver and servos provides a degree of redundancy, so even if the motor battery fails, you still have power for the control surfaces.

Low Voltage Cutoff (LVC)
Some types of batteries, notably lithium polymer (lipo), can be damaged if discharged below a certain voltage. Most ESCs now include a Low Voltage Cutoff function. As you are flying, if the battery voltage drops below a pre-set level, the LVC reduces or cuts off power to the motor only, while the ESC continues to provide power to the receiver and servos. This gives you a chance to land the plane before the battery is damaged and while there is still enough power to operate the receiver and servos.

- Jeff

Leslie Ward

Wow, that is the greatest info, now I can understand how the typical system works, and spend some more $$$
Thanks everyone, & Aloha, Les

Leslie Ward

So is the power to reciever, as shown on the schematic, delivered thru the cable from BEC ?
Aloha, once more, Les

jdetray

Yes, the center conductor (usually red in color) in the 3-wire cable carries power from the ESC's BEC to the receiver. The signal wire (may be any of several colors) in the same cable carries throttle signals from the receiver to the ESC. The third wire (usually black or brown) in the 3-wire cable is the ground or common.

- Jeff

Leslie Ward

Thanks JDE,
For your time and patience, greatlyappreciated,
Aloha once again, Les

Glacier Girl

My Feedback: (4)

Hey don't forget about UBEC's, or stand alone units.
Like was explained above, very well I must add, if the stock ESC is an Opto or not equipt with a built in BEC, or if the built in BEC is not able to handle the load, through too many servos or too high of a power feed, another option is a UBEC.

A built in BEC in a ESC, can only handle so much, amp and volts, otherwise all the magic smoke leaks out. If you are running more servos or higher voltage then the specs allow on the BEC, you must disconnect it. And use something in it's place. Disconnecting is as easy as removing the red wire from the ESC's plug that goes to the RX. Just pop it out of the plug and insulate it so it doesn't short against anything.

Now you can decide to either add a separate RX battery pack or a UBEC. A UBEC is wired to the main pack, most times with a switch, so it can shut off power to your system. It too has a plug that goes to any on the RX connectors, even Y connected to another lead.

Couple of benefits of a UBEC. Lot lighter weight then a separate RX pack, can handle higher voltage inputs and amp draws over the built in BEC, and in some cases is adjustable for voltage output. Like said above, 4.8 or 6 volts in most cases is the voltage used to power an RX/ servos. Jumping to 6 volts makes the servos work faster and makes them stronger.

That's why when you look at servo specs, you'll see both 4.8 and 6 volt listings of speed and output.

God I love electrics!

jdetray

Thanks for mentioning that, GG.

Les, the standalone BECs such as the [link=http://www.koolflightsystems.com/ultimatebec.htm]Ultimate BEC[/link], the [link=http://www.dimensionengineering.com/ParkBEC.htm]ParkBEC[/link], and others are a good solution if your ESC doesn't have a BEC or if the BEC is not adequate to power the servos in a particular plane.

As GG said, these standalone BECs are often a better choice than a second battery pack, especially if you're trying to keep the weight down.

- Jeff.