40 A ESC

[beng]

Have a small 40" WS calls for a 1200Kv motor 1800 to 2200 battery and 20 to 30 A ESC. I have a 40 A ESC, will it be okay to use????? I can not get it to bind with a 20 or 30 ESC (some day some one has got to get with me on how to USE OR SET up the DX8) thanks

[WintrSol]

You can always go higher in the Amp rating of the ESC; you just get a wider margin of safety. No advice on the DX8, sorry.

[xviper]

You need to tell us what cell count you are planning to use with that. A typical 1200kv outrunner will likely be OK with a 30A ESC running on 3S. If you're going with 4S, the 40A would be better. Also, if you over-prop it, other possibilities need to be considered. The size of the ESC shouldn't affect whether or not it will bind. What matters is if the ESC has a built-in BEC or if it's an "ortho", which has no BEC. If it has no BEC, you'll need an external BEC. Don't you have the manual for your DX8? Gen 1 or Gen 2? I've had the Gen 1 and am now on the Gen 2. They aren't hard to figure out for the basic functions.

[beng]

xviper2, The 1800 are 3s but all the 2200 are 4s. So if I run with a 4s the 40A would be okay on the 1200 Kv motor, once I get this going I do want to go with bigger motors......As you know I'm new....so what is BEC? The DX8 is a G-2 model, I have tried to read this book and a lot I'm beginning to understand, but also a lot is... "WHAT" The model shop and field is a 3 hour round trip. Was thinking to go Friday and take the book and motors, ECS and batteries and try to get someone to help... (We are 85 to 90 deg. here in Georgia, so how is Canada doing??????) beng

[xviper]

Beng, you're better off going with the 40A. You can run both 3s and 4s on that. However, having said that, you need to know the approx. size and pitch of prop to go with that motor or you'll easily exceed the capacity of the ESC and motor. One or the other or both can burn up. Find out what normally goes in that plane in terms of motor size, ESC size and prop size. I have no idea what a 40" WS is. You need to state these details so people can help you better.
A BEC is "Battery Eliminator Circuit". It's what provides the receiver with power and from there, provides all your servos with power. Without a BEC, no power to the Rx, hence no bind, no servo function. An external BEC is one that is powered by another battery. "Ortho" ESCs have no BECs built-in. Read the ESC and it should tell you the details of the size of BEC that's in it. If it says nothing, likely no BEC.
I'm currently using the G-2. It's a great Tx. One option is to search YouTube for instructions on how to do simple set ups with it.

[crankestein]

I noticed in another forum people were using some device that supplies constant 5V to the receiver. I think its used if no BEC available.

[xviper]

I noticed in another forum people were using some device that supplies constant 5V to the receiver. I think its used if no BEC available.

You can get all sorts of external BECs when an "ortho" ESC is used. 5V is typical but you can get them a bit higher or a bit less. Most receivers won't handle much more. It's also important to note the amperage of the BEC. A "rule of thumb" is a typical servo takes about 0.5A, so if you have 10 servos, it would draw about 5A, however, it's not likely that anyone will operate all the servos at once. Retracts can draw much more.
PS, you can also provide the RX with an auxiliary battery to provide constant voltage. These are typically LiFe batteries and plug directly into the RX.

[WintrSol]

You can get all sorts of external BECs when an "ortho" ESC is used. 5V is typical but you can get them a bit higher or a bit less. Most receivers won't handle much more. It's also important to note the amperage of the BEC. A "rule of thumb" is a typical servo takes about 0.5A, so if you have 10 servos, it would draw about 5A, however, it's not likely that anyone will operate all the servos at once. Retracts can draw much more.
PS, you can also provide the RX with an auxiliary battery to provide constant voltage. These are typically LiFe batteries and plug directly into the RX.

Modern receivers typically reduce the 'battery' supply to about 3.3V to operate the internal chips, and can tolerate a relatively wide range in input Voltages; it's the servos that are likely the limitation. Classically, a receiver or servo would be rated for 4.8V, the nominal Voltage of a 4S NiCd pack, which would have a full-charge Voltage of just over 6V peak (however briefly in operation). Many servo makers still follow this pattern - Futaba, for example, will rate a servo for 4.8V (4S) or 6.0V (5S); allowing for the increase to full charge, 5S would be ~7.5V peak.

A LiFe battery would be either 3.3V nominal (1S), or 6.6V nominal (2S), with a full charge Voltage of 3.6V or 7.2V; a 1S may be too low a Voltage to operate the servos well, and 2S could damage servos not rated for that high a Voltage. You have to find the specs to confirm if your servos can handle that much Voltage.