Kontronics

[hopntod]

Do I need a seperate BEC for a Jazz 80-6-18?

[hopntod]

After some more searching I find that I probably do need a separate BEC so why do I need it if it has one built in?

[Jafa]

You can use the BEC that is built into your Jazz controller
It's a very good BEC

You can use a seperate battery for the RX and Servos
Some people use a 7.4v LiPoly for this purpose
That means they need a regulator to get the voltage down to 5.x

[hopntod]

Thank you for the response Jafa.Please bear with me one second here,if I use a step-down voltage regulator between my gyro and tail servo as I have on my other helis equipped with a 9254, then would not I be good to go? With out the extra weight of a RX battery?

[AusAnt]

Hopntod,

I don't think you'll even need the step down for the gyro servo. I had a look on the Kontronic site and couldn't find the voltage that this BEC outputs at, but it is most likely to be 4.8 or 5V. Step downs are usually only needed for BEC's putting out higher voltages such as 6V. If you could verify this output voltage from the manual or by contacting the vendor or Kontronic, then you can be sure.

This is a great BEC in this ESC (it is a switching BEC, which is what the nice external ones are, as opposed to a non-switching BEC found in most smaller controllers). It also outputs at 4A, which is quite a lot for an integrated BEC.

I have this exact controller, which I am about to use in a logo 500. I have chosen to use an external BEC only because I am really conservative, :roll: and I figure that if the ESC is working hard and generating a lot of heat, and the BEC is doing the same, there is more chance on a hot day of it shutting down due to thermal overload. I am also using a 5A BEC for just a little more capacity. However, like I said, I am usually way over the top with these sorts of things, and I am sure that most people would reccomend that this BEC is fantastic and more than up to it. I am also using very high drain servos in mine, which made me go to the external BEC.

Obviously you are not going over 6s (all that this is rated for) and you should be sweet. Maybe as a precaution, just feel your ESC after each flight for a while, and if it is really hot, maybe think about an external BEC then.

Hope this helps. I presume this is for your logo - you would probably be just as well to post this type of question there - lots of guys there who fly this same gear and are much more experienced than me :wink:

Ant

[hopntod]

Thanks Ant,so now I understand it is a matter of distributing the heat.I have scoured the logo forum and did find that some were using an external BEC along with the 80-6-18.I am looking at the western robotics 6-5 and I thought I might try to mod a heat sink to the jazz.Your advice is greatly appreciated.

[AusAnt]

Good one hopntod,

I just see it as cheap insurance - theres a lot of money spinning around up there :)

I have the Western Robotics Hercules 6/5 volt 5amp model. There is also a 3 amp model, which would actually be a step backwards (other than heat separation) from your inbuilt ESC, so if you are going this route you may as well go the 5 amp. like this one
http://www.rcflightstore.com/product_info.php?cPath=60&products_id=820

I assume you know you will have to disable the inbuilt BEC if you go with an external - instructions should be in the manual

I am also doing a heatsink on my ESC. If you look up OICU812's threads, he shows his mod where he cut down a computer heatsink, and used a thermal epoxy from computer store to glue it on. He could give you more details there if you want them. I was getting some other stuff from this shop in Japan (if you use EMS mail it gets to Canada in about 5 days) so I got this one. It comes with an extra heatshrink to cut the heatrshrink off the ESC, add the heatsink, then re-shrink the ESC. Although I am not sure as the fins wouldn't have such good airflow then. I think I might follow OICU812's method. Here are the heatsinks anyway,
http://www.aircraft-world.com/shopexd.asp?id=4434

Ant

[hopntod]

Thanks for the link Ant.I will have a look at that site to see if there is anything else I can use.It is hard to justify the shipping cost on one small item. Todd