Opto ESC and UBEC ??

[Romeo Whisky]

I vaguely recollect reading a thread on here about the issue of using an OPTO ESC with a UBEC, and that for some reason it was said to be preferable to use a separate RX pack.

 

As you might gather I can't  recollect exactly what the issues were, can someone remind me?

[Tim Mackey]

HERE

 

extract

"standalone switchmode regulators even these, when used in conjunction with an OPTO style ESC will compromise the OPTO isolation feature of the ESC. The only sure way to retain its feature of radio isolation is to use a seperate battery completely. Using a standalone BEC merely restores the common battery positive and negative rails being tied back to the ESC and defeats the object. BEC and OPTO are as it were.... mutually exclusive".

Edited By Timbo - Administrator on 06/03/2010 09:02:30

[Romeo Whisky]

Thanks Timbo - I knew my aged memory wasn't imagining it! 

[Mike Downs]

I am converting a twin i/c to electric and am having trouble using two opto type ESC's..I can only get one working ! Any ideas? please

[Chris Bott - Moderator]

Hi Mike

How are they connected? Are you using one battery for each motor or one common one? Do you have the leads to the receiver connected via a "Y" lead to the throttle channel or to two separate channels?

The best check to do to start with is to make sure each one operates individually in a normal single engine configuration.

[Mike Downs]

Hi Chris,

they are connected through a Y lead from the throttle channel. The power leads to both are through a Y connection and I intend to run it on a single battery (Lipo 3S 4000mAh)

The motors are 2200kV x2 and the ESC's are 2x40A opto ( I am going to use a seperate power pack for the reciever) with the props being 9x6

One quick question..... do you think that the above set up would be OK...I can't check it up with a Watt meter until I get the ESC going!

Cheers

Mike D

[Chris Bott - Moderator]

Hi Mike

That should work fine. All you can do is break it down and try them separately.

If one still fails to work then maybe swap motors between ESC's to work out which is the troublesome unit.

You should suspect and try to eliminate any of the following:-

Faulty ESC
Faulty motor
Faulty Y lead
Faulty Y connection from the LiPo

[Chris Bott - Moderator]

Mike I've just re-read your post where you ask about the setup.

3S, 2200kV and 9x6 props doesn't quite add up for me, I think there's a good chance they will draw more than 40A each.

Having said that, I have no experience of exactly this sort of setup.

Anyone else have an opinion?

[Pete B]

Any more info on the exact motor, model, span, anticipated AUW, etc? A link to the motor would be helpful.

Some of the smaller 2200Kv motors run a 5 x 4 'ish prop on 3S, so 9x6 could be way outside its capacity.

Pete

[Mike Downs]

I have changed the suspect ESC opto and everything sprang to life! Hooray!

The set up is 2x220Kv motors,through 2x40Amp ESC opto turning 9x6 APCe props. I have wired the power through a y lead and the power is 4000mAh 3s 11.2 lipo. A.U.W=5lb 40z

On the wattmeter.......31A.......299W

I don't know how long the flights will be as the weather is so poor at the moment,but running it on the benchfor 5mins there is no discernable heating on the battery ,ESC or the motors. It feels like it will have enough umph..I would like to design a sort of thrust measuring jig for models with tractor props.

Does anyone know of a good method of making one?

Pushers are a doddle as you only have to put them on the scales nose down,note the weight,open up the throttle and note the difference.