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To BEC or not to BEC


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  • 2 weeks later...
Hi Peter...not sure I advised using a separate battery did I ? I usually use the main flight battery to power my UBECs ,as this keeps weight down and charging simpler also.
Also regarding the twin batteries for twin motors..again I usually suggest one large battery ( or at least having the two batteries connected in parallel ) - this eliminates the chance of one battery running down to a level that may activate the LVC before the other.
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A practical question
 
The leads from the Lipo are quite chunky, with either a bullet or Deans plug connector,
 
The Ubec lead is light weight in comparison.
 
Where do you tap into the Lipo power lead and how. Particularly to keep the arrangement both safe from handling etc. and neat to look at and route.
 
I have a UBEC in my parts box for ages now, but have been reticent to use it.
 
Erfolg
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hi, as a newbie to this elec lark can someone plese explain all these short forms?  UBEC,OPTO etc.etc.  Timbo, as you know i'm building a lanc and going the elec way which I've never done before.  you really should, as someone earlier up the list suggested, write a book with all this lingo explained.  All this sounds as though it should be really important to me (next year when it's finished as the winter is here and my workshop is in the garage so nowt gets done in colder months) I know, I'm  nesh  lol. Over the winter I will be going into this field to purchase some elec bits for the lanc and i really need to know what to get that is right for my model.  please exp[lain all these terms even if it's only so I'll sleep tonight!  lol  scuba

Edited By Phil Wood - Moderator on 05/11/2009 17:30:41

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Hi Phil, just had a quick flik through that and it looks brill.  Thanks ever so much and you timbo for all the info on it.  Give me anything mechanical and i can usually figure it out but elecs have always left me cold.  anything more complicated than E=IR and I'm lost!  Will take my time and study it all. Perhaps I'll understand you all when i get back.  scuba.
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I have no idea.  I said i was totally left cold by elecs.  The only thing i can think of it E =IR which we learnt at school but perhaps I'm getting mixed up with E=MC2 which I do know about.  But other than that I'm U/S. Youngs Modulus.....never heard if it.  What does it apply to?    scuba 
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Young's Law is very simple, yet after reading the link I was not so sure.
 
Now if talking of difficult, well, that's EMF, Ahh Faradays Law of Induction, of course there are many other ways of confusing yourself.
 
The important thing is, is to solder the UBEC to the bullet connector and cover with heat shrink. It just means that moulded housings which I have used are not appropriate!
 
Ohhhh well, there are always some constraints.
 
Just thought I would add Poisson's Ratio, totally irrelevant, but hey
 
Erfolg
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 This gets worse..........more laws i never heard of!    Fish's Law.....now that's another new one on me!  Can I have chips with mine pls.  .  But you could try some salt and vinegar to soften the housings or perhaps to harden them up, not sure what it would do but it would certanly go well with Fish's Law.  scuba

Edited By Phil Wood - Moderator on 05/11/2009 21:04:41

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Being a Deans user, I was interested to find this solution to connecting a BEC to the Li-Po/ESC circuit when trawling the Web.
 
I am no Master of Electrickery so I make no claims as to the efficacy, or otherwise, of this home-brewed widget but it seems pretty neat, and easy, to me!
 
I would think the connection to the BEC might be varied to suit the user.

As I have unashamedly blagged this from elsewhere, I should credit Ben Strasser and Dimension Engineering.com
 
Pete
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Peter
 
I have looked at the solution shown in the link.
 
My first question is do you attempt to solder each of the Deans plugs together?
 
The second would be, is this solution any better than soldering the ESC leads to the plug tails and protecting the joint mechanically as well as electicallay, by as substantial length of heat shrink?
 
I will admit that the solutions provide seem to be the only practical methods, although I have reservations of soldering light cable to heavy cable and ensuring that the joint is not a weak point in the system. I much prefer plugs, if well engineered, yet recognise that no such products exists.
 
Erfolg
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I quite like that idea Peter. Erfolg - the issue with trying to solder direct to the plug tails is lack of surface area, and the higher risk of "undoing" the very necessary excellent joint of the main power leads to those tails. I have in the past when using Deans, sliced a section of insulation off the main leads a few inches away from the plug, attached the UBEC leads at that point, then sleeved with heatrshrink.
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Looks a good method. I'm not a Deans user and tend to use 4mm Gold for my battery connectors as standard up to 6s.
 
Timbo suggested that I link 3 batteries I'm using for a new model in parallel to power twin motors through their individual ESCs and I was thinking as to how to both apply the UBEC and provide a means of parralel linking the batteries whilst being able to seperate them for individual charging and use in other aircraft.
 
Is there any 'connector' you can recommend which would allow me to do these things please?
 
Many thanks
 
Peter
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Erfolg, I don't see a problem with soldering the Deans together, provided you tin them first and make it a quick operation to avoid too much heat build-up in the plastic. They'd go in a second or two linking them like this. I always put a corresponding plug/socket on the connector I'm soldering anyway to act as a heatsink and retain the rigidity of the connector.
I think the epoxy, provided the bared tails iare short and neat, would be more than adequate as a mechanical support, the insulation being firmly held in the goop.
I've managed, with varying degreees of success in terms of neatness, to solder two wires to a Deans at the same time. I've also done as Timbo suggests, spliced the BEC further along the line and that is much easier. I think the big advantage of the Ben Strasser method is the convenience of just plugging it in-line if you need to move the BEC between models.
 
Pete
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Posted by Peter Roberts on 06/11/2009 12:15:49:
Looks a good method. I'm not a Deans user and tend to use 4mm Gold for my battery connectors as standard up to 6s.
 
Timbo suggested that I link 3 batteries I'm using for a new model in parallel to power twin motors through their individual ESCs and I was thinking as to how to both apply the UBEC and provide a means of parralel linking the batteries whilst being able to seperate them for individual charging and use in other aircraft.
 
Is there any 'connector' you can recommend which would allow me to do these things please?
 
Many thanks
 
Peter
 
 Did I ? Why 3 batteries Pete? TBH the number of batteries in parallel is not the issue...2 3 4 or 100, the principle is that making them all into one large battery ( assuming model layout permits of course ) removes the chance of one pack running low before the other(s) and maybe kicking in the LVC. Of course consideration should be given to charging ability etc. If your charger can handle the high currents involved, and you dont intend to use the packs in other models, then I would "hard wire" them all into one pack, including the balance leads. This keeps them all balanced together.
Otherwise, use parallel harnesses which are available from BRC and so on, or make up your own. In this case, ensure they are at the same potential before connecting together for use or charge.
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You could connect the UBEC to the 2 x outside leads of the balance plug - as these are effectively connected directly to the packs main positive and negative leads.
( but again I dont really advise it as the maximum current capacity of the balance leads on many packs is very limited )
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  • 1 year later...
I have built an electric twin (Peter Miller American Nightmare) with a lipo and ESC  to each motor,these being mounted in  the wings behind the motors.In order to achieve correct ballance I need weight in the nose and find that a standard Nmh Rx pack is just about the right weight so am using this to power the Rx, having first disconected the pos wire from the ESCs Y lead.
This model is initially fitted with 35 mhz so 4 cell Nmh should be Ok for Rx supply.
Should I wish to change to 2.4Ghz Rx (Futaba) I have been advised that 6v is safer.
Question - If I were to replace the Nmh with a 2cell lipo could I use a seperate (spare)ESC as a regulator to power the Rx to save me from having to buy a seperate regulator.
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