BEC trouble

[uss silversides]

Here is my problem]HOT[/i]. However there were no apparent shorts so I looked the regulator's package over more carefully. On the back it said "1 amp max". Duh.

Correct me if I am wrong, but I am putting way too much amperage into this regulator, right? The problem however is that I can't seem to find a bigger one anywhere.

At this point I might just break down and buy a BEC from Subtech or somewhere else. Do most hobby shops carry them? If I have a choice how many amps should it be rated for if I am moving three servos?

Thanks,
Jonathan

[JWLaRue]

Hi Jonathan,

It sounds like you

Hi Jonathan,

It sounds like you may have been drawing too many amps through the BEC, but you didn't say what you had it hooked up to and what the amperage draw was. If you had it supplying the input voltage to the radio receiver, then I wouldn't think that you were drawing too much current.

Does the BEC work correctly if you turn things off and allow it to cool down?

The BEC from SubTech uses the LM2940 rectifier chip from National Semiconductor.....and it's rated for one amp current draw.

Another thought....did you add a heatsink to the rectifier chip? It'll need one. The heatsink fins on my SubTech BECs do get hot.

-hope this helps,

Jeff

p.s. I deleted those extra postings that you asked me to!

[Guest]

Jonathan,
Why would you want a

Jonathan,
Why would you want a BEC if you are using a 6V battery? 6V is not too much for the radio, and you would then have more than the limited 1 amp output of the BEC to run as many servos as needed. Also, most BEC's require a minimum of 7.2V input, to put out about 5V.

[uss silversides]

Dr. Broder,

That is wonderful. I

Dr. Broder,

That is wonderful. I just figured the 6 volt battery would be too much for the receiver. Thanks!

Mr. LaRue,

Actually I didn't have anything plugged into the BEC. I hooked it up to the battery and just like that it heated up. And yes, I did have a heatsink. At least now I can forget about it and just use the main battery!

Thanks,
Jonathan

[slats]

6 volts for the radio.....
Yep

6 volts for the radio.....
Yep most of the time that's 100% ok, but I'd check the spec of your radio rx. I have a couple of radios that specified 4.8v for the radio. On 6v I have had problems with one. The radio in my collection that seems to want no more than 5 volts is my Robbe F14.
That said you should be pretty much Ok.
John

[anonymous]

Dear Jonathan,

I am still puzzled

Dear Jonathan,

I am still puzzled by the problem with the voltage regulator - there should not be much to go wrong.

You will need slightly more than 6v to give you 5v after regulation,. (You can and maybe should use "low dropout" regulators for R/C - but lets keep it simple for the time being.)

With the input pin of the regulator connected to your battery and the centre pin connected to ground - you should get 5v at the output pin with no heating effect etc.

If you do the regulator is connected the wrong way round (easily done) or the device is faulty.

Hope this helps. IMHO I prefer 12 v electrics for subs - lower amps in cables and you can can easily regulate voltage down rather than up!

David

My Webpage

[uss silversides]

John,

Hmmmm...... My radio is a

John,

Hmmmm...... My radio is a 4-channel Hitec Laser. Everything I find about the receiver says 4.8 volts.

David,

That has been bugging me too. I can't seem to find anything wrong with it though.

Everything is now seeming to point towards using an individual rx battery. I have plenty of space for one, but I have wanted to avoid the headache of charging and keeping an eye on a second battery. However this stupid BEC has given enough of a headache itself. I kinda defeated the purpose of that one. So what do you think? Rx battery, main battery, or BEC?

Jonathan

[ramius-ii]

Hi Johnathan]http://www.subcommittee.com/forum/icon_smile.gif
It sounds to

Hi Johnathan]http://www.subcommittee.com/forum/icon_smile.gif[/img]
It sounds to me like you may have the input and output reversed? http://cache.national.com/ds/LM/LM341.pdf is a link where you can see what's in and out. As David said, it's easy to get things backwards and if you do not have anything connected to the output pin, there is no heat. If you do get heat then either the device is bad or not wired correctly.

Best, Ed

[JWLaRue]

...and it's definitely time to

...and it's definitely time to get the VOM out and do some testing......

-Jeff

[craigf]

A couple of things]

[color=#000080]A couple of things]

[uss silversides]

It sounds like Craig might

It sounds like Craig might have hit it. The leads to the chip are long. But there are caps . I do have the voltage going in the right way though.

I received today (in response to an email I sent) an email from Hitec saying that the 6v battery would be just fine for the receiver. The BEC is still bugging me though.

Thanks,
Jonathan



Edited By USS Silversides on 1107564168

[craigf]

Oops, forgot the most important

[color=#000080]Oops, forgot the most important thing]

[uss silversides]

That's got to be it.

That's got to be it. Thanks! Now I can forget about it!

Jonathan

[craigf]

I don't mean to belabor

[color=#000080]I don't mean to belabor this point, but we thrashed it out with Hitec in another RC forum over dead receivers]

[uss silversides]

Craig,

I appreciate your wanting to

Craig,

I appreciate your wanting to make sure I don't kill my receiver. Electronics are the one area I don't really care for, mostly because I lack the know-how to do it right. So maybe you could elaborate a bit more on this rectifier diode. Where I can get it, where do I put it, etc.

While on the subject of electronics, could someone please tell me how to determine what size fuses to get?

I really appreciate the help.

Jonathan