This may be a stupid question but.....

[am4x4]

If you are running a 6cell 7.2v battery and you wanted to run your servo on 7.2v why would you need a BEC if you wired your servo straight to the battery like some people do when using a BEC? I am sure I am missing something here but does the BEC do anything else besides stepping the voltage down when using big volt batteries?

[Grizzly4x4]

Originally Posted by am4x4

If you are running a 6cell 7.2v battery and you wanted to run your servo on 7.2v why would you need a BEC if you wired your servo straight to the battery like some people do when using a BEC? I am sure I am missing something here but does the BEC do anything else besides stepping the voltage down when using big volt batteries?

Because when you are done charging the battery it is at about 8.4 volts and that can smoke servos. That's where the BEC comes in.

Back before you could buy a BEC we used to wire the servo directly to the battery. Some servos would live and some would burn up.

[Khador12]

The CC because has a higher current than most internal because. This can produce a more consistant current to the servo. It is more important to use an external because when using 3 or 4 cell lipo.

[am4x4]

Originally Posted by Grizzly4x4

Because when you are done charging the battery it is at about 8.4 volts and that can smoke servos. That's where the BEC comes in.

Back before you could buy a BEC we used to wire the servo directly to the battery. Some servos would live and some would burn up.

I had noticed that too but I thought it might drop down to 7.2 as soon as it got some load on it. So you are saying it might work but could burn up the servo. The servo in question is a stock axial AS-2, word on the street is that it is a rebadged futaba. Any guesses at to it's life span if I tried direct powering it.

[Rockcrawler]

Originally Posted by am4x4

I had noticed that too but I thought it might drop down to 7.2 as soon as it got some load on it. So you are saying it might work but could burn up the servo. The servo in question is a stock axial AS-2, word on the street is that it is a rebadged futaba. Any guesses at to it's life span if I tried direct powering it.

IMO, it will work for a few seconds.

It "could" work, but I would not chance it. Even the high end servo's don't like that much voltage.

[brazwewn]

I am running 7.4v to my servo. However, it is rated for it and I am using a CCBEC. The other advantage is the voltage remains at the programmed voltage as long as the battery voltage is above the programmed voltage. So, the servo should work the same at fully charged and a run down pack.

Wes

[am4x4]

Originally Posted by brazwewn

I am running 7.4v to my servo. However, it is rated for it and I am using a CCBEC. The other advantage is the voltage remains at the programmed voltage as long as the battery voltage is above the programmed voltage. So, the servo should work the same at fully charged and a run down pack.

Wes

I am asking about this for a buddies crawler, mine is running a CC BEC at 7.something and it works fine. I guess the big issue just the fact that the batteries actually make more voltage than they are rated for. We are just trying to keep his build cheap but I guess a BEC is cheaper than burning up servos.

[dezrik]

Its only 20 bucks + shipping

[01_DiscoII]

So it is still wise to run a BEC even with a 6 or 7 cell NiMH? I just assumed these were only for lipo rigs.

[cogfounder]

Originally Posted by 01_DiscoII

So it is still wise to run a BEC even with a 6 or 7 cell NiMH? I just assumed these were only for lipo rigs.

Its a good idea just because the CCBEC provides a constant, regulated
voltage to the CONTROL end of your servos/steering,
right up until the voltage drops so low that things just shut down.
(low voltage shut-off)

Bad things happen when you lose that control........... LOL!

But it dont help if you dont wire it correctly..........

To answer your question, YES!!!! ALWAYS!!!!
Its only 20 bucks of insurance FCS!

BUT, wire it correctly, with a COMMON GROUND!!!!

[Olle P]

Originally Posted by Khador12

The CC because has a higher current than most internal because.

The CC BEC is preferred only because the output voltage is programmable to fairly high values.
The current required can alternatively be provided by cheaper BECs that are limited to 6.0V output.

Originally Posted by am4x4

I guess the big issue just the fact that the batteries actually make more voltage than they are rated for.

The servo voltage ratings take this into account. A 6.0V servo is designed for 6V batteries (up to 7V feed), and so on.

My servo is rated for 7.2V, so I run it straight off my 2S LiPo with possibly some reduced life span down the road. But the servo is too weak and needs to be replaced as soon as I can afford it anyway...