Servo voltage set up

[TacoCrawler]

So I have a servo requiring 10 v - 12 volts.
I have Castle Pro BEC to supply power to the servo.

The questions I have are...

Will a 3s supply enough voltage thru the BEC to feed the servo ?
Or do I need a 4s Lipo in order to supply 12 volts all the time ?
I wish to avoid any opportunity for brown outs if by chance the servo does
not receive 12.6 volts all the time.
I wish to tie in to the main battery packs for BEC power.
But I tend to switch from 3s to 4s Lipos.
Or should I use a separate 4s Lipo battery to supply power to the BEC,
hence supplying consistent power to the servo all the time ?
Or will a 3s Lipo suffice ?
I realize a 3s might drop below 12 volts during its discharge.
Where as a 4s would not.
What 4s mah battery would I need get to supply the BEC/servo. (the smaller the better to reduce weight added)
As my primary Lipo power supply is 3s - 4s - 6500 mah - 8000 mah ?
Maybe I'm over thinking my situation ? But I wish to be sure ?

 

[ferp420]

If your servo is 12v it shouldn't need a bec if your running 3s
4s you might need a bec depending on the servo
Running directly off a lipo is your best source for power for your servo but that won't help on 4s if your servo maxed out at 12.6v
Your servo likely runs on voltage from 6v to 12v so if it's only getting 11.1 volts it won't hurt it
they usually state the minimum and maximum voltage in the servo specs so you could look it up if your worried about it

 

[TacoCrawler]

If your servo is 12v it shouldn't need a bec if your running 3s
4s you might need a bec depending on the servo
Running directly off a lipo is your best source for power for your servo but that won't help on 4s if your servo maxed out at 12.6v
Your servo likely runs on voltage from 6v to 12v so if it's only getting 11.1 volts it won't hurt it
they usually state the minimum and maximum voltage in the servo specs so you could look it up if your worried about it

The minimum voltage supply of this servo is 10 v - 12.6 v
I would like to supply the servo with 12.6 v if possible.
To obtain the highest specifications. (speed & torque)

DS51150 @ 150 kg v

https://www.ebay.com/itm/403983536423?var=673864822846

I purchased the BEC because I plan on running 8s, eventually.

 

[ferp420]

Your 3s battery will hit the low voltage cut off before you drop to 10v
Your good

 

[TacoCrawler]

Your 3s battery will hit the low voltage cut off before you drop to 10v
Your good

Good to know and thank you.
But I still intend on utilizing the BEC regardless,
because I have an overhead light bar I wish to power too.
And the BEC has two pigtail plugs attached, one for the servo
and another to power up some Lights or maybe another for a rear steering servo.
I dunno but this BEC has nearly limitless voltage adjustment using the Castle Link.
So I've little to no use of the RTR voltage set up. Overkill I know (for now) ;-)
BTW with BEC's 20 amp capability I could almost power a welder with it ! ? Lol

 

[Druxus]

Another thing to point out is bec's aren't 100% efficient. So you will be slightly lower then pack voltage. If you set the bec at 12v and the pack is at 11.1v the output of the bec might be closer to 10.9-11v.

 

[TacoCrawler]

Another thing to point out is bec's aren't 100% efficient. So you will be slightly lower then pack voltage. If you set the bec at 12v and the pack is at 11.1v the output of the bec might be closer to 10.9-11v.

I can agree with you on the error ^v on efficiencies for most BEC's sold.
But is probably not that much efficiency error in a Castle Creations made BEC.
These are not cheap Chinese knock off BEC's.
I trust Castle Creations to produce the most accurate efficient BEC's.
This particular BEC is a $ 50.00 dollar Pro model.

 

[ferp420]

The castle bec is a good unit but it's still only a regulator there's no transformer so it won't make more than is available and there's always some loss but still it won't affect your servo cause of the lipo low voltage cutoff

 

[TacoCrawler]

The castle bec is a good unit but it's still only a regulator there's no transformer so it won't make more than is available and there's always some loss but still it won't affect your servo cause of the lipo low voltage cutoff

My 20 amp Pro may be different. I has a heatsink on it anyway.
It's definitely different then my two 10a Castle BEC's which have no cooling whatsoever.
The SCX6's internal BEC voltage can be either set to 6.0v or 7.4v - tho' the default is set at 6.0v
Doubt I'll ever bother to do a voltage change for this rtr system.
Most probably when the 1/5 (12.6 volt hungry) servo gets installed.