Quark

[jacobsjo87]

My question is do I need to run a bec with the quark 125b if I am running s maxamps 5s pack. If so is the castle creations a good choice. If I dont have to run one then I would prefer not to run one. Also does anyone know the formula for calculating the horsepower of an electic motor. Just because I am curious what my Neu 1515 2.5d is making on my 5s pack.

Thanks,
Josh

[wallot]

you have to run UBEC with 5S lipo on quark. CC is a good one

745Watts = 1 hp

Watts = Volts x Amps

[jacobsjo87]

What exactly does the UBEC do? What would happen if you didn't run one? I am new to this stuff so I am just trying to understand it. Thanks for the help.

[BrianG]

A UBEC stands for Universal Battery Eliminator Circuit. It is essentially a small switching power supply that converts your high battery voltage to 5v or 6v for your receiver and servos.

The switching nature makes it very efficient compared to a typical BEC inside the ESC, which is a linear regulator. With a linear regulator, the act of stepping down the voltage can create LOTS of heat, and gets worse as the battery voltage gets higher and the servo load increases. Eventually, it thermals and shuts down. Not good.

At anything over 2s lipo or 7 cells, the built-in ESC BEC should be disabled and a UBEC used instead.

[Serum]

what batteries are you planning on using? (capacity)

If you take a look at the site that's in Brian his signature you can see how to wire the UBEC

The initial goal of the UBEC is to replace the heavy receiver battery-pack. Since there is a larger battery available, this voltages needs to be adjusted to the right voltage for the receiver/servo's.

[jacobsjo87]

Thanks for all of the information. My battery is a 5000mah. So basically the bec in esc is not efficient and makes to much heat overheating the esc. I ran the car once like it is (without the ubec) and the esc was pretty warm. Though it was only 30 degrees outside. I hope I did not do any damage to my electronics.

[Arct1k]

Brian but if like the new MMM or MGM it has a switching bec built in then all is ok... Quark like the MM I assume use linear Becs

I'd understood from you too that the effeciency on higher voltages with a switching bec is much better - i.e. less heat but also less load on your batteries - i.e. longer run times

[BrianG]

Yeah, the some of the newer ESCs have built-in UBECs, but the Quark and MM definitely use linear regulation.

And yes, runtime does increase. In a linear BEC, the output current is what is being drawn from the main batteries no matter what the voltage difference is. A UBEC is more of a "power transformer".

For a 5s battery setup and say you have a 3A servo load:

- In a linear regulator, the current being pulled from the main batteries is the same as the current on the linear regulator output, 3A in this case.
- In a UBEC, the current being pulling from the main batteries is only around 1.29A (figuring in a 25% efficiency loss - but it's usually a little better than that). That's less than half the current, so runtime will increase a little.

[JERRY2KONE]

Thanks for the elementary education BG. Just listening to you seasoned vets spew the knowledge that is built up in there is really something. What is cool about the RCM forum is that there are several sources and opinions throwing their hats into the ring all at once virtually educating the rest of us every time you place a reply to one of these threads. I am a retired Naval engineer and I am still learning things every day on here about simple thing that I either have not used in years, or just did not know. I for one am greatful for what you guys have to share with us. Thanks BG, Serum, Sikes, and the rest of you as well. This site rocks with a great deal of knowledge and experience. Keep up the great work guys.