Battery voltage should only drop a few tenths of a Volt, that shouldn't matter to any servo. BEC voltage can drop more than that under load from the servo, it would be nice if you could share some measurements from yours.

All my info is based on what I've read in this thread and forum. I don't have any data logging equipment to determine voltage drop, I might be able to getting a reading with a volt meter?

I have attached a table with amp draw from a savox 2271sg. As you can see it doesn't draw that many amps. What actually happens based on my experience with my data logging is that the combination of the motor and servo amp draw is too great for the receiver and there is a subsequent brown-out.

Do you have any data about voltage fluctuation on the battery or bec?

That is very nice information though!

I have amp draw and voltage for the battery that I can post later tonight. Then you can see how low it gets.

What esc,rx and servo are you using?
What voltage is it running at?
Thanks


Sorry just noticed to posted the servo model

sounds perfect thanks!

Here are 2 short runs that show voltage drop. There is about a 1v swing, which is what my system hated. I'm using an MT-4 with a Novak Pulse (these tests were done with a Havoc Pro SC) and a Trinity 4XS 3800. One of these was done with the 3800 and the other with a Novak 8.5.

Thanks great info, very cool.

Well there we have it! So BEC's are the way to go

Unless you're running a HV servo. That is because the BEC can only provide as much voltage as the battery is capable of producing. If you're running an external BEC at 6 volts, you shouldn't have any issues. If you're trying to get 7.4 volts to the servo, you can see that the battery is incapable of maintaining that (at least in my case). Which is why I run a separate battery. One of these at 13g, you'd never even notice the weight and never have to worry about anything.