Current Draw

I have been using Hitec 785HB sail winches which draw 285ma no load operating. I recently modified a Hitec 805 BB into a winch. It draws 830ma no load operating. This is making me wonder about my wiring harness. I use a “Y” cable to power the servo directly but my concern is the connectors, the switch and the wire. Should I be upgrading my stuff? I use alkaline batteries(for now), is the spring clip battery box a concern? Any thoughts or observations?

One figure I’d like to see quoted on servo specs is current draw at their rated torque or at least stall current. The figures would take a lot of the guess work out of calculating battery capacity and also your question about connectors.
In any event, using 5 cells virtually makes a soldered battery pack a necessity.

Hitech publishes the current drain of SOME of it’s servos. I usually check the site. My digital high torque servo draws up to 4.2 amps (6v) at stall! It is probably close to stalled in some sailing situations, so I have a 7.2v, 2300mah nano phosphate battery pack(DeWalt cells) with a CC BEC set to knock the voltage to 6v as a precaution. It can provide 5A.

Hi Don,

The no-load draw is not the important number for sizing. What is important is peak at/near stall.

The wires on the servo should be sized for its current draw as supplied. Use a Y with at least that wire size, or bigger between the battery and servo.

I use a 10 amp sub-miniture toggle switch (SPST on-off).

I have read that the battery box connections are not good enough. The recommendation is a soldered battery pack.

If you really want to know how much current you are drawing with your set up under different conditions, use an amp meter.
You can use either a clamp on meter or just a small analog meter in series. You can buy small analog amp meters(1-10amps) cheap from most electronic supply places.