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[ixion]

I have fitted a representation of a working engine cooling outlet in my trawler. It is just a pump that picks up water from under the boat and pumps it out of the side and it works great when I have tested it connected to a battery. I want to operate it from my Spektrum DX6i using the 5th channel which is a on/off toggle switch. What do I need to connect it to the RX and using the RX power as opposed to a seperate battery?
Thanks

[FullLeatherJacket]

Firstly you should appreciate that a drain on the Rx battery like this will discharge it faster than normal, so you will be able to sail for less time until the radio stops functioning. It would also introduce a very "dirty" component into a circuit which is already sensitive to RF noise. All in all, not a good idea unless the pump motor is very low-drain (unlikely) and heavily suppressed.

That said, for any solution to be offered then you will need to measure the current which the pump is taking under load (i.e. when it's actually pumping water) and to confirm what voltage the test battery is, and then come back to the Forum with the answers.
 
If the pump is pulling more than about 250mA then it's certainly not advisable to run it from the Rx battery. If it's less than 1A then you could use a separate BEC regulator to drop the main motor battery voltage for the pump. Any more than that and the best solution would be to use a separate battery for the pump, of the correct voltage, and switch it from the Rx via a simple relay switch (e.g. ACTion P43).

FLJ

[ixion]

Thank you FLJ, I take on board what you say about a seperate battery.

[Big Ada]

Hi Ixion,

I thought someone had made this work by putting a inlet scoop between the prop and the rudder then run a pipe to exit through the side of the hull, rather like an engine cooling setup. The forward motion of the boat would force water up and through the pipe.
No pump required.

Len.

[roycv]

Hi just to add to this, I have a boat with a big ish prop its actually a Motor sailor, so that when the engine is on (my choice) and prop turning I can see the water being pumped out, the pick up is after the prop and close to the blade.  The unexpected part is that the water comes out in pulses so it looks quite realistic.
regards to all, Roy