Good advice from Robert. The ESC you have chosen is rated at 12v and 50Amp.
However this is the forward current limit the reverse current is 20 amp max.
Most modern transmitters have a simple switch to reverse the direction of servo's and ESC's. if you set up your model with the ESC channel on your transmitter in the Normal position then the ESC will allow you the 50 Amp max current. Sometimes your motor will be turning in the wrong direction and you may correct this by altering the switch on your Transmitter to Reverse. The ESC is now limited to its reverse current rating Ie 20 not 50 amps! To avoid this you should reverse the two wires from the ESC to the motor so that the ESC can run in forward mode at 50 amp.

As advised a fuse ( rated at less than the ESC's max current) is really essential in the battery power feed at this level of current.
Good luck with the model
Dave

Thanks for that Robert & Peter, Speed controller is a OVERLANDER TORNADO 50AMP WATERPROOF MARINE SPEED CONTROLLER from Howes and it's rated at up to 12v
Regards
Chris

I'm restoring a 34" Aerokits Fireboat and am planning on running it on a 12v Lead Acid battery driving a VW heater motor via a speed controller with BEC. I'm fairly new to this RC bit and have just noticed that most servos have a maximum working voltage of 6v. is there a common workaround for this and/or are voltage reducers available, or am I just looking at the wrong servos.

All help welcomed
MTIA
Chris

what speed controler are you using?

Peter

I use a sealed 12V 7A gel cell in my Sea Queen, they are pretty cheap and easily available as it was what a lot of R/C aircraft people use to power the flight boxes and starter motors. Being a gell cell there is no maintenance and you can mount it on its side if necessary

http://www.hobbico.com/fieldequip/hcap0800.html

First make sure your ESC / BEC is rated to and take a 12V input as not all are. The ESC / BEC will power your receiver with somewhere between 4.8 & 6V so no need to worry about the other servos.

You also need to make sure your Rx says BEC.

Consider adding an inline fuse too.

Robert