Model Boat Mayhem

Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: gyronuts on November 05, 2009, 09:44:20 PM

Title: brushless motor on 6v gel cell
Post by: gyronuts on November 05, 2009, 09:44:20 PM
Hi,
    Having problems with my dynamic dive submarine using a johnson motor( funny old thing!!) and a 6v gel cell.  It flattens the 8amp battery very quickly ( 10 to 12 mins!!!). It is presently running a 5 blade very coarse pitch brass prop.
However, I  have three  200w brushless motors... 900, 1190 and 1570 kv.
Which one should i fit and which prop should I use. I want sufficient speed to dive and not have to go home early to recharge the battery.
The battery consists of 2 x 6v 4amp batteries which presently are wired as 6v 8 amp but could be 12v 4 amp.
Model is a 45" version of HMS Unseen. thanks. bill
Title: Re: brushless motor on 6v gel cell
Post by: nick_75au on November 06, 2009, 03:56:46 AM
Well a 1000 Kv motor will draw 3-4 amps at 6 volts on a 40 mm 3 blade prop, I would put the lowest Kv you have and run on 6 volts, You may even consider a 2:1 gearbox  if the prop is more than 50 mm.
 200 watts at 6 volts is 33 amps so if the motors are "over propped" then you will see quite high currents.
Nick
Title: Re: brushless motor on 6v gel cell
Post by: gyronuts on November 23, 2009, 04:25:10 PM
well fitted an old maxim brushless motor in the sub with a 6v 8a/hr gel cell and it sails great. Fitted a brushless to the Perkasa running on a 12v 7a/hr gel cell and also works great. Bill
Title: Re: brushless motor on 6v gel cell
Post by: gyronuts on December 06, 2009, 08:58:50 PM
some pics with the brushless. Bill
Title: Re: brushless motor on 6v gel cell
Post by: nick_75au on December 07, 2009, 09:17:24 AM
Hi Bill
Very Nice, glad it worked out

Nick