From Facebook....
Just an update on the progress of my Severn class 1/12th scale. Work on the water tight door going well, now looking at a rough internal layout of electronics, and built the battery boxes to prevent any internal movement, all will require securing in the bottom of the hull. Layout of motors, battery boxes and servo tower shown. Will send more pics as progress moves forward.
There are 2 x distribution boards to help keep wiring connections tidy. A twin and single fuse board. 6 channel receiver. Sound unit and amp/mixer. Elec control unit to reduce the voltage to 7.2 for the bow thruster. A single relay switching unit. Multi flasher unit for blue flashing light. Parallel power board to link the 2 batteries providing a single power supply.
Action Electronics provide sound info, components and diagrams which should help.
Roger - Can your lead acid batteries take the current draw of your brushless motors?
Jim - Hi Roger the main power will come from 2 x 12v / 7 amp hour batteries, with the accessories running off 1 x 12v / 8.6 amp hour battery. I have copied below the motor spec for your info:
Type: BL4030
No. Of cells: 5 to 7S Li-Poly
Max. efficiency: 86%
Max. efficiency current: 40 to 50A (>78%)
No load current / 10 V: 2.1 A
Current capacity: 51A / 60s
Dimensions: 41 x 20 mm
Shaft diameter: 8 mm
Weight: 325 g/ 11.5oz
Recommended model weight: 3 - 6kg
Recommended prop without gearbox: 14 x 7, 16x 10
Adam - Might I ask, What size the brushless motors are?
Jim Pinner - Hi Adam they are Emax BL 4030 385KV 55A outrunners.
Type: BL4030
No. Of cells: 5 to 7S Li-Poly…See more
Adam - Thanks for the information Are they beefy enough for the Severn??
That 3 Sla alone must be roughly 7.8kg
Plus the weight of everything else..
And might i say the Severn builds into a lovely Lifeboat.
Jim Pinner - Adam I am reliably informed from Adrian Gosling at Speedline Models that these are more than adequate
giving excess scale speed. I agree that it is developing into a very attractive model, a bit of a head turner
even if I say so myself.
Adam - Hopefully the SLA batteries will give you enough current flow, if memory serves someone said 15 minutes run
time on Sla and that the batteries can't supply enough juice to keep up.
Have a look on Mayhem main site and go through the search function or possibly brushless section.
Or contact Phil Locke or Brian Roberts and ask there spec.
Jim Pinner - I currently have approx 500 pics of the build so far. I know how sad is that but I like to keep tabs on the
build of the various components from parts to completed unit.
Adam - Not Sad at all.... The more pictures the better it's all about enjoyment and if your pics help someone who might
be struggling then that's brilliant and the best part of the hobby, everyone helps each other.
Jim Pinner - Thanks Adam very interesting, I'm not looking to run this thing all day so I am going to continue with the 2 lead acid 12v and see where we go. Currently sourcing suitable ESC's for this, going fan cooled as I haven't got water pick up on my hull. Thanks for the link.
Adam - Jim, not a problem. Car esc forward and instant reverse. Might I ask where you sourced the 4030's??…See more
Jim Pinner - I ordered them at the same time as the boat and SPEEDLINE models sourced and sent them.
My props are 60mm 5 blade, just a note for you the original build that was reviewed in the Model Boats
mag back in the past was fitted with 4x850's, don't know how they compare with 900's?
Adam - 850's are 9990 rpm 12V 3 pole motor.
900 is 6-40V
6500rpm
12 pole.
Thanks for the information. I did consider brushless same as yourself however these 900's are brand new
and never been used. In fact there are two for sale in USA £85 each incl postage.