Model Boat Mayhem - Forum

Dry Dock / Shipyard: Builds & Questions => Sports boats, Race, Power and Leisure Boats: => Topic started by: Davo on March 28, 2018, 04:22:26 PM

Title: Aerokits Sea Queen. Going Brushless. Power back-up
Post by: Davo on March 28, 2018, 04:22:26 PM
Not having benefit of a local club and lake, my refurbishment of the Sea Queen was based on the many useful articles on the MBM forum. So the electrics, as installed in my other thread, are still very much experimental. I have access to a natural lake which is largely surrounded by reeds and trees. So, unless my wife is doing her wild swimming, retrieval of a dead boat is complicated and I live in fear of a tripped fuse.
It occurred to me that a power back-up, by way of a fused bypass of the main 60amp fuse, would provide at least the possibility of getting the boat back on a reduced throttle.  My radio box still had the throttle servo from I/C days and the Futaba T6L radio had spare channels; one of which was just a flick switch. For this idea to work the Rx has to have a BEC supply independent of the motor ESC (and before the fuse) or be battery powered. The existing BEC from the ESC has been interrupted by a short extension lead which has had the red wire disconnected. This allows the original system to be reinstated pondside if required, by just removing this lead.
A 30amp fused loop was introduced to bypass the main fuse and is operated via a micro-switch activated by the old servo. Just remains to be field (pond) tested.
My only concern with the new Futaba 2.4GHz system is the very short aerial. I have a hole in the cabin window to poke about 60mm out for reception but wondered how fussy these aerials are. Would it work inside the cabin? Any advice gratefully received.
David
Title: Re: Aerokits Sea Queen. Going Brushless. Power back-up
Post by: shadysadie on March 29, 2018, 07:56:33 PM
As long as the Rx. is above water level (the higher the better) it will be fine so the cabin will be OK..
Title: Re: Aerokits Sea Queen. Going Brushless. Power back-up
Post by: Davo on April 02, 2018, 03:03:19 PM
So, having fitted a short 100mm extension lead between the motor ESC and RX, with the red power cable disconnected, the RX went on to battery power. (The extension lead can be removed to restore the original set up if required). Manually tripping the 60amp fuse stopped the motor as expected. But a flick of the switch brought in the 30amp backup circuit and the motor was back in action.  I have also made up a short lead that takes power from the main battery (pre-fuse) and so could be used with an independent BEC supply.
Lets hope for some better weather to try it out on water.
Must have a look to see what devices can be used to measure motor power consumption at sea. It would also be nice to have a RX battery power meter.
David
Title: Re: Aerokits Sea Queen. Going Brushless. Power back-up
Post by: Davo on June 03, 2018, 10:48:42 PM
Well, it has been some time since the re-wire but today the SQ had further sea trials. It met all my expectations and performed without the 60amp fuse kicking out. I could also switch to the stand-by 30amp system as the RX has its own power.
However, the next weak link in the chain was the 60amp ESC which did a few thermal cuts outs; restoring power after a few minutes of drifting. It eventually proved too much and the ESC died. So a replacement of a much higher rating and water cooling needs to be bought.
The Action Man looked well and suits the boat though you do need a foot well in the centre deck. Moving the battery slightly balanced his weight.  The lack of spray in the photos is down to the four spray rails added to the hull as can be seen in the photo.
Looking forward to more running days with a new ESC.
David
Title: Re: Aerokits Sea Queen. Going Brushless. Power back-up
Post by: ChrisF on June 04, 2018, 10:16:48 AM
Looks good on the water.

Reminds me I must crack on with my powered boats. Had a go with the yacht yesterday but the wind was very light. Very pleasant in the sun though.

Chris