Brushless motor controller, assistance please.

I have been running a large Turnigy motor on 24V through a RC controller of unknown make marked only with 80/100, it was in my 'it'll come in handy one day' box. The controller has a finned ally casing and is mounted in a die cast ally box with no provision for cooling as I am only drawing 12A from the batteries and thought temperature rise would not be an issue. However, after about 30mins running the controller starts to fail and can be reset by switching off for a few seconds, whereby it will run for some time before the problem re-occurs. I could mount it such that there is a better heat sink but am quite prepared to purchase a more appropriate ESC as I would prefer one with reverse and one that does not require a 'servo tester' to control it. I require only 300 watts normal cruising with occasional bursts of say 600 watts.

I have noticed that Castle Special Projects manufacture a controller 'The Monster Mamba' which appears suitable, but your comments and suggestions would be most welcome.

Geoff V

Geoff,

The problem with these RC controllers is that they aren't really designed to run at low rpm and high current (so tend to get hot when run like this) and also they aren't really designed to be run for long periods of time. The Castle Creations controllers are much better than the others, but they are pretty expensive.

I run all my motors using cheap ebike brushless controllers. These are easily capable of driving fairly big outrunner motors, the only snag being that the motors are best modified by fitting Hall position sensors (if you search this forum you'll find a few threads on fitting sensors). You can use a sensorless ebike controller to drive these motors, and that might well be a good option if you don't want to bother modifying the motor. For the power level that you are using, a sensorless 6 FET Xiechang would be fine (I use the same controller but with sensors). If you contact this ebay seller: http://www.ebay.com/itm/24V-250W-brushless-controller-E-bike-scooter-/260882371745?pt=LH_DefaultDomain_0&hash=item3cbdcd14a1 who is very well known here, he should be able to either sell you the sensorless version of this controller, or sell you the small sensorless add on module (if he can't, I still have a couple of the add-on modules spare).

Ignore the "250 watt" rating, as it's not really very true. If you look at the spec you'll see that the current limit is set for 18 A, which at 24 V is 430 W! If you don't mind tinkering, then the same seller can sell you a bare 6 FET controller board that you can then fit your own FETs to and get much better efficiency at low voltages. For example, I've built a couple of boat controllers using these units and used IRLB3034 FETs, which have very low losses even when run at a few tens of amps. The other nice feature of these controllers is that they have a DC voltage input for the throttle (meaning they can be easily interfaced to a pot for speed control) and they have a reverse capability built in - simple close the throttle, flick a low power switch and open the throttle again to go astern.

Jeremy

Apologies for not thanking you sooner for your advise, I have emailed both ecrazyman and Castle Special Projects, so far without responce, well I say without responce, Castle SP email was returned saying 'In box full!'

There are two other queries I have.

Firstly, how desirable/necessary are feed back sensors for my application?
Secondly, will the BL2418 handle occasional powers of 650watts as I desire?

My thanks in anticipation.

Geoff V

Geoff,
My own brushless outboard uses a Turnigy 100A controller driving a Turnigy 80-100 motor and the esc is mounted with its heatsink in direct contact with the inside of the diecast box. I have never had overheating problems either at low power or full power (about 30A). So if your esc is not mounted this way it might be worth trying.
On the other hand, if I ever make another one or modify this one, I would consider a sensorless bike controller for its advantages that Jeremy mentions - can be controlled with a pot and easy reversing.

Alan

Thank you for your comments.

I did consider re-working the existing controller by paying much greater attention to the heat sink, but the concensus seems to be that the RC controllers are best left to their original design application hence my desire to purchase a more appropriate ESC. I've not so far managed to make contact with ecrazyman but have ordered a controller anyway, this Indian summer won't last for ever and I would like to make progress with a new setup before Winter sets in.

I am also keen to see how you tackled your e-outboard, gear ratios, drive mechanism etc., do you have any pictures?

Geoff V

Geoff,
this link should get you some pictures and brief description
http://uk-hbbr-forum.967333.n3.nabble.c ... 25171.html
I copied it from jeremy's post in a thread "outboard conversion" here.
I didn't do much calculation really - the little boat I had went slowly on a Minn Kota drawing about 190w so I guessed that I would need about 600w to travel at a useful speed (in a heavy 11.5ft grp dinghy) and also guessed that the Turnigy 80-100 130kV would give me roughly what I was looking for on a donor leg which used a 3hp 6000rpm motor originally. Too much guesswork but I got just what I wanted. No extra gearing required, just direct drive through a solid coupling. Motor mounted up on pillars due to problems close coupling (won't take up your thread here). The esc is controlled with a Neodym wattmeter which has a built in servo tester. Due to water ingress its display no longer works and I don't really trust it for long term reliability, also it is difficult to mount in a way which keeps water out.
No pictures of the controller but it is not pretty like yours and Jeremys.
By the way, your Stirling engine running a generator might make a nice hybrid....

edit - sorry, link doesn't work, please refer to the thread "outboard conversion"

Alan

Thanks for the link to your photographs, I eventually found it, have not seen UK-HBBR before, looks like some more good reading.

Still no reply from either ecrazyman or Castle SP so I've also ordered a Turnigy 100A controller from HK which I can fit as a direct replacement for my existing 'unknown' controller. I am currently thinking of ordering another Turnigy 80/100 motor which I would re-wire and fit Hall sensors to go with the ebike ESC along with better bearings etc. as I don't want to be without a serviceable electric propulsion unit.

Not sure about a Stirling engine hybrid, I'm a bit of a purist and have trouble seeing the point in carrying all the extra mass, for extended range a large PV panel would make sense. If the SE was powerfull enough I would have used it alone to drive my boat, but 100W is just too little for the Cat which is why I started to play with electric propulsion and so far the electric route is to my mind far better in terms of performance, controlability, although it is not as quiet.

Have you any plans for a Mk2 outboard/inboard, with the knowledge gained where do you plan to go next?

Geoff V

You've answered my unasked question; solar PV would be more efficient than SE.
The only plan I have for the outboard is to close couple the motor to the adapter plate and then make a finned aluminium cover for the motor to replace the plastic BDH container which currently covers it. This will make the outboard as compact as possible. I'm hoping for adequate cooling and no eddy current problems. This will have to wait until my "material" filled garage becomes a workshop and I can install a lathe, probably by the end of the year. Also, the efficiency and weed shedding of those folding props seems so good that making one should be on the cards.
Your comment about the noise of a brushless motor is very interesting considering that they are so much quieter than an IC outboard. Once you've experienced silence, nothing else is good enough! Does anyone know if there is a non-squeaky brushless motor/controller system? Are e-bike motors squeaky?