Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: CJ on May 18, 2012, 06:43:15 pm
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Evening Gents,
Just a few questions that I hope someone can answer, I have just purchased one of these......
(http://s13.postimage.org/k2a3ewhzn/1024x1024_632559.jpg) (http://postimage.org/image/k2a3ewhzn/)
as I have stripped the guts out of my Fairmile B due to upgrading to 2.4ghz after a loss of control moment >:-o ......
(http://s16.postimage.org/ws99utehd/DSC_1225.jpg) (http://postimage.org/image/ws99utehd/)
Has anyone used these at all and can advise on water cooling, it was dropped on me today and I have no experience with this whatsoever - the 800 I pulled out of it was fine and never overheated but I am just thinking now as someone mentioned in passing to me that it may be worth doing.
As I have the guts out and room to work I would rather do now than have to face doing in the future !!!
Any advice as always greatly appreciated :embarrassed:
CJ
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How long is the model and what prop is on her.
The 850 will rev about 9000 rpm on 12 volts (almost twice that of the 800).
It will pull about 7-11 amps usually and shouldn't need watercooling on 12 volts unless you are fitting a big prop and making it work hard.
Bob
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Hi Bob,
Thanks for the info, she's 145cm or 57" in old money :} and on 1 x 55mm prop, power is from a 12v 12 Ahr battery.
She ran OK could of just done with a little bit more oomph so whilst upgrading to 2.4 the servo's and wiring etc. I thought may as well do the motor, {:-{ worried now as the yes - the old one is kicking at 4900rpm, the 850 is 9700 rpm - worried my little bit of oomph may make her take off !!!!
Is it worth dropping to the new 800 ?? @ 5100 rpm ??
Thanks for the advice on the watercooling though - the motor isn't packed tight with lots of breathing space but just wanted to check !!
Thanks
CJ
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If you want a bit more speed go with the 850, you don't have to use full throttle all the time and can be useful for getting out of trouble if needed.
I would advise cooling if you are going to exceed the voltage to say 18 volts, but shouldn't need it on 12 volts.
Bob
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My thoughts are that it should be fine as is. Id fit it and try it. If unhappy then its easy enough to retro fit water cooling or a fan on the motor shaft. John.
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Thank you Gents,
Think I'll take that advice and stick the 850 in, I'll hold off on the water cooling too if it's no major job, no experience of that so unsure where to inlet/ outlet. Will see how she gets on and shout again if needed.
Thank you.
CJ
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Just to pick up on this again, Is suppression needed still these days - using 2.4ghz now, but just wondering am I likely to cause me (or anyone else !!) any issues ??
Thoughts please ??
CJ
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Not strictly speaking, but interference can get into the signal wire or ESC so belt and braces I still do.
Bob
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I believe the 850 is supressed inside the can.
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Yeah looks it now, cheers :-))
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Hi I have 3 of these in a 1:24 scale Perkasa lots of power and don't get hot even after 20mins full throttle, I have installed water cooling also but doesn't need it Tom
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Yeah - Cheers for that, I did actually go for a 30 min full throttle run with an extinguisher on standby just in case - but was all good :-))
Cheers