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[Bluechrisp]

Hello All,

I first wanted to put in a Dark Horse motor in my Sea Queen (wood ply) on 14.4V 6800Mah batts, but reading many post this afternoon I'm not sure now, I want a long run time with her on the pond, ( some of our circuits take over an hour). So after much ummming and rrrring, I think I have the right brushless motor? I take it a 1000 to 2000Kv  inrunner is in order to go with the batt set up or should I go for a higher KV and lower Voltage.?

So a 60 amp or higher ESC, with forward and reverse?   

As you you can see i'm a techno freak now 

CP

[Roadrunner]

Endurance running with brushless motors is quite a feat as they use so much power you will be adding a lot of battery's to run in parallel which is in turn causes a lot of weight, if using lipos it becomes an expensive venture.

Seeing how the boat is single screw (1 prop) i would be more inclined to use a single 555 or 600 size brushed motor, (around the £10 mark for a 600 motor) a 15amp esc (£22) and run using a 6v or 12v LA battery of a high MH (between £5 -10) rating for long run times, example being a 12v 7ah battery would give you about an hour maybe a bit more, the LA are heavy why i did say use a 6v 4.5ah battery would give you 30 mins or so, but its lighter then a 12v.

Your not after out right speed with the boat your after a simple plane which i think a LA and a brushed motor would achieve quite well, its also WAY cheaper, with the advantage of having reverse if needed, i know only one esc for brushless motors that has a reverse but its only 50Amp rating and £75,

If you want to go brushless like many lifeboat builders are doing now then i suggest you look through the life boat section of suggestion on what they are doing, but do remember that you won't be getting long run times past 20 mins with brushless motors and the bigger they are the shorter time you get.

[HS93 (RIP)]

Roadrunner I  know you don't like brushless motors from some of your previous posts , but what you have just said about them was all wrong, brushless motor are more efficient FACT so they will run longer for the same batteries, you can run a brushless motor on any batteries even potatoes if you want so there is no reason why you cannot run on SLA batteries. brushless motors are equivalent in price and last longer as they do not have brushes to wear. most boat brushless speed controllers have reverse and they are an equivalent price to brushed controllers , so Bluechrisp if you run brushless you will have longer faster running with reverse and you can run any batteries you want,
this is from someone who has been messing about with brushless a good few years.


speed controller
http://www.giantcod.co.uk/seaking25a-brushless-boat-version-p-405852.html

Peter

[Roadrunner]

I have no issues with brushless motors its the lipos that are my turn off, which I have to face my fear of them due to my most recent purchase, try to keep up with me  

But if he decided to fit a 60amp drawn brushless motor.. i am in no doubt that a seaking 25a brushless esc with reverse is going to last all of 2 seconds before it catches fire!

You should always used a esc that's got a higher amp rating then the motor you using and that's not just the stall rating either, why do you think we install fuses in brushed motors? saves the poor esc from blow outs....

The sea queen is a rather large model basically 4 foot, that's a lot of boat to move, and its is going to be heavier then any of the fast electrics that use 60amp brushless motors, a boat that size will require motors in the 540-600 case sizes which are even higher amp rates then 60 generally... although there are a few that have lower amp rates with larger cases,

As an example i just purchased a Leopard 2860/4050 brushless motor, which is 28mm wide its an equivalent 380 brushed motor size, it requires a minimum of 85amp on its draw, so i have purchased a matching 120amp esc to suit, all to be fitted in a boat tha'ts 26" long and weighs no more then then 1kg if that! (those two items alone .. £150 . do that with a brushed motor... £35 or there about's and that's a big 600 size plugged in!

However i did suggest a standard brushed motor setup due to their ability's to endure long run times at less cost over the equivent brushless motors ( regardless if i'm right or not about them) a brushed setup will be so much cheaper and do what is required.

You also forget... NHMI packs do not all discharge at high rates, some do, and some do not... and if the nhmi packs that are being used in this case the 6800's i have my doubts if they even hold that volume of mha and being Chinese cheepies.. i have no doubt they can't discharge at 50amp, which is another cause for the battery's to burn out or worse blow up!

As i said its best to see what the life boat boys are doing with their setup's for a better opinion then mine... after all im not powering a model for a 1 hour lap of a track i'm doing a 6mins +10 sec mill time race... endurance is not something i have to worry about but speed is!  

[ACTion]

Excuse me for appearing to be the happy idiot here. I know the square root of Sweet Fanny Adams about using brushless motors but I do know about Darke Horse 785 geared ones. I can say that a DH motor running on 14.4v and using a 45mm 3-blade brass prop will not draw more than about ten amps flat out. This would be a good combination  for a 34" Sea Commander for a very nippy performance and a 46" Sea Queen for something more stately.
That being the case - and bearing in mind the statement that "brushless motors are far more efficient than brushed ones" - why on earth do you need a 60A speed controller? OK, so they may make better use of the power supplied but if it takes 60A to run at their most efficient then the maths doesn't work out at all.
Imagine a (mythical) 6AH battery. If a brushed motor running at 50% efficiency draws 10A then it will run for 6/10 x 50% hours, or 18 minutes. If another (brushless) motor draws 60A but runs at 95% efficiency then it will run for 6/60 x 95% hours, or 5.7 minutes. OK, so it's gonna go like greased weasel pooh for that six minutes but that's not the pinnacle of all model boating, is it? As RR points out, this is no fast electric demon machine. Even if the motor "only" draws 30A it will not run for much more than half the time that the brushed one will, and 50% is a deliberately low estimate of the efficiency of the DH motors.
Horses for courses? (Now watch the ripples spread.........................)
DM

[Stavros]

Right then I'll now throw a spanner in the works here all you need in that craft is a 900 motor coupled up to a 55mm prop,that motor will get a 49ins perkassa up on the plane on 24v and give well over 45 mins run times and draws less than 5amp.They are now available fro our man ACTion


Stav

[Roadrunner]

A 900 motor drawing 5 amps a 55mm prop? err... ok?

Graupner Speed 900BB Torque (6373)
Nominal voltage 12 V
Operating voltage range 6-40 V
No-load rpm 6500 min–1
No-load current drain 1,1 A
Current drain at max. efficiency 8 A
Current drain when stalled 54 A
Max. efficiency without gearbox 71 %

8 amps under load your up to at least 11 if not closer to 15, with a 55mm plain prop.

I can understand where you get the run time from, but 24v battery's are very heavy, nearly 4kg worth, i based that on running two 12v 7ah in series but even running 2, 12v 3ah will still be up at the 3.5kg mark. lots of weight to carry reducing the plane potential, power to weight remember.

Dave (ACTion man) is right what is the point of running a 60amp brushless motor for a boat that size when a brushed motor will do the job better and not draw even half as much amps!
Your not after 'go like stink' your after the model to get up on a good plane for a reasonable amount of time. Yes a brushless motor can do that, but at the expense of run time as i pointed out in my first post, regardless what battery it runs off, as Dave so well puts with his figures.

The only low draw brushless motor i can find is this, but its still a 380 size the bigger the motor size the more amps it requires.. 540 sizes.. need well... 100-150 amps or more 250! (why you think they sell 300 amps escs for brushless?!)  http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=4197

Motor Size: 2445 (370L)
Speed: 2900kv
ESC Required: 20A
Voltage Range: 6~12v
No Load Curr: .5A
Max Load: 34A
Diameter: 24.2mm
Front Mounting Hole Distance: 16mm
Front Mount Thread Size: M3
Shaft Diameter: 2mm
Shaft Length: 12mm
Weight: 95grams

So the odds of running a big enough brushless for more then 8 mins is doubtful, stick with brushed and buy your gear from Action, it will be worth it  

[Stavros]

Roadrunner did I mention the Graupener speed900bb torgue ddi I heck as like,If you had BOTHERED to look at the ACTion website before you have tried to belittle me you would have found this Motor...http://www.action-electronics.co.uk/pdfs/MOTORS03.pdf
Also taken off MMB web site
  MMB 900 12 POLE MOTOR
 
6-24 VOLTS
 
NO LOAD SPEED 6500 RPM ON 12 VOLTS
 
NO LOAD CURRENT 1.1 AMPS
 
LENGTH 90mm
 

DIAMETER 52mm
 

http://www.youtube.com/watch?v=fp3RNTVk1z4.....Video of the Perkassa running,and YES it draws less than 5 amps,before you try and belittle me GET YOUR FACT RIGHT BEFORE POSTING

Stav
 
 

[Roadrunner]

oh dear someone's got their knickers in a twist right now eh,.. i normaly do get my facts right dumb nuts... NO LOAD CURRENT 1.1A.... but when a boats moving it under load.. dur.. 8amps draw its the same as the Graupner (did you not notice the stats are the same for both motors??)... I've been doing this a while...  or why would a 20A esc be recommended for the motor and not a 10amp?

Keep digging... i'm having a right laugh tonight.

[CF-FZG]

oh dear someone's got their knickers in a twist right now eh,.. i normaly do get my facts right dumb nuts... NO LOAD CURRENT 1.1A.... but when a boats moving it under load.. dur.. 8amps draw its the same as the Graupner (did you not notice the stats are the same for both motors??)... I've been doing this a while...  or why would a 20A esc be recommended for the motor and not a 10amp?

Keep digging... i'm having a right laugh tonight.

Well some of us are having a laugh at you tonight, expressing such 'expert' knowledge of brushless motors  

You describe yourself as a self appointed guru - haven't seen anything to justify that comment

Stick to expressing your mediocre opinion about brushed motors

[HS93 (RIP)]

A 900 motor drawing 5 amps a 55mm prop? err... ok?

Graupner Speed 900BB Torque (6373)
Nominal voltage 12 V
Operating voltage range 6-40 V
No-load rpm 6500 min–1
No-load current drain 1,1 A
Current drain at max. efficiency 8 A
Current drain when stalled 54 A
Max. efficiency without gearbox 71 %

8 amps under load your up to at least 11 if not closer to 15, with a 55mm plain prop.

I can understand where you get the run time from, but 24v battery's are very heavy, nearly 4kg worth, i based that on running two 12v 7ah in series but even running 2, 12v 3ah will still be up at the 3.5kg mark. lots of weight to carry reducing the plane potential, power to weight remember.

Dave (ACTion man) is right what is the point of running a 60amp brushless motor for a boat that size when a brushed motor will do the job better and not draw even half as much amps!
Your not after 'go like stink' your after the model to get up on a good plane for a reasonable amount of time. Yes a brushless motor can do that, but at the expense of run time as i pointed out in my first post, regardless what battery it runs off, as Dave so well puts with his figures.

The only low draw brushless motor i can find is this, but its still a 380 size the bigger the motor size the more amps it requires.. 540 sizes.. need well... 100-150 amps or more 250! (why you think they sell 300 amps escs for brushless?!)  http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=4197

Motor Size: 2445 (370L)
Speed: 2900kv
ESC Required: 20A
Voltage Range: 6~12v
No Load Curr: .5A
Max Load: 34A
Diameter: 24.2mm
Front Mounting Hole Distance: 16mm
Front Mount Thread Size: M3
Shaft Diameter: 2mm
Shaft Length: 12mm
Weight: 95grams

So the odds of running a big enough brushless for more then 8 mins is doubtful, stick with brushed and buy your gear from Action, it will be worth it  

Bluechrisp original post was for a Dark Horse motor in his sea queen or a brushless the information  I put was an equivalent in power, you came up with a  2900kv motor what where you putting that in a sea plane ? you need something like this http://www.giantcod.co.uk/xyh5055-580kv-brushless-outrunner-p-403285.html  to make it really go there are a few members on hear using similar kva motors, and yes I know how to make BIG boats go with brushless power.
 

[Bluechrisp]

Evening,

Oh dear what have I started, well there was me thinking It was going to be just a walk in the park 

I think I'll make some bits more clearly or clarify, the circuit we use is based on a route, not at full throttle all the time but takes about an hour for the whole team/group to get around, these could be a varaity of craft. So with the brushed or Brushless I wanted to have good performance to call upon or if just wizzing about a good run time.

Some interesting thoughts and avenues to follow up, I am using a pair of 7.2V 6800 I have used these on the Tsekoa each doing about 34 minutes before it drops off, 2 x 500e and a water pump, used at full thottle, this was done to check them out. I think they did well. 

I think in any case I will try to use 2 x 2 7.2 6800 batts, this where Dave comes in with a specially built double P103? thhis would keep the range there and power there too? 
Due to the small size of the compartments I am unable to fit a good size 12V.

I, being not o'fay thought that brushless could be a good way to go... 

I'll just read on abit and report in once more, just abit more cleaning upto do.

CP

[Stavros]

Roadrunner how wrong your are in your assumptions with and I quote

I can understand where you get the run time from, but 24v battery's are very heavy, nearly 4kg worth, i based that on running two 12v 7ah in series but even running 2, 12v 3ah will still be up at the 3.5kg mark. lots of weight to carry reducing the plane potential, power to weight remember.

Dont use them I use stick packs in her so YES I DO get the quoted run times and YES it DRAWS less than What I quoted,it is NOT the same MOTOR similar YES


Stav

[HS93 (RIP)]

Bluechrisp have a look on this link to someone who has been running a nice sea queen there are some videos of it on mayhem at a recent event it goes very well and was not an expensive set up

peter


http://modelfireboats.com/forum/thread.php?thread=3205

[Subculture]

Some things to think about the differences between brushless and brushed-

A brushless motor has no commutator or brushes to wear out and cause friction. This means a cooler running motor, better efficiency, and and critically the motor maintains top performance for as long as the bearings last out. Brushed motors tend to decrease in performance as the brushed and commutator wear down, this is less of an issue with lower performance motors.

Now the downside, most brushless motors and controllers are sensorless. This means the low speed running characteristics are generally inferior to that of a brushed motor. For sports and fast scale use, this isn't anything to be concerned about- the speed control is more than adequate. For very low speeds where fine control is required, you really need a sensored motor and controller or a good quality brushed motor.

Giving recommendations on kv is tricky without knowing what prop you are running, and what speed you hope to achieve.

[Bluechrisp]

Bluechrisp original post was for a Dark Horse motor in his sea queen or a brushless the information  I put was an equivalent in power, you came up with a  2900kv motor what where you putting that in a sea plane ? you need something like this http://www.giantcod.co.uk/xyh5055-580kv-brushless-outrunner-p-403285.html  to make it really go there are a few members on hear using similar kva motors, and yes I know how to make BIG boats go with brushless power.
 

I have little or now knowledge of brushless and seem to think it's magic and it works, so hence the first post, not reallising just how much there is out there, so for my info and my decision what would I need to use with this XYH5055, could I use 7.2V paired together forming 14.4V, or what would you suggest? 

CP

[HS93 (RIP)]

I have little or now knowledge of brushless and seem to think it's magic and it works, so hence the first post, not reallising just how much there is out there, so for my info and my decision what would I need to use with this XYH5055, could I use 7.2V paired together forming 14.4V, or what would you suggest? 

CP

yes no problem that is how most people run them .you can buy a lead to do it so you just plug them togethere.

Peter

[CF-FZG]

As an example i just purchased a Leopard 2860/4050 brushless motor, which is 28mm wide its an equivalent 380 brushed motor size, it requires a minimum of 85amp on its draw, so i have purchased a matching 120amp esc to suit, all to be fitted in a boat tha'ts 26" long and weighs no more then then 1kg if that! (those two items alone .. £150 . do that with a brushed motor... £35 or there about's and that's a big 600 size plugged in!

Equivalent to a 380 size means nothing - apart from the physical size.

It's not a minimum of 80A - it's rated at a maximom of 80A - a huge difference.

to compare it to a £35 600 brushed motor and esc is also wrong - why buy a £150 BL setup if the 600 will do the same job.

That Leopard motor is designed to turn a small(ish) diameter, high pitch prop at very high speed, (upto 56,000 rpm), not something that a 600 is capable of.

[Roadrunner]

uff its like working with small children tonight...

That Leopard motor is designed to turn a small(ish) diameter, high pitch prop at very high speed, (upto 56,000 rpm), not something that a 600 is capable of.

Yes i know ... since i'm about to run a 35mm 1.2 pitch..  and yes i said that its only an equivalent 380 case size, not power! and its not 80- amps its 85 (you cant even get that right put some glasses on eh!) your trying to having a dig, but you forgot the stall current.. I didn't.. stall current 100amps... my esc 120 and a 150 burst current.. guarantees my esc won't blow wasting a ton when the prop gets caught up on a bit of weed or a swan feather like they do so often.

and to give you some heads up... im new to brushless and have never claimed to be a brushless expert hence my original two posting, ''ask the life boat builders  who know'', I just gave my advice on why not use brushed in the damn first place, as its cheaper, not everyone's got deep pockets do they?!

 CF-FZG when you contribute the forum make sure its something worth while, I've yet to see any help from your end at all in all 43 posts...... frankly your one of those little poop stirrers,(most likely an alternate account of someone i expect, not the first post you have tried it on with me with and failed)  carful playing with fire bud it burns   

Dont use them I use stick packs in her so YES I DO get the quoted run times and YES it DRAWS less than What I quoted,it is NOT the same MOTOR similar YES

My assumption was using LA over stick packs but umm what's cheaper?! do i need to spell that out? L.... A....

 If you want to argue over the motors then you need to find all the specs for the actions 900 size... the only info given is the dimensions and no load of 1.1amp but you don't run a boat at 1.1 amp under no load do you.. no... the amps used is as quoted 8amp + (until proven other wise)  if your getting 5 then good for you but i have my doubts.. the reason i say that is that a torpedo 850 is drawing 5.4amps at 12v optimum load but no one really runs the motors at optimum load now do they, (and your running at 24, that's twice the voltage not necessarily the amps you didn't provide your packs amperage so i'm still assuming)  its usually over given the props size and pitch, even how many blades changes the load current being drawn.

Really this has become a repetitive argument I've seen before... each motor is different no two a like, the Graupner 900's are quoting 8 amps (proven) if the Actions or MMBs are different then that's not my problem i can only argue with facts in front of me and until you have the right ones in front of you to argue (and prove it) with then i'm sorry you have nothing to stand on till then. Find the facts and then come back and argue.

Listen Bluechrisp if you want to use a brushless motor go over to the life boat section and pm one of the guys who are using them for his advice on what he's done and how long a run time he gets, if you want to go brushed well phone Dave at ACTion he will give it to you straight and won't steer you wrong. That's the best bit of advice i think your going to get on the forum tonight anyway...

[nick_75au]

Try this, Article aims at displacement, but if you want to go planing speed use the max RPM of the prop in the chart.

Cheers
Nick

[Subculture]

These are excellent motors-

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6246

Haven't fitted one in a boat yet, but they're very torquey, and I use one in a Lazybee aeroplane, and it can prop hang (plane weighs about 300 grams). They'll supply in excess of 100watts all day long.

A reversible ESC that will easily handle the power of this motor-

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11742

[crunchie]

I see you've changed your silly little subtitle to 'temporarily inactive due to personal choice'. Good riddance.

Don't let the door hit you on the backside on your way out.

[nick_75au]

 

I have 2 of them in my Axe bow along with the ESC's 40 mm 5 blade Raboesh props on 11.1 volts, does about 20 Kph on 14 amps per motor flat chat.

http://www.youtube.com/watch?v=tbXt4Clk8QA

Stavros, I'm surprised by your quoted amp draw, how did you test the current draw? A 55 mm prop will pull more than 5 amps if its spinning at more than about 2500 RPM regardless of the motor used.

Nick

[Nige52]

Nice video Nick!
I was looking out for any Crocs hanging about 

[nick_75au]

Nice video Nick!
I was looking out for any Crocs hanging about 

We are just a little far south  but one was caught in the Logan river 100 odd  years ago. The lake drains into the Logan

Here is a quick Video of John Darkes brushed Perkassa, the motors are the ones Mr ACTion mentioned, it uses 55 mm props and draws about 20 amps per motor on 24 ish volts. About 1/2 hour runtime when not being quite so silly

http://www.youtube.com/watch?v=KRcDsCpqidY

Cheers
nick