Help With Brushless Conversion Appreciated

[DWJL511]

I wld like to convert my Proboat Volere EP 22 to brushless, but need some help in finding right motor and ESC. Hope you guys can offer me some advice.

The boat is only 22 inches. It?s a classic wooden speedboat, so it?s obviously not for racing/high speed. I do want it to run faster than stock though.

Someone did a successful conversion on YouTube. Here?s his video to give you an idea of what I mean:

http://www.youtube.com/watch?v=KQXUFSS20XI

So I basically need a 540 brushless motor, and I want to use just a 2S (7.4v) lipo.

I saw this motor on Dealextreme and I wonder if you guys could tell me whether it?s a good enough for the boat in terms of speed and power:



Is the kv too high? Shld I go for lower KV like this one?:



Another question I have is that the stock motor is water cooled by a coil and I would like to use back the coil. But seeing that the above brushless motors have cooling fins (i.e. not typical smooth surface), will the coil still work since there's less contact surface? Here's a pict of the stock motor and cooling coil:



Thanks for any help and advice. If you have better motors to suggest, pls tell me. tks!

[Adrianli]

These two motors kv too high for a scale speed. Try to look for kv ard 2000+ range. Also what type of can size length u looking for, S, L or XL???

[DWJL511]

These two motors kv too high for a scale speed. Try to look for kv ard 2000+ range. Also what type of can size length u looking for, S, L or XL???

The guy in the vid is using a 9.5T 3300kv motor. Plenty of power so his throttle is set at 80%. The lowest kv rating I can find for the same model/brand is 2950kv:



Will this be better? I dun mind having some extra power for non-scale speed, hehe.

As for the can size of the motor, I think the diameter and length of these brushless motors will fit. Not 100% sure though, I need to take out the stock motor and coil to do some proper measurements. The guy in the vid just said 540 motor and it was a drop-in fit for him.

[Adrianli]

The length of the motor determines the amt of power(watts) u want. See this feigao chart :




Probably u should work backwards and determine how much rpm u wish to run.

For direct drive :

motor kv x lipo norminal voltage = rpm

[DWJL511]

That chart looks Greek to me, man.

I wouldn't know what RPM I want as I have no idea how a certain RPM value translates to how fast the boat will actually move on water. All I know is that I want a speed that is something like what was achieved in the vid, so how many RPMs is that?

I just need to know whether the motor is an overkill or too weak. I do hear your point that the kv is perhaps too high, so I'll go for something like 2500?3000kv max.

As for can size, I just need one that will fit snugly into the stock cooling coil.

[Adrianli]

That chart looks Greek to me, man.

I wouldn't know what RPM I want as I have no idea how a certain RPM value translates to how fast the boat will actually move on water. All I know is that I want a speed that is something like what was achieved in the vid, so how many RPMs is that?

I just need to know whether the motor is an overkill or too weak. I do hear your point that the kv is perhaps too high, so I'll go for something like 2500?3000kv max.

As for can size, I just need one that will fit snugly into the stock cooling coil.

I am not sure what speed you are looking at. Any rough figures??? 20mph or 30mph??? Normally for speed boats, we aim to achieve 30,000rpm and for SAW runs, up to 50,000rpm. U have to measure ur current rpm on stock setup and determine ur own ideal rpm for the required speed.

If I were to setup, I would preferably want to run my motor n esc at 100% efficiency and not get an overspec motor and run it at 80% efficiency.

All 540size motor will have the same can diameter size 36mm. But the length is different depends on ur application. U have to decide how much power u want and the size of boat it is pushing. Normally 540S is good up to 25" boats, 540L is good up to 30" boats and 540XL is good up to 35" boats. Any bigger, u need to increase the motor can diameter to prevent motor burn out.

[DWJL511]

I am not sure what speed you are looking at. Any rough figures??? 20mph or 30mph??? Normally for speed boats, we aim to achieve 30,000rpm and for SAW runs, up to 50,000rpm. U have to measure ur current rpm on stock setup and determine ur own ideal rpm for the required speed.

If I were to setup, I would preferably want to run my motor n esc at 100% efficiency and not get an overspec motor and run it at 80% efficiency.

All 540size motor will have the same can diameter size 36mm. But the length is different depends on ur application. U have to decide how much power u want and the size of boat it is pushing. Normally 540S is good up to 25" boats, 540L is good up to 30" boats and 540XL is good up to 35" boats. Any bigger, u need to increase the motor can diameter to prevent motor burn out.

Hi Adrian,

For the speed, I really don't know how fast 20mph or 30mph is as I have no experience (I really can't tell). That's why I posted earlier a vid of same boat that's been converted to brushless. That's roughly the speed I'm looking at. So is that abt 20mph or more/less? (pls see vid). Of cse want it significantly faster than stock otherwise why upgrade.

As for the size of boat, I said earlier that is a 22"-only wooden classic speed boat.

I already ordered a budget 13T 2950kv brushless motor that's 50mm in can length, so I guess that's abt the same length as a Feigao 540S (51mm), which you said is good for boats up to 25". Also, intend to use only 2S lipo, abt 1500-2000mah.

Right now I need a water-cooled suitable ESC. Based on the limited info I have, wld you be able to roughly recommend how much Amps I should get to be safe/keep things cool? 35A, 60A, 90A, 120A? Am considering the Seaking ones from Jethobby (very ex$ though). Tks for any help man.

[Adrianli]

Hi Adrian,

For the speed, I really don't know how fast 20mph or 30mph is as I have no experience (I really can't tell). That's why I posted earlier a vid of same boat that's been converted to brushless. That's roughly the speed I'm looking at. So is that abt 20mph or more/less? (pls see vid). Of cse want it significantly faster than stock otherwise why upgrade.

As for the size of boat, I said earlier that is a 22"-only wooden classic speed boat.

I already ordered a budget 13T 2950kv brushless motor that's 50mm in can length, so I guess that's abt the same length as a Feigao 540S (51mm), which you said is good for boats up to 25". Also, intend to use only 2S lipo, abt 1500-2000mah.

Right now I need a water-cooled suitable ESC. Based on the limited info I have, wld you be able to roughly recommend how much Amps I should get to be safe/keep things cool? 35A, 60A, 90A, 120A? Am considering the Seaking ones from Jethobby (very ex$ though). Tks for any help man.

The one on youtube should be ard 10+ to 20mph only.

Next, what prop size and how many blades u using??? Tis is to determine ur esc.

[DWJL511]

The one on youtube should be ard 10+ to 20mph only.

Next, what prop size and how many blades u using??? Tis is to determine ur esc.

ok tks.

The stock prop is 2-bladed, I think abt 3cm max (sorry, exact length/specs not given by manufacturer)

[Adrianli]

Ok, input it into FE Calculator.

Estimated AMP draw is 25A with a run time of 5mins and est speed of 24mph.

Get a 35A ESC will do.

[DWJL511]

Ok tks Adrian! Vid person uses 35A too. If I want longer run time more mah will do?

[Adrianli]

Ok tks Adrian! Vid person uses 35A too. If I want longer run time more mah will do?

Yes. But take note, the increase in weight(batt capacity) will also affect the boat performance.

[DWJL511]

Yes. But take note, the increase in weight(batt capacity) will also affect the boat performance.

Ok man, tks for all the help Adrian, appreciate it.

[Adrianli]

Ok man, tks for all the help Adrian, appreciate it.

No problem lah. Just helping out fellow sailor.

[hydro rob]

No problem lah. Just helping out fellow sailor.

where did u get that calculator