Nitro/Brushless conversion

[blackcat26]

I have a nitro Elam hull and have decided to convert it to brushless. My main question is about the battery/motor combo. Should I use a high kv motor and run (2) 2s li-po's, or Run the BJ 26 motor on (2) 3s li-po's? Is there an advantage to either of these setups? I realize the 3s setup will obviously be heavier......Any thoughts? :help:

[Jesse J]

I vote heavily for the proboat 6S option. I did one and it almost hit 60 and still handled like a dream. She weighed over 6lbs when in the water and it didn't seem to notice.

The main difference is amp draw an torque factor. If you go high KV low voltage, your amp spikes will eventually kill an esc rated for fewer than 150 - 200 amps. If you go low KV high voltage (my preference) you have lower amperage draw and much lower amp spikes which all equal less wear and tear on esc AND motor.

Another advantage is that you can go lower voltage and slow her down if needed - like if you want to race or let someone else drive.

Here is a couple videos of mine (now somebody else's)
http://www.youtube.com/watch?v=WyGTfIDlI7Q
http://www.youtube.com/watch?v=lijVS_FGYos

Here is my build thread (http://forums.offshoreelectrics.com/showthread.php?t=7672) you gotta scroll down some - it was a dual build thread with Bustitup

[blackcat26]

Thanks Jesse. Since this post I took your advice on the setup......I have a new hull and wanna try a few new things on this one. What do you think about that Align 600xl outrunner for this? There is a guy on you tube that has a Miss Bud running 6s on the 1700kv version. I looked up the stats on the motor and it has a good integrated fan and handles 1600w or something. I was thinking, water cooled motor mount and slap that baby in there!

[Fluid]

If starting from scratch I see no reason to go with an untried setup....if you want reliability that is. First define your goals - oval racing, SAW racing, sport running, run time, speeds, etc. If you do not make this decision first you will probably not be fully pleased. Don't trust what you see on YouTube, many of the vanity videos there don't tell the whole story....

Outrunners in confined hulls are an accident waiting to happen, especially if you put the packs ahead of the motor. IME it's better to use a proven setup like a Feigao 8XL or 9XL on 4S. You can keep amp draw in check by not overpropping and have speeds of 50+ on good 4S cells. If you want to use 6S, then a 12XL or 13XL is a good choice and if you don't get greedy amp draw will be lower. The very high rpm from a BJ26 or similar Kv motor on 6S will eventually cause reliability issues with the drive train. Far better to use lower rpm and more torque/bigger prop to drive this hydro.



.

[Jesse J]

If starting from scratch I see no reason to go with an untried setup....if you want reliability that is. First define your goals - oval racing, SAW racing, sport running, run time, speeds, etc. If you do not make this decision first you will probably not be fully pleased. Don't trust what you see on YouTube, many of the vanity videos there don't tell the whole story....

Outrunners in confined hulls are an accident waiting to happen, especially if you put the packs ahead of the motor. IME it's better to use a proven setup like a Feigao 8XL or 9XL on 4S. You can keep amp draw in check by not overpropping and have speeds of 50+ on good 4S cells. If you want to use 6S, then a 12XL or 13XL is a good choice and if you don't get greedy amp draw will be lower. The very high rpm from a BJ26 or similar Kv motor on 6S will eventually cause reliability issues with the drive train. Far better to use lower rpm and more torque/bigger prop to drive this hydro.



.

Good info, thanks Jay. what are you referring to with drive train issues? cable destruction? what about using .078 piano wire?

I have a couple more hulls waiting for set ups - will probably go 11/12 XL on 6S. She definitely handled great at 6lb weight.

Also, reinforcing the tunnel from the motor mount to the transom (glass or CF) will enhance rigidity and increase speeds and handling significantly.

[blackcat26]

OK thanks Fluid. Out of curiosity what are the problems with the outrunners? Is is a heat issue or having the can constantly rotating and possibly destroying something that contacts it?

[blackcat26]

Can anybody tackle this question? If it's a dumb one I am sorry but you have to learn somehow......Before my question I had already ordered one and got to run it yesterday. My speed from the Black Jack motor to this went up 7mph and still tweaking it in. The nice thing about this outrunner is that the outside can does not rotate allowing it to be water cooled. Changed props from a x442 to a x447 and she didn't seem to mind.