esc selection help
10-21-2010 | 03:17 PM
#27
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From: Peterborough,
ON, CANADA
RE: esc selection help
LOL you said it all STUDENT I was there many years ago when you were still messing your diaper and have actually worked in the industry for years. You must have glossed over that part.
Good Luck is all I have to say.
As NF says this will disappear like so many other big dreams and we'll never see a finished working model or hear any more about it.
Talk is cheap but it's still time to pay up. Build it!
There is a lot of info in the electronics sections of the forums, should help with the research a bit, somebody might even have some code they can give you to start with.
I have no more to say as the finished product or lack of it will speak for itself.
Good luck, you'll need it if you really think you know more than the engineers at places like Castle, Etti etc. I know they only have teams of engineers and software designers and have a lot more R&D money behind them.
Good Luck is all I have to say.
As NF says this will disappear like so many other big dreams and we'll never see a finished working model or hear any more about it.
Talk is cheap but it's still time to pay up. Build it!
There is a lot of info in the electronics sections of the forums, should help with the research a bit, somebody might even have some code they can give you to start with.
I have no more to say as the finished product or lack of it will speak for itself.
Good luck, you'll need it if you really think you know more than the engineers at places like Castle, Etti etc. I know they only have teams of engineers and software designers and have a lot more R&D money behind them.
10-21-2010 | 03:33 PM
#28
RE: esc selection help
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Despite repeated reminders on forum rules, you just dont get it.
A report has been filed.
Despite repeated reminders on forum rules, you just dont get it.
A report has been filed.
10-22-2010 | 03:04 PM
#29
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From: wakeman, OH
RE: esc selection help
ORIGINAL: NobodyFamous
240 is super over kill. I'd say the 180 is over kill.<div>
</div><div>Real quick for you. . Watts = Volts x Amps</div><div>
</div><div>The motor is what will ultimately draw as many amps as it wants, so start there.</div><div>
</div><div>Your motor's supper huge ultimate power output is rated at 3500watts</div><div>
</div><div>In a chart this means</div><div>
</div><div>2s (7.4V) x 472.97 = 3500 watts</div><div>3s (11.1V) x 315.31 = 3500 watts</div><div>4s (14.8V) x 236.48A = 3500 watts</div><div>6s (22.2V) x 157.65A = 3500 watts</div><div>
</div><div>Now given that you can put out 3500 watts at only 2s 7.4V the size of the wires required to handle almost 500 amps would be huge, and all efficiency would be lost. You would also have to swing such a huge prop because RPM would be so slow. It can be done though.</div><div>
</div><div>A quick guide.</div><div>Watts is equal to Horse Power, in the sense that it is a measurement of power. Power is what moves the boat (well work is. . .)</div><div>1 HP = 745 Watts</div><div>
</div><div>Watts = Volts x Amps, so no matter how you move electricity, via amps or volts, the combined output is the watts.</div><div>
</div><div>it is easier to move electricity in the form of volts, less loss occurs.</div><div>
</div><div>As for RPM, 30,000 is the goal. So your motor spinning at 15,000 RPM/V (1500Kv) will turn 33,300 RPM Just right. (these are all unloaded RPM)</div>
240 is super over kill. I'd say the 180 is over kill.<div>
</div><div>Real quick for you. . Watts = Volts x Amps</div><div>
</div><div>The motor is what will ultimately draw as many amps as it wants, so start there.</div><div>
</div><div>Your motor's supper huge ultimate power output is rated at 3500watts</div><div>
</div><div>In a chart this means</div><div>
</div><div>2s (7.4V) x 472.97 = 3500 watts</div><div>3s (11.1V) x 315.31 = 3500 watts</div><div>4s (14.8V) x 236.48A = 3500 watts</div><div>6s (22.2V) x 157.65A = 3500 watts</div><div>
</div><div>Now given that you can put out 3500 watts at only 2s 7.4V the size of the wires required to handle almost 500 amps would be huge, and all efficiency would be lost. You would also have to swing such a huge prop because RPM would be so slow. It can be done though.</div><div>
</div><div>A quick guide.</div><div>Watts is equal to Horse Power, in the sense that it is a measurement of power. Power is what moves the boat (well work is. . .)</div><div>1 HP = 745 Watts</div><div>
</div><div>Watts = Volts x Amps, so no matter how you move electricity, via amps or volts, the combined output is the watts.</div><div>
</div><div>it is easier to move electricity in the form of volts, less loss occurs.</div><div>
</div><div>As for RPM, 30,000 is the goal. So your motor spinning at 15,000 RPM/V (1500Kv) will turn 33,300 RPM Just right. (these are all unloaded RPM)</div>
things are starting to make so much sense, the reason i plan to go with the 240 is so that i can switch motors if i want without worry. but if i read correctly from what you posted this motor may draw as high as 236.48 amps on 4s, which i may also decide to run. the 240 will handle all of that.
one last question, if the goal is 30k rpm and in a perfect world all of our boats turn 30k how are some of these guys getting boats into the high 60's and even into the 70's? any guesses on what kinda of speed i can look forward to? my goal is to pass the 50mph mark
10-22-2010 | 04:56 PM
#30
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From: Cheverie, NS, CANADA
RE: esc selection help
if it was guaranteed (the perfect world) that your prop was spinning 30,000 rpm, one guy would be faster then the other (also assuming slippage was the same) by what is referred to as pitch.<div>
</div><div>Pitch is the distance (horizontally) a prop will move through the water in 1 rotation. This is determined by the angle, shape, and size of the blades.</div><div>
</div><div>The motor has to have enough power (watts/HP) to turn the prop. The bigger the prop, the farther you try to push the boat each rotation, the more power you need. approximately 30,000 rpm is chosen for a large number of reasons. Balance, friction, motor efficiency. . . </div>
</div><div>Pitch is the distance (horizontally) a prop will move through the water in 1 rotation. This is determined by the angle, shape, and size of the blades.</div><div>
</div><div>The motor has to have enough power (watts/HP) to turn the prop. The bigger the prop, the farther you try to push the boat each rotation, the more power you need. approximately 30,000 rpm is chosen for a large number of reasons. Balance, friction, motor efficiency. . . </div>
10-22-2010 | 05:48 PM
#31
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From: BrisbaneQLD, AUSTRALIA
RE: esc selection help
With Apologies to the OP for a minor hijack
Hi I have a power wheels as well, I have 2, 700 motors on 24 volts and Ive driven both on one of these with 2 kids on board
, it will handle 4 (I've done it in a big model boat)
http://www.robotcombat.com/products/IFI-V885.html
Nick
ORIGINAL: NobodyFamous
Does this mean brushed motors (1 phase) and brushless (3 phase) because I have some monster 800 brushed motors I'd like to use (maybe even as a power wheel upgrade) but no one makes a decent brushed ESC with big amp output.</div>
Does this mean brushed motors (1 phase) and brushless (3 phase) because I have some monster 800 brushed motors I'd like to use (maybe even as a power wheel upgrade) but no one makes a decent brushed ESC with big amp output.</div>
, it will handle 4 (I've done it in a big model boat)http://www.robotcombat.com/products/IFI-V885.html
Nick
