New to hobby, have questions.

[MrGoFast]

I’d like to start off by saying I AM NEW AND KNOW VERTUALLY NOTHING!

I bought a boat form exceed, the Fiberglass Shark 650EP. It came with a 2858-4122kv Brushless motor and a 70A Brushless ESC.

http://www.nitrorcx.com/99b-10021-650-ep-artr.html

I did not read the instructions carefully enough and used a 3cell lipo, which I understand now ran the motor to fast 11.1X4155=45,752rpm, WAY too fast! The ESC burned and when I say it burned I mean it was on fire! Lol
Questions I have,
1) Did it burn because at that rpm the motor pulled too much current (amperes) from the ESC, more than the 70a it is rated at?
2) The first number (2858) is the physical size of the motor, yes?
3) The 4122kv is the rpm per Volt, yes?
4) How do I decide what amp size of esc should be used for what motor? How does this work?
Is this a true statement? “Brushless motors should be run no faster than about 30,000rpms
-1000kv motor can be run on a 7cell lipo (29.6V) at 29,600rpms
-2000kv motor can be run on 4cell lipo (14.8V) at 29,600rpms
-2700kv motor can be run on 3cell lipo (11.1V) at 29,970rpms
-4000kv motor can be run on 2cell lipo (7.4V) at 29,600rpms
Do these numbers make sense?
And if they do, how do I decide how many amps an esc should have for a given set-up? I am very confused. I need help!!!!
I have gone ahead and ordered these as replacements. Good choices?
http://www.hobbyking.com/hobbyking/s..._Boat_ESC.html
http://www.hobbyking.com/hobbyking/s...r_2630kv_.html

[MrGoFast]

No takers. Even justy a, "you're on the right track" would be nice! Thanks guys.

[rcboatmanwithkids2880]

Hi Mate ,

This is the best F/E Forum in the world , consider how many post have been written in this field of R/C hobbies . The answers you are looking for have already been posted , in most circumstances more then once . There are a number of things that you should be searching this site for , including an Excel spreadsheet that contains Cell Count appropriate to your BL Motors KV rating .

Search to see if other forum members have the same boat as you and what componentry they are being successful with. ...

All the best in F/E R/C Boating ,
Brad
Oz

[dana]

1. Probably
2. Yes can size
3.Yes kv X volt = rpm
4. Go with 60 amp to have headroom and future motor upgrade
25000-35000 rpm good for sport boating. Saw racing can go up to 40000 and more but only for quick runs.
Most of my boats for fun sport running are at about 33000 rpm, but I don't over prop.
Hope this helps

[MrGoFast]

1. Probably
2. Yes can size
3.Yes kv X volt = rpm
4. Go with 60 amp to have headroom and future motor upgrade
25000-35000 rpm good for sport boating. Saw racing can go up to 40000 and more but only for quick runs.
Most of my boats for fun sport running are at about 33000 rpm, but I don't over prop.
Hope this helps

Hey man thank you, very helpful.

[properchopper]

Welcome Mr. "GoFast". Not to worry, most peoples' first boat results in what could charitably called a "learning experience". Hang on, it gets better ! Here's a chart which helps determine what KV motor works in the generally acceptable rpm range for reasonable operation given your chosen battery voltage. For the "S" rating, remember that 1 "S" = 3.7 volts so your 3S pack = 11.1 volts

kv_voltage[1].pdf

The esc you ordered is good for lots of larger applications. Many of us use it for 30"-34" inch boats pulling +/- 150 or more amps with motors puting out @ 3000 watts.

The motor you chose may work in your 22" boat, but choose a smallish prop. That motor is rated at 38 amps and 700 watts max. A slightly bigger motor would give some more power/speed and provide some more reliability.

Tony
[email protected]

[Basstronics]

Huge ESC, tiny motor in a smaller boat.

I personally dont like the motor you chose, its just to weak.

The ESC is an extreme overkill and will be gigantic in your hull.

The 120A would of been a MUCH better choice:
http://www.hobbyking.com/hobbyking/s..._Boat_ESC.html

[MrGoFast]

hey guys, thanks ALOT!

Could you suggest a more appropriate motor for this boat in the 2858 size or should I just move up to a larger motor. What wattage and amps should I be looking at? Thanks again guys. The motor i ordered was not very expensive I wouldn't mind ordering another more appropriate motor, suggestions?

I do plan on a larger boat in the future.

[rcboatmanwithkids2880]

Hi Mate ,

I would be at least be considering a 36 - 40 mm diameter BL Motor , leopard may be a great budget motor for your boat . Check out that Excel Spreadsheet ( somebody post a link ?? ) on this forum and go from there , also consider a T180 amp ESC to take care of the added load of a 4 pole motor ( such as Leopard ) , as you should have room for it in your mono . Given the availability of components , this should not pose to much trouble ....

Brad
Oz

[darryl whitman]

just remember Leopard motors dont like high timing on them , only about 1to 3 degree advance.

[dana]

just remember Leopard motors dont like high timing on them , only about 1to 3 degree advance.

This is not true at all.

[darryl whitman]

This is not true at all.

dana , most Leopard s are (D) type wound , an (D) type motors dont like the timing advance over 4 degrees.
I didnt make my self clear, sorry.

[dana]

I agree d winds like 3 or less, but I would say 40 percent of leopards are y wind.

[MrGoFast]

Hey man thanks for this info. I have ordered the 180amp turnigy,

http://www.hobbyking.com/hobbyking/s..._Boat_ESC.html

I know extreme over kill, I didn't want to order another one for my next boat. I have mocked up a box of its dimensions and it does fit....just. LOL

Is there a link to that explains timing?

[dana]

D wind 1-3, y wind 7.5-15