okay ive been running my losi 1/10 Xcelorin 7500Kv Brushless Combo for a while on my grupner jet boat set up, and its been working fine since. but recently my aftermarket esc watercool fried my esc up = [. now im looking for a new esc. but i dont want to spend another $130 on a new one from horizonhobby. i dont realy know about brushelss stuff too much. the original esc & motor specs are

ESC Specs
Type: Sensorless Brushless
Forward: Y
Reverse: Y
Brake: Y
Time Delay Brake: Y
Throttle Limiting: Y (adjustable in 10% steps)
Programmable: Full (via quick program card or PC)
Continuous Maximum Current: 100A
Momentary Peak Current: 540A
Input Connector Types: Losi EC3 style
Dimensions (WxLxH): 1.16 x 1.54 x 1.3 in (29.5 x 39 x 33.2mm)
Weight: 1.7 oz (48 g)
BEC Voltage: 6.1V, 3A
PWM Frequency: Optimized for Spektrum or traditional radio systems

Motor Specs
Type: Sensorless Brushless
Size: 540
Bearings or Bushings: Precision ball bearings
Voltage: NiMH 6-12-cell; LiPo 2-3-cell
RPM/Volt (Kv): 7500Kv
Weight: 6.35 oz (180 g)
Overall Diameter: 1.4 in (35.8mm)
Shaft Diameter: 0.125 in (3.17mm) with flat
Shaft Length: 0.18 in (4.6mm)
Overall Length: 2.15 in (35.8mm)


it says Continuous Maximum Current: 100A and Momentary Peak Current: 540A does that mean to be able to run the same motor i have, i would need the same continuous & peak amps????????????????????


im looking through ebay right now and found this one [link=http://cgi.ebay.com/RC-boat-brushless-motor-ESC-w-water-cool-60A-max-380A_W0QQitemZ140259247905QQihZ004QQcategoryZ34058 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem]ebay link[/link]

the specs are

Model Sea King 60A
Con.t Current 60A
Burst Current 380A
resistance 0.0007 ohm
Working Voltage 4-12cells NiCad or Nimh / 2-4cell lipo
BEC output 6v/1.5a
Weight 32g

would it work? i dont wana fry another esc.

Did you say 7500kv XL? In a boat? That sounds way too high IMO.

How many cells were you putting in this boat?

The setup you're using is really for a car system. It's to be used w/one of those gear systems.

i run it with 3 cell lipo .yea its too high but i had the brushless set up before i got into boats. i just didnt want to buy another brushless. anyways amy suggestion on what to get? what brand how many kv etc..

Could you say the specs of the boat first? Like size? Sry, I'm not aquainted w/graupner stuff.

I agree that 7500KV on 3S is way too high, on a jet it will hardly work up to one third throttle, or am I mistaken?

Did you read this, on the eBay add:
When using 9-12cells NiCad(NiMh) or 4cell (14.8v) lipo, you must disable the output of the built in BEC and using external UBEC device to power up the receiver and servo.

Running 3S you're on the edge and you may cause the BEC to overheat, adding that to the ludicrous rpm's (for a jet/boat) the motor is capable of, I have my doubts if this ESC will play along...

Regards, Jan.

If you're talking about the Graupner Jet Sprint with the mini-jet; the adviced motor is a Speed 500 or Speed 600 with 17000 rpm on 7,2V.

I doubt this small jet will work with your motor beyond one third throttle...

But, prove me wrong, show us a video!

Regards, Jan.

Bottom line. Do not use a 7500kv motor in a boat. On 3 cell LiPo that's 80 000RPM. THere is no prop or impeller small enough to run effectively on this kind of RPM. If your ESC did not burn up your motor or battery would have.

Read the stickied thread on top of the electric forum and use an appropriate setup next time.

Ryan

The graupner jet sprint is only about 450mm according to the graupner website. Did you really use a boat that size w/an XL motor size?

i put the setting to very low timing and 60% throttle. lowest of the low. i trust all your opinions but i only did this because i had the 7500kv before i had my boat. ive never had wny problems till i shorted the esc.

anyways ill post some pics of my set up later on when i take some pics.

its NQD jet boat with graupner jet drve.

heres the pics

Beyond the other problems noted running constantly at 60% throttle will kill your esc as well
Ghost

so what would be a proper kv range selection for a 2 or 3 cell lipo?

For something in the really high speed, i would estimate that it would range between 3600-4000kv w/a motor can size of 380 XL.
But that's for the really intense micro racing stuff like minicat usa.

For your boat type and size i would estimate probably around 2500-3500kv w/2-3s and 380 xl motor IMO.