motors help needed !

[splashfast]

ok this is the first time ive built anything electric powered allways had nitro

ive been looking at motors for days now and dont have a clue what im looking at
what do all those numbers mean etc
is there a thread on this forum that explains any of this ??

am i looking for revs or voltage or something else ?
also are brushless motors that are sold for cars etc any good for boats ? they seem to be about the same price but thought it best to check first ?

many thanks
darren

[scoota]

all those numbers mean ? lets say your looking at a Leopard 4074 - 2200 kv motor

the 40 = 40mm dia
the 74 = 74 mm long
the 2200KV means for every volt you apply to the motor it will spin at 2200 RPM

lets say your going to run 4s set up which = 14.8 Volts times that by the KV of the motor , which in this case would be 14.8 volts x 2200kv = 32,560 total rpm the motor will be putting out , the more volts you apply the more RPM the motor will put out , the motors do have a Max volts you can run them on ..

IF you let us know what type of boat you want to build we can help a bit better , with the size of MOTOR , KV ,ESC & how many cells to run ....

Jason

[splashfast]

Thanks jason its a 42 inch racing catamaran im hoping to build it with a single motor setup i spoke to allan at aztec and he has pointed me in the right direction for the hardware etc but ive been looking at motors for days now and esc and im totally lost

[splashfast]

ok i looked at a feigao 540 xl 8 motor that was rated at 2084 per volt

so if i use two lipo 2s 2500 7.4 v that would give me 30843.2 revs per volt ???

i get this part now but the motors stats say that at 25c 62a and 40c 100a

im going to guess that means at a temp of 25c the max amps it can take is 62 ?
and at 40c it can take 100amps ? is this correct or am i way off the mark ?

many thanks
darren

[scoota]

Maybe the Leopard 5692 /1340KV on 6s with a seaking 180amp ESC or swordfish 240 amp ESC .

There are a lot of guys on here that have built big cats, that im sure will post some suggestions ...

http://www.offshoreelectrics.com/pro...?prod=leo-5692

http://www.offshoreelectrics.com/pro...ef-sword-240hv

[sailr]

That 540 motor is way too small for the big hull you have. Scoota's suggestion is a good one.

[scoota]

you want to get 35c /5000+ mah lipos for good discharge & run times ....

[splashfast]

ok thanks guys im thinking that leapord motor looks the best option so far was looking at sourcing one in the uk but no joy as of yet

also i found this while looking what do you guys think ??

http://www.giantcod.co.uk/xyh5065-410kv-brushless-outrunner-p-404748.html

[scoota]

the KV is way to low on that motor & outrunner motors are hard to keep cool inside a hull , even with a water cooled mount.. you need to aim for 25,000 to 35,000 rpm range for good speeds , i would stick to an inrunner motor as you can run a water jacket on them for better cooling ..

[scoota]

Found this guy , but he is way too dear , i would ship one from OSE ...

http://cgi.ebay.co.uk/LEOPARD-5692-Brushless-Motor-540kv-UK-SELLER-/320578810448

[splashfast]

yeah i found his ad too lol yes i think the best option would be to order from ose

apart from the kv i should be looking for 25,000 to 35,000 rpm to give me a good turn of speed for this size boat

thanks you so much for your help scoota things are much clearer now about motors etc
now i just need to get my head around all this batt speak lol but ill save that for another thread want to get my hardware and motors/mounts etc fitted then ill be looking at esc,s and batt etc

many thanks you scoota

[Diesel6401]

What about a Leopard 4082 with a trusty Seaking 180 on 5s for sport, 6s for . He would be able to use a standard leopard cooling jacket & mount. JMO

[scoota]

Just keep in mind , the big Leopard motors have a 30mm between the mounting screws , most standard motor mounts have a 25mm spacing , something to look at when ordering a mount for your boat ....

[splashfast]

thanks guys those leopard motors look the mutts

do you think it would be over kill to stick two of them in ?? and on that note if i did decide to get two would that mean i need an esc and seperate lipos for each motor or do you make them share ?? sorry for asking so many noobish questions but i really do know diddly squat about the boat scene and electric motors

[scoota]

thanks guys those leopard motors look the mutts

do you think it would be over kill to stick two of them in ?? and on that note if i did decide to get two would that mean i need an esc and seperate lipos for each motor or do you make them share ?? sorry for asking so many noobish questions but i really do know diddly squat about the boat scene and electric motors

That big Leopard motor is rated at 4 Horse Power that is plenty for your hull , if you went twins you would have to look at smaller motors , with higher KV rating...