leapord 2860 3400kv what esc to run 4 cell lipos?

[Vin-m]

looking at geting 2x 2860 3400kv leapord motors and was wondering if 2x seaking 90 amp esc would be enought to run 2x 4cell 5000mah 50c batteries in a ekos with out melting them??? or do i need to go to 120amp esc's? prolly gonna prop it between 36mm-38mm at most.

[Doby]

50,000 RPM!!!!!!!!...Use qty 2, 300 amp swordfish controllers.

Try 3S instead.

[NativePaul]

^^^^^
Agreed

This is a popular 3s Mono/Hydro1 motor here, 90A is not enough ESC for these, on 3s I recommend 120A.

300A ESCs are pretty heavy for a boat these motors will suit, so I would suggest 200-240A units and smaller props than you suggest if you want to run 4s.

[Vin-m]

what speeds would i get out of 120amp esc running 3cells on a king of shaves c1? and why such the high amp for running 4 cells? sorry if these seem like dumb questions but im kinda new to swapping out motors and esc's so any help is appreciated. i currently run 4cells with 60 amp esc on my king of shaves p1 and my miss excite and they are spining 1.6 40mm props and the stock outrunners get to 135 degrees but the esc doesnt even break 95 degrees?

[Vin-m]

hows this guy doin it with 70 amp esc's? http://www.youtube.com/watch?v=-Bxg13vML6Q
are these just short burst runs or somethin? hes got another video 7 mins long no cuts and says temps arent hot.........
im basically looking to run mid to upper 50s with this boat using leapords and seaking stuff but want something w good run times and no heating issues...... open to suggestions .

[NativePaul]

Our Monos run mid 40s for 6 minutes and hydros low to mid 50s for 5 minutes both on singles with 4500mAh 3s, Higher speeds are possible by propping up but runtime would reduce and bigger ESCs would be needed to remain reliable.

There is a big difference between what is proven race reliable and what 1 guy gets away with, the setups above only pull an average of 40-50A, it is possible that someone might get away with a 45A ESC, but I have seen more 90A ESCs blow than 120s despite 120A being by far the most common size so I couldn't recommend anything less in good faith, I have seen spikes over 120A on my own leopard 2860 3400kv 3s Hydro1 which averages around 50A.

I don't know your boats but I suspect their motors have a lower KV than 3400, a quick search says the stock P1 has a 2000Kv outrunner as does the miss Excite, so unless you have swapped motors you would be trying to spin your prop over 23,000rpm faster with the 3400kv leopards on 4s than you are trying to spin it now on 4s which will pull a MASSIVE amount more amps if you tried running the same prop, you could try propping down to the same amp draw but the smallest commercially available metal prop I know of is 28MM which may not be small enough. 2000kv on 4s gives a theoretical unloaded KV of 33,600rpm the 3400KV Leopard on just 3s gives 42,840 which is a pretty big increase already and you will need to prop down in order to keep the same amp draw, but the motor will take the amps a 1.4 pitch 36mm prop will draw in a reasonably set up hull so if you didn't mind getting shorter runtimes than you get now (or using higher mAh batteries) you could go faster, If your ESC is up to the increased amp draw.

I found the 7 minute Video and he is running Feiago 3809XLs which are quoted at 2610KV which while still being pretty high revving are still 4s capable, Leopard 3400s would be trying to spin over 13,000RPM faster and probably managing to spin a lot more than that much faster as Feigaos weren't known for having good voltage under load, if you tried spinning the same prop your amp draw would be huge. While the running in the video is far from a SAW type short runtime, during that 7 minute video he probably has the throttle wide open for about a minute with a lot off pootling around, I have never driven a boat in that manner so I can't say for sure, but the long times going pretty slow but fast enough to keep a flow through the cooling system between bursts of wide open throttle could be helping keep things cool.

[Vin-m]

so would it be more reliable if i dropped down to 2860 2730kv leapords w/4cell? And would it be faster then the 2860 3400kv 3 cell set up? runing the ekos c1 so this is gonna be a dual motor set up.and what should i prop it at. i am happy with speeds around 50+ i just want reliability dont really want to replace esc's and motors all the time. like i said before im new to swapping out motors and esc's so not sure what matches up with what. thanks again for the help.

[Vin-m]

anyone know if this is a beter set up for king of shaves c1 dual motors?^^^^^^^^^and about how fast would it be

[NativePaul]

sorry, I thought I replied but my laptop must have eaten it.

2730 KV is much more suitable for 4s, it is still pretty high but will be OK if you don't throw a big prop on it, it will be a bit faster than the 3400 on 3s at the same current or will pull less current for the same speed, but I would still go for a 120A ESC, for the small to non existent differences in size, weight and cost of a 120A Chinese ESC over a 90A Chinese ESC, I wouldn't consider getting the 90. Speeds will of course vary with prop size but that setup is capable of 50+ with props in the mid 30s (mm), always start small with props and work up in size checking for heat.