Lehner Motors Help

[cheeko]

Hi Guys

Just wondering what would be the best combo for Lehner 2240/5 running on 5s, Twin with 447/2 prop
I have checked the table and on 5s max amps is 254amp and on 6s about 295amps

last thing i want to do is buy to big of ESC and fry the baby, i have seen some HPR boats with same motors using HK180A

any suggestions

Cheers

[photohoward1]

What is the RPM of the Motor per/V

[cheeko]

the RPM per/V is 2959

[Fluid]

What a "table" says is meaningless, what matters is how you load the motor. This is an extreme setup with loaded rpm in the 50,000 rpm range - deep in SAW-only territory with the potential to pull well over 400 amps. What experience do you have with high speed FE boats? This is a recipe for burned equipment unless you have a lot of experience. It is not just the choice of equipment, it is the total package - driveline, CG, trim and setup in addition to the correct choice of parts. You might get lucky, or you might let out the smoke....


One last thing - don't believe everything you see on YouTube.



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[photohoward1]

5s is over over 56,000 rpm. 6s is over 67,000 RPM. Never going to work. Everything will fry. at best they are 4s SAW motors.

[cheeko]

I have purchased a boat in the fs forum 41" Fatasm by keith bradley with twin 2240/5 motors I'm not going to break any records, don't care really, i have a few boats with some nice speeds i have never fried a controller, i usually research alot before posting anything, i usually find my answer, but on this situation i'm confused, the motors are wired in WYE configuration, which lowers the rpm kv

http://www.lehner-motoren.com/calc/diagramm_en.php

this is the table i got for my amps at max, I see people with same setup motors and they run HW 180A, i would rather fry a controller then the motors

[Fluid]

The table only shows what the maker feels is "max" for the motor, not the max the motor will pull...that depends on the props and setup. The table clearly shows that when loaded heavily the motor will pull over 300 amps, the limit of the table NOT of the motor. Is the Kv 2959 with the Wye wind or with the delta? That Kv is better suited to 4S, but even that is pretty high. The props will determine if anything fries, start small. What did the original owner use for voltage, ESC and props?

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[cheeko]

The table only shows what the maker feels is "max" for the motor, not the max the motor will pull...that depends on the props and setup. The table clearly shows that when loaded heavily the motor will pull over 300 amps, the limit of the table NOT of the motor. Is the Kv 2959 with the Wye wind or with the delta? That Kv is better suited to 4S, but even that is pretty high. The props will determine if anything fries, start small. What did the original owner use for voltage, ESC and props?

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Mate i think the boat is still in the F/S 41" Fatasm keith bradley built

The original owner had swordfish 200HV and i think was going to run on 5s, the new person has never had it wet so it could have went in smoke.

it is definetly in WYE configuration and i was going to use 447 props, what do you recommend, im going to get a ESC that constant 250A and burst 350A or so.
all 8mm Bullets, havnt got batteries yet so i will either run series or just single per motor so not much Amp draw there. Probably use 40C batteries to 65C nanotech which i have alot lying around and i think there great batteries.

cheers all for your help, don't learn if you don't ask

I'm definitely doing to have a datalogger so i should be able to see before it blow what it pulls, rather fry controller then Motor, my work techs can usually fix the controllers for me, so im lucky

[keithbradley]

2240/5 is 2959kv in Delta, 1710kv in Wye. Try 6s with x442s to start.
How fast are you trying to go?

[cheeko]

2240/5 is 2959kv in Delta, 1710kv in Wye. Try 6s with x442s to start.
How fast are you trying to go?

Cheers Keith, just more on info of what best controller it had a Swordfish 200A in it, Just a nice sport boat I'm not breaking any records

Cheers

[keithbradley]

Cheers Keith, just more on info of what best controller it had a Swordfish 200A in it, Just a nice sport boat I'm not breaking any records

Cheers

I like the MGM 28026 ESCs for sport.

[cheeko]

I like the MGM 28026 ESCs for sport.

Cheers Keith, MGM is definitely a nice, this would handle the 6s on WYE configuration

[iop65]

41" boat on 5s/6s ?
42mm prop ?

i would choose 8s / 10s for that size and use a lower kv motor with bigger prop

[keithbradley]

41" boat on 5s/6s ?
42mm prop ?

i would choose 8s / 10s for that size and use a lower kv motor with bigger prop

Why? Please explain.

[ManuelW]

You can easily use T180's and later on upgrade to 2x 6S if your are getting used to the speeds achieved with 2x5S. Pretty decent setup configuration!

regards,
Manuel