SSS 56-154 500kv 12S

[mickgc29]

As anyone used this motor in a Rc boat
Just trying to figure out what prop this would turn on 12s

I have the 56-123 500kv
That I was going to use
But the boat is 62inch long and just about 19inch wide and is going to be raced in the sea and very heavy
will this motor be ok
I only need a speed of 60mph and batteries to last 7 minutes

I am also looking at the 56-133 500kv
As this will allow me to use 12s and 18s

As I am new to electric boats any info
Would be great
I have emailed TFL on this question
And so far no reply on prop size

Regards Michael


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[NativePaul]

This size boat is well out of my comfort zone so I could be wrong, you say only 60mph and 7 mins but that sounds like a heck of a task to me with a very heavy 62" boat setup for the sea, much harder than with a typical 42-45" 12s/petrol/gas hull.
Is this for OMRA?
Are you allowed twins?
Is there any battery capacity limit?

[Bande1]

prop - 7016/X670 or ABC 2716
to last 7 minutes at that speed will take somewhere in the neighborhood of 20,000-30,000 mah
or 6000 grams of battery.

its really hard to be accurate on battery cause I really dont have a clue what the hull will take to go 60mph. My guess is at least 6kw-7kw.

[mickgc29]

This is the specs for the 56-133
I am looking at going 12-18s
And 16,000 to 20,000
This motor is 12,000 consent
18,000 max I guess for short bursts

I was playing with the calculator on here
And with a 500kv motor on only 12s
I would need to be running a 78mm prop to do 58-60 mph


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[Bande1]

first you need to know how to actually use the calculator. the props I gave you will get you close. it takes a lot of data logging and experience to actually punch in the right parameters.

second, 12s is only good for about 7kw. Lipo's only out put 140-150A on cheaper side, and 175-185A on the higher end side of batteries. Multiply voltage under load by the realistic amps to be pushed. 41v X 150A = 6150w. For 7 minute runs you want to stay well below the motors max ratings. with a boat that size aim for 16,000-20,000 RPM to put you in a prop range of at least 62mm and up.

here's a sample of the calculator with parameters I find pretty consistent with reality both engine RPM, battery voltage under load, and prop slip....20-25%.
Screenshot 2023-11-24 6.09.59 PM.jpg

you are generally going to have to buy 2-4 props before you dial in the system for runtime and speed. Since you want a wildly long runtime you should go as high of voltage and low of KV as possible and get the amps down to under 100A. 18s to 20s would be pretty good to get you there.

an example: my 42" catamaran with 12s running 60mph could do 5 laps of 16 seconds around the race course and the batteries would be 20% left. 6500mah packs weighing 540g each. About 90 seconds runtime maximum @ 7,000w. There's an other member here that runs 86mph in his 42 cat with twin 56mm motors and pulls 13kw to go that speed. 6500w per motor. So, 7 minutes is over the top long and basically unrealistic unless you run at 40mph or something. 60mph and 7 minutes in a boat that large is a gargantuan task. the boat will need 2 people to launch and weigh over 25lbs.

[mickgc29]

Yes I?ll be racing in offshore mbe
Not be doing 60mph all the time
Just need to be able to do this speed to over take slower boats down the straights
Last year I was running a 56-94 650kv
On 12s in a 58 inch phantom 145
Which ran well but a few guys have a similar setups so i want to try or
Just want to build something a little faster and different for next year
Thank you for your advice and knowledge on this


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[mickgc29]

first you need to know how to actually use the calculator. the props I gave you will get you close. it takes a lot of data logging and experience to actually punch in the right parameters.

second, 12s is only good for about 7kw. Lipo's only out put 140-150A on cheaper side, and 175-185A on the higher end side of batteries. Multiply voltage under load by the realistic amps to be pushed. 41v X 150A = 6150w. For 7 minute runs you want to stay well below the motors max ratings. with a boat that size aim for 16,000-20,000 RPM to put you in a prop range of at least 62mm and up.

here's a sample of the calculator with parameters I find pretty consistent with reality both engine RPM, battery voltage under load, and prop slip....20-25%.
[ATTACH=CONFIG]178168[/ATTACH]

you are generally going to have to buy 2-4 props before you dial in the system for runtime and speed. Since you want a wildly long runtime you should go as high of voltage and low of KV as possible and get the amps down to under 100A. 18s to 20s would be pretty good to get you there.

an example: my 42" catamaran with 12s running 60mph could do 5 laps of 16 seconds around the race course and the batteries would be 20% left. 6500mah packs weighing 540g each. About 90 seconds runtime maximum @ 7,000w. There's an other member here that runs 86mph in his 42 cat with twin 56mm motors and pulls 13kw to go that speed. 6500w per motor. So, 7 minutes is over the top long and basically unrealistic unless you run at 40mph or something. 60mph and 7 minutes in a boat that large is a gargantuan task. the boat will need 2 people to launch and weigh over 25lbs.

first you need to know how to actually use the calculator. the props I gave you will get you close. it takes a lot of data logging and experience to actually punch in the right parameters.

second, 12s is only good for about 7kw. Lipo's only out put 140-150A on cheaper side, and 175-185A on the higher end side of batteries. Multiply voltage under load by the realistic amps to be pushed. 41v X 150A = 6150w. For 7 minute runs you want to stay well below the motors max ratings. with a boat that size aim for 16,000-20,000 RPM to put you in a prop range of at least 62mm and up.

here's a sample of the calculator with parameters I find pretty consistent with reality both engine RPM, battery voltage under load, and prop slip....20-25%.
[ATTACH=CONFIG]178168[/ATTACH]

you are generally going to have to buy 2-4 props before you dial in the system for runtime and speed. Since you want a wildly long runtime you should go as high of voltage and low of KV as possible and get the amps down to under 100A. 18s to 20s would be pretty good to get you there.

an example: my 42" catamaran with 12s running 60mph could do 5 laps of 16 seconds around the race course and the batteries would be 20% left. 6500mah packs weighing 540g each. About 90 seconds runtime maximum @ 7,000w. There's an other member here that runs 86mph in his 42 cat with twin 56mm motors and pulls 13kw to go that speed. 6500w per motor. So, 7 minutes is over the top long and basically unrealistic unless you run at 40mph or something. 60mph and 7 minutes in a boat that large is a gargantuan task. the boat will need 2 people to launch and weigh over 25lbs.

So it be best to stay with a rpm of no more than 20000
So if I was to go for a 18s setup
You would drop the KV down to 350kv ?
As 500kv on 66.6 volts is going to be over 30,000
I understand that the current would be lower on this setup also


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[Bande1]

yeah and again just to get you in that prop range. I really dont know anything about the type of racing youre doing though. Im just saying to say in the larger prop range. so take it with a grain of salt.

[Peter A]

I have done this in the past, raced an electric offshore boat against gassers. Let me share some of what I learned.
I started by figuring out what sort of speeds I needed to achieve. I put 4s 2P in my pursuit and ran it on the same course as the gassers were running at a race. I ran it for 6 mins, did 12 laps at a top speed of 70 kph. The gassers were racing two 20 minute races and a 1 hour race. The 12 laps in 6 min equaled 40 laps over 20 min. The highest lap count for a 20 min race that day was 36 laps. So now I had my goal speed.
The biggest batts I could get were Multistar 20,000 mah. So working back from there, I worked out that I needed to be able to hit 70 kph and have an amp draw under 60A.
I purchased a HK Osprey and set it up with a TP4060 580 kv on 10s. Running a Prather 245 detoungued, it achieved the 70 kph max speed and was able to do 20 min races on 20,000 mah. The big advantage was that I could keep going around when gassers often stoppped, and I could out turn at the bouys with a smaller boat.
Year two I changed the motor to a TP 4070 440kv on 12s.
While not the fastest boat on the water, it was competitive enough to gain some respect. The best days I had were 5th out of a field of 19, and 2nd out of 12. This was on total laps done.
Something else I learned is that that heavier weight of the boat does not effect it's top speed, and the extra weight was a big advantage in rougher water.

So in all this, you need to work out what sort of current draw you will have and use enough battery capacity to be able to complete a race. Personally I think you don't need a boat that big to do well.
I am currently building a 43"Cigarette hull with a steerable outdrive, mostly just for fun. However I have a couple of the 6s 20,000 mah batts and am hoping that I can achieve 15-20 min runtime on a 6s setup, and I may race some offshore with it this year again. I have just painted the boat and will put it all together and test it over the coming weeks. I try and post a build thread but I am not having much joy posting pics of late.

[vvviivvv]

Not sure the esc youd get to run 18s? which in some country's in Europe you actually need HV training for using...

I know MGM go up to 15s, there is that alien ESC that does 16 but i don't think they are that great...

[Punisher 67]

The 56154 is a huge motor , here is on next to a Lehner 30100 , You can even go bigger with the Tenshock 64130 motor pictured next to the 56154
sorry no performance specs yet though . I have a 57 inch Apache with a Lehner 3080/11 477kv running on two banks of 12 cell 5000's that will do
about 80km and run time is about 10 minutes varied throttle . The Apache weighs in at 32 lbs fully loaded with everything , The prop was a
Octura X462 2 blade .