TP 4050 1950kv on 6s

[Hotrods]

I run two 4050 2100 kv on 6S on my Cheetah with 180's no problems with mine.

[danzuby]

I'm running pretty big batteries 8000mah and the quality is second to none but that's just my opinion. I only ask because I want other people's opinions input. I haven't shot anybody's theory down I am trying to learn. I don't have the answers I only write what I have experienced so far and no I'm not running wide open for 30 minutes but I have run half throttle continuously for that amount of time and more. The other information that I'm getting for the possible changes is coming from a boat speed calculator that lets you put in hull type, motor kv, number of cells, specific prop type and manufacturer and it calculates approximate speed. The boat did 50mph with the stock prop and cheap batteries, after in stalling a Dasboata race prepped Octura X642 I got 53mph and the upgrade Max amps batteries put me at 56mph. As for the person who claims the amp draw at 17 amps you got the numbers reversed it's 71 lol.

[Mxkid261]

30 minute run times??? Does it have a sail on it??

[danzuby]

yep and it got Max amps written all over it

[danzuby]

I get 4-5 minute runs with a 2minute cool down between each run(using an onboard electric water pump) and I come in at 22.5 volts on 6s so I figure I could do 1 more run but I don't because I'm not one to beat my batteries like that.

[Mxkid261]

Well at least their over priced batteries come with stickers??

[CraigP]

Hey Dan buddy, just FYI, but Fluid is THE MAN when it comes to RC boats, literally writing the book on the subject matter. He has been in it since the 60’s, and has raced anything that floats. I just want you to know who you are addressing... As to his assertion that your boat could only draw 17A if it was to run for 25 minutes on an 8000mah capacity battery, he is absolutely correct! 8000mah is the same as 8AH, one is in milliamperes (only God knows why they continue using milliamperes) and the other is amps. It’s a simple linear extrapolation. The math is:

First, you can’t use 100% of the battery. Need to leave at lease 25% capacity, or the battery will go bad very quickly. So, 8X0.75= 6AH of capacity available. Next, find the time ratio between the battery spec and the stated runtime:
60/25= 2.4, which means you can use the battery at 2.4 the specified rate before its used up. So, 6X2.4= 14.4A

So it does seem to be a spot of magic to run a boat that big for that long on that few of amps. You mentioned 71A, so doing the math from that direction is: 6/71=0.0845, this is the time ratio. Multiply the specified time by the ratio to yield the expected runtime: 0.0845*60=5.07 minutes. If you had two 8ah batts in parallel, you could double that to 10 minutes. But most of us will be stuck on the stated 71A for 56mph on a Cat seems highly efficient.

[kfxguy]

yep and it got Max amps written all over it

Max amps. Lol.

Unfortunately when you posted that you lost quite a few credibility points around here. Hate to break the news to you but max Amps is probably the worst battery you can buy. And hugely overpriced.


We seem to get a unfortunate sucker for those batteries from time time. They do have good marketing and cool stickers tho.

[danzuby]

Point taken. I agree they are way over priced but the 2 sets I have seem to work far better then anything else I used including the 8400mah traxxas batteries and they don't get very hot like the other batteries I've used. I've also been playing around with Vant batteries they are about half the cost and have the same dual core cell configuration 3s2p the 7600mah packs will do 570amp continuous. What are you batteries of choice if you don't mind me asking?

[Hotrods]

Point taken. I agree they are way over priced but the 2 sets I have seem to work far better then anything else I used including the 8400mah traxxas batteries and they don't get very hot like the other batteries I've used. I've also been playing around with Vant batteries they are about half the cost and have the same dual core cell configuration 3s2p the 7600mah packs will do 570amp continuous. What are you batteries of choice if you don't mind me asking?

Revolectrix are hard to beat

[danzuby]

The M41 I'm gonna class as a 36" cat they claim it as 39" but I measure from the transom to the end of the bow and it reads 36". The stock motor is 84mm long and not much room for anything longer unless I want to do some trimming which I can do. I have seen the 4060 as and upgrade from RCBB and I'm kinda leaning in the direction and I seen a lot of squabbling back and forth here between low kv big prop vs high kv small prop. With the 3684 1800kv that I'm running now with the X642 is ok but I can't prop up, so I'm stuck at 56mph. I don't need to be in the SAW class but I'd like a bit more. If I do the 4060 I think I'm gonna continue to play the high kv small prop game the 1750kv on 6s with X645 gives me 62mph load rpm 32,000 at 83% efficiency the 1950kv on the X645 nets me 69mph load rpm 36,000 at 80% efficiency. If I choose to do the 1220kv on 6s I would have to use an X665 just to hit 62mph according to RC Boat Calculator.

[R2315]

Revolectrix are hard to beat

+1 on Revo's, I might try Giant Power this season

[danzuby]

Ok Craig all respect will be given hear I am not out to disrespect anyone I am hear to learn because I'm not rolling in cash and cant afford to waste a bunch of money making mistakes on the trial and error method if ya know what I mean. Aside from this forum the only thing I have to rely on is the RC boat calculator. Some here swear by big can low kv big prop others are smaller can high kv smaller prop. the one person says 4070 1220 kv the calculator says I would have to run X665 on 6s to hit 60mph. Thank you all for your time and Fluid I hope I didn't offend you. I do realize that the wealth of knowledge and experience with some of you is priceless and commands to utmost respect.

[Mxkid261]

Revo, dinogy, giant power, roaring top

[danzuby]

Nice packs good price but wont work for me I have to run 2-3s packs in series and Revo doesn't seem to have 3s packs that I saw, but Thanks