daytona run time

[urbs00007]

first run with daytona 37" yielded 2-1/2 minutes run time ( cell brought down to 3.79 v, 2828 ma put back in. running 2- dinogy 3-s 5000ma 65c packs in series. leopard 4082 1600 kv. seaking 180 with supplied cap bank. ose cnc 44mm prop (1.73x2.45 in) prop is definately smaller blade than m445. first electric cat for me. ran perfectly flat and straight. torque rolls on startup. ran full throttle almost whole run on calm to slight ripples. everything under 90 degrees. is this a good run-time for this setup? speed estimated to be 55-60 mph. just would like more run-time. have a m445 . should i try that? or move cg back ? if i put on the m445 isnt that just going to load system more and reduce run-times further?

[NativePaul]

I don't know which CNC props OSE sells but all I have seen pull less load than the equivalent diameter Octura, so I would be very surprised if the M445 didn't give you shorter run times than you are getting now.

If you are pulling 2.828Ah from the battery in 2.5 minutes your average amp draw is 68A, which is very reasonable for 55-60mph, you can almost certainly improve it a touch with fine tuning, and ripples on the water all the time will improve it a shade too, but I doubt there is anything you can do to lower your amp draw dramatically without slowing you down also.

A smaller prop would reduce your amp draw but also slow you down, you could try cutting your current prop, which will lower amp draw a little and may not slow you down (or send it to one of the prop pros if you are not comfortable doing it).

You do have room to use more of your battery though, while the less you pull out of your battery the longer it will last, it is far more noticable an effect when it gets very near to empty and it starts heating itself up, most people see leaving 20% in your battery as a good compromise between battery longevity and run time, with your 5,000mAh battery using 4,000mAh would leave you the usual 20% left in your pack and should give you an extra minute, taking your runtime up to 3.5minutes.

You could run bigger capacity cells, an 8,000mAh battery should net you over 5 minutes runtime with your current setup while still leaving 20% in you pack.

[urbs00007]

I don't know which CNC props OSE sells but all I have seen pull less load than the equivalent diameter Octura, so I would be very surprised if the M445 didn't give you shorter run times than you are getting now.

If you are pulling 2.828Ah from the battery in 2.5 minutes your average amp draw is 68A, which is very reasonable for 55-60mph, you can almost certainly improve it a touch with fine tuning, and ripples on the water all the time will improve it a shade too, but I doubt there is anything you can do to lower your amp draw dramatically without slowing you down also.

A smaller prop would reduce your amp draw but also slow you down, you could try cutting your current prop, which will lower amp draw a little and may not slow you down (or send it to one of the prop pros if you are not comfortable doing it).

You do have room to use more of your battery though, while the less you pull out of your battery the longer it will last, it is far more noticable an effect when it gets very near to empty and it starts heating itself up, most people see leaving 20% in your battery as a good compromise between battery longevity and run time, with your 5,000mAh battery using 4,000mAh would leave you the usual 20% left in your pack and should give you an extra minute, taking your runtime up to 3.5minutes.

You could run bigger capacity cells, an 8,000mAh battery should net you over 5 minutes runtime with your current setup while still leaving 20% in you pack.

if I take the pack down to 1000 ma wouldn't that take cells too low ? how low can I take cells down to? maybe run 3 minutes and check things?

[NativePaul]

1000mAh is 20% of 5000mAh, most people think 20% is a good level but there is no right or wrong, if you want to leave more or less in your packs it is up to you, I leave a lot less in the packs of most of my race boats, but I wouldn't recommend following suit as I know it wrecks the packs very quickly, my sport boats I tend to only empty about half way as I am generally trying to eek life out of wrecked old race packs.

[Brushless55]

first run with daytona 37" yielded 2-1/2 minutes run time ( cell brought down to 3.79 v, 2828 ma put back in. running 2- dinogy 3-s 5000ma 65c packs in series. leopard 4082 1600 kv. seaking 180 with supplied cap bank. ose cnc 44mm prop (1.73x2.45 in) prop is definately smaller blade than m445. first electric cat for me. ran perfectly flat and straight. torque rolls on startup. ran full throttle almost whole run on calm to slight ripples. everything under 90 degrees. is this a good run-time for this setup? speed estimated to be 55-60 mph. just would like more run-time. have a m445 . should i try that? or move cg back ? if i put on the m445 isnt that just going to load system more and reduce run-times further?

What your doing sounds right bro
FE boats have short runtimes vs cars, trucks, and planes because they pull more constant amps than most any other rc

most of our races in D20 last less than 2min and my packs come back with 20-25% left