What size or how many mAh

[boatnik]

Thanks very much CraigP! Your input helps a lot! My goal is simply sport boating. I have no desire to get involved in competitive racing. I'm looking for the fastest speed, with a decent run time and reliability. In other words, I'd like to get as much speed as I can without burning up motors, ESC's and batteries. Would you elaborate a little more on your equations in the 3rd paragraph? The LiPo I've been using is rated at 3s (11.1v) 30c 2200mah. I've never used a 6s LiPo in this boat. In your 4th paragraph you say my motor is a 6s motor. How did you determine that? I am running a 440 prop on this boat. A few remarks on props would be a tremendous help. How to choose the right prop....What do the numbers mean....If your boat cavatates, how does one address the problem? Thanks again CraigP!

[CraigP]

What I was showing is the reliable, safe power available using 2 and 3s batteries. The motor spec states that 30A is max, so those equations shows the power (Watts) you can get reliably at those voltages, which are just fractions of the 800W the motor can potentially deliver. I'm also showing just how many amps you would have to run to get 800W, or max power. It's Watts that make the boat go... That motor is rated at 26V but only 30A, so it's not a good fit for lower voltages. What you want is a motor more like a 17V motor with a current rating of 47A.

This discussion assumes you need or desire the 800W to get some speed out of it, by pushing a bigger prop. I'm not sure on the availability of 3 or 2s motors, I just don't use low voltage setups...

You can hook up low voltage to that motor and put a big prop on it, but it will run very hot or burn up. I too do not race and want a fast, reliable boat. To accomplish that goal, I drop my working amps by using HV packs such as 6-8s. These electrical designs need to be taken from a starting point, then worked through. Many just put parts in boats and see what they get. Often they end up letting all the magic smoke out! Don't be one of those guys....

[NativePaul]

Boatnik, that is not a 6s motor, the max of 26v just means that is just the maximum the bearings are rated for. Please Ignore CraigP and dont run it on 6s. You have a decent mild 3s setup there, more powerfull and eficient than what it came with from the factory, I would guess you are along the right lines with a 40mm prop too. What brand and type of 40mm prop are you running? Surface drive props are prone to cavitating when running submerged, switching to a differnt prop the same size may help that. increasing diameter will help too, but that increases amp draw and heat too, so if you go bigger just run for 30 second then bring it in and check temps, if things are cool go a minute and check again, carry on, continuing to slowly add runtime to your testing untill you are getting a full run.

CraigP, advising a newbie to run 6s on a 28mm 2350KV motor is totaly irresponsible. That is someone asking for a reliable sport setup, and you are telling them to run 60,000rpm unloaded on 30A electrics! there isnt a prop that size available, and even if there was it would be a SAWs setup with a risk of smoke on every run, for a specialist lightweight boat not a plastic submerged drive RTR.

[CraigP]

Paul, you are out of line! I did not tell him to run it on 6s. He wants his boat to scoot, so he's going to need 800W to do that. As my equations clearly show, he cannot do that on that motor without seriously over amping it. I recommended a 17v, 50A motor as a better way to make the wattage he needs to hit his speed expectations. That motor has a 30A MAX rate. So your advice is to put 11.1v in it, prop it up and let him burn his electronics up. What a freaking idiot! So who is the unresponsible one now! I was telling him he needs another motor, and trying to give him the math as to why. I also told him it's not a good motor choice, the kv is not in line with the voltage rating. You almost have to overamp it to get 800W out of it. It's a weak motor choice for any boat!

Boat, make up your own mind. I showed you the equations. Use or ignore, it's your choice. There is a Leopard 2845 rated at 18v, 45A and 3300kv that would be a nice fit to 11.1v I'm done with this post.... Paul, say hello to the Queen for me...

[ray schrauwen]

This is not boatniks thread and things are beginning to unravel.

Boatnik needs his own thread.

Mods need to take care of this.

[ray schrauwen]

Its a ProBoat stock 1050 kV motor and a ABC 1817

I think the problem started with this typo of 1050kv when it was supposed to be 1500kv.

Craig jumped in because he is familiar with this kv in his setup.

[boatnik]

It seems obvious that I am a new member and a newcomer to rc boating. I'm trying my best to learn how to navigate this blog. Ray Schrauwen's suggestion that I should start my own thread is spot on. How do I do that? I haven't seen any instructions on how to start a new thread. Thank you everyone for your patience.

[CraigP]

Hit the "Forum" tab, then go to the rc boating folder. Under that, there should be "+Post New Thread" on the upper-right side of the screen. Put in a Title that is appropriate and makes sense to people seeing it. Then, type away!

[boatnik]

Thanks CraigP

[Buoyhunter]

Thanks for all the info. Do the MMEU guys have a different website or club related meetings? I know Rochester Hills is this weekend but is somebody typically out at the pond on weekends?

[T.S.Davis]

We try to keep everyone informed here but sometimes we get lazy. It's worse as the season starts to wind down.

Typically we are out every Wed evening about 5:00. Then every Saturday at 10:00am until about 2:00pm or so. This weekend is an exception. None of us will be there as we have two club members getting married. How cool is that!