powering large boats with electric

[expresscraft]

ok you guys are going to lose me, what i posted has not been bought yet,this is just the info my customer has given me,so when i respond to his request, i need to tell him why his parts that he is asking for will not work, and what i would recommend.and of course why i would recommend it.please do not take for granted that i know anything....I really do not, out side of setting his boat up. i will be fine there, but im looking for very specific answers, i may have just been giving one and not know it.lol, a hobby wing seaking 180/360a is that a motor? mambaxl2 is from castle correct? but i thought there mamba stuff was for cars?what would work with the 10s batteries he is willing to go with?for me i just want to make our hull look and perform great, so bigger is better to a point.(I guess)I would like to recommend him the most bang for the buck, without buying something he will pay for every time he uses it.

[martin]

If it was my boat with those size motors on 10s i would be using something like 750 - 800kv keeping things under 30000rpm unloaded.

[nata2run]

Big leopards (5692 or 5698) and Swordfish 240HV ESC's are a good start. Even better if you can power it with 12s. So 730kv-900kv twin setup should be sweet. 55-65 props should be no problem. That in a 60" should get you 80+ mph.

[Fluid]

Tom, be careful here. You will get lots of advice, mostly from guys who have little to no experience with large FE boats (see above) - be wary of what they recommend, well-meant though it may be.

In answer to your customer's comments:
- Those Leopard motors have way too high of a Kv (rpm/volt). He will have a short run time and will burn up his equipment.
- The Swordfish ESCs are okay although every one of the lower amp versions I have actually seen has failed.
- One 10S (37 volts nominal) pack for each motor is the right choice.
- The 50mm props are too small for that large boat, efficiency will be poor. Figure on 55-60 mm as a mimimum, larger is usually better.

A 60" MTI will run well on two large motors with 10S batteries for each motor. Choose motors with a Kv (rpm/volt) between 700 and 800, this will let the motor spin a large enough prop (60-65mm) to adequately push that large hull. I'd recommend Castle 2028 motors as an excellent quality, reasonably priced choice. The Leopard motors are budget, I don't know how well or how long they will work. Neu 2215 motors are top-of-the-line as are Lehner 3060s but the latter are priced very high.

Speed controllers are less easy to define. The Swordfish controllers are budget, some like them some don't. I have seen better luck with the Castle ICE200HV v2 controllers. The top-of-the-line are Schulze 40-160s but those are currently priced through the roof.

All the power in an FE boat is in the packs. Cheap packs will fail and can burn - seen it too often in large boats. For the 10S setups required for that big hull, I'd recommend two 5S/5000 mAh packs (or one 4S/5000 mAh and one 6S/5000 mAH) in series for each motor. Those will deliver 10S (37 volts nominal) and enough run time to be fun. I'd recommend getting packs with a mid- to top-level pricing from a reliable source with a minimum of a 40C discharge rating.

Remember the holy grail of FE boats - build it so there is NO WATER IN THE HULL after a run. Follow that and you'll avoid a LOT of problems.

It will be fun to see your large cat run on FE power. The Gemans have been doing that for years with the HPR and other hulls, every one I've seen has been built like a watch with top quality components.


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[expresscraft]

ok, so is the leopard 5692 available in 730-900 kv?if so you are saying we should go with what he is asking for, only in a lower kv,and 12s instead of 10 s. correct?and instead of a x450 prop go 455-465. thanks again guys .

[nata2run]

Muld's setup with TP motors seem to be going ok 94" hull and SF ESC's. As with every new boat/setup you should prop conservatively. I powered my 54" mystic with 448 props and ran 82mph. Small props can still move bigger hulls.....just depends. I'm assuming every newbie in electrics is on some sort of budget before go all out? Lehner & Shulze are top $$ and require a bit of knowledge as well. You can burn it just as easy as everything else.

[expresscraft]

Hey Fluid, i posted at the same time you did,and before i saw your post,if you where building the boat what would you get?batteries type and brand, i have a dealer set up with great planes and horizon and can get castle products through them pretty easy.have not checked with O.S.E and will support him and his great site as much as i can.castle will work for me if they have the items to do a big boat, they have been very good in cars.not bad service either.

[nata2run]

ok, so is the leopard 5692 available in 730-900 kv?if so you are saying we should go with what he is asking for, only in a lower kv,and 12s instead of 10 s. correct?and instead of a x450 prop go 455-465. thanks again guys .

Low kv and higher cell count will usually pull less amps, that means keeping things cooler, and less risk of cooking everything. A friend is comfortably running a 65-70mm prop on a 54" hull with 730kv and 12s. Had it been a 1400 kv on 6s could be a heat problem.

[expresscraft]

I agree nata, but this boat will be beyond a proboat,RTR. I can't give him the ability to use it. but I do want to start off with the right stuff. Does not have to be the most expensive just good.I know I will get conflicting info on this thread.but the more info the better.And in the end, I will run bye what I can gather and it will be his choice.I have herd good and bad on the swordfish and castle esc's, for me I just know I have a dealer set up to get castle, I'm not sure on the swordfish. and I do have to keep the doors open so every bit helps,plus why not support the companies that support me.I would really love to get a few complete list of what you guys would use if it was your build.battery brand is a big deal, And i agree you will get what you pay for to a point, but then the price goes way up for just a little more.that's not what I'm after.please keep in mind, I have no problem with spending someone else's money for a great build.and once you go big,it's going to be pricey, that I can handle. what I can't do, is send him something that,s expensive anyways and does not work well.

[nata2run]

Well it's not just you get what you pay for! Some have the ability to get beyond norm out of budget setups. CC is cool, no problem in using that, that goes for both motors and ESC's. The Neu motors would definetly be a nice addition to almost any hull. In the end it really comes down to setup! Every bit is just as important as the other, no good to have Lehners and Shulze with the wrong prop? This is a sensitive subject to discuss, and as mentioned many times already, you will hear a lot.! This is where it gets interesting. At least now you know that you need a motor in the 569x or 202x size, low kv, and a good ESC to power them. Castle or SF should be fine.

[T.S.Davis]

You really don't need 12s. Negative nancy pants on again. What experience level has the person running this boat got?

There is a reason that both organized racing bodies limit us to 10s. This wont be a heat racing boat so "legal" doesn't matter but if the guy running it isn't super experienced it might not be a grand idea. 12s can kill you if you get it wrong. 10s can smart like hell but probably wont kill you.

I concour with what Jay (Fluid) posted. 10s twins will move that quite nicely. The closer you get to that 800kv mark the larger rotor you're going to want. Any of the Neu 22 series motors would work if the client was willing/able to spend a few more bucks on motors. Just pick one in the right KV range. Like maybe a 2215/2y.....ish.

Just another 2 cents.

[nata2run]

You really don't need 12s. Negative nancy pants on again. What experience level has the person running this boat got?

There is a reason that both organized racing bodies limit us to 10s. This wont be a heat racing boat so "legal" doesn't matter but if the guy running it isn't super experienced it might not be a grand idea. 12s can kill you if you get it wrong. 10s can smart like hell but probably wont kill you.

I concour with what Jay (Fluid) posted. 10s twins will move that quite nicely. The closer you get to that 800kv mark the larger rotor you're going to want. Any of the Neu 22 series motors would work if the client was willing/able to spend a few more bucks on motors. Just pick one in the right KV range. Like maybe a 2215/2y.....ish.

Just another 2 cents.

Not being a smart a$$ here..... But I don't know what I'd rather. Zap from 50v or props in the guts? Hmm. Boats are for people with respect for logic! They are not toys either way. Safety is no 1. But yes plenty power in 10s. I only plan to run on 8s and that should get me way past 100mph in my 54"

[expresscraft]

ok so lets stay with 10s as that's what he wanted to begin with,I do have a question, the 730kv will swing more prop less rpm? the 1090 is more rpm's less prop, less run time? And I do understand set up will also play a roll but in general my bigger boats will be looking for more prop and less kv.Am I correct on this thinking? also I probably don't want to send a boat that could be really dangerous short of running into someone, to a customer I do not even know. so would you say 10's is probably where my cap should be?And just let customers go from there.I am very glad to be getting this info, will help a lot in me having an idea of what im talking about, And of course that will equal more boaters in our hobby.That's great for all of us.

[T.S.Davis]

If it were me........I wouldn't sell them a complete turn key boat. Just for liability reasons. I'm clearly paranoid about the safety concerns though. I would maybe do everything but the batteries so you have some degree of separation between you and it actually running. Probably a silly way of thinking on my part. People are nuts though. A 60" 100mph boat should scare the poopoo out of even seasoned racers.

I wouldn't go over 10s and I've been doing this for......a while I guess.......seems like forever. I've seen some of the most experienced guys I know dead short 10s. World record holders. We're human. Why push it? Again, opinions will vary on this 10s,12s,14s,when are we getting stupid cell count thing. Safest route for the end user is 10s.

You're on the right track with your kv thinking. Less kv larger prop. More kv smaller prop. You "can" get the same run time with the higher kv motors but in order to do that you have to reduce prop size. At some point your turning a prop a p'scillion rpm and just boiling water with tons of slip and no thrust. Boat ends up slow to achieve equal run time because you can't get the bite you want. That's a rule of thumb. There are exceptions. I've seen it work. I do high kv with some boats just cuz I know how and on a tested setup. It's hard on drive lines for all the obvious reasons. We all like to have perfectly balanced props but if it's off it's really off at 40000 rpm.

Not to make your head explode but there is also the option to parallel packs. Meaning each motor gets TWO 10s pack in parallel. So 10s2p. Instead of having 10s5000mah you end up with 10s10000mah. It's more weight but basically it's like doubling the size of the gas tank. At 60" with twins the thing is already going to weight a ton. With 2P you could run longer and/or push up the amperage and go faster. It's more connectors and harnessing to manage inside the boat though. Not for the feint of heart.

It's rocket science. haha

[madmikepags]

Hey express send me one of the hulls and I'll build it up!!!!!!! big motors big batts big speedos!!!!!