Newbie with electric power questions on scratch built cat.

[cforcht]

Hi folks. new to the forum. little background. I am well versed in RC planes helis and even boats for the most part. however its all been fuel powered up to now. I am in the process of building a cat from the ground up and had the intentions of powering it with a twin inline gas engine. after trying to get everything to play nice together, I'm beginning to believe electric would be a better solution. which brings me to the questions of where do I begin? anyone with some motor/prop suggestions would be greatly appreciated. any other advice would also be appreciated. Yes I have done some googling and havent found anything that really fits what I am doing. mostly because this boat is 96" from bow to rudder. so its not exactly common to find any setups of this scale in electric. thanks in advance. Oh and I do want to stay with a twin drive.

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[fweasel]

I've got nothing for you, but Wow! Definitely in for more pictures as things progress.

[Fluid]

There are so many ways to go, we need more information:

- speed expectations
- runtime expectations
- budget

With the above info we can give you appropriate recommendations.



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[cforcht]

fair questions,
this is more of a weekend warrior project so it doesnt have to be the fastest thing on the water but I dont want it to be tug boat slow either. not going to be racing or anything. I have a full size car for that pursuit. this is just for fun. as for run time I really dont know what to expect here. cost is subjective. not looking to break the bank but then again Im not one for going as dirt cheap as possible either. I tend to run closer to the higher end of things.

while waiting to be confirmed as an OSE member I did some googling and I was looking at the leopard 56111 950kv motors on a 10S setup as possible candidates. but dont know if they are a quality motor or not. or even if they would be well suited or not. Like I said before electrics are not my gig. but I do see the benefits of their use in certain areas. this being one of them. as it would be much easier to get going as opposed to tuning a twin cylinder with twin carbs. not to mention the hassle of starting it and fueling etc etc. at this point in the build I am not committed to the fuel powered route. the only thing in the driveline that has been actually mounted is the rudders. so now is the time to ask the questions I am asking. if this works out I have a little bit smaller version of this cat (78") that I cut on the laser as a test for the new laser I bought that I may finish out in electric as well. any recommendations welcome. thanks for any help.

[Fluid]

Not many folks in NA have built boats this size, and there is no way to build a decent one successfully and cheap. One good-quality motor is the Castle 2028, with a Kv of 800. In a boat that size you could run either 8S (29 volts nominal) or 10S (37 volts). 8S allows larger props and power is close to a typical gas motor. 10S may be a bit faster but uses smaller less efficient props.

I would consider the TP motors as next-best, with the Leopards next. High-end motors would be Neu and Lehner.

You'll want at least 5000 mAh packs in parallel. Quality depends roughly on price.

High voltage speed controllers are a crap shoot right now. Some have good luck with Swordfish, and some like the Flyer. Minimum 250 amps continuous.

I'm sure others will chime in too.


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[cforcht]

Not many folks in NA have built boats this size, and there is no way to build a decent one successfully and cheap. One good-quality motor is the Castle 2028, with a Kv of 800. In a boat that size you could run either 8S (29 volts nominal) or 10S (37 volts). 8S allows larger props and power is close to a typical gas motor. 10S may be a bit faster but uses smaller less efficient props.

I would consider the TP motors as next-best, with the Leopards next. High-end motors would be Neu and Lehner.

You'll want at least 5000 mAh packs in parallel. Quality depends roughly on price.

High voltage speed controllers are a crap shoot right now. Some have good luck with Swordfish, and some like the Flyer. Minimum 250 amps continuous.

I'm sure others will chime in too.


.

yes I have noticed this size of boat is rare. thats why I felt it required signing up here and asking some questions from those of you who are more versed in the electric setups in boats. I have heard of castle and I know they've been around for some time. they were pretty popular in the heli community when I was heavily immersed in it some years ago. I noticed the 2028 has a ribbed case and didnt see any offering for a water cooled jacket available for it. not to fret though I can make those. same for the mounts, couplers etc. 8S batteries are easier to find than 10S or at least thats my finding on a quick search. any brand of batteries to avoid? thanks for the input.

[Espresso]

Unless you're going with a pair of 3080 Lehner motors & MGM ESC route, I think it would be better to stick with gas. 90"+ is a pretty big watercraft to move. Your's will be framed up with wood then FG/CF so it would probably weigh a bit more than a MHZ or HPR 92" vacuum formed hull. Runtime and heat would not be on your side for a heavy electric setup. A Lehner/MGM setup would run you ~$4K before lipos. A nice gas setup would probably come in at a much lower cost.

[cforcht]

Unless you're going with a pair of 3080 Lehner motors & MGM ESC route, I think it would be better to stick with gas. 90"+ is a pretty big watercraft to move. Your's will be framed up with wood then FG/CF so it would probably weigh a bit more than a MHZ or HPR 92" vacuum formed hull. Runtime and heat would not be on your side for a heavy electric setup. A Lehner/MGM setup would run you ~$4K before lipos. A nice gas setup would probably come in at a much lower cost.

I do realize this will be heavier than a laid up glass boat or even one vacuum formed. but as I mentioned it does not have to be the fastest thing on the water and I would like to go electric with it. if it doesnt work I can always revert to gas. as for the Lehner motor OMG those are far more than I am looking to spend especially since this is just something I am tinkering with. and I would place those at the top end of the spectrum which I mentioned I wasnt looking for. the castle or the leopard is more inline with what I was expecting. no it may not be stellar in the speed dept but its not going to break the bank either. if it turns out its dismal then I have a couple other hulls I can put the electrics into instead. but thanks for the input. heck if this doesnt work out I can always take the boat and make a mold from it and then lay one up in glass. something I hadnt considered before. might have to ponder more on that route.

[grsboats]

I would suggest you to take a look at HPR model boats(swiss made boats and top quality)...Hans Peter makes the HPR 233 that is near the size of your project. If Lerhner are too much for you I would stick to Tppower motors that are a very good option. Gill

[cforcht]

be it good or bad, right or wrong we are going electric. Just got done making the mounts for them. I went with the Leopard motors mostly because they came with the water jacket. we shall see how it goes.

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[Espresso]

Nice mounts. Your shop is able to craft some quality parts. Are you making your own hardware too?

[cforcht]

No I bought the hardware, I made the mounts so they fit where I need them to fit. some things I make, some I buy, just depends on the time I have available. I have a CNC machine shop at home and make my living doing that, so time on the machines is not always available for my own trinkets.

[fweasel]

Just out of curiosity, after the CAD drawings are done, how long did those mounts take to cut on the machine?

[cforcht]

actually not long at all. the side plates took about 5 minutes. could have been faster if I needed to make more, but wasnt in a real hurry. the motor rings were a little longer because of the extra operations for drilling tapping the sides and splitting the ring. but not a great deal. more setup time than actual run time. if you wanna see something that has loads of hours in it here ya go. 1/3 scale small block Chevy V8. not quite done yet though. yes it will run when its complete. and the blower is functional. not just for show.

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a link to the rest of the pics

http://s999.photobucket.com/user/cforcht/library/mini%20V8?sort=2&page=1

[fweasel]

Impressive. What's the application?