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.


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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.

150809

[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?

[cforcht]

Impressive. What's the application?

no application. just always wanted to build a miniature V8 engine.

[fweasel]

no application. just always wanted to build a miniature V8 engine.
I would file that under the application: Because I could.

[cforcht]

its very much like a full size engine. in addition to the supercharger being functional. its electric start, cast iron sleeved cylinders, cast iron piston rings, roller cam and lifters, roller rocker arms, functioning water pump and distributor. ignition is handled by an electronic CDI ignition module. similar to what I use on the large scale gas powered air planes I fly.

[srislash]

its very much like a full size engine. in addition to the supercharger being functional. its electric start, cast iron sleeved cylinders, cast iron piston rings, roller cam and lifters, roller rocker arms, functioning water pump and distributor. ignition is handled by an electronic CDI ignition module. similar to what I use on the large scale gas powered air planes I fly.

Now that sir, is impressive. Being a small block chev lover this tweaks me in a good way. PLEASE post when running.

As far as your build, keep the wires as short as possible where possible, even #cell batteries have less wire then uneven counts(this is due to layout). So for 10s run a 4s and a 6s rather than 2 5s packs.
And Flier 16s 300amp ESC's seem to be holding up well. Hifie Swordfish and I believe Seaking are working on bigger better things in the very near future.

Shawn

[cforcht]

Now that sir, is impressive. Being a small block chev lover this tweaks me in a good way. PLEASE post when running.

As far as your build, keep the wires as short as possible where possible, even #cell batteries have less wire then uneven counts(this is due to layout). So for 10s run a 4s and a 6s rather than 2 5s packs.
And Flier 16s 300amp ESC's seem to be holding up well. Hifie Swordfish and I believe Seaking are working on bigger better things in the very near future.

Shawn

hmmm didnt know that about the packs. good to know. thanks.

[Beaux]

Very nice indeed.