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Author Topic: ELECTRIC vs. IC  (Read 7630 times)

LOCURA

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ELECTRIC vs. IC
« on: October 16, 2009, 08:58:23 PM »

Hi
I am newto RC boating and need some advice before further investment. I have already purchased a 120 watt ESC but am being told that a large racing hull needs a Zenoah. I understand the world water speed record is held by electric, so why does a large Lipo brushless setup not compete in something like a Prestwich Sigma???

Any advice would help guide me,  thanks

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andygh

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Re: ELECTRIC V IC
« Reply #1 on: October 16, 2009, 10:22:37 PM »

120 watt at what voltage?

IC is fast alright but many waters won't allow them
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nick_75au

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Re: ELECTRIC V IC
« Reply #2 on: October 17, 2009, 09:37:00 AM »

120 watt esc is only 10 amps at 12 volts good for a 18"- 24" at the very most, a 120 amp esc at 24 volts would be barely closer to the mark for a Zenoah which can output the equivalent of over 3000 watts even in stock form.
The limiting factor with electric, particularly fast electric is running time, 120 amps will suck a 5000 mAH battery in a matter of 2-3 minutes at full throttle.
Big FE can be done, just $$$$$ required :}

The world speed record is held by a rigger style boat designed for 2 passes only before either batteries flat or components are fried, think top fuel dragster ;)

Nick
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The Doc

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Re: ELECTRIC V IC
« Reply #3 on: October 17, 2009, 02:30:17 PM »

Hi Richard

Are you coming to the lake tomorrow found the book for the charger you wanted that ESC you have is rated at 80amp at 22.2 volts or have you bought a 120amp one? also got a power supply if you still need one.

Alan
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LOCURA

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Re: ELECTRIC V IC
« Reply #4 on: October 17, 2009, 05:16:55 PM »

Thanks for the replies,
Yes Alan, see you tomorrow, but could be months before I understand the "Black Art" of electrics.

Oops again, I should learn more before I spend! Good info coming in, my bad judgement on what is required.


The ESC is the Castle Creations 120 amp Hydra Water Cooled ESC. The ad says "Up to 120 or 240A continuous current. 6S lipo".
Max Volts: 25V. Not sure if I can use top end of this info i.e. 240 amps at 25 volts.


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nick_75au

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Re: ELECTRIC V IC
« Reply #5 on: October 18, 2009, 12:02:45 AM »

That is a nice ESC,  :-)) their MAX voltage is a "do not exceed" rating, I once asked them about running 24 volt gels (28v fully charged) no will damage. They do a 240 amp ESC in the same series hence the ad's different specifications.

Now you wont be able to get Zenoah speeds but a respectable speed maybe 30 + Kph can be achieved on the sigma hull, go for a smaller hull and 100 kph is achievable.

Data logger an almost essential piece of kit to keep an eye on things
Nick
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Bill D203

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Re: ELECTRIC V IC
« Reply #6 on: October 18, 2009, 01:16:11 AM »

With a tuned Zen and a 1 liter fuel tank the boat will run for 25/40 Min's, Try running that long and fast with a elecy boat.  Even Lipo cells which are real cool bits of kit it will run out so quick you will be disappointed very soon after you set of.
The other thing is a small amount of weed will stop a elecy boat, but a Zen will just chop it up and spit it out the back.
OK so I'm bias for the petrol boats, but I have played around with some electric boats myself and I know what given the choice i would pick every time.
Anyway what ever you go for JUST ENJOY IT cause thats what it's all about. Good Luck.
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nick_75au

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Re: ELECTRIC V IC
« Reply #7 on: October 18, 2009, 06:08:31 AM »

Its a toss up, fuel has limited places to run and leccy has limited running time. If you live close(or willing to travel) to a IC allowed lake or the ocean go for IC. Dont know bout the weed Ive got a leccy setup that ripped the blades off a brass prop with out even hesitating, HP is HP no matter the source. :D
Nick
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tigertiger

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Re: ELECTRIC vs. IC
« Reply #8 on: October 18, 2009, 08:00:25 AM »

***topic title modified***
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steamboatbob

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Re: ELECTRIC vs. IC
« Reply #9 on: October 25, 2009, 01:40:02 PM »

This reminds me to post more on my slomo

I used to run a 5070 kv motor on 14.8 before i did one run and fried the ESC (100Amp)

reason why it was drawing 90 Amps before it got to the water

three thing you need to ponder and balance out in an electric motor Motor, esc, and the Battery in a fast electric
this is the basis of my slomoshun build
I will use Brushless as an example to simplify things
firstly figure out what voltage you want to run on and the budget you are willing to pay

Motor
Most motors have a chart available either on line or when you get them as to the current draw 90% of the time this is no load current I ended up getting a 2887 KV motor as it draws only 55 Amps under no load and chain that to a 14.8 V Battery and you have 42727.6 RPM (KVof motor times Battery Voltage).
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steamboatbob

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Re: ELECTRIC vs. IC
« Reply #10 on: October 25, 2009, 01:50:03 PM »

Esc

Castle Creations do a wonderful Esc But they are expensive
ETTI do a very comparable ESC 150 opto which handles 6-30V 150AConstant currant and 300 Burst Current fully watercooled and water proof and I have not read about many that have gone bust for no reason.

Battery

I use a LIPO in my Slo-Mo only due to the high currant draw basically a Flightmax 30C 5000mah  battery at 14.8 Volts now all this jargon means this 30*5 = 150 so my battery can handle a constant 150Amp current draw ("C" rating of battery* Ah rating of battery) as most batteries are measured in mah just divide the mah rating by 1000 to give you the Ah rating and times by the C rating or current rating of the battery.

all of this adds up in my Slo-Mo-Shun to a heck of a lot of speed a new video is coming soon so watch for it

and to top it all off you need to get a propeller to match your boat type and drive line
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LOCURA

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Re: ELECTRIC vs. IC
« Reply #11 on: October 25, 2009, 09:05:19 PM »

I have watched my friend The Doc slowly achieve a fast petrol boat and after reading nick 75aus info I have sold both my electrics and bought a Prestwich Sigma 51 with the race Zenoah. I now feel I can tackle most types of inland water with decent running time.

Perhaps it is a cop-out but electrics seem to be tooooo technical

Thanks for all the help.
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andyn

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Re: ELECTRIC vs. IC
« Reply #12 on: October 25, 2009, 09:11:01 PM »

If it were a choice between owning electric boats or IC only, the electrics wouldn't get a second glance from me. Enjoy your lovely smelly, dirty, oily, noisy Sigma :-)) :-)) :-))
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nick_75au

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Re: ELECTRIC vs. IC
« Reply #13 on: October 26, 2009, 11:30:08 AM »

Just for prosperity's sake here is the info I fudged together on an electric setup fo LOCURA over a couple of e-mails (Hope you don't mind)


I've got a 60 inch hull that I'm running electric in, It has 4 700s in it, the fastest its been so far is 16 KPH (working on that just changed from Lead to Li-po batteries) so I think the motor you have is too small,   (just ran it on the weekend except for an Receiver failure I know it was over 25 Kph now)

BL3 Brushless Watercooled Motor  3650. 3300 rpm per volt.( High rpm) For 8.4 to 12 volts. 3S to  4S lipo or 7 to 16 Nicad or NIMH packs. Mounting hole spacing of 19mm or 25mm. Diameter 43mm, length 63mm., shaft diameter 4mm. Replacement for 700 size motors but MUCH more powerful. I have been assured this will take 18.5 volts!! I also have 2 packs of 18.5 volt 4000ma lipos and the ESC mentioned. I wonder if I have any of the recipe?

Now I'm by know means an expert but I think I can get you in the ball park.
If you can, get  6s lipo, the maximum the  ESC can handle  4s means higher amp draw and a higher KV motor. A Zenoah spins around 15-17'000 rpm but 30 Kph can be had by a stock brush cutter motor that barely makes 10'000 Rpm, so a motor with a Kv that matches up to that figure at intended voltage should give similar performance. 10'000/ 18.5 gives a KV of 540, bump to 600-650Kv to give a loaded rpm. At 22.5 volt (6s)  440Kv, a kv of 500 including fudge factor will do the job. A large 55-50 or similar size outrunner (cheap from HobbyKing.com) with the above Kv ratings  will work using 55+  mm props. You could go with a Neu inrunner (very expensive) with similar Kv as well.

I would expect an amp draw of around 40-50 amps with a 500 Kv motor and 6s Lipo, a bit more with the lower voltage

Regards Nick
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andyn

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Re: ELECTRIC vs. IC
« Reply #14 on: October 26, 2009, 11:48:06 AM »

To get anywhere near the speed of an IC boat with an electric, you need to spend twice as much money...

That motor would be absolutely nowhere near big enough for a Sigma, its only an inch round...

This is what the Sigma does:
http://www.youtube.com/watch?v=9_JdHMxfgpQ
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HS93 (RIP)

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Re: ELECTRIC vs. IC
« Reply #15 on: October 26, 2009, 11:53:35 AM »

 Andyn

try     Diameter 43mm, length 63mm., shaft diameter 4mm  if you read the post screw spacing is 25mm.


http://www.youtube.com/watch?v=IMoLFdmECHw

and they start when you want them to Oh and what holds the model boat speed record er electric

Peter
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Bill D203

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Re: ELECTRIC vs. IC
« Reply #16 on: October 26, 2009, 04:33:52 PM »

Now then before WW3 breaks out. If you like electrics then so be it. If you like Nitro good, If like me I run Petrol boats which suites me. 1 cheap to run. 1 gal of petrol will last me for weeks. 2 they are easy to start. Bit of choke, pull on the starter cord and your away. I have not yet meet a electric boat that can stay up with me for run time yet, However over a short time i have seen one which can keep up with me speed wise.  While he was changing /charging battery's i had packed up for the morning. Yes battery's have come on a very long way but so has the 26cc water petrol engine. Oh yes before anyone says about the Ex noise mine is under the limit set by OMRA & our local council.  I have heard some very noise elcy boats when they are going flat out.
As I said before what ever you go for ENJOY IT !!
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LOCURA

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Re: ELECTRIC vs. IC
« Reply #17 on: October 26, 2009, 04:36:43 PM »

I am still at the basic learning stage and do not want to get into HOT water {-), but the thing that finally changed my mind is length of running time. the 84 mph run was over something like 16 seconds (?), I am sure the Sigma with a Zenoah would continue for 15 mins on a tank full (please advise).
Drag racing or Le Mans 24 hours springs to mind, its horses for courses.

I like the idea of OMRA, are there many electric boats that go offshore racing, there seems to be quite a few Zenoah engined boats?

Thanks for feedback, I learn with every reply

Any phone numbers for the girls in your boat Bill D203?  <*<
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Bill D203

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Re: ELECTRIC vs. IC
« Reply #18 on: October 26, 2009, 04:45:26 PM »

I am still at the basic learning stage and do not want to get into HOT water {-), but the thing that finally changed my mind is length of running time. the 84 mph run was over something like 16 seconds (?), I am sure the Sigma with a Zenoah would continue for 15 mins on a tank full (please advise).
Drag racing or Le Mans 24 hours springs to mind, its horses for courses.

I like the idea of OMRA, are there many electric boats that go offshore racing, there seems to be quite a few Zenoah engined boats?

Thanks for feedback, I learn with every reply
I stand to be corrected but OMRA dose not have an elcy class boat. They start with the Z class with is the 12 size nitro and all the way up to 50cc petrol.
The Zen dose offer good value for money. Loads of spare parts can be got at affordable prices, which is maybe why they are popular in OMRA. As I said also fairly cheap to run. Tesco unleaded and a short of 2 stoke oil.
As for running time 40 mins per liter if you don't go to mad. Most boats have 1 to 2 liters tanks.  Nitro fuel is over 20.00 per gal for the normal stuff and alot more as the nitro % gose up.
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LOCURA

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Re: ELECTRIC vs. IC
« Reply #19 on: October 26, 2009, 04:52:49 PM »

Thanks for reply Bill

Does anyone use Castrol R or its equivalent, or just 2 stroke oil on a race tuned Zenoah.
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Bill D203

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Re: ELECTRIC vs. IC
« Reply #20 on: October 26, 2009, 05:11:17 PM »

Thanks for reply Bill

Does anyone use Castrol R or its equivalent, or just 2 stroke oil on a race tuned Zenoah.
I don't think i have seen anyone using Castrol R. Just plan old 2 stroke oil. Some recomend a Honda oil which I am going to try out very soon.
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omra85

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Re: ELECTRIC vs. IC
« Reply #21 on: October 26, 2009, 07:48:59 PM »

As Bill says - each have their merits and downfalls.
At the Torquay Chase boat event a few weeks ago (where you control your model from a full sized speedboat) one person did run an electric boat. He completed the 4 mile + course in just over 18 minutes! As there is no electric class in OMRA, he didn't qualify for championship points, but his time was a very respectable effort given that its run in open seas.
Its a bit like cars - if you want to deliver milk for 4 hours, don't use a Maclaren F1  {-) %%

Danny
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Bill D203

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Re: ELECTRIC vs. IC
« Reply #22 on: October 26, 2009, 08:14:25 PM »

I am still at the basic learning stage and do not want to get into HOT water {-), but the thing that finally changed my mind is length of running time. the 84 mph run was over something like 16 seconds (?), I am sure the Sigma with a Zenoah would continue for 15 mins on a tank full (please advise).
Drag racing or Le Mans 24 hours springs to mind, its horses for courses.

I like the idea of OMRA, are there many electric boats that go offshore racing, there seems to be quite a few Zenoah engined boats?

Thanks for feedback, I learn with every reply

Any phone numbers for the girls in your boat Bill D203?  <*<
Just spoted the last bit. The bloke in the middle is Tarqiun. Tracy (dark hair) Sharon (Blond).
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andyn

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Re: ELECTRIC vs. IC
« Reply #23 on: October 26, 2009, 10:48:01 PM »

Could have sworn I posted here earlier, where'd it go?
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nick_75au

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Re: ELECTRIC vs. IC
« Reply #24 on: October 27, 2009, 04:35:24 AM »

Sorry, should have mentioned aiming for 30 Kph or so (A nice sport setup) Utilising the ESC he had purchased, about the same as a basic Whipper Snipper motor I guess, Moot point as Locura is going to use I.C. which for a big boat like this makes sense.

http://hpr06.speedtoy.com/setup.htm, check some of the speeds  %% these guys are getting hows 181 Kph on 32 Nimh
 
http://www.swissmodelpowerboatteam.ch/index.html
are running 2.33 meter class 1 cats on electric at 120 KPH for 1/2 our races, the catch is I believe it takes a couple of days to charge the 1 million Lipos in them and I would hate to think of how much it cost.

Nick
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