mblombardi3605

Boat frame is built, ready for decking. I was going to use my trusty Pico 67, but I just granaded it in my outrigger. Want to know if there is a tried and true electric combo that could reach the speeds of my last Circus Circus? (71mph, North East Nationals, 1994)

eboat

Do you know that electric speed cost alot more than nitro speed and will run alot shorter of time per outing ?

andybenton

we can make her go as fast as your pockets are deep. XD

that being said. (with no budget in mind)

i would get a nue brand motor, just because they are proven preformers, most of the really fast boats youll see, are powered by nue.

heres a link to a page where a bunch of there motors are listed, not sure which one youll need for your application. but someone else surely will. and im betting they will chime in.
http://www.offshoreelectrics.com/pro...ushless+Motors

castle creations also makes really nice motors,
http://www.offshoreelectrics.com/pro...eations+Motors

as far as the esc goes

http://www.offshoreelectrics.com/pro...er-seaking-180

^^^ this one will do you well.

happy boating, and i hope someone comes along that can help more than i did, and give you more/better advice on the motor, and batteries.

coriolan

Would be cheaper to buy another .67 rather than go to the electric "dark side" once you consider the price of what you'll need to buy for a short run and long charging time. An electric setup to run an 1/8 scale hydro build for IC would cost you twice the price of a race ready CMB,PICCO,OPS or ROSSI. A K&B .67 from Meccoa would even be cheaper:
https://shop.mecoa.com/shopdisplayproducts.asp?id=26
Beside the cost, fitting the size of batteries you would need in a wooden Dumas kit at a proper CG position would be impossible between the rails. Since you already run glow IC and have the starting equipment and skill going electric would be painfull financialy and being used to a Picco .67 performances in an outrigger most likely disapointing!

srt10

My Feedback: (20)

hey bro, what is the length of your hull?
the price of electric has come down a lot!
you can build FE (Fast Electrics) without breaking the bank
this motor on 10s would haul!
http://www.offshoreelectrics.com/pro...o-5692&cat=148

Hydro Junkie

Good luck getting a K&B .67. Hell, I can't even get a flywheel for a front exhaust K&B .45 from MECOA. I don't know if you noticed or not but the MECOA website says that the .67 is "in process", meaning that the parts are supposed to be being made and will be available in 2-12 weeks. I waited 6 months for a flywheel that never was produced Here is what someone is putting into a 2011 Valken scale boat, a NEU 1527 1.5Y on Hyperion 10S1P 5000mah

srt10

My Feedback: (20)

what size is that hull?
that's a good amount of power

Hydro Junkie

The Valken is the former Bud T-5 and in this case, it's a 1/8th scale boat. According to the MHR on the R/C Unlimiteds web page, the hull is 43.25 long and 21.75 wide not counting the allowable variances

vasek

My Feedback: (4)

I thought this size hydro would need 10s2p... how long would it run on 1p?

srt10

My Feedback: (20)

On 1p it may only run 2min... 2p is much needed for that much power..

Hydro Junkie

If the boat is build lite enough and properly set up and balanced, it will be able to run a full 5 lap heat and mill time in much less than 2 minutes and still have some juice left over

srt10

My Feedback: (20)

Yeah, you would want to run 2p..

mblombardi3605

srt10

My Feedback: (20)

If you want to run 10s I would go with the 730kv version...
to many rpms with the wrong prop will smoke your esc and motor.. but great motor choice
and you will need to run 10s2p for decent runtimes.. and also I would run a min of 30c on the packs when running parallel
those motors can pull over 100amps cont.

mblombardi3605

Am I incorrect when thinking 2 of these packs are equal to a 10s2p?

mblombardi3605

Also what mah is suggested?

srt10

My Feedback: (20)

two of them wired in series gets you 10s1p
the packs you posted are 5s
so you would need 4 total..
two packs wired in series, then those two sets wired in parallel
the total Mah with those packs would be 11,000mah

mblombardi3605

Ok, I need four packs to get this done. Now, what Mah (2500-7300)? This seems to have a large bearing on price. Explain therelationship behind Mah and power. Also the relationship in C sizing of the cells would help here.

Hydro Junkie

I'm no expert on batteries but I think I can help you out a little.
MAH=MilliAmp Hours. You can think of this as how big your gas tank is. The higher the number, the more electrons the battery can store as well as supply for use as needed. Using your listed sizes, the 2500 can supply(in theory ayway) 2.5 amps continuously for an hour while your 7300 can supply 7.3 amps for an hour. So how does this relaite to your boat? Your boat will use a much higher amount of current(amperage) than the 2.5 and 7.3 amps and will need it much quicker. For sake of arguement, lets say your boat needs to be able to run for up to 10 minutes and at full throttle. By multiplying the amount of amps by 6 (there are 6 10 minute segments in an hour) you will know how many amps you can run without running out of power. This means that with the 2500, you will have a maximum current draw of 15 amps available while with the 7300, you will have a maximum draw of 43.8 amps, allowing the battery pack to hold up for the whole 10 minutes. If you end up pulling more current from the batteries, they won't last the whole 10 minutes before going dead.

The term "power" is sort of subjective. I've been taught in several electrical classes that power=wattage and wattage=amperage multiplied by voltage. Above, I refered to MAh as how big your fuel tank is. You can think of amperage as gallons per hour of fuel while voltage is like the fuel pressure from the fuel pump. Going back to SRT10's last post, he said that you need to use four packs to get 11,000 MAh wired so that the packs are two sets of two packs in series, with the two pairs hooked up in a "Y" arrangement. This would be the same as having four fuel tanks and pumps. The series sets will double the voltage or pump pressure without increasing current flow while wiring in parallel will roughly double current flow without increasing voltage. In the arrangement given, each series leg will give you 5500MAh at whatever the voltage is, that being roughly twice the voltage supplied by one pack
I hope all of this makes sense

andybenton

the c rating of a battery back relates to the amperage the battery can supply.

srt10

My Feedback: (20)

Mah = is like your gas tank, or runtime
10,000mah is usually the limit in racing
so 4 5s 5,000mah packs wired together would work good, or 2 5,000mah 10s packs wired in series
C rating is the power (amps) a pack has times the mah
so take the packs you linked to 5500mah x 25c = 137.5amps cont. (4 packs wired in series and parallel would = 275amps cont.)
or 5000mah 40c packs would have 200amps cont. (4 packs wired in series and parallel would = 400amps cont.)
its better to have more amps than the motor needs, to little and the packs could puff
but the ones you linked to with only 25C might work just fine
these motors can pull 125-150amps cont. [:-]

Von Ohain

A few errors corrected:

*Neu (not nue. a brand of motors)

MAH = Mega*Ampere*Hour (One million amperes for one hour)
mAH = Milli*Ampere*Hour (One thousandth of an ampere for one hour)

Power = Work * Time = Force * Velocity (The definition of power, and its not subjective. It's an absolute definition)

Kv (K index v) is a constant, and is defined as V^-1. It's a measure of a motors angular velocity (measured in RPM) per volt the motor supplied before switching. It applies to all DC motors, although usually only specified on BLDC within our hobby.


mAH is a measure of the amount of work a battery can perform on a full charge, before going empty. It equates to the more scientific correct unit Joule by a factor of 3.6.
C rating is a specification of how much power the battery can perform, relative to its work storage capacity (C = power capacity/work capacity).

srt10

My Feedback: (20)

So back to the hobby... and this thread that most understand...

Von Ohain

That was the version hobbyist should understand, given they want to build their setups themselves and not do RTR.
And I believe most of you do understand the majority of it already, although possibly using incorrect terms and definitions to describe it.
If you REALLY want to see the scientists explanation (you don't), you will have to operate only in SI units, and derive all units down to the 7 basic units.
Which means, you will measure voltage in current, weight, distance and time....

srt10

My Feedback: (20)

I'm just going to sit back and laugh my a&& off! [:-]

KV = RPM per volt
Mah = basically gas tank or runtime
C rating = the punch the pack has x the gas tank (Mah) of the pack

most want to understand FE as easily as they can
and to tell someone they don't want to see scientist explanation for toys, says only one thing... smart ***** PRIDE
and your right, no one wants to see that crap on these forums!
you never know who is sitting back reading these forums and just what they have under their belts for knowledge
some never even had a high school deploma buy yet they set FE records every year and help others do the same
we all learn by helping eachother, not by puffing our chests out and pretending to be bad ***** because of a degree ..