sundogz

I found [link=http://www.ebay.com/itm/LEOPARD-2040-13T-KV4450-2-Poles-Brushless-Motor-IM012-/130644403327?pt=Radio_Control_Parts_Accessories&hash=item1e6b03647f]this motor[/link] on Ebay and it looks to be a more appropriate motor for use with a 2S lipo. It is 4450kv and should balance the top end speed, eliminating that dead space in the top 25% of throttle movement. Be sure to use it with a water jacket such as [link=http://www.ebay.com/itm/Water-Cooling-Jacket-for-20mm-RC-Boat-Plane-Motors-New-/260832115659?pt=Radio_Control_Parts_Accessories&hash=item3cbace3bcb]this one.[/link].

cmsrp

I put a small bag of silica gel (as included in the packaging with electrical items) in the balloon also. This stops any condensation that could appear.
I've been doing this for years without a single problem...

mike50001

half way through my second conversion, an drilling the coupling for the new motor ive messed it up.

anyone know anywhere to get a coupling for a 4mm shaft motor? all the ones ive seen so far are to big to fit into the drive.

spektrumFlux

may I know does the Leopard Motor fit into stock motor mounting without the need for modification?

Thanks

sundogz

Yes, it should fit just like it is.

spektrumFlux

great thanks. :-)
then I will order this Loepard + water jacket combo for better run performance instead of the 2040L 4800kv motor.

spektrumFlux

seehuusen

No, the Lipo c rating is an indication on how fast that battery can discharge, I.e. how much juice you can feed the motor, more is better

spektrumFlux

thanks for clearing my doubts as I thought using a 2S 40~80C, 50~100C, etc Lipo battery might be too much for the 60A + 4450kv combo to handle. :-)

Ratrunner

another thing to consider with C ratings...

the C rating is referenced from the capacity of the battery.

so a 2000mah 20C battery can handle 40000mah load (or 40A constant)
while a 2500mah 20C battery will handle 50000mah load (or 50A constant)

so the same C rating will vary depending on the capacity of the battery.

some manufacturers are better at claiming genuine C rating than others.

the higher C rating simply means that for a given load, the battery voltage will not
sag under that load. 

Jason.

sundogz

I don't think so. I've always had the understanding that the C rating had nothing to do with the capacity of the battery (if I'm wrong, please post a link to your information source). I believe Seehuusen explained it better: "The Lipo c rating is an indication on how fast that battery can discharge, I.e. how much juice you can feed the motor, more is better". But you had the rest of it almost right - "for a given load, (with a higher C rating) the battery voltage will (have less of a tendency to) sag under that load. So for Spectrumflux the same advice holds - buy the highest C rating that you can afford!

Ratrunner

http://www.commonsenserc.com/page.ph...explained.html

here's a link that explains it.

the c rating is dependant on the capacity of the pack.
that's what the "C" stands for Capacity.

so for example, when a battery says it can be charged at 1C it means that you can charge at the rate of the capacity of the pack.
ie, 1C on a 5000 mah pack, means a charge rate of 5 amps. 1C on an 8000 mah pack means an 8 amp charge rate.

the same logic applies to discharge rates.

Jason.

sundogz

Thanks for that link Ratrunner - live and learn! It is still hard to believe that you could charge an 80C 5000mah lipo at 400amps!

Wheelnut

My Feedback: (81)

Hey guys, could someone post a link of the water fitting that you are using on the jet rudder? Isn't it called a statter or something?
I was looking at this, but I think it needs to be plastic.
http://www.offshoreelectrics.com/pro...od=ros-SPD-102

JohnA24

Hey Guys, I happended to be surfing around when I bumped into this Ratrunner's post. I couldn't let this one go by without giving a warning.

NEVER charge Lipos at an amp rate greater than that recommended by the battery manufacturer!!. That's how fires are started.

"C" rating refers to the maximum discharge rate only, not the charge rate.

There is some confusion here about MAh and C ratings and what they are. Here's how it was explained to me once:

If you think of a battery as a fuel tank, the MAh rating is the capacity of electricity, or "fuel" it can hold. MAh stands for Milliamp hours, or how much power a battery can discharge over time. For example in an hour, a fully charged 2500 MAh battery will give up 2500 milliamps (or 2.5 amps), its entire charge. The same battery can discharge 5000 milliamps (5.0 amps) in 1/2 hour. (By the way, you should never discharge a Lipo more that 70%-80% of its capacity or you'll ruin the battery in no time.)

The C rating refers to how much of a battery's total capacity it can discharge at any one time. A 1C rated Lipo can only supply a maximum of 2500 milliamps (2.5A) while a battery rated at 10C can give up 25 amps. A 30C battery could give up a whopping 75 amps. Remember though, you've only got 2500 MAh in the battery. At 30C the entire battery's charge would be gone in 2 minutes. Since you should never completely discharge a Lipo, a motor drawing a full 75 amps should only be run for about a minute.

This is why you need to consider a motor's amp rathing when you match it with a battery. If your motor has a 25 amp rating, then your battery better be able to supply that much current - or your battery will be destroyed - I've puffed Lipos in the past trying to get more speed out of FE boats.

Wheelnut

My Feedback: (81)

Thanks Jonh, very true. Also there are some batteries that are coming out with larger C ratings now. I believe they are up to 4C charge rate on some batts.

seehuusen

thanks for taking the time to explain that John, you're bang on mate

Wheelnut

My Feedback: (81)

Anyone? Please

Ratrunner

that's spot on also.

some of us have chargers that can handle up to 20A charge rates, so we can charge at those higher levels.

as has been stated here, always follow the manufacturers recommended MAX C for charge rates.
you can always charge slower, but NEVER higher.

Jason.

spektrumFlux

thanks folks for all the guidance. :-)

seehuusen

I used a piece of copper pipe, then drilled a hole in the stator housing, put it through, glued it in, added the hose to it and hey presto WATER COOLING
There are definitely photos of this in this thread

I use an 11.5kg servo, fits perfectly in there, but it's lying down

sundogz

Jason, how can that be 'spot on' also. Isn't that what I had said earlier, but you disagreed with? You said it had to do with capacity while Seehuusen agreed it is only about discharge? LOL, I better edit my earlier post - I wouldn't want anyone to get the wrong impression. Thanks anyways. []

exaturbo

it's about BOTH maximum charge and discharge rates as well as related to the capacity of the pack.

the maximum C rate for a pack will be written on it for both discharge and charge.
these will be 2 DIFFERENT multiples of the CAPACITY of the pack.


an example of one of my 3S nanotech packs is as follows.

it's a 3S 11.1V 4400 mah pack.
it's rated at 40C constant, and 70C burst for DISCHARGE. that's 4400 x 40 or 176A constant discharge rate

it's rated at 8C maximum for CHARGE rate. that's a maximum of 4400 x 8 or 35.2A maximum charge rate

hope this clears things up a little ?

jason.

pouleman

Hi all just finally finished reading the whole 115 pages and have an idea of what i am getting and would like to see what others think. I really want a 3S set up and would like it to be bigger than 2040 and mount right up i am open to getting a different coupler as i understand this place has some that will work correct? Anyways i am open to any ideas let me know what you think

motor
ESC
battery

Also will that motor mount to the pump that is my only concern with it.

Thanks, Joe

seehuusen

the motor you chose is the only thing I could think of, not being big enough (the length ads more torque from my understanding)