Real Ampdraw discussions etc.

[puttekula]

Hi all.

Ok, since there are many speculations around how many cells that can be used for that many KV for that size of hull and with this size of prop and what
amp draw there is going to be. (And most often, how fast is the mix going to be as well...)

Is there anyone that have meassured such things, or done some calculations out of real world tests?

Inputs as "oh no u idiot, u are going to smoke that esc in seconds" , "the esc is going to melt thru the bottom of the hull or "hey stupid,
that battery is exploding" doesnt count.... Such comments are in my eyes no more worthy than those done by unexperienced people trying to
come to own conclusions based from common sense and thinking "outside the box" mixed with inputs from different readings.

I know that there are many experienced people out there, but someone got to have done some "real science" as well?

So, lets see what there is out there...

[AlanN]

One could always try the "search" function prior to posting.

[puttekula]

Ok, to make it a bit more clear. Is it possible to have all posted in one thread? Instead of searching the whole forum for a couple of hours/days?

[photohoward1]

Knowledge takes time. This has been posted to death. Many, Many guys have done real world logging and posted them here and on many of the forums.
Beside reading the forums for hours on end is how we all learn about what works and doesn't. It's like free School.

[puttekula]

Oh yes, I know knowledge takes time. And that this has been posted to death. But wouldnt it bee great to have one single clean thread with
all that info instead of having it spread over the whole "school period"? Like a book with all the answers..

[Chilli]

There are too many variables to come up with difinitive set of guidelines on what will work for every boat. I totally agree with what Howard said. When I first got into FE's I spent so many hours on this board (and others) that I would go to bed and just lay there while my head was spinning with all the info I picked up. It's taken me three years just to get a grasp on props. Many of the old timers that didnt have the luxury of data logging learned via school of hard knocks and I for one are thankfull that they take the time to share thier knowledge after taking the financial hits of learning what doesnt work.

If you don't have the time to surf this board for hours on end, than start a thread and while stating your specific goals ask for set up recommendations. What hull you want to run, what purpose (sport, top speed or racing), and how much you want to spend. You will get the answers you need. Some of the FE'ers on the board can be a little coarse, but thier intentions are good. They want new boaters to have a good first experience.

[jamespl]

Just buy an eagle tree or similar. That will give you all the real world data you need on your setup.

[puttekula]

Just a foreword about myself. Im a person, forever seeking in technical solutions combined with common sense, skills, thinking outside the box and last but dont least, experience. Im half German and maybe thats one explanation.
Plz be lenient with me as Im very willing to learn. Although it most often doesnt show...
I know that I will get an answer for my specifik project (from the guys that knows) here at this great forum. And if some of them are a bit coarse, I dont give a sh..t. Its probably their way of explaining. And if they
were like that as person in real life, they would never be here answering questions... So thats cool by me.
Dont get me wrong, I like surfing around. And as Im one of those "dig to the bottom guys" I dont take a no for granted. But as I seldom find "real info" amongst the threads (I think Im little of that myself) I think its very hard to get me convicted unless otherwise is proved. Because I dont think "5 sec fingerwarm" motor and "3,2 minutes of driving gave me 56% of the batt capacity draw" thingy is the real thing.
I think if this info could get into one thread with just the system setup without any variables would help alot of people, like me. And it would save alot of time for the "experts" answering the same questions all the time.
And for Alan to save time to point out to search the forum... ;o)

[D. Newland]

Don't know if this is what you're looking for, but to test a given setup without purchasing an Eagletree or having an ESC that has logging software on it, do this:

Fully charge your pack. Run boat for a specific amount of time and at full throttle or in a manner that you typically run the boat.

Recharge pack and document mAh amount put back in.

(3600/runtime in seconds) X Amps put back into pack = Average amp draw.

Hypothetical: 90 second run drained the pack by 3000 mAh.

3600 / 90 seconds = 40. 40 X Amps put back into pack 3.000 = 120 average amp draw.

[puttekula]

Good info to the people posting info.
A logging system is the best.
The other suggestion is dependent if the run is performed at full power with turns taken
at maximum speed/thrust and no cruising to shore.
Are we getting close?

[MarkF]

Like already posted there are way to many variable. You will get a better answer if you give a specific boat and set up. And then you will see all the different answers you get from guys running the same set up.

Mark

[puttekula]

Mark.
As I already wrote. I know of all the variables. But in this thread I am not searching for a specific setup fot my ride. Im looking for a thread that
different people that are serious (like you) that know certain facts about just that specific setup to poste...

s for an example.

FE30 Insane
Bla bla motor/bla kv
Bla blabattery bla 4s1p
Bla bla prop
Bla bla esc
Bla bla runtime under full "thrust"
Bla bla ampdraw
Bla bla speed
and so on....

[keithbradley]

OP, I think what you're missing is that any given setup will net different results depending on how the boat is built and set up, prop work, weight, ect. Add to that the fact that there are literally thousands of possible setups, it's not likely that we will get one comprehensive list.
What we can do is compare your setup to setups we have logged and give you an educated guess.

[properchopper]

Peter, I fully understand and agree with your quest for the "bottom line" data. The thing is, even when data graphs are posted, using the results to achieve repeatability often doesn't take in to account the multitude of differing variables in a duplicate setup. Well developed "seat of the pants" advice from those that have "been there/done that" is my learning tree.

I'll agree that there's lots of freely given advice from those that suggest what they "think" rather than what they've personally experienced in real world conditions. It takes a while to grow a filter to discern the difference between what's supposed rather than what's actually been tried out. The "supposers" are generally well-meaning, but often give bad advice.

OTOH many pedigreed FE people on these forums will be generous, forthcoming, and sometimes painfully direct in serving up the unadorned truth, only to be ignored by those who want to graduate to a realm of high performance without doing the footwork.

I'm nowhere near the Guru status of many of the highly pedigreed responders here, yet I get a handfull of pm's a month from ambitious FE people that want to shortcut the learning process and dump in over-volted massive setups in questionably manufactured hulls (or most frequently nicely made RTR's with "as delivered" performance envelopes) to make them run substantially faster than their design limitations will allow. Some listen, often they don't. And yeah, it's frustrating.

Cest' La Vie (French for "whatever" - Tony)

Here's a good chart. Just numbers, but I'm relatively sure it was developed from lots of real-world testing. (May not be what you're after, but I'm out ; nap time)

kv_voltage[1].pdf

[puttekula]

Thx Tony... Appreciate it, as allways...