I am consistantly able to get 3+ minutes more runtime from my 6S setup geared for 30mph than my 5S setup gear for 30mph. This obviously proves that current is reduced with higher voltage.

Yes, higher voltage will decrease your current (assuming you adjust your gearing to match speed). I think it is unfortunate that people do not use more efficient setups to achieve longer runtimes. I would love to adopt an 8S setup but I can not find a suitable esc for the job (w/ 4 pole motor). I tried the castle HV110 but it doesn't work well with a pistal grip TX.

You are using the cells to get more runtime. Not for more speed. (30mph vs 30mph)

So the statement is correct.

By dropping the gearing down on motor. You change the torque load on
motor and also changes the amp draw. Also with more voltage on a motor
you don't have to run as hard so the amp draw is not as bad. If the truck
will flip over at 750watts. The higher voltage will make the truck flip with less
throttle input.

When you got to 5s you stated you changed the gearing.
You are adding more current avilible with another cells as well.
If some one has an eagle tree. It would show up better.

I too noticed increased runtime with more cells, but that turned out to be simply that you are into the throttle less to achieve the same speed. The max power with a higher voltage setup is higher, so you don't need to push the batts as hard to get the speed you want. There is some savings with higher rpm since there is a little more "resistance" so that helps too.

That square heatsink looks ugly, is it for sitting flat or something?

You will get better efficiency overall with higher voltages. All losses associated with resistance goes down with the current.

Power loss = Sum[I^2*R(x)],
where R(x) resistance of:
- motor
- wires
- connectors
- FET's
- Cap's
- Batteries
- ...

Going really high in Voltage is not good as well :) There are obvious reasons and electrical.

Artur

Doh! How could I forget wiring losses! :007:

Serum, I probably missed your post.. I skipped a few posts on the first page, sorry. I'm sure you tried to make the same point as me.

We are having some difficulty making it clear to sleebus and maybe some others....

Please guys, don't get this confused with changing motors, and/gearing with a change in voltage. That's a different subject.

Try again:

A motor DOES draw more amps with higher voltage, under the same load.

Sleebus, let's use that motor in the picture you talk about as an example. It doesn't have a built-in current limiter that forces the motor to only draw the rated 1hp, or 746 watts. That is only a rating on what the motor can do within spec, without self-destructing or stalling, etc. Each motor has a limit to what it can do, for both short cycles and continuous duty.

If that motor produces 1 hp at 110V, then it would indeed produce more power at higher voltage. But at some point it will burn up, literally. That is why we have different motors that are designed to run at higher voltage. They are a different wind, and draw less amps and turn a lower rpm per volt. So when this "high volt" motor is run at the higher voltage, it can produce the same hp at half the amps. It's a DIFFERENT motor.

I wish you were right sleebus, because we could have our cake and eat it too. :004:

Let's not forget that a motor is designed for a certain range of voltage and won't work well if at all, if you go too extreme.

Please consider this, back to r/c stuff. I think this may clear things up:

Take a normal r/c car 540 brushed motor made for running on 6 cells and try running it with 3 cells, or 12 cells. What happens?

It will barely move a car on 3 cells, and it not draw twice the amps or produce equal speeds as it did on 6 cells. Under your arguments, we should be able to just gear up and have equal performance at double the amp draw, since the motor is a constant source of power under changing voltage.

It would be ballistic fast on 12 cells for a short time until it blows up, and will produce much more power, indicating much higher amp draw. No matter what you do with gearing, the increase in power will be dramatic.

Notice it doesn't magicly become a self-current-limiting device on 12 cells and only produce the exact same amount of power as it did on 6 cells, while drawing only half the amps and thus doubling runtime. Again, even changing the gearing will not make up the differences.

Well, I have been doing some testing lately. I do not have a watt meter but I can tell you this.
5S 3200mAh Lipo with 24/51 gearing = 14min runtime
6S 3200mAh Lipo with 24/51 gearing = 16min runtime
Just for a comparison:
6S 3200mAh Lipo with 20/51 gearing = 17+min runtime

These test cases are reproducable and, call me crazy but, they seem to indicate that a lower current is achieved at higher voltage with the SAME gear ratio.

Now, before you call me crazy, understand that I realize every motor has its limits but if you run the motor within its efficiency range, it seems the higher the voltage, the better. My motor is rated for 6S and it seems that 6S is the most efficient as well.

The problem I see star scream. You probably couldn't run the motor at a wide open or as much throttle as you did with 5s as you did with 6s.
By adding the extra cell. You accually added more watts to be drawn.
If each cell is capable of making or running 1000 watts a piece of run time.
Then you have 5000 with 5s and 6000 with 6s. Just an example.

My testing area is only so big so I can only drive the truck at a certain max speed without losing control. The test runs are as consistant as I can make them. The advantage of 6S is the truck reaches the max speed faster than with 5S. With that said, it seems that I am at WOT more on 5S than with 6S so maybe that is playing into this discrepancy in runtime :030:
None the less, the discrepency is there so it seems to be an advantage in a racing scenerio.

Come on guys.... :) you keep throwing in variables.... just focus on the laws of physics, a theoretical setup. You can't just say you got more run time bashing your car therefore the setup is draws less amps. It shows that it draws less "average amps" for your car the way you drive it etc etc, but not as an absolute.

Although this is an interesting observation in it's own right, and valuable information for you to have for your setup.

What would be a true test is a dyno that records exact amps etc with an exact specific load every time. Run the same motor on the 4s,5s,6s on the dyno and it would pull more amps on 5s and 6s...

When running a car, you are using a constantly variable speed control, and variable load, etc etc.... that doesn't do anything to argue the point either way. I know it's somewhat repeateable, but not to the degree you can base anything off of to change the basic motor theory that's already established.

hee hee

For what it's worth to the naysayers:

When I had my data recorder in my 1/8, I ran a 3s lipo pack once with the same gearing as I have done on 4s, and the amps were less. I'm sure the graphs are on my laptop if anyone would like to see them. Speeds and amps are higher on 4s.

Now if I were to run 4s and try to baby the throttle and mimick the speeds of the 3s (and/or change the gearing) then maybe I could make the 4s draw the same of less amps than the 3s... but that's not the point of the discussion.

That's for mounting the motor Nick...

I like the 6s more than 5s or 4s. As long as the truck can take it.

More juice more fun! After reading that whole thread, this is what I got out of it......HEADACHE! you guys are all nutz! I plug, play, and run the crap out of it. Although I learned some from here, most will come in due time. I like stats, but for me, i need the results to prove what I'm saying. An eagletree for me would be in order to understand much of what you guys are all saying.:032:

It's really not that complicated... just difficult to get on the same page I think.

It's just the basics here, and it's simple math. I'm not an EE, but this is pretty easy.... W=VxA

Think of it as a hole in a pipe. volts is like water pressure. internal resistance
is like the size of the hole. The more pressure you put the more water going
to come out. If you put a restriction like the esc that can limit the which
would be like a vavle. No matter how much you put on it if you cut the vavle
back you won't get more water out. Even though you have more pressure.

I believe you are wrong there, if it was parallel you would add amp capacity, not in series. In series you add voltage and not amp capacity, but the wattage would still go up like you were saying, just not on amps but voltage

Seems to me that this electrical debate was not the point of his orignal post as there is nothing electricly unique about the motor. vs any other brushless motor. Its just a little lower KV than most here run, and some very unclear motor specs. (the observation of which kicked of the whole electical debate)

That said...

The setup is definatly a very simple way of doing an electric conversion using the standard nitro motor mounts. The mount however is limiting as far as gearing chioces. The chassis slots for the nitro mount are the full extent of the adjustability. It would basically force you to run the same gearing as the nitro motors.

The picture of the system set up in a buggy has a few inconsistancies from the description and the picture of the actual motor/heatsink/mount assembly. The assembled buggy picture doesn't show a heatsink on the motor like the motor picture above. Everything in the description referes to Lipoly voltages, but the setup shows 2 x 6 cell packs. The wires dont apear to be coming out the front of the motor in the assembly photo. Bottom line, I think the layout of the whole assembly poor. Battery weight is way out to the sides(but it is balanced side to side and front to back)

The wires coming from the front of the motor right by the pinion looks like its tempting fate to me. There had to be a reason for it, but I cant figure what it is.

Overall, It looks like they were going for the no brainer brushless conversion and stopped short of making it a no brainer.

My guess is they won't sell to many of these. Interesting idea though.