DA_cookie_monst

iTrader: (1)

Colin, make it simple for you.

Lets say a motor will take 80watts max power, and it will take it whether you have 5 or 6 cell, so, current draw is i=p/v

so, for 6 cell 80/7.2v=11.11A

so, for 5 cell 80/6v=13.33

So for the same max speed, because your motor see's less voltage, it draws more current, the cell then has to be stronger and hold its voltage more stable and for longer periods. I would be guessing but I reckon, 5 cell cars on a proper track will start to get to feel softer during the race, as the motor will still be using the same amount of power, but drawing far more current from the cells. So the cells HAVE to work harder to acheive the same result as a 6 cell powering to the same level.

6cell may damage motos (because people just don't understand that giving her 100% from the esc is just pointless) but 5 cell will muller cells.

Nathan Parker

Sean T Guy

Colin , "ANSWER" Yes , I've had enough..LMFAO.
Seriously though , Why dont we just get rid of the weight restriction with 6 cells , I could make 1430gms with 6 cells....Thats got to be better!!!!
Question , "What have I started now"..

MR JOLLY

what if motor is not taking 80w in 5 cell but it takes 80w in 6 cell ????

motor in 5 cell run`s more effiecient .........


Sean your just a defeatest anyway ,
how are the cows down that way

chris_dono

Don't see why this has come into it

I can make < 1300g with a 2 cell lipo and have more MaH than any NimH out there so far....

Sean T Guy

Because we are talking about weight , cells and how many amps are pulled from a motor....Do you see now?

Colin , the cows are moo-ing. They are all mad anyway.

Skiddins

The trouble is, a motor will not take it (the same Wattage) if the voltage is different.

Power in electric motors is directly proportional to current and voltage, if you reduce the Voltage you reduce the current and subsequently, the Wattage.

Purely for the sake of argument;

A motor rated at 10A@10V will produce 100W.

Half the voltage and you halve the current, so now it's getting 5A@5V which only produces 25W.

It works the other way as well, double it and you'll get
400W (and a small rotating cooker )

I fI try it on my dyno, put a load on at 4V, then reduce the voltage to 2V, the current drops fractionally, but that does mean it is producing less power and of course, less RPM.

Skiddins

BJ

Thank you some one understands!!

With this scenario there are two ways at looking at it, and with R/C stuff if the voltage is dropped then the overall power is dropped hence less current.
The main reason mod 4 cell not working or very close to dumping is that they also changed the amount of turns at the same time i.e 5 turns. Less turns, less resistance higher amp draw.

DA_cookie_monst

iTrader: (1)

yes and no, remember, the motor is being over driven in 6 cell, so you are putting 'excess' power into it, hence the heat, but once you drop down to 5 cell, you can't as you don't have the voltage to rampt the torque up, but the motor will perform similar by pulling more current.

chris_dono

wasn't the original reason for this whole 5-cell thing to lower costs ?

Nathan Parker

Electric motors do not draw a constant current reguardless of the load. The laws of physics still apply... power in must equal power out. Electric motors automatically vary their current demand based on the load they are given; the more you tax the motor, the more current it draws.

By gearing the motor up you are changing the load on the motor

Hence there is more current draw and more amps being drawn.

DA_cookie_monst

iTrader: (1)

plus your cells are capable of givin the current it is asking, they are capable of more current than it can cope with in 6 cell, so the cells get an easy(ish) life, in 5 cell, it hammers the cells more.

skiv

so the morall to this story is it aint gonna work lol.

reduce cost its not gonna happen
wear and tear is going to be the same
reduce the speed for safety,thats why we have brca insurence and gas cars are alot faster.
beginers are gonna get even more confused

DA_cookie_monst

iTrader: (1)

basically, yes, there is no such thing as a free lunch, the cars will go as fast or faster with the less weight, cells will be sucked dry, cars will be made more fragile (down to weight).

If you want to go slower, put a slower motor in it, it is that simple....

Terry_S

iTrader: (3)

... or have longer races or use some form of limiter!

DA I liked your true comment about ESC settings, Colin is quite right people often just can't be bothered to change the settings. There are 'smooth' or limited settings available, don't have to always use the most punchy ones!!!