RCRat

iTrader: (3)

Can someone help me understand the Amp rating systems on BL systems?

For example I have seen some that say 35A...but they can handle a 3S lipo.
And I've seen others that say 200A that can't......

or does it not have anything to do with voltage?

spcpicard

iTrader: (14)

It depends on what type of motor you are running and what volts. If you are running a high KV motor with low voltage (ex 2 cell lipo 7.4) then you will pull more amps than say with a lower KV motor with higher voltage to acheive the same RPM's. Some esc's are rated 3 cell (11.1) lipos with a lower kv motor and only 2 cell with a higher KV motor due to the higher amps. Esc's experience the highest amps when accelerating and trying to push the motor from 0 to top speed, but usually it's only brief. In general you want to try to put the highest voltage with the lowest KV motor to reduce the amps, some motors are higher kv to get the most out of the batteries that may be limited to the size of the chassis of the rc, but the trade off is a higher amp load on the batteries and esc, which ends with more heat.

Hope this helps.

RCRat

iTrader: (3)

Okay so an example is a 35A ESC with a 4300KV motor running a 2S (4000mah)

I'm just worried it will get to hot and burn up...or that it is a dog and doesn't want to move a Slash around.

spcpicard

iTrader: (14)

35amp is kinda low, I would suggest going with atleat a CC sidewinder esc, they are pretty cheap and are rated at 75 amps I think. In all of my 1/10 scales I've always used the CC mamba max esc's and they never missed a beat, but that esc is kinda pricey. If you gear correctly you should be fine, on the slash I would think 16/86 would be a good start, tighten your spur fully and back it off 1/4 of a turn. I am guessing the slash comes with an 86 spur, check your temps and you should be okay, if you are running on a high traction surface you may need to gear down more. BTW the losi pinions work the best with the traxxas spurs, I've tried the Robinson racing and traxxas ones and they sharpen really quick.

Drifting101

iTrader: (8)

So its the hobby wing system right?

I am running the 10t not the 9t but i have a 5000 mah lipo in it and when the ground temp is 46 degrees(C) (so its hot) the esc only hit 65 degrees (C) and the motor hit 80 degrees (C) wich is about right for a senserless

This is in a T4

RCRat

iTrader: (3)

Yep it is the Hobbywing system....you like it?

Drifting101

iTrader: (8)

Yes i like it better than my GTB....the only problem is that there is a small cogging but the is un noticable unless you hold the throttle so little (other than nutral) that a normal motor wouldnt even move

94eg!

iTrader: (17)

Voltage and amperage are two separate things. Together they make power. Volts (charge) x Amps (current) = watts (power). To get more power, you need more of one or both...

BTW: The eZRun system (35A/9T combo) has been purchased by many many people, and I've still yet to hear any real bad news. The only thing to watch out for is the cheap on/off switch. Some have removed and soldered the wires so it's always on when the battery is plugged in...

RobbieS

iTrader: (95)

Amp rating has nothing to do with how many cells a speed control will handle.

I've heard many good things about the hobbywing esc.

The other thing you have to look at when looking at amp rating are the giving you the actually continuous operating rate or the peak operating rate.

For example that 35 amp speedo has a peak current rate of 190 amps. Once you have your vehicle moving it draws very little amperage but when you take off, climb over a pipe, or any thing else that puts a heavy load on the motor you can easily get over the 35 amp rating but only for a second or so. The electronics have no problem handling that heavy load for a very short period.

Drifting101

iTrader: (8)

I have also heard that the switches are very hit and miss. Mine is good it actually fell of a went under my truck it is scratched but fine