Metallover

You will get more watts with more voltage. It is like giving your car half throttle and getting 100 horsepower and giving it full throttle and getting 200hp. Or doyou mean using a motor rated for that many watts?

j.m.

To figure out the wattage, or power output of an electric motor you multiply the input voltage by the amperage, and then by the efficiency of the motor at that given amp draw.

If you have a motor runnning on 10v DC drawing 10 amps with an efficiency of 80%, the motor is putting out 80 watts.

The same motor on 15v DC putting out the same amount of power would only draw 6.7 amps, assuming the output power to amperage draw ratio is linear for that motor.

Formula:

W=AxVxE

Output power in watts=Amp draw X input voltage X efficiency at the given amp draw

If you don't understand this, just remember that high voltage setups are more efficient for a specific power output than a lower voltage setup.

bhcvc

I can see more voltage equals more power (P=VI), but you always read that if you gear a car too tall for speed, that will overheat the motor. So I assume that it is the additional load due to the taller gearing that results in further current draw?

Example:

Car 1:
14.8V @ 50A = 740W
Gearing "A" = short gearing
35mph

Car2:
11.1V @ 50A = 555W
Gearing "B" = tall gearing
35mph

Car2 consumes less power, but if everyone cautions against gearing too tall to achieve the speed you want, something MUST be creating more current draw. I'm assuming the P=VI equation needs to be enhanced with a load element, but not sure how. The most common recommendation I read is to "use more voltage to get more speed, don't use gearing which will overheat the motor". Which eludes that the load element adds a LOT of additional power requirement.

For the motor I have (2776kV), I'm maxed on what voltage I can run. It's already slightly past 40k rpm, so I can't run 5s or 6s.

Edit - just saw jm's reply.

jm - that assumes a constant power output. Doesn't current draw increase tho if you increase the voltage?
Or is it assuming you control the current with the throttle and thus shift the current down the curve (by using less throttle) to achieve the same output power? But at full throttle, the current would increase resulting in more power output, in which case it's no longer an equal power situation.

Metallover

That's a good explination. Just to back up my post above, you won't have a constant amp draw with rc.

j.m.

The motor amp draw(and therefore power output) is based on load. Forget all you know about IC engines.

If the motor is geared to have the car go the same speed on 3s and 5s, the load on the motor will be the same.

You need to choose a motor that has a peak efficiency rating of where you plan to run the car at the most.
(if you race, then this is not full throttle)

Current does not increase if you don't increase the load. When you add cells, it has almost the same effect on motor performance as decreasing the number of turns (brushed motor) or increasing the Kv (brushless).
(cept you also gain torque)

The motor will be spinning at a higher rpm on an HV setup to mimick the "low" voltage setup, so motor selection is critical.

In the real world, amp draw and power output for an electric motor are not linear, but they are very close. Much closer than on an IC engine.

traxxaspede

if i had the money ide convert an 8ight 2 put in a big brushless and 5 or 6 cell lipo (or 2x3 cell)

J.D.T

the problem is everyone beleives the ratings, they seem that the 15 series neu is capable of making 4000 watts, yes the 1527 with the proper voltage will indeed make 4000 watts but your 1515 on 4s ain't even half, most 6s setups are bairly capable of making over 2000 watts and that sure as ship digiddy ain't constant!!!

j.m.

A 1527 has a larger diameter than a 1515, I think that's what usually throws people off.

A big car (truggy) would work fine with a 1521. Not sure if you could even squeez a 1527 in there.

You should think about one of these:
http://www.offshoreelectrics.com/pro...prod=fei-580-L

fusebmx13

Is this a very good pack for a MMM with a 2200 neu? My brother just got 2 of them for his truck.
[link]http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6350&Product_Name=ZIPPY-H_5000mAh_3S1P_20-30C_Lipoly_Pack[/link]

J.D.T

6s may get a little warm on the 2200 depending on driving style so watch them temps, the zippys are ok, I have only seen one that was bad when new, they don't seem to last as long as a hyperion or quality cells but for 1/3 the price that should be expected IMO.
JM, we only tried one 580, the 1326, it was fine on 5s but blew the rotor on 6s, it was running pretty darn hard until we heard the dreaded rotor pop we all fear, he is working with the flying club rep he got if from but no word yet on warranty or not, its totally trashed otherwise he would have just bought another rotor and fixed it. Since it was a one day trial I can't say for sure or not if its stronger than the neu 1515 or lehner 1950 that is usually in the truck. Have you had one yet, whats your opinion on them?

vedardo

you should try true rc batterys the very good for a fraction of the price of a hyperion or max amps i use the 4s true rc with my mmm combo 2200kv with a 15/46 gearing one my mbx5t and it works great

hdmm

What did you use for a motor mount to convert to electric? I have a 2.5 T-Maxx that's giving me trouble and I want to go electric with it. Is there any other things I need to do to it, like with the transmission or anything wlse when converting it to electric?

hdmm

[&:]

Metallover

The picture above has an emaxx motor plate with possibly a whole emaxx transmission. I don't know how most people do it, but you can use a piece of angle stock as the mount and put the motor right where the engine was. I can't help you with any specifics.

hdmm

Thanks for the info, I guess I can make a motor plate of some kind. My biggest concern is the tranny. Don;t know how the T-maxx one would work with electric or if I would have to go with a E-maxx version.

Metallover

If the tranny is a two speed then you will probably want to lock it into second gear. Otherwise it should be fine unless the system you choose has more power then the tranny can take.

vedardo

this is my mugen e-mbx5t with the rcnctek motor mount , mmm combo 2200kv motor, hitec hs-5955tg servo ,custom 1inch lowered shock towers (car looks all slammed), jammin super big bore shocks, custom hinge pin plate and shock tower are custom cause made out of 7075 metal and doesnt use bushings anymore, custom servo mount with esc mount and reciver mount

here are pics














all custom parts are at this page rcnctek.com

Almighty ODST

What do you all recommend for a revo electric conversion, tekno r/c conversion kit or emaxx tranny? what all is involved with putting an emaxx tranny on it?

Metallover

I would personally go with a tekno mount and battery tray. You could make a tekno like mount yourself with a piece of angle stock so you don't even need to buy anything.

j.m.

The stock revo tranny works just fine, right?

So all you would need it a motor mount.

The RC monster one works well, too. So i've heard.

You don't need to buy a battery tray either.

bhcvc

I have an RC Monster mount on my TTR ST-1. Works great. Looks pretty much exactly like the tekno ones. They just replace the rear center diff mount/bulkhead. Conversions are pretty easy. The hardest part if probably the layout...well, at least if you have a AM or FM system as you have to place the RX as far away from other things as possible, whereas with a 2.4GHz you can put it anywhere you want.

vedardo

this is my mugen e-mbx5t with the rcnctek motor mount , mmm combo 2200kv motor, hitec hs-5955tg servo ,custom 1inch lowered shock towers (car looks all slammed), jammin super big bore shocks, custom hinge pin plate and shock tower are custom cause made out of 7075 metal and doesnt use bushings anymore, custom servo mount with esc mount and reciver mount

here are pics














all custom parts are at this page rcnctek.com

cat samich

im still kinda new to the whole brushless scene, three questions

where do i buy these fiegao motors?

how do i choose the right one?

how do i fit it into a truggy lol?

Metallover

Go to rc-monster.com to find the fiegao motors. They are in the top 10 sold products. You can get a motor mount and pinion there too. They have great service. If you tell what voltage you are using then you can find the right motor. Are you using 4s, 5s, or 6s?

I thought I'd post pics of my crt .5 conversion I recently finished. It uses an outrunner direct drive setup. I run it on 3-4s lipo. I don't even have to disable the bec on 4s.[8D] I just ordered some proline gladiators today. Can't wait...


In different stages of building


after a horrible crash

fnished product



I want to get one of those new castle outrunners when they come out. The way it sounds they are going to be insaine!

iTz Nicholas

http://www.hobbycity.com/hobbycity/s...hless_Inrunner

Does anyone have experience with that motor. I might get one for an 8ight T conversion.