MCD MT "clone" 1/5 Conversion

[Takedown]

Originally Posted by What's_nitro?

What did you enter for voltage/current draw? The motor you want can only handle 350W. That's less than 1/2 HP. There's no way it will handle 4000W. 350W is in brushed 540 motor territory. I think you'd be lucky if you got 20 mph with that setup your looking at. I'm all for the conversion, but you need to do some more research before you buy. I would want at least 1000W in that truck to get good performance out of it. 1000W is easy: 20V @ 50A. etc. You should shoot Aqwut a PM. He has a lot of experience with big, powerful conversions. Good luck!

The thing I dont understand is. I own a currie 400w 24v scooter. I can wheelie with ease on a full battery and can hit 21mph. Im dropping 50w and upping the voltage by almost double. This would be plenty of power for my 1/5?

[killajb]

I think the wattage issue may be due to different usage of the unit of measure (the watt). For example: I've seen where brushless systems provide EagleTree data indicating they produce upwards of 3000 watts using a NEU 15-series motor @ 6s.

However, there's no way I could install a 1515 NEU motor and 24v worth of batteries on my pocket bike and move at all or any real speed. But my 1200-watt motor will propel my pocket bike (with me on it) to 28 mph.

Perhaps someone else can chime in on this and explain the logic. Without trying to do calculations, I do know from experience with the permanent DC magnet motors that you could build a potent 1/5 scale vehicle with a 350w motor that's normally rated at 24v. I think the size and weight of the motor make it ideal for use and the fact that you can "over-volt" the motors to 48v without much harm since it's being used for a RC vehicle and not to haul someone around.

[Takedown]

Thats exactly what I was thinking killajb. I want to get to the bottom of this. Since my 1/5 has both a Tranny and a Center Diff it took me awhile to calculate everything just right.

Heres is the layout I plan to run and its specs...

[lutach]

Torque from different size also has a major role in a low watt brushless motor. I've seen electric cars (real size) that only has a 3000-5000 watt motor, but they can go as fast as 50mph. It's the torque that's making it go that fast. You can go with one of the large outrunner type motor and it has plenty of torque to move a 1/5 scale to fun speeds or a efficient running set up for long run times.

[Takedown]

I do have high hopes with my setup. Im expecting atleast 30mph with higher gearing and some good torque and runtimes.

[Takedown]

Ok here is a few pics of the battery placement. In the pics I am using a 4.5ah 12v lead acid which is the same size and the 5ah 12v. I also have a few pics of the fan mod I did. As you can tell its dark and gloomy outside. Its rained all day and is suppose to rain tommoro...

Fan Mod..






Battery placements...

[brushlessboy16]

is the 12v pack bolted down?

[killajb]

This seems like a very interesting project and I may just try one myself..

I already have a few scooter motors. As well, I have plenty of SLA batteries to try out. The 4.5ah battery is still a beast for this set-up. My fastest pocket bike was when I used lighter, less amp-hour batteries to save overall weight. Try Home Depot, they sell 6v and 12v SLA batteries in 1-2ah range. They are a lot smaller, still cheap and will enable you to place the batteries for better balance. I think a 48v setup would fly. By "over-volting" my permanent magnet DC motors, they seemed to have less torque but obviously way more top end, ideal for RC.

[Takedown]

No they arent secured yet. Ill use some xl G3 straps if they fit and I have to make 3 trays. Killajb- I can get three 12v 5ah pb's online shipped for $56.

[rootar]

so how much "gas powering" weight did you remove and how much are the PB batts and electric motor gonna weigh in comparison to what you took out?

[Takedown]

It will actually weigh 3lbs more with it fully converted. It weighed 31lbs with the gas engine and a full tank of gas. I calculated it to weigh around 35-36lbs loaded with the pb's, giant brushed motor and the esc. but it should have a significant power increase so its worth it.

[rootar]

how will the suspension handle the extra 3lbs or so? i dont guess that 3lbs is that big of a deal when it already weighs 31+ ....

[Takedown]

Originally Posted by rootar

how will the suspension handle the extra 3lbs or so? i dont guess that 3lbs is that big of a deal when it already weighs 31+ ....

Its at full rebound under 31lbs of load. And all four shocks can be adjusted 1in lower on the barrel to make it rebound faster. I would think it would handle 40lbs.

[Takedown]

Ok guys yet another new plan/idea.... I ditched the tranny and will be going directly off the center diff. But heres the catch. I will not be running a setup you guys are thinking of with a pinion meshing with the diff gear. I removed the diff gear completly. I will be running chain drive. I will purchase both the pinion sproket gear and the center diff sproket gear here- http://www.electricscooterparts.com/sprockets.html I will be buying a 11t #25 chain 8mm bore and a 14t #25 chain 8mm bore sproket.

Also here is the final specs of this setup...




I also found some really cheap wire "10awg-8awg" for this project- http://www.electricscooterparts.com/wire.html

[lutach]

Sounds good. Have you looked into spending a little extra $$$ on A123 cells and making a nice pack out of them. I know a 10,000mAh 25-30C 10S lipo packs would weigh about the same or less then the lead acid packs. Get your self a good ESC that will handle the current loads and your set.