Mayhem ST Brushless Conversion Project

[hunter306]

I started my new Mayhem ST Brushless project this evening. I haven't seen one of these converted yet (though it's really just a Mayhem buggy with long arms) so I figured I'd post up a build thread. I've got all the parts trickling in slowly to complete it.

So far, this is the list:

-Mayhem ST Truggy Chassis
-Feigao 9XL - 1853kv Motor
-Mamba Monster Max (crossing my fingers!)
-RC-Monster Motor mount for Mayhem Buggy/Muggy
-16t Hardened Pinion Gear against 48t spur.
-Batteries -TBD!

I'm still deciding between Polyquest 5s and NueEnergy 5s batteries for the project. My budget is tight, so I've only got about 250 dollars to spend on the battery. Any input on my two choices so far would be SUPER appreciated.


Here are a few pictures:

[gimpygolden]

Where's the battery gonna fit?
You might check out the Zippy-R 4800's
http://www.hobbycity.com/hobbycity/s...idproduct=7238
I'm going to grab a couple, people have been doing well with them.

[lincpimp]

Looks good, I have some spares that may work for you, pm if you are interested, I will sell very cheap...

SWK9194 Quad Brake Rotor Set
SWK3028 Rear Shock Set
SWK9171B 17mm Wheel Hubs
SWK3108 Steering Servo Saver

[hunter306]

Hey gimpy,

The chassis hasn't been weeded of all the unnecessary items yet. The radio box is going, the servo mount is going, the plastic flange for the antenna mount... that whole upper half of the chassis should be pretty roomy for a decent sized battery. I'll weed the chassis out as I get the next couple'a parts in to make room.

This evening was really just mocking up the parts that I had, and pulling the Nitro Engine out of her to make room for the goodies.

Keep your eyes peeled, I'll update this as soon as the next couple'a parts come in.

---

As for batteries, I really want to get something that is going to be high-quality enough to last. I haven't heard of the Zippy packs before, are they pretty reputable? I got alot of recommendations for Hyperions, Polyquest (enerland), and NeuEnergy when I was inquiring, so I'm surprised i didn't hear that name.

-J

[e-mike]

for 250$ you can buy two 5 cell pack ... i have 4(3 cell 4800mah 25c)and wow work so good under hight amp draw

[gimpygolden]

Supposedly the Zippy-R's use Enerland cells as well. The thought many have is the cells are 2nds maybe not as well matched as PQ or other top brands. Read around on them some, but most people seem happy with em'. I'll let you know in about a week.

[hunter306]

Originally Posted by gimpygolden

Supposedly the Zippy-R's use Enerland cells as well. The thought many have is the cells are 2nds maybe not as well matched as PQ or other top brands. Read around on them some, but most people seem happy with em'. I'll let you know in about a week.

Wow... I just checked out the prices. The Zippy-R's seem like a real good bargin.

I'd definitely be interested to hear what you find out about them Gimp! Let us all know.

Enerland cells at a reasonably low price would be real nice.

[hunter306]

Update on the Mayhem, weeded out the electronics box and the rest of the goodies and got the RC-M motor mount put in place. I am running into a problem where the motor can hits the rear-end braking system. The can rubs the brake pads and prevents me from getting the gear mesh tight enough to run.

More on that when I improvise a solution.

Here are some pictures of the mount hooked up.

[bdebde]

Mike makes a spacer to fit in between the motor and the mount.

[hunter306]

Hey Bdebde, Thanks for the information. I started looking at the design, and decided that the Electronic (motor) brakes would be more than sufficient for this truck. It's not quite a full-sized truggy so the electronics should be able to handle those duties.

I removed the mechanical brakes front and rear, and eliminated a bunch of weight as well as simplifying the setup significantly!

Now I've just gotta do some detail work.

[hunter306]

Well, a couple of things worked out this evening. First, I sold the Mamba Monster Max I was planning on using for the build, I'm too nervous about failure of the controller to run it -- I think I'll wait until they really do get all of the bugs worked out before I replace the current controller. Second, the 9XL Motor is rated for 75amp continous MAX. The Monster Max was significant overkill for the job.

I swapped in an old BK/Warrior that I had laying around. It fits the build well, as I wasn't planning on doing anything but bashing around the streets of the neighborhood anyway. I still have to figure out how to program the BK, but it's current settings work fine (as evidenced below) for testing.

Ended up using an old IB4200 - 7cell pack for testing. I'm getting a TON of cogging right off the line, which I'm attributing to steep gearing and poor amp delivery from my battery pack. I may fashion another pack to use in here until I get my lithium poly.


Here are a few more images... I rough-fitted everything and took it for a test drive. Ultimately, I'd like to add a small cooling fan to that ESC and do some wire management!

[hunter306]

Picked up a Lithium Polymer to replace the NiMH cells... Nue 5s5000mah 30c setup.

Should be nice and overkill. I've dropped down to 12t pinion 48t spur to compensate for the extra voltage.

[jhautz]

Nice battery. Make sure you run some sort of external LVC on the BK controller so you don't ruin it. The BK esc doesn't have a built in LVC

[hunter306]

The BK apparently is the 7018 model, I think I'm good for 18 cells on it at 70amps continuous... I DO however need to get that Lipo cutoff.

Can anyone make a recommendation on a good Lipo cutoff that I should try out?

I've never had a ESC without a built-in one... so I'm not real familiar with my options.

Thanks guys.
-J

[DRIFT_BUGGY]

Looking good, nice choice in battery