Mayhem ST Brushless Conversion Project
 

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:
http://www.deependstudios.com/mayhemst/mayhem_001.jpg

http://www.deependstudios.com/mayhemst/mayhem_002.jpg

http://www.deependstudios.com/mayhemst/mayhem_003.jpg

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.

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

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.

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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

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

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.

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.
http://www.deependstudios.com/mayhemst/mayhem_004.jpg

http://www.deependstudios.com/mayhemst/mayhem_005.jpg

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

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.

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!

http://www.deependstudios.com/mayhemst/mayhem_006.jpg

http://www.deependstudios.com/mayhemst/mayhem_007.jpg

http://www.deependstudios.com/mayhemst/mayhem_008.jpg

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.

http://www.deependstudios.com/images/nue_5s.jpg

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

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

Looking good, nice choice in battery

Can anyone make a suggestion for a LVC that supports 5s?

I've looked around, but haven't turned up an external module. If anyone can point me in the direction, that would be appreciated.

Mike had a car LVC in his store. Not sure if he still does or not. You have to pay attention to how the LVC works. If it is a plane LVC, when it kicks in it may just throw you into full reverse.... which would be a bad thing.:tongue: You need to find one that will put the car controller to neutral position.

If that is the 70A BK controller you might want to think about adding a fan on the heatsink. Its on the small side for 1/8 applications.

J, I checked out the RC-M store this morning but didn't see anything stand out as an option... I'm toying with the idea of replacing the controller with one that has a built in LVC -- Since like you said -- 70 amp is a little on the low side for 1/8th truggy.

With the 9XL I think the maximum current rating is only 74amp continuous... so far with my 12cell NiMh test, I didn't have any issues with the combination, and the less-tall gearing.


With the 5s lipo, I think Its going to heat up a little bit more... Might have to drop by the rat-shack tonite and get a little DC fan to put on there.

Just a quick picture all trimmed up. Still have to form the lipo battery tray, that's on the schedule for this evening!

http://www.deependstudios.com/mayhemst/mayhem_009.jpg

Finished up the Battery Tray yesterday night... Hopefully I can get it mounted in the ST this evening and maiden the whole setup!

Here's the battery tray.

http://www.deependstudios.com/mayhemst/mayhem_010.jpg

http://www.deependstudios.com/mayhemst/mayhem_011.jpg

Nice battery tray, what is it made of?

Hey Bdebde,

I used aluminum to make the tray, cut it here in the shop then bent it to size. Still need to get it mounted though, maybe tomorrow.

what coating is that

BB,

Coated with two coats of Rustoleum Heavy-Duty Primer, and 2 finish Coats of Rustoleum Flat Black High-Temp Coating.

very nice :D

great job on the battery tray

i have been looking for a 5cell lvc for awile too, i havent been able to find anything over 4 cell

Hey SemiPro, thanks for the compliment. The tray came out much nicer than my first attempt (back when I finished an LST2 conversion!)

--

Here is the setup now, with everything installed and running. I will eventually add a BEC, but for now, the RX pack works excellent, and I can run my BK Warrior setup without the bec enabled.

http://www.deependstudios.com/mayhemst/mayhem_012.jpg

http://www.deependstudios.com/mayhemst/mayhem_013.jpg

how much for one of those trays?

PM Sent, It's hand-made but I tried to give you a reasonable figure to work with. :mdr:

very impressive build....can i ask where you bought your battery ?thanks...awesome job

Check your PM, I don't wanna advertise another site on here - since RC-M has been cool enough to provide decent forums.

And.. Thanks for the compliment... It came out better than I expected.

Albeit, significantly more expensive.

LOL...yeah ,i'm in the process of a CRT X1 conversion...turning out to be a little more expensive then i figured ...thanks for the info