Dual brushless question
 

Ok, let me explain myself first. I was thinking about building a XTM MMT with dual KB45 11XL's, dual Turnigy 100a HV ESC's with 10s LiPo for each setup.
My question is: HobbyCity has HV BEC's that'll handle up to 10s LiPo, and my question is will I need one BEC for 1 ESC or 2 BEC's? Like one for each ESC?

Bearing in mind those escs are plane/heli items, with poor brakes and no reverse (more like a handbrake, but adjusting the throttle epa may help), I think you will only need one BEC. The escs will need to be connected ot the Rx via a Y-lead, and the BEC should plug into the circuit between the single leg of the Y, and the Rx, then connect it to one of the running batts. You should use a seperate LVC too ideally, connected to the battery supplying the BEC. That way when that cell hits LVC first, the whole system will shut down.

Well, I will use mechanical brakes. About the LVC, what if one of my other packs drops voltage before that one does?

Hmm, tricky. The BEC should drain that pack 1st, since it places a small, but significant load onto it- only reason for the other pack(s) to drain quicker would be a bad cell, different Mah/C rating, or perhaps if a fault occured and the other system ended up doing all the work without you realising it (you'd see a drop in speed though, so it would be obvious that there was a problem with one motor/esc).

If you paralleled the battery packs together though (UNSLOW balancer), then they would discharge at the same rate, and hit LVC together:

http://i115.photobucket.com/albums/n...lharnessv3.jpg

http://i115.photobucket.com/albums/n...lelharness.jpg

You will love the XTM. Have you bought one already?? The MMT is the baddest MT I have driven and owned. They have an almost 17" wheelbase so they are prefect for high speeds. How do you plan on mounting the twin motors?? Their isn't much room around the spur bracing. Will be curious to see how you fit it.

I have not bought it yet. Still saving for all the components. I was thinking about taking out the engine, receiver box, battery box, and brake servo. (It will be relocated), and mount one motor per side of the spur.

Its cheaper to buy a roller then buying the complete truck and parting it out. One thing about the factory parts that are nitro, is the parts aren't worth squat. I found a roller complete for 175 that was in excellent condition and didn't jump on it. If I find another for that price I am buying it on the spot.

Where did you find that?

One of the local hobby shops. If I find another or an extra and your interested in one,let me know.

Definitely!

I will check tomm if you want. My local LHS takes in trades all the time and they are a big XTM dealer.

That would be super! Thanks man!! If you have time, could you snap a pic or two for me?

Now remember its a full roller with wheels and body, but no electronics or nitro parts.......ready for your servos and motor setup. Which you can take a look at my MMT setup if you wish...I have pictures of it online.

Sure.......tell you what give me about 15 mins and I will find out. I can call and find out tonight....lol.

Cool! Can you measure the distance between the back of the steering servo mount to the front of the center differential (to check for room for batteries)?