Running a Novak GTB on 3S?
 

My 1:10 speed buggy is running a GTB/3.5R setup, pulling 85 amps at speed (so far gps'ed @ 63mph, working on tires/best gearing still). I'm really thinking about going 3S for the same/more wattage at less amps (will use a selection of lower KV motors already on hand for this of course). Thing is...I'd hate to just bail on the GTB for a MM, so I looked up what the GTB is made of...

Mosfets at rated at 30v, BEC regulator is rated at 26v. Who knows what else is in there and the ratings on those parts, but I think I got the main stuff covered, so it should work. I also improved the GTB cooling via some simple cooling improvements I learned from my water-cooled hot rod computer hobby, so temps shouldnt be too much of an issue. I'll use a 'SmartStop' for lipo cutoff duties. The only thing I'm wondering about is what is sequencing the motor and its voltage rating, along with the sensor system, so I look to you guys for some advice...

Anyone try a GTB on 3S? Any thoughts on this?

replace the capacitor, its rated at 10V6800uF, you'll have to change it to a 16V rating capacitor.

sensor system uses BEC regulated power, and consumes very small current.

So change the capacitor, and GO AHEAD.

Could you take some pictures of the components that makes the GTB tick :lol:? A picture of the MOSFETs and the brain board would be very nice.

If my camera was here I could do that... I will open one up and see if I can read the numbers...

Thank you lincpimp.

I would be more worried about the 3.5R on 3s than the GTB... Although the GTB sure would have a heck of a time handling that power I imagine.

I have wanted to run a 13.5 or a 10.5 motor on 3s for a while. I did try the 13.5 in a pede with a sidewinder, but it lacked the torque of a similar kv s can motor...

If it makes any difference, I run a Trinity 13.5 on 3s 4000mah Lipo in my XTM X-Cellerator (great truck) with a MM. For the tight track I drive that truck on this combo is great.

Cap...forgot about that one, gonna check it, thanks!

While on the ancillary items subject...stock fan needs to go as it is direct off the battery, need a 12v unit vs. the 5v used by Novak...and use the spacers if improving thermal conductivity to the heatsink issues...no spacers = burnt up fan, lol.

Here is what was hiding in my GTB...

Mosfets

BEC regulator

I didnt break apart the board sandwich, so beyond these two is just a few supporting smc's. Who wants to crack open their GTB to see what's on the other side? :)

Do you happen to have a picture to see how everything is up in there?

No photo, sorry

GTB uses MOSFETs from a variety of vendor, IR, ST, and Vishay.
Here are pictures I took about a year ago when repairing my GTB, which got strangely burnt BRAND NEW.

http://bbs.rcfans.com/attachments/da...FTukQAxlBA.jpg

http://bbs.rcfans.com/attachments/da...0LjNYe3MyD.jpg

Or you can go read this thread, sorry it's written in Chinese.
http://bbs.rcfans.com/viewthread.php...8222&highlight=

That is awesome, thank you.

A while back I actually emailed novak about this question except using an external bec instead, and they still said not to do it as it would damage the components inside the esc. But maybe they didn't understand the part about using the external bec. Either way if you do try to put 3s on the gtb, you must use an external bec. The linear bec of the gtb can't handle much more voltage of 6 nimh cells. That's why its not even rated for 7 cells ni-mh.

This is kind of funny.

How sure are we about the BEC not being good enough in the GTB theory? My understanding of the 3A regulator data sheet in the thread says it is good for 26v, should be good enough, unless there are more parts to the GTB BEC? I really wish I had the guts to pull mine apart more and dig deeper into the circuits, but I dont want to be lifting any smc's or connections off the boards so....

BTW, what tires are on your avatar vehicle? I like the looks of 'em! Right now I'm cobbling up some belted Ofna tires to some 17mm adapters, should work out well, just adapt the adapters to the vehicle, right? lol Only problem is I am totally inept glueing tires and they seem to have swelled at the rim after glueing making them uneven which in turn should guarantee premature gyro occilation, so now I'm looking at getting some Medialpro Tarmac premounts...just gotta get a confirmation of in stock from the vendor. I need to keep the wheel speed down as my last foray into duct-tape'ed Schumacher Menace tires ended with the duct tape coming loose in spots. Nice tires otherwise, but 1/8 scale wheels seem better for what I want to do. The tires you have seem very low profile, are they under 100mm?