My brushless Revo

[BrianG]

Conductance is just the inverse of resistance, but would definitely be another mode on the meter. I have a Fluke 87 and it doesn't have it. Also, you'd need near-zero loss meter leads to accurately measure really small resistances (or large conductances). The .2 ohm coils was more than likely just your meter lead resistance. Short them together for a baseline value - it'll probably be about the same. An "open" from the wires to the case is good. At least you know there isn't a phase or two shorting to the can.

[BrianG]

Originally Posted by squeeforever

Perhaps your right Brian. I don't think it can be to expensive to fix a controller that works and isn't burnt to a crisp.

Hopefully it's not a few burnt FETs. If there is no obvious damage when they pull the heatsink off, there is no way to find the burnt one(s) since they are all in parallel. Just one more reason to have a two-part controller: one part with the "brains" and the other for the power section. At least you'd only replace half of it if something blew in the power section (the most likely place) and might be simple to build oneself.

[Finnster]

Well, I went ahead and tried a CC Mamba Max ESC and tossed the BK aside for repair. I pulled the BEC and and put it 14 cells. My impressions? :004: :027:

It ran really nicely and thru 2 packs it did not thermal. The Esc was running ~150, but the motor did get up to 160 by the end. It had been hovering around 140-150 most of the time. Some hill climbing, high speed stuff, running around in grass, and a bit of psuedo-crawling.

It was a nice little bash session, but nothing too crazy, I was just really testing the setup and the esc. The CC esc is absolutely amazing, what a little power house. I can't wait for the monster maxx. Before anyone jumps in, yes, I know it is running the ESC above spec. But I've done things like this before with success. I'm taking it easy on the esc, and so far it is doing well. I do have a 25mm fan I want to mount, but allelectronics sent me the 20mm fan instead, so I need to exchange it.

Top speed was somewhere just south of 40 I would guess. I didn't have my gun on me, but I did enough testing with the Rusty that I would say this is a pretty close number. The truck handles awesome. Much better than my maxx ever did. It was gripping well and would tend to slide the rear end out on most surfaces and only rolled at high speeds on high traction asphalt. Ac ouple crashes were a bit ugly. I really need to get a roll bar in there. :P I got a couple ideas.

The only real worry is the motor temps, it getting hotter than I was really expecting, so I'm wondering if I need to go down a tooth to 14t/51. Of course its the one I didn't buy... Could take a little pressure of the esc too which wouldn't hurt. The esc is really smooth and doesn't cog. The revo will wheelie with ease. I'll post some mroe pics later. Thanks to everyone, esp Brian for all your help.

[BrianG]

Wow, great. Although you are braver than I by using more cells than specified. I know manufacturers build in a safety zone, but I hate running higher voltage/current than rated. That little ESC must have been lost on a Revo - it's about the size of a receiver module!!

BTW: glad to help!

[Finnster]

Originally Posted by BrianG

Wow, great. Although you are braver than I by using more cells than specified. I know manufacturers build in a safety zone, but I hate running higher voltage/current than rated. That little ESC must have been lost on a Revo - it's about the size of a receiver module!!

BTW: glad to help!

Haha, I'm not sure how brave I was considering a CC engineer said it could be done (voltage wise anyway.) I don't think I'd take this thing racing, but so far so good, lets see how it holds up.

[Serum]

I heard more of the BEC issues with more than 12 cells. and if i recall correct, the mamba maxx esc was initially meant for 14 cells.

[Finnster]

A few little updates:

I added a 40mm fan on top of the esc and it is staying cool, but I haven't been able to go really hard on it yet. The motor got to 140 but the esc was only 115. Very good. The only prob now is I have some interference probs. I'm only getting about 70ft of range. I have the Rx where one of the steering servos was, so it may be too close ot the motor. Its gotten worse since thefan. Don't know if its just coincidence, so its just adding enough more int thats it wiggin the rx out. It tried a batt pack, so its not the ubec. I need to move it to the back, but need to come up with a mount that won't interfere with the shocks for easy service or getting to the slipper nut.

I also made a rollcage form the UHMWPE, not necc the prettiest, but it works really well. Very light and naturally springy so it won't bend. Need to prottect those expensive electronics! Will post pics when finally done.

Serum: somewhere I read that it was even 16 cells, but that was early testing, like ~1/05. I don't thnk it will have a prob on 14 so long asa it stays cool.

[Finnster]

Still continuing the beta testing, its been hard to get a lot of time running it lately. It looks like the range prob was bc of the Rx, it may be fried. I moved it around to the back and it was still glitchy. Put it in the TRX TQ3 Am and now it is fine.

Got a great run in today. I was only able to run hard for ~15 min. Its been slightly rainy out so I took it to a park where I was running of damp pavement and grass. Helluva lot of fun. I was blasting all about. The Revo handling is amazing. Its was just damp enough that the rear tires would slide instead of flipping the truck so I was doing hard powerslides, high speed runs and some fast running thru the grass. Outside temp was ~68. The motor got to ~120 and the esc never broke 90F. :018: The batts were ~100F. Had to shut it down earlier than I wanted as I ran it thru a big puddle after a good slide. Silly me, I know I was tempting it, but I was having too much fun. Had to get back to work anyway. Looks like I'll have a few rainy days for it to sit and dry off in teh house.

The fan does wonders. I did a quick test the other day to see if it was just the environment by unplugging the fan. The esc temp shot up to 140 after a couple mins in the grass. It had been running 1teens, outside temp ~87. Plugged it back in and temps dropped back down.

The last mod I may do is try to mount a 25mm 5v fan on the esc instead of the large 40mm. I want to protect the esc mount a bit more and the standoffs for the 40mm fan are abit higher than the top of the motor plate. I don't want it to get crushed on a bad lid landing or a nasty rollover. I am throughly impressed w/ the CC esc so far.

Oh, lastly, I put gold/tan springs on there w/ 60wt in the rear.. Seems pretty good, but im not a racer so there may be a better combo. The thing is a wheelie machine, I put a wing and def helps as a rollbar and looks killer. Looks fast just sitting there. :)

[Finnster]

As mentioned above, my FM Tx is fubared :( so I just stuck the TRX Am Rx on there as a temp fix. Mount is a bit ghetto (twist tie) but will be fixed soon, but works well enough now.

[Finnster]

[Mike.L]

nice revo finnister:)your batterys will definatly be snug.

[Finnster]

Weighed the truck.

4280g w/o batts (9.4 lbs)
5180g rtr 14 cells (11.4 lbs)

So far everything is stock (even dual servos still) exc for those parts changed for the conversion.

The rollcage weighs ~55g, whereas a stock 2055 ervos wieghs 41g. :)

[Finnster]

A short update:

The MM esc has been working great, so decided to push it a bit more and thru a new 15 cell GP3700 batt on tonite. Peak voltage was ~21V, so I think its still at a safe zone with the 25V caps, but pretty close to the edge.

I've wanted to get a radared run in, so figured this would be the time to do it. :) The good news is nothing exploded, in fact nothing even got hot, granted it was only 65F outside (100 esc, 140 motor.)

I did 5 passes, but they weren't as consistant as I really wanted. I had a long stretch of open flat road, ~100 yards run-up to me, and a clear parking lot in back to slow down. The speeds were as follows: 46, 49, 43, 41 and 41. I am throwing out the 49, just seemed a bit too fast. I do have a rustler that has doen 48 reliably, and I'm not sure this was faster, but this was pretty close. Hard to say..

It was quite a bit faster than the well-used 14 cell GP3300 batt I normally use, which I was *guessing* was pushing the truck high 30s-40.

OTOH, something did blow up after the first few runs, the bearing holding the top gear. It started wobbling and caused the spur to strip a bit. My radar techinique is good, I start measuring about 60 yds out and hold it until ~15-20yds, truck moving straight at me (sometimes have to jump :) .)

So I'm not sure where I'd put the speed, but def mid 40s doesn't seem too off. I'd like to do some more runs, but pulled it in to check temps and the god awful noise under breaking and discovered the messed-up input gear and packed it up.

I'd love to drag a nitro and really see where its at. I've only driven a nitro once (a 2.5 tmaxx) and it was no where close. Has anyone seen any radar/GPS speeds for some nitro Revo's? I know TRX says 45+ for the 3.3.

Edit: Did finally get a single st. servo a while back and moved the esc down into the other slot. cleaner and more protected that way. I've had some pretty good flips and crashes bashing off-road, so the tucked away esc truns down the cringe factor a few notches on impact. Have to say this Revo is TOUGH. :)

thats good to know that the MM could handle 15 cells.

now the question is, will you dare :mad:1 try 16? or 5s lipo?:032:

[coolhandcountry]

5s lipo is only a maxx of 21 volts. So the peak voltage is about the same.