Couple of issues wih my Mamba Max - Page 5 - RC-Monster Forums

rchippie · 03.02.2007, 08:43 PM

Here's another update.

I just ran my mbx5 with 7xl & MM on a 11/51 or 4.6 ratio. I disconected the fan for this test i got about 8 1/2 plus minutes before thermal. I temped the controller it was about 175- 180. I then connected the fan & the temps dropped to 120 in less than a minute. What do you guys think ?. I could go lower on the pinion but i would loose to much speed

BrianG · 03.02.2007, 10:06 PM

I take it you're running 4s? That's a pretty good total gear ratio (15.3:1) considering it's a buggy. Ratios in the range of 9:1 to 11:1 are more common so it's not a gearing issue. It sounds like the 7xl is simply pulling enough average current to heat up the ESC quickly. Can't forget the MM is a 10th scale ESC meant for lighter duty use and smaller motors, so you might just be stuck using a fan or adding more heatsink area.

rchippie · 10:46 PM

Quote:

Originally Posted by BrianG

I take it you're running 4s? That's a pretty good total gear ratio (15.3:1) considering it's a buggy. Ratios in the range of 9:1 to 11:1 are more common so it's not a gearing issue. It sounds like the 7xl is simply pulling enough average current to heat up the ESC quickly. Can't forget the MM is a 10th scale ESC meant for lighter duty use and smaller motors, so you might just be stuck using a fan or adding more heatsink area.

Brian thank's for your repliy. I purposly did not use a fan for this test to see how long i could get, & i got about 8 1/2 plus minutes. Know i will hook up the fan & see how long i get . I'm running 14 cells. If it's the motor What fiego motor would you suggest ?.

BrianG · 03.02.2007, 10:52 PM

Someone else with experience on using the MM on a heavier truck will have to chime in here, but I think anything under a 9XL will thermal eventually, but that'll probably be too slow. Gearing up to compensate for speed will just take you back where you started temp-wise due to the added load. If you're handy, you can try to fab an added heatsink if you don't want to use a fan. Just my $0.02.

rchippie · 10:56 PM

Quote:

Originally Posted by BrianG

Someone else with experience on using the MM on a heavier truck will have to chime in here, but I think anything under a 9XL will thermal eventually, but that'll probably be too slow. Gearing up to compensate for speed will just take you back where you started temp-wise due to the added load. If you're handy, you can try to fab an added heatsink if you don't want to use a fan. Just my $0.02.

Using a fan is not a problem at all. I just disconected for testing purposes. I have a 9L motor would that better if not what would you suggest motor wise for 14 cells ?.

BrianG · 11:01 PM

LOL, the problem with using a smaller motor is that it will be loaded more and still draw the current to heat the ESC. It's really the mass of the truck that's the problem IMO. It takes power to get the truck moving. You'd have more motor options if the ESC handled more than 4s safely. If you don't mind using a fan, I'd stick to what you have and just use the fan and/or more heatsink area.

You might also try to reduce the timing and/or "start power" to the lowest setting. That will ease the burden somewhat and should help temps.

rchippie · 03.02.2007, 11:08 PM

Quote:

Originally Posted by BrianG

LOL, the problem with using a smaller motor is that it will be loaded more and still draw the current to heat the ESC. It's really the mass of the truck that's the problem IMO. It takes power to get the truck moving. You'd have more motor options if the ESC handled more than 4s safely. If you don't mind using a fan, I'd stick to what you have and just use the fan and/or more heatsink area.

You might also try to reduce the timing and/or "start power" to the lowest setting. That will ease the burden somewhat and should help temps.

This is a mugen mbx5 buggy not a truck.

BrianG · 03.03.2007, 12:39 AM

Yeah, I knew that. I don't know why I said "truck"; maybe just easier to type...

rchippie · 03.03.2007, 12:42 AM

Quote:

Originally Posted by BrianG

Yeah, I knew that. I don't know why I said "truck"; maybe just easier to type...

:005: LOL Im going to try it know with a fan. Is there any other fiego motor you might recomend to use with the MM on 14 cells ?.

BrianG · 03.03.2007, 01:13 AM

How heavy is the "truck" ;)? If 10lbs or less, you might be able to go with an L size motor, but I'd see what the experts say (Squee, MM, CHC, etc). :)

glassdoctor · 03.03.2007, 02:06 AM

Just as a reference... I have had a MM over 200 without a thermal. I believe they aren't supposed to thermal till the sinks hit about 210-220ish. The internal temps is what counts of course, but 180 or so shouldn't trip it. Mine hits that all the time in my XX4/7700.

squeeforever · 03.03.2007, 02:07 AM

Personally, I think an 8XL might be a better option, but it could still possble be an ESC problem. I would stick with an XL for sure. Perhaps you can gear even lower? Try the Century 9T pinion. Let us know how the fan helps!

rchippie · 03.03.2007, 02:12 AM

Quote:

Originally Posted by squeeforever

Personally, I think an 8XL might be a better option, but it could still possble be an ESC problem. I would stick with an XL for sure. Perhaps you can gear even lower? Try the Century 9T pinion. Let us know how the fan helps!

Squee & glass doctor thank's for the repliy. If i stick with the 7xl i really could'nt go to a 10t pinion because i would loose to much speed. Why would a 8XL be better in your opinion ?. I do plan on using the fan in my next testing session.

squeeforever · 03.03.2007, 02:23 AM

The 8XL will pull less amps. Simply as that. So the ESC will heat up less. It's like running a 10L instead of a 9L. Also, it will allow you to gear up as well.

rchippie · 03.03.2007, 02:26 AM

Quote:

Originally Posted by squeeforever

The 8XL will pull less amps. Simply as that. So the ESC will heat up less. It's like running a 10L instead of a 9L. Also, it will allow you to gear up as well.

Do you have one you would like to trade foar a 7XL ?.