Exposing the heatsink on your MMM?
 

Hi fellow monsters,

How many of you guys have cut the top off your MMM? I'm thinking about doing mine as I am wrecking a fan almost every drive or so due to the conditions I am driving in. Can anyone recommend a way to seal the circuit board from getting dust/rocks/moisture in it once the top is chopped?

cheers

Hot glue? I have a feeling this may affect your warranty...

i have cut the top off of almost everyone of my monsters, and they still got warrantied, dont worry about sealing them, you will be fine

thanks Big Greg. Are you running any form of fan on the ESC now or did you get a BIG reduction in cooling efficiency chopping the top?

I cut the top off my V1 MMM and it ran fine with good temps. That is until it blew up (not temp related - it was just sitting there and burst into flame). Yeah, removing the fan reduces the cooling effectiveness, but leaving the fins more exposed without restriction offsets that.

no im not running any type of fan, exposing the heatsink probably drops temps 10-20 degrees

I hate to say it, but a case design more like the hvmaxx wouldnt be a bad thing- seal the electronics to prevent dirt and dust entering the case, but leave the fins sticking up & out of the case. If you have a solid 'curtain' fin runnig around the outside of the heatsink, you can seal the case effectively- then a fan on top the heatsink can cool it, again rather like a vxl optional item (looks better than a normal 25-30mm fan slapped ontop). Just an idea...

CC sells the case and fan combo for approx $12. So if it doesn't work out just buy a new case/fan. I might do the same.
I wish CC would build a heavy duty fan that can hold up to some real abuse. That would be the ticket.

My fan started to make groaning noises recently and I took it apart and blasted it with the air compressor and now its back to pretty much normal.

In the wurx!

i'm like brian...
NO FANS!!
but i'm not gonna tamper with my MMM in any way either.

so i try and run my setup so the fan like never comes on...i cant understand why so many people are complaining about fans failing...mine always comes on when needed and is still quiet...quite strange if you ask me.

I see no real need for a fan on 4S if geared correctly, so I agree with you there. But I would also like to keep the ESC as cool as possible , hence chopping the top.

On 5s however, IMO a fan or open case is a must, the heat generated in the ESC & motor so much greater. My motor temp goes up 20C running 5S over 4S

but i run 6s:lol:

I'm going to try a new heat sink and if it works like the man behind it says it will, it'll make a fan obsolete. When it gets here, I'll post my results.

Without a fan? What's your gearing?

He means that he runs 6S which is going to produce alot more heat and a higher chance of the of the ESC reaching critical temp hence why having the fan is a good backup plan

You're seeing such an increase in temps because you're using the same gearing.

I put together a 6S setup on an Emaxx using a heli 8 pole outrunner geared for 32mph. I was SHOCKED at how cool everything ran. This was with a MMPro btw. A good indication that amp draw was relatively low.

Motor temps and Esc temps both relate to efficiency losses. These losses stack up and create more heat as amp draw increases. :yes:

To increase the voltage and drop the amp load on the motor means more power with less heat. You must gear down to see this.

You guys have it wrong. Everything is cooler on 6S if your geared & motored properly. I run 6S with 1400 to 1700Kv motors, I take the fan out & forget about it. Always cool.

Power= Voltage X Current

As Voltage goes up, current goes down. Current thru the system is what causes heat not voltage.

If your stuff gets hotter on 5 or 6 S then you have the wrong motor or gearing at least.

With 6S/1400Kv, I use 950 to 1000mA in a 5 minute qualifier with a 2 minute warm up at a fairly large track (NorCal).

I have only ran a fan on one setup.
I was pushing that though.
I think exposed heat sink is not a bad idea.
As long as not to much foreign materials went into ESC.

You have perked my interest dear sir! :oh:

i'm only geared for 40mph, 17/65 on an e-maxx tranny in a revo.

my peak amp spikes are only 70A and i can barely get that much power to the ground regardless.

it's all about the Watts required!

25.4v from a 6s peak voltage x 70A for 40mph = 1778W
16.8v from 4s peak voltage to attain same speed still requires 1778W of power to get that kind of acceleration to that speed.

so 1778W / 16.8v = 105.8A in theroy.

all in all, more amps = more heat

hence higher voltage is better for temps, wanna run 60mph but getting too hot?
try running 12s, same principle.

if you need your fan to be on all the time then if it fails then you are fecked!! no backup plan or anything, least if my fan were to be broken, i'd still be able to finish the race and hopefully find the dead fan before it was needed by the ESC.

I have been thinking of removing my MMM case altogether, and submersing the ESC in a bath of silicone fluid. I haven't done it yet as I cannot find a clear plastic sealable box in a suitable size for the ESC. This will keep it cool (and I could add another heatsink to the outside of the box), and make it waterproof.
Has anyone done this? I want the clear box so that I can see the lights on the ESC.