Some UBECs are able to go into "bypass mode" if the voltage falls below acceptable limits for the switcher to work right. It would depend on the UBEC though. Running a UBEC at 7.4 would work, but you might get slightly less voltage than 6v. However, 2s can get as low as 6v near cutoff, so your servos may see less than 6v at that point.

To help eliminate the problems with drop-out voltage at 2s, consider using a 5v UBEC. Even 2s near cutoff (6v) lets you use a UBEC with a 1v drop-out voltage. You'll also get more consistent servo performance because of the more consistent voltage.

The CC-BEC is programmable from 4.8v to 9v so I could set it to 5v... then it would at least be consistant.

I'm glad I at least got a good servo, it will still do .08sec at 5v and the torque is still overkill....

Ah, that good servo was a good idea then if you will run 5v instead of 6. Plus a high quality servo will last longer too. Probably a good purchase.

Keep in mind that as you raise the voltage and change to a more effecient motor the esc will most likely see a lower amp draw and run cooler. IU have found this and am slowly swithing over to lower kv motors and higher voltage batteries.

I used to have to run a fan on my MM (stock) with my 10l feigao on 4s lipo. I added a Novak Pwer cap (#5674 2700uf 25v) to the board where the power wires go in, and now I do not need the fan. My system is mild, but I had Griffinru mod a MM for me and it ran a 7xl in a 1/8 buggy that was geared for 40mph, and did not get hot even after a 40min run!

I like your idea with the heatsinks on both sides, it would be nice to be able to mover the "brains" so that both heatsinks would be able to "work" at the same rate. Considering that you will be using large amounts of caps, a small fan will mostlikely provide all the air flow you need. I am sure that your system will run cool, even with a higher draw 2s sytem.

hey guys, anyone know of a way to fix a fet that was not soldered down properly?

http://photos.imageevent.com/drknow6...%20480x320.jpg

if the picture stops working like most of mine have, you can go to
http://imageevent.com/drknow65/rccarstuff
and look at photo #19 (be sure to click "original" on the size option at the bottom) or view #20 to see just the one fet...
I tried heating it with a soldering gun and then soldering with a 30watt iron to no avail. The minor damage that was done to one corner was done when removing the heat sink, it was already lifted which is why the sink was not attached properly to begin with.

Any ideas?

here is a link to the fet info itself if this helps or if you're just curious...
http://www.ortodoxism.ro/datasheets/...3S_Rev1.11.pdf

Lincpimp, there will be two fans, a pusher and a puller fan. The board will be standing up vertical with a sink on the left and a sink on the right. The brain board will be on longer wires to make space for the heat sink. So the air will be flowing thru both heat sinks equally. kind of like a tunnel with fans at both ends and the power board standing up in the middle.

You can get a better idea of what I am saying if you look at the wiring setup in my previous post.

I do plan on stepping up the voltage and motor, just in small increments.

Start with 220 grit, finish with 500.
Brass is easy to find.
I don't think that finned copper heatsink required for our application. Just copper/brass plate on the bottom and stock heatsink on top, with FAN should be good up to 150W of dissipating power ~80 Degrees C. You can stick brass plate in between top FET's and Alum heatsink, but that would be just a caviar :)
You need to make entire sandwich work for your heat spreading needs - brass/copper plates/FET's/PCB/FET's/Top heatsink. Brass/Copper for speed and Alum/PCB for mass (Cp).
And, yes you can ran FAN from internal power, just keep it under 100mA and solder on capacitor.

Update, just ordered all my bit, pieces, and wires. So excited, to bad next day air is out of the budget :)

I also have been chatting with PatrickDelC on a different forum and he is willing to sell me an additional power board, just waiting to get a PM from him to see what he wants for it.

Anyone around here have an extra power board (the newer style) they want to sell? I wasn't planning on doing the dual board thing but the idea is itching at me, so if I can find one cheap...

How has the success been for the guys running 5s and 6s on the modded MM's?

Artur, I decided to go with aluminum heat sinks as copper is heavier than I thought. I will use the brass on the brain board and it's components.

So far only one person that I know of has had the Mod2 treatment (double decker) done to their MM, and it was running fine until they got a stone caught in their gears which caused the motor to stall = instant death to the esc....

I shipped double-decker to Mike only and looks like he is pretty happy with it, no smoke yet :)

I am in process of fixing the one which "caught stone".

Hehe, the esc got 'stoned' and blew smoke out... sorry, that was a lame gag.

Hi GriffinRU. What are your thoughts about the new MM having 30 fets vs the old with 36.

So far looks like better fet and there are improvements in layout as well.
I'm in process of creating double decker from new (3d, 4th?) generation.
We will see how it works.

hey can some one shot me a link to the origanal post I can find it and want to know how to take off the heat sink and do the mods to my mm esc thanks for your help

http://forum.rcdesign.ru/index.php?a...showentry=4093

All the info right there.

Heatgun works great, just heat it up to 80-100C and carefully remove it with razor blade or similar tool...

In case you are going to use screwdriver method -> do not press too hard on PCB and watch for copper traces an so...